SECTION 8 WHITEWATER RIVER REGION MONITORING ANNUAL REPORT MONITORING YEAR

Transcription

1 WHITEWATER RIVER REGION ANNUAL REPORT YEAR July 1, 2013 June 30, 2014

2 TABLE OF CONTENTS EXECUTIVE SUMMARY... ES INTRODUCTION SUMMARY OF REPORTING REQUIREMENTS CONSOLIDATED PROGRAM PRECIPITATION WITHIN THE WWR NON-URBAN RUNOFF SOURCES OF WATER IN THE WWR WILDFIRES IN THE WWR WATER QUALITY Wet Weather Mobilization Criteria Monitoring Stations and Beneficial Uses Illicit Connection/Illegal Discharge Elimination Monitoring Events Summary of Analytical Data and Results INTEGRATED ANALYSIS Water Quality Parameters Measured Outside the Normal Range Mann-Kendall Long-Term Trend Analysis Analysis of Mann-Kendall Long-Term Trends in Relation to WQO Exceedances Identification of Potential Urban Sources Evaluation of the Effectiveness of Existing BMPs SPECIAL STUDIES AND REGIONAL ACTIVITIES Desert Task Force LID DemonStration Facility California Stormwater Quality Association CVSC Bacterial Indicator TMDL Southern California Stormwater Monitoring Coalition Southern California Water Committee PROGRAM ACCOMPLISHMENTS AND RECOMMENDATIONS FOR FUTURE Program Accomplishments Monitoring Year Program Other Monitoring Efforts During the Monitoring Year REFERENCES ii

3 Tables Table E Monitoring Year Monitoring Program... ES-1 Table 8-1: Precipitation Gauging Station Information... 6 Table 8-2: Annual Rainfall (inches)... 6 Table 8-3: Percent of Normal Annual Rainfall = Current Year/Average Year... 7 Table 8-4: Average Annual Precipitation... 8 Table 8-5: Wildfires Occurring within the WWR during the Past Three Years Table 8-6: Monitoring Station Summary Table 8-7: Permit Monitoring Requirements Summary Table 8-8: Field Parameters and Constituents of Concern Required for Monitoring Table 8-9: Applicable Basin Plan WQOs by Monitoring Station Table 8-10: Potentially Applicable Basin Plan WQOs MUN Beneficial Use only Table 8-11: Monitoring Event Summary and Wet Weather Data Table 8-12: Concentrations of Monitored Constituents WWR MS4 Outfall Stations31 Table 8-13: Concentrations of Monitored Constituents WWR Receiving Water Stations Table 8-14: Concentrations of Monitored Constituents Additional Dry Weather Event at CVSC at Avenue 52 Bridge Receiving Water Station Table 8-15: Normal Range for E. coli (Constituent of Concern) Table 8-16: Normal Range for Dissolved Oxygen (DO) (Field Parameter) Table 8-17: Mann-Kendall Long-Term Dry Weather Water Quality Trends Table 8-18: Mann-Kendall Long-Term Wet Weather Water Quality Trends Table 8-19: Total Number of Samples (n) and Percent (%) Results Above the Basin Plan WQOs for Table 8-20: Currently Available Treatment Control BMP Technology Effluent Concentrations for Select WWR Monitoring Program Parameters Figures Figure 8-1: Overview of Recent Wildfires within the WWR Figure 8-2: WWR Monitoring Sites Location Map Attachments A: Glossary B: Monitoring Station Descriptions and Daily Rainfall for the Monitoring Year C: Lists of WWR Monitoring Program Parameters Analyzed and Planned D: Graphical Results for the Period of Record (electronic version only) E: Tabular Results for the Period of Record (electronic version only) F: Description of Parameters Analyzed within the Current Whitewater River Region MS4 Monitoring Program G: Identification of Never-Detected Constituents H: CASQA 2013 Annual Report (electronic version only) 8-iii

4 EXECUTIVE SUMMARY The California Regional Water Quality Control Board Colorado River Basin Region (Regional Board) issued Urban Runoff Waste Discharge Requirements via Order No. R , National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) Permit No. CAS (2008 MS4 Permit) (Regional Board, 2008). The Permittees identified in the 2008 MS4 Permit as jointly responsible for compliance include: the Riverside County Flood Control and Water Conservation District (District), County of Riverside (County), Coachella Valley Water District (CVWD), and incorporated Cities of Riverside County within the Whitewater River Basin (Permittees). The area of the County addressed by this MS4 Permit is referred to as the Whitewater Region (WWR). The monitoring year consists of the period between July 1, 2013 and June 30, Purpose and Goals The purpose of the WWR monitoring program is to support the development and implementation of an effective MS4 management program. The WWR monitoring program data help to characterize pollutants associated with urban runoff, identify receiving waters, which, without additional action to control pollution from urban runoff, cannot reasonably be expected to achieve or maintain applicable water quality standards, and track improvements based upon implementation of the MS4 management program and preventative best management practices (BMPs). In addition to this Monitoring Annual Report, the Regional Board also reviews bacterial indicator (E. coli) data collected at CVSC monitoring stations in the context of TMDL implementation efforts. The Coachella Valley Stormwater Channel (CVSC) Bacterial Indicator Total Maximum Daily Load (TMDL) was approved by the United States Environmental Protection Agency (USEPA) on April 27, Monitoring Program Overview The Consolidated Monitoring Program (CMP) addresses the Monitoring and Reporting Program (MRP) requirements specified in the 2008 MS4 Permit. For the purposes of this Monitoring Annual Report, the guidance from the draft 2011 WWR Monitoring Plan (CMP Volume V) was in effect. During the monitoring year, water quality samples were collected at receiving water and MS4 outfall monitoring stations. Samples were analyzed for program-specific water quality parameters (Table E-1) during wet weather and dry weather events. The WWR is an arid desert area, and flows in the receiving waters are ephemeral. Samples were only collected when there was sufficient flow for sample collection. When flow was insufficient for sample collection, the monitoring event was recorded as visited not sampled (VNS). During the monitoring year, no wet weather events met the mobilization criteria at the Upper Whitewater River at Canyon Road Crossing receiving water station (i.e., no flow was observed at Golf Center Parkway) and no samples were collected. Monitoring at this receiving water station is not required under the 2013 MS4 Permit. 8-ES-1

5 Monitoring Program Receiving Water Monitoring MS4 Outfall Monitoring Table E Monitoring Year Monitoring Program Monitoring Frequency Sampling Requirement Type Required Wet Weather Dry Weather Wet Weather Dry Weather / IC/ID Field parameters, E. coli, metals, nutrients and TDS Priority pollutants Field parameters, E. coli, metals, nutrients and TDS Priority pollutants Field parameters, E. coli, metals, nutrients and TDS Priority pollutants Visual observations Field parameters, E. coli Twice annually Once per Permit cycle (Years 2-4) Twice annually, if flowing Once per Permit cycle (Years 2-4) Twice annually Once per Permit cycle (Years 2-4) Quarterly Twice annually, if flowing Monitoring Stations Upper Whitewater River at Canyon Road Crossing (719WWT813)* CVSC at Avenue 52 Bridge (719CVS884) Ramsey Street Storm Drain (719RMS782) Portola Avenue Storm Drain (719POR817) Avenue 52 Storm Drain (719AVE785) * Monitoring during wet weather events only, if and only if flow was observed at Golf Center Parkway. TDS total dissolved solids IC/ID Illicit Connection/Illicit Discharge Analyses Water quality data were compared to applicable water quality objectives (WQOs) based on the receiving water beneficial uses defined in the Water Quality Control Plan for the Colorado River Basin (Basin Plan). While the WQOs do not apply to discharges of urban runoff to receiving waters (i.e., from MS4 outfalls), these station results were compared to the WQOs for their respective receiving waters as a general means of assessing whether individual MS4 outfalls may be contributing to water quality conditions in receiving waters. Monitoring data were also evaluated for statistically significant longterm trends. Progress of the WWR Monitoring Program Wet Weather Programs Elevated concentrations of bacterial indicators (E. coli) appear to be widespread in wet weather runoff monitored at WWR monitoring stations. In the CVSC, anthropogenic sources of bacterial indicators are currently being addressed by the Permittee's TMDL implementation program. Furthermore, the CVCS is owned and operated by the CVWD, which prohibits public access to this facility, making recreational activities or contact with wet weather flows unlikely. Elevated bacterial indicator levels at the Ramsey Street Storm Drain MS4 outfall station likely did not impact beneficial uses of the San Gorgonio River receiving water given that flows likely evaporated and/or infiltrated along the three miles of ephemeral stream prior to reaching the receiving water. At the Portola Avenue Storm Drain MS4 outfall station, it is likely that the low flow sampled (0.85 cfs) evaporated and/or infiltrated within the ephemeral wash and the elevated bacterial indicator level measured did not impact beneficial uses even if flow did reach the dry riverbed of the receiving water. 8-ES-2

6 Wet weather flows at CVSC at Avenue 52 Bridge receiving water station represent background conditions within the CVSC. Measurements of ph were within the ph WQO range. The August 26, 2013 dissolved oxygen (DO) concentration was less than the WQO minimum criteria. Although the Mann-Kendall trend analysis did not identify a statistically significant long-term trend, wet weather DO measurements at the receiving water station have been below the WQO for 44% of the period of record. Depressed DO may be attributed to lower flow rates because of the seasonally dry conditions in the WWR. Dry Weather Programs Dry weather water quality impacts associated with urban runoff from the MS4 are limited given that the illicit connection/illicit discharge (IC/ID) program quarterly investigations generally find MS4 outfall stations are dry, ponded, or have insubstantial flow for sample collection (i.e., VNS results). Sampleable flow during the dry weather monitoring activities was limited to one of three MS4 outfall stations. No flow was observed in the Whitewater River wash (ephemeral stream) adjacent to the Portola Avenue Storm Drain (719POR817) during monitored dry weather events; therefore, the WQOs were not applied because sampled flows evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Two dry weather events were monitored at the CVSC at Avenue 52 Bridge receiving water station. Bacterial indicator and ph results met applicable water quality standards for both dry weather events. The August 20, 2013 DO concentration was less than the WQO minimum criteria. Although the Mann-Kendall trend analysis did not identify a statistically significant long-term trend, dry weather DO measurements at the receiving water station have been below the WQO for 77% of the period of record. Dry weather flows at this receiving water station generally characterize discharges from the Valley Sanitation District (VSD) wastewater treatment plant (WWTP), a permitted discharge from a publicly owned treatment works (POTW) to the CVSC. Depressed DO may be attributed to lower flow rates because of the dry conditions in the WWR (i.e., an average of 61% below normal precipitation). Provisions Implemented Under the CVSC Bacterial Indicator TMDL The City of Coachella has constructed three dry weather diversions for their MS4 facilities that previously discharged into the CVSC, including a diversion upstream of the Avenue 52 Storm Drain MS4 outfall station. As mentioned previously, this MS4 outfall station was VNS during quarterly IC/ID site visits conducted during the monitoring year. Monitoring at this MS4 outfall station is not required under the 2013 MS4 Permit. During the monitoring year, the Permittees implemented monitoring at MS4 outfalls to assess contributions of bacterial indicators from anthropogenic sources to the CVSC. Based on these findings, the Permittees plan to continue developing BMPs and outreach focused on eliminating urban sources of bacterial indicators. 8-ES-3

7 Monitoring Year Program The draft 2011 WWR Monitoring Plan (CMP Volume V) was finalized in July 2014 to reflect the improvements made in methods and procedures in the last few years and to include the most current monitoring program requirements based on the 2013 MS4 Permit. In the monitoring year, the Permittees will implement provisions under the 2013 MS4 Permit and MRP in accordance with the 2014 CMP. Major changes to the WWR monitoring program include: Sample analysis for an expanded list of constituents of concern; Monitoring at fewer monitoring stations (i.e., two MS4 outfall stations and one receiving water station); Improved documentation of conditions at MS4 outfall stations in order to distinguish samples that represent discharges to surface receiving waters from small flows that may evaporate and/or infiltrate prior to reaching the receiving water; and Streamlining the Monitoring Annual Report to focus on assessment of monitoring data required under the 2013 Permit period. (Long-term trend analyses are only required during the monitoring year; Period of record attachments will focus on 2013 water quality parameters.) Permittees will continue to monitor bacterial indicators in accordance with the CVSC Bacterial Indicator TMDL, monitor DO and investigate depressed DO concentrations in the WWR, and work closely with the contracted laboratory(s) to improve data quality assurance and quality control (QA/QC). 8-ES-4

8 8.0 INTRODUCTION This Monitoring Annual Report addresses the monitoring and reporting (MRP) requirements specified in Order No. R National Pollutant Discharge Elimination System (NPDES) Permit No. CAS (2008 MS4 Permit), issued by the California Regional Water Quality Control Board Colorado River Basin Region (Regional Board). The Permittees identified in this municipal separate storm sewer system (MS4) permit as jointly responsible for compliance include: the Riverside County Flood Control and Water Conservation District (District), County of Riverside (County), Coachella Valley Water District (CVWD), and incorporated Cities of Riverside County within the Whitewater Region (collectively, Permittees). The area of Riverside County addressed by the MS4 permit is referred to as the Whitewater Region (WWR). The Permittees, in conjunction with other agencies located in Riverside County, developed the Consolidated Monitoring Program (CMP) to coordinate monitoring programs in the three regions in Riverside County. The District developed and implemented a monitoring program in compliance with the requirements outlined in the MRP, and with reference to the Water Quality Control Plan for the Colorado River Basin (Basin Plan) as it pertains to the WWR, the Southern California Monitoring Coalition (SMC) "Model Monitoring Program (MMP) for MS4s in Southern California" (SMC, 2004), and the CMP. In 2014, the WWR CMP was redeveloped based upon the new monitoring requirements established in the 2013 MS4 Permit, Order No. R The new monitoring requirements under the 2013 MS4 Permit began July 1, 2014 and changes made to the WWR CMP will be discussed in more detail in next year's Monitoring Annual Report. The Monitoring Annual Report presents the results of water quality monitoring conducted during the period of July 1, 2013 to June 30, 2014 ( monitoring year). The monitoring year is the bridge year between implementation of the old 2008 MS4 Permit requirements and the new 2013 MS4 Permit, and it represents the fifth and final year of monitoring and reporting in accordance with the requirements of the 2008 MS4 Permit. This document contains information regarding reporting requirements, the CMP, precipitation within the WWR, non-urban wastewater discharges and other sources of runoff, information regarding recent wildfires within the WWR, special studies conducted during the monitoring year, as well as comprehensive interpretations and conclusions based on the monitoring data, as required under the 2008 MS4 Permit. A glossary and list of commonly used terms and definitions are presented in Attachment A. 8-1

9 8.1 SUMMARY OF REPORTING REQUIREMENTS The reporting requirements of the 2008 MS4 Permit and the subsections that address them are summarized below. Reporting Requirement A: A Monitoring Annual Report must be submitted to the Executive Officer stating the results of all monitoring performed and other reportable activities by January 15 th of each year. This Monitoring Annual Report for the WWR fulfills that requirement. Reporting Requirement B: Monitoring reports shall provide: 1. Monitoring station descriptions: see Section and Attachment B of this document. 2. Monitoring and analysis protocols: see Sections 8.2, 8.7, and Attachment C of this document and the 2013 Quality Assurance Project Plan (QAPP) (Volume II of the CMP). 3. Quality Assurance/Quality Control (QA/QC) procedures: see Section 8.2 and the 2013 QAPP (Volume II of the CMP) monitoring events: see Section of this document. 5. Identification of methods for evaluating the monitoring data: see Section of this document. 6. Summaries of analytical data and results: see Section of this document. 7. Graphical summaries of monitoring data: see Attachment D (electronic version only) of this document. Reporting Requirement C: Monitoring reports shall contain: 1. An analysis of the findings of the each monitoring year: see Sections and 8.7 of this document. 2. Identification of "acute water quality problems": see Section of this document for interpretation of this label and analysis of water quality parameters measured above Basin Plan water quality objectives (WQOs) and outside of "normal ranges" (i.e., based on historical data for each monitoring station). Reporting Requirement D: Monitoring reports shall include: 3. Identification and analysis of long-term trends in stormwater or receiving water quality: see Section of this document. 4. Analysis of long-term trends for signs of "chronic water quality problems": see Section of this document and analysis of long-term trends in the context of WQO exceedances. 8-2

10 5. Identification of potential urban sources related to long-term trends where constituents have also been measured above WQOs: see Section of this document. 6. Evaluation of the effectiveness of existing best management practices (BMPs): see Section of this document. 7. Recommendations for necessary future actions: see Section 8.9 of this document. Reporting Requirement E: Monitoring reports shall use a standard report format, including: 8. An introduction: see Section 8.0 of this document. 9. A summary of special studies participated in during each monitoring year: see Section 8.8 of this document. 10. Comprehensive interpretations and conclusions: see Section 8.7 of this document. 11. Recommendations for necessary future actions: see Section 8.9 of this document. 8-3

11 8.2 CONSOLIDATED PROGRAM In general the CMP describes methods for each type of monitoring, program-specific procedures, and analytical requirements, including but not limited to: 1. Wet weather monitoring; 2. Dry weather monitoring; 3. MS4 outfall IC/ID monitoring; 4. Use of monitoring equipment; 5. Field sampling and data collection procedures; 6. QA/QC procedures; and 7. Laboratory analytical methods, including the reporting and detection limits. The CMP identifies MRP requirements pursuant to the MS4 permits and applicable to the MS4s in the WWR, Santa Margarita Region (SMR), and Santa Ana Region (SAR) of Riverside County. Region-specific appendices of the CMP address specific MS4 permit provisions. The CMP was revised in November 2012 to incorporate a regional QAPP. As a result of lessons learned during the monitoring year, the CMP was updated to reflect programmatic adjustments (dated November 2013). Updates included global revisions to provide standardization and clarity, updates of key staff assignments, and improvements to sampling procedures. Also, in anticipation of future program changes, the CMP has undergone further revision and enhancement in all volumes (dated July 2014), which included the addition of a glossary (Volume VI) for clarity of commonly used terms. The regional QAPP references separate monitoring plans for each Region. These separate monitoring plans were developed for the SAR and SMR to reflect specific MS4 permit provisions in the MRP for each region. The draft 2011 WWR Monitoring Plan (CMP Volume V) was finalized in July 2014 to reflect the lessons learned in the last few years and to include the most current monitoring program requirements based on the 2013 MS4 Permit. The CMP is reviewed and updated as needed based on program findings and changes. For the purposes of this Monitoring Annual Report, the guidance from the draft 2011 WWR Monitoring Plan (CMP Volume V) was in effect. The CMP outlined four objectives applicable to this document: 1. Develop and support an effective MS4 management program. 2. Identify those receiving waters, which, without additional action to control pollution from urban runoff, cannot reasonably be expected to achieve or maintain applicable water quality standards. 3. Characterize pollutants associated with urban runoff and assess the influence of urban landuses on receiving water quality. 4. Analyze and interpret the collected data to identify trends, if any, both to prevent impairments through the implementation of preventative BMPs and to track improvements based on the MS4 management program. 8-4

12 These objectives support the goal of the Riverside County Urban Runoff Management Program (URMP), which is to manage the quality of urban runoff within the Permittees' jurisdiction to prevent impacts on receiving waters. The goal of the CMP is to support the regional urban runoff monitoring programs conducted in Riverside County with consistent practices and procedures while accounting for and incorporating program differences among the three distinct regions. These objectives are also a superset of the MMP core management questions developed by the SMC. The CMP includes the following monitoring types for the WWR: 1. Receiving water monitoring (wet weather and dry weather); and 2. MS4 outfall monitoring (wet weather and dry weather/ IC/ID). In addition, the following standardized guidance and procedures are provided in the 2013 QAPP: 1. Project/task organization (i.e., identification of key staff and roles); 2. Monitoring frequencies; 3. Mobilization criteria; 4. Sampling, handling, and transport methods; 5. Sample ID format; 6. Documents and records; 7. Laboratory analytical methods, including the reporting and detection limits; 8. QA/QC procedures and frequencies (e.g., field sampling and laboratory analysis); 9. Instrument/equipment inspection, maintenance, and calibration; and 10. Data review, validation, and management. Samples were collected by field staff under chain-of-custody procedures and were submitted to E.S. Babcock & Sons, Inc. (Babcock) 1, an analytical laboratory certified by the National Environmental Laboratory Accreditation Program (NELAP) (NELAP Certificate No. 0201CA) and California Department of Health Services Environmental Laboratory Accreditation Program (ELAP) (ELAP Certification No. 1156) for analysis. A list of monitored parameters and analytical methods used during is presented in Attachment C. Babcock participated in the SMC Laboratory Intercalibration Study (Southern California Coastal Watershed Research Project, [SCCWRP], 2010). Summaries of monitoring activities are provided in Section The use of company, trademark, or brand names does not constitute a recommendation of a particular product. 8-5

13 8.3 PRECIPITATION WITHIN THE WWR Five precipitation gauging stations within the WWR were used to derive average annual rainfall statistics and provide historical context for monitoring events. The locations and key parameters for the historical records from these five precipitation gauging stations are presented in Table 8-1. Table 8-2 presents a summary of the annual rainfall records for the five precipitation gauging stations located in the WWR from 1993 to This period reflects the time in which the WWR was under application and coverage by a MS4 Permit. Daily rainfall totals for the monitoring year for each of the five precipitation gauging stations are provided in Attachment B. Table 8-1: Precipitation Gauging Station Information Station Name ID No Average Annual Rainfall (inches) Years of Record Location* Latitude + Longitude + Banning S/1E-14 33:54: :51:05.0 Palm Springs S/4E-15 33:49: :32:41.0 Desert Hot Springs S/4E-25 33:58: :29:40.0 Rancho Mirage S/5E-11 33:46: :26:00.0 Cathedral City S/5E-33 33:46: :27:27.0 * Describes the general location of the precipitation gauge, divided by township, range and section. + Latitude and longitude are reported in degrees, minutes and seconds. Table 8-2: Annual Rainfall (inches) Monitoring Palm Desert Hot Rancho Cathedral Banning Year Springs Springs Mirage City

14 Table 8-3 presents the annual rainfall as a percent of normal for each of the five precipitation gauging stations. Percent of normal rainfall is calculated using the current year rainfall (Table 8-2) and dividing it by the average annual rainfall (Table 8-1). In this analysis, if the current year rainfall equals the average annual rainfall, the result would be 100%. For example, in the monitoring year, the Banning precipitation gauging station received 7.67/16.03 = 48% or 0.48 times the average annual rainfall. Table 8-3: Percent of Normal Annual Rainfall = Current Year/Average Year Monitoring Palm Desert Hot Rancho Cathedral Regional Banning Year Springs Springs Mirage City Average Characterization dry wet very dry dry very wet very dry dry normal very dry dry dry very wet dry very dry normal normal wet wet dry dry dry Dry Regional average precipitation more than 20% below the annual average. Normal Regional average precipitation within 20% of the annual average. Wet Regional average precipitation more than 20% above the annual average. Table 8-4 presents the annual rainfall as a percent of normal rainfall for the WWR as a whole. In this analysis, the portion of rainfall above or below average would be determined by comparing the average regional rainfall (i.e., average column in Table 8-3) with the normal baseline, (i.e., the average current year rainfall equals the average annual rainfall defined in Table 8-1). Based on this analysis, the monitoring year is characterized as dry with an average of 61% below normal precipitation. 8-7

15 Table 8-4: Average Annual Precipitation Monitoring Year % Above Average % Below Average Characterization* dry wet very dry dry very wet very dry dry normal very dry dry dry very wet dry very dry normal normal wet wet dry dry dry Dry Regional average precipitation more than 20% below the annual average. Normal Regional average precipitation within 20% of the annual average. Wet Regional average precipitation more than 20% above the annual average. 8-8

16 8.4 NON-URBAN RUNOFF SOURCES OF WATER IN THE WWR According to the CVWD Urban Water Management Plan (CVWD, 2005), the Coachella Valley Stormwater Channel (CVSC) Bacterial Indicator TMDL (approved by the United States Environmental Protection Agency [USEPA] on April 27, 2012), and the Implementation Plan for Bacterial Indicators in the CVSC (CVWD, 2007), sources of water that may be found in surface waters within the WWR that are not related to urban runoff may include: Snowmelt; Releases of imported water (Colorado River water) for groundwater recharge; Subsurface agricultural drainage system discharges; Reclaimed wastewater discharges to the CVSC; Municipal water well blow-off discharges; Groundwater; Miscellaneous wastewater discharges approved by the Regional Board; and Discharges from fish hatchery operations. The permit acknowledges that stormwater flows from non-urbanized areas (National Forests, State Parks, wilderness, and agriculture) to MS4s may affect flow and water quality, and that runoff from non-urbanized areas that may impact surface water quality in the WWR are from outside of the Permittees jurisdiction. According to the permit definition of urban runoff, "The quality of the discharges from the MS4 varies considerably and is affected by, among other things, past and present land use activities, basin hydrology, geography and geology, season, the frequency and duration of storm events, and the presence of past or present illegal and allowed disposal practices and IC. The Permittees lack legal jurisdiction over discharges into their respective MS4 facilities from agricultural activities, California and Federal facilities, utilities and special districts, Native American tribal lands, wastewater management agencies and other point and non-point source discharges otherwise permitted by or under the jurisdiction of the Regional Board. The Regional Board recognizes that the Permittees should not be held responsible for such facilities and/or discharges." Visual surveys of the WWR have been conducted continually since March These visual surveys focused mainly on verifying the following: Locations and conditions of Permittee outfalls; Locations and conditions of MS4 outfall stations; and Presence or lack of water in receiving waters and MS4 outfalls. These observations indicate that the arid environment of the WWR strongly influences hydraulic connectivity between MS4 outfall stations and the receiving waters. During 8-9

17 dry conditions, such as observed during the monitoring year, hydraulic connectivity would be expected only during extreme storm events (e.g., flash flood conditions). The information obtained from these surveys is also used to update the WWR NPDES base maps (Attachment B). Base maps are updated annually. 8-10

18 8.5 WILDFIRES IN THE WWR The residual effects of the wildfires that occurred in the WWR may impact water quality both in the short term and for several years after their initial burn due to loss of ground cover and chemical changes in the soil (USFS, 2009; Meixner and Wohlgemuth, 2004; SCCWRP, 2009). Naturally occurring elements that are typically retained by forest vegetation can be washed away during storm events subsequent to a wildfire, in addition to large amounts of sediment. Daniel Cozad, former Deputy General Manager of the Santa Ana Watershed Project Authority (SAWPA), stated, "Normally, the forest filters water naturally absorbing nitrates, phosphorus, and other elements. Because of the fires, more contaminants will reach stream channels. Increasingly, rain will cause rocks and soil that usually trap particulate matter on the forest floor to fill watercourses, washing pollutants such as lead, mercury, copper, zinc, and phosphorus into debris basins and groundwater" (Cozad, 2004). Other potential sources of post-wildfire pollutants include fire retardants and suppression chemicals, aerially-deposited particulates, partially burned organic matter, and ash. Ash deposition caused by southern California wildfires has been shown to affect other constituent levels in fire-influenced waterbodies, such as increased alkalinity and, thus, ph, in soil samples. For example, Ballona Creek in Los Angeles County had disproportionately higher copper and zinc concentrations after the 2003 wildfires (SCCWRP, 2009). Where burns have occurred in residential areas, soil samples also contained greater concentrations of arsenic, lead, antimony, copper, zinc, and chromium, as observed during the 2007 Harris Wildfire in Southern California (USGS, 2007; SCCWRP, 2009). Because it takes several years for ashes and sediments displaced by wildfires to be washed down to the receiving waters, elevated concentrations of these pollutants could be the result of wildfires that occurred in previous years. Wildfires are considered a possible source of pollutants during source investigations. The District continues to track wildfires in Riverside County in order to document potential future impacts to receiving water(s). Table 8-5 presents information about the wildfires that have occurred in the region since 2011, including the name, start date, number of acres burned, and location of each wildfire. Figure 8-1 shows the locations of the wildfires and the MS4 outfall stations that may show water quality impacts from those wildfires (for simplicity, the last three digits of each monitoring station are used to identify locations). 8-11

19 Table 8-5: Wildfires Occurring within the WWR during the Past Three Years Monitoring Year Incident No. Fire Name Start Date Acres Location Latitude Longitude CA-RRU Silver 08/07/ ,292 Poppet Flats CA-BDF Tram 08/06/ Palm Springs Tram Monitoring Year Incident No. Fire Name CA-BDF-8526 Hathaway 06/09/2013 3,825 CA-RRU Gorgonio 05/04/ Start Date Acres Location Latitude Longitude North of the City of Banning Highway 243, one mile south of Banning CA-RRU Summit 05/01/ Banning Bench CA-RRU Sunset Monitoring Year Incident No. Fire Name CA-RRU Palm CA-BDF Windy Point 10/17/2012 NR South of the City of Banning Start Date Acres Location Latitude Longitude 02/29/2012 NR CA-RRU Banning 09/07/ CA-RRU Valley 08/03/ CA-RRU School 07/13/ Palm Drive at 20th Avenue Desert Hot Springs /25/ Angel Canyon San Gorgonio Avenue, City of Banning South of the City of Banning School House Road, City of Banning CA-RRU View 06/18/ Cabazon Source: GeoMAC Wildfire Information ( NR Not reported. Acreage not provided by GeoMAC or CalFire. 8-12

20 Figure 8-1: Overview of Recent Wildfires within the WWR 8-13

21 8.6 WATER QUALITY The 2008 MS4 Permit required water quality monitoring at MS4 outfall stations and receiving water stations. Dry weather MS4 outfall IC/ID and wet weather MS4 outfall monitoring is required at three MS4 outfall stations, including the Ramsey Street Storm Drain (719RMS782), Portola Avenue Storm Drain MS4 outfall (719POR817), and Avenue 52 Storm Drain MS4 outfall (719AVE785). Dry weather and wet weather monitoring is required at the CVSC Receiving Water at the Avenue 52 Bridge (719CVS884) receiving water station. Wet weather monitoring is also required at the Upper Whitewater River Receiving Water at Canyon Road Crossing, before the Trout Farm (719WWT813) receiving water station when regional stormwater flows are observed at Golf Center Parkway in Indio. The latter site is the reference station for the WWR and has no urban landuses tributary to the monitoring station. Ninety-seven percent of the landuses adjacent to the Upper Whitewater River receiving water station are exempt public uses. The remaining 3% of the landuse areas are in commercial and parks and recreation landuses. Figure 8-2 shows the general location of the WWR monitoring sites. Table 8-6 provides a summary of the locations and characteristics of each MS4 outfall and receiving water station, including the latitudes and longitudes, receiving waters, HUCs, and Permittee jurisdictions. A list of analytical parameters for each monitoring station and event is provided in Attachment C. Station Type MS4 Outfall Receiving Water Station ID 719RMS AVE POR WWT CVS Former Station ID Table 8-6: Monitoring Station Summary Station Name Ramsey Street Storm Drain Avenue 52 Storm Drain Portola Ave Storm Drain Upper Whitewater River at Canyon Road Crossing CVSC at Avenue 52 Bridge Latitude / Longitude 33 o 55' 30.5" -116 o 51' 31.5" 33 o 40' 17.4" -116 o 08' 56.4" 33 o 44' 16.8" -116 o 22' 24.6" 33 o 59' 01.5" -116 o 39' 07.8" 33 o 40' 20.9" -116 o 08' 57.8" Receiving Water Smith Creek Receiving Water used to Identify WQOs ± San Gorgonio River HUC Permittee Jurisdiction Banning CVSC CVSC Coachella Washes (Ephemeral Streams) Whitewater River Washes (Ephemeral Streams) Whitewater River Palm Desert County CVSC CVSC Coachella HUC Hydrologic unit code. This describes the watershed subarea in which each monitoring station drains. ± The receiving water and associated beneficial uses for individual monitoring stations are used to identify the corresponding WQOs. Not all applicable receiving waters are listed in the Basin Plan (i.e., Smith Creek); the most applicable receiving water and associated beneficial uses/wqos are used for comparison purposes. 8-14

22 Figure 8-2: WWR Monitoring Sites Location Map 8-15

23 The 2008 MS4 Permit defines field parameters and constituents of concern. Priority pollutants are defined in Attachment D of the 2008 MS4 Permit. At a minimum, the 2008 MS4 Permit requires collection of the following samples: MS4 Outfall: Ramsey Street Storm Drain (719RMS782) o Two wet weather samples for field parameters and constituents of concern; o One wet weather sample during years 2 to 4 of the monitoring program for analysis of priority pollutants (completed during the monitoring year, third year of the 2008 MS4 Permit); o Two dry weather samples for field parameters and E. coli; and o Quarterly IC/ID monitoring (concurrently with dry weather monitoring). MS4 Outfall: Portola Avenue Storm Drain (719POR817) o Two wet weather samples for field parameters and constituents of concern; o One wet weather sample during years 2 to 4 of the monitoring program for analysis of the priority pollutants (completed during monitoring year, third year of the 2008 MS4 Permit); o Two dry weather samples for field parameters and E. coli; and o Quarterly IC/ID monitoring (concurrently with dry weather monitoring). MS4 Outfall: Avenue 52 Storm Drain (719AVE785) o Two wet weather samples for field parameters and constituents of concern; o One wet weather sample during years 2 to 4 of the monitoring program for analysis of the priority pollutants (completed during monitoring year, third year of the 2008 MS4 Permit); o Two dry weather samples for field parameters and E. coli; and o Quarterly IC/ID monitoring (concurrently with dry weather monitoring). Receiving Water: CVSC at Avenue 52 Bridge (719CVS884) o Two wet weather samples for field parameters and constituents of concern; o One wet weather sample during years 2 to 4 of the monitoring program for analysis of the priority pollutants (completed during monitoring year, second year of the 2008 MS4 Permit); o Two dry weather samples for field parameters and constituents of concern; and o One dry weather sample during years 2 to 4 of the monitoring program for the priority pollutants (completed during monitoring year, fourth year of the 2008 MS4 Permit). Receiving Water: Upper Whitewater River at Canyon Road Crossing (719WWT813) (WWR reference station) o Two wet weather samples collected "when there is hydraulic connectivity throughout the WWR, as evidenced by regional stormwater flows detected at Golf Center Parkway" for field parameters and constituents of concern; and 8-16

24 o One wet weather sample during years 2 to 4 of the monitoring program for analysis of the priority pollutants (completed during monitoring year, second year of the 2008 MS4 Permit). Table 8-7 presents a summary of the 2008 MS4 Permit monitoring requirements and monitoring conducted in accordance with these requirements during the monitoring year. The arid environment of the WWR strongly influences flow and hydraulic connectivity between MS4 outfall stations and the receiving waters. The MS4 outfall stations were frequently dry during monitoring events, observed water was ponded, and/or there was insufficient flow for sample collection; therefore, these monitoring events are reported as visited not sampled (VNS). Table 8-7: Permit Monitoring Requirements Summary Station / Station ID Ramsey Street Storm Drain (719RMS782) Monitoring Type Dry Weather and Outfall IC/ID Wet Weather Dry Weather and Outfall IC/ID Constituent(s) Field Parameters E. coli Visual Observations Field Parameters E. coli Metals Nutrients and Other Priority Pollutants Field Parameters E. coli Visual Observations Frequency Required Twice Annually Twice Annually Quarterly Twice Annually Twice Annually Twice Annually Twice Annually Once per Permit cycle Twice Annually Twice Annually Quarterly Requirement Met? Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Comments (a) VNS (2 events) Conducted concurrently with IC/ID monitoring. No evidence of IC/ID observed or suspected. Measurements and samples collected (2 events) Completed in (3 rd year of Permit) Measurements and samples collected (2 events) Conducted concurrently with IC/ID monitoring. No evidence of IC/ID observed or suspected. Portola Avenue Storm Drain (719POR817) Wet Weather Field Parameters E. coli Metals Twice Annually Twice Annually Twice Annually Yes Yes Yes VNS (1 event) Only one wet event met mobilization criteria. Nutrients and Other Twice Annually Yes Priority Pollutants Once per Permit cycle Yes Completed in (3 rd year of Permit) 8-17

25 Table 8-7: Permit Monitoring Requirements Summary (continued) Station / Monitoring Frequency Requirement Constituent(s) Comments (a) Station ID Type Required Met? Field Twice Yes VNS (4 events) Parameters Annually Avenue 52 Storm Drain (719AVE785) CVSC at Avenue 52 Bridge (719CVS884) Upper Whitewater River at Canyon Road Crossing (719WWT813) Dry Weather and Outfall IC/ID Wet Weather Dry Weather Wet Weather Wet Weather E. coli Visual Observations Field Parameters E. coli Metals Nutrients and Other Priority Pollutants Field Parameters E. coli Metals Nutrients and Other Priority Pollutants Field Parameters E. coli Metals Nutrients and Other Priority Pollutants Field Parameters E. coli Metals Nutrients and Other Priority Pollutants Twice Annually Quarterly Twice Annually Twice Annually Twice Annually Twice Annually Once per Permit cycle Twice Annually Twice Annually Twice Annually Twice Annually Once per Permit cycle Twice Annually Twice Annually Twice Annually Twice Annually Once per Permit cycle Twice Annually 5 Twice Annually 5 Twice Annually 5 Twice annually 5 Once per Permit cycle Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Conducted concurrently with IC/ID monitoring No evidence of IC/ID observed or suspected. Measurements and samples collected (2 events) Completed in (3 rd year of Permit) Measurements and samples collected (3 events) (b) Completed in (4 th year of Permit) (c) Measurements and samples collected (2 events) Completed in (2 nd year of Permit) No measurements or samples collected. No wet events met mobilization criteria. (d) Completed in (2 nd year of Permit term) 8-18

26 Table 8-7 Notes VNS Visited Not Sampled (a) See Section of the document for additional comments on site characteristics and conditions during monitoring events. (b) A third dry weather event was monitored. Additional data have been incorporated into trend analyses and reported separately. (c) Two dry weather events were monitored. (d) Sampling is dependent on flows being observed at Golf Center Parkway. Table 8-8 presents field parameters and constituents of concern required for the WWR monitoring in accordance with the 2008 MS4 Permit. Field parameters were measured in the field and constituents of concern were analyzed by the analytical laboratory. Table 8-8: Field Parameters and Constituents of Concern Required for Monitoring Field Parameters Constituents of Concern WWR Sampling Requirements Measured in the Field Total Metals Bacterial Indicator Nutrients and Other Temperature ph Specific Conductance Turbidity Dissolved Oxygen (DO) Arsenic Barium Cadmium Chromium, Total Lead Mercury Selenium E. coli Ammonia as Nitrogen (N) Nitrate as Nitrogen (N) Orthophosphorus Total Dissolved Solids (TDS) Total Kjeldahl Nitrogen (TKN) Total Nitrogen (calculation) Total Phosphorus Section L.10.B of the 2008 MS4 Permit requires priority pollutant sampling during at least one of the last three years of the 5-year permit cycle. Priority pollutant sampling was not conducted during the monitoring year because this monitoring requirement had been fulfilled as of the monitoring year. Occurrences of priority pollutant sampling at each monitoring station are summarized in Table 8-7. The full list of priority pollutants is provided in Attachment D of the 2008 MS4 Permit. The results from the monitoring year for MS4 outfall and receiving water stations are discussed in Section Attachment D and Attachment E of this Monitoring Annual Report include results from the monitoring year, as well as historical data from previous years of monitoring. 8-19

27 8.6.1 WET WEATHER MOBILIZATION CRITERIA The 2008 MS4 Permit requires collection of a minimum of two wet weather samples during the monitoring year. There is no defined wet season in the WWR because both general winter thunderstorms and summer monsoonal storms are experienced. As defined in the 2013 QAPP (Volume II of the CMP), the wet season generally falls between October 1 st and May 31 st, annually. Two National Weather Service (NWS) weather forecasts are closely monitored by District staff: The normal 7-day forecast for the possibility of a rain event; and The quantitative precipitation statement (QPS), within three days of an anticipated storm, to determine how much rain is predicted to fall in 6-hour increments over the next 72-hour period. If a storm event is forecasted by the NWS quantitative precipitation forecast (QPF) to be greater than 0.10 inch within the next 48 hours and there is at least 72 hours between the forecasted event and a previous measureable (>0.10 inch) rainfall event, storm event monitoring will be conducted according to the following mobilization criteria: The District will follow the decision chart and procedures outlined in Figure 10-1 of the 2013 QAPP. Pursuant to NWS standard practice, "likely" represents a probability of precipitation of at least 60%. Mobilization will occur when the NSW QPS forecast shows likely rainfall of 0.3 inch in 6 hours and/or 0.5 inch in 24 hours. This gives the District the greatest chance to sample a representative storm event. 2 For mobilization to occur, criteria must be met 24 hours in advance of sampling for coordination with property owners, consultants and sampling personnel. Field crews are not mobilized during or near certain holidays (Thanksgiving, the day after Thanksgiving, Christmas Eve, Christmas Day, New Year's Eve, and New Year's Day) if the mobilization or laboratory analysis continued through that holiday. The first sampleable wet weather event may be different than the first storm event of a monitoring year. Based on the District's monitoring experience, storm event forecasts of less than 0.5 inch in 24 hours do not typically result in measurable runoff and translate into false start wet weather events. In accordance with the 2008 MS4 Permit, Section L.5, sample mobilization is contingent upon sample holding time and normal working hours of a contract laboratory. For safety reasons, wet weather monitoring only occurs when adequate sunlight is available for sampling (see 2008 MS4 Permit Section L.6). 2 The District derived the representative storm event to be 0.38-inch and 1.14-inches in depth and 6 and 18 hours in duration (2013 QAPP, Vol. II of CMP). 8-20

28 8.6.2 STATIONS AND BENEFICIAL USES The Basin Plan establishes WQOs applicable to receiving waters in the WWR for a number of pollutants based on beneficial uses. For receiving water monitoring stations, the water quality data can be compared directly to the respective WQOs for each receiving water. As a general means of assessing whether individual MS4 outfalls may be contributing to changing receiving water conditions, water quality data from samples collected at MS4 outfall stations also were compared to WQOs for their respective receiving waters reaches. The designated beneficial uses specified in the Basin Plan for each of these receiving waters are listed below. A discussion of monitoring stations within each receiving water and the potential applications and limitations of beneficial uses at each station follows each list of beneficial uses. Upper Whitewater River Beneficial Uses: Agricultural (AGR); Cold freshwater habitat (COLD); Groundwater recharge (GWR); Municipal (MUN); Hydropower generation (POW). Water contact recreation (REC-1); Non-contact water recreation (REC-2); Warm freshwater habitat (WARM) (intermittent); and Wildlife habitat (WILD). As shown in landuse maps provided in Attachment B, the reference receiving water monitoring station for the WWR is Upper Whitewater River at Canyon Road Crossing (719WWT813). The Upper Whitewater River at Canyon Road Crossing receiving water station is located outside the developed portion of the WWR and not influenced by urbanization. The Whitewater River is typically dry during non-storm conditions and the Whitewater River remains dry for prolonged periods; therefore, development (i.e., golf course facilities) has been constructed in the bed of the Whitewater River. The only times when there is water in the Upper Whitewater River are during flash flood conditions. Other Whitewater River Beneficial Uses Washes (Ephemeral Streams): Freshwater replenishment (FRSH) (intermittent); GWR (intermittent); REC-2 (intermittent); WARM (intermittent); and WILD (intermittent). In accordance with Basin Plan Table 2-3, footnote 14, the Portola Avenue Storm Drain discharges to a reach of the Whitewater River that is subject to the beneficial use classifications for washes (ephemeral streams). The Portola Avenue Storm Drain MS4 8-21

29 outfall station (719POR817) is located approximately 20 miles downstream of the Upper Whitewater River at Canyon Road Crossing receiving water station. There are several diversions and recharge basins located between these two locations; therefore, conditions in the receiving water where the Portola Avenue Storm Drain discharges to the Whitewater River differ from the upstream reference station. The WQOs for Whitewater River washes (ephemeral streams) are intermittent and only apply to the Portola Avenue Storm Drain MS4 outfall data if sufficient flow exists. Conditions in the Whitewater River are typically dry during non-storm conditions, and the Whitewater River remains dry for prolonged periods. The beneficial uses in the wash below the spreading grounds above the CVSC (Figure 8-2) are not realized due to the absence of water during non-storm periods (dry weather events). The beneficial uses in the reach are also not realized due to the short duration of flow when it does occur; generally, the only times when there is flow in the Whitewater River are during flash flood conditions. Therefore, for the purposes of this Monitoring Annual Report, the intermittent WQOs are applied to Portola Avenue Storm Drain MS4 outfall wet weather monitoring data if flow is observed in the receiving water ("sufficient flow"). San Gorgonio River Beneficial Uses: AGR; COLD; GWR; REC-1; REC-2; WILD; and MUN (potential). 3 The Ramsey Street Storm Drain discharges to Smith Creek, which is a tributary of the San Gorgonio River. Smith Creek and the San Gorgonio River are both ephemeral. San Gorgonio River is the closest downstream receiving water to the Ramsey Street Storm Drain MS4 outfall station (719RMS782) with Basin Plan-listed beneficial uses and WQOs (i.e., Smith Creek does not appear in the Basin Plan). Given the several miles of dry ephemeral stream separating the MS4 outfall and receiving water, the San Gorgonio River beneficial uses were applied to evaluate monitoring data from the Ramsey Street Storm Drain MS4 outfall station on a limited basis. The San Gorgonio River beneficial uses are typically not realized due to the absence of water and short duration when flow does occur. Flows from the Ramsey Street Storm Drain must travel over one mile through coarse sand and rock before reaching Smith Creek; then travel another approximately 1.5 miles before reaching the confluence with the San Gorgonio River. When dry weather flow occurs at the Ramsey Street Storm Drain, flow evaporates and/or infiltrates without reaching the receiving water; therefore, 3 According to Basin Plan Table 2-3, footnote 11, "Potential use designations will be determined on a caseby-case basis as necessary in accordance with the Sources of Drinking Water Policy." 8-22

30 the San Gorgonio River WQOs are not applied to Ramsey Street Storm Drain dry weather data. Based on historical observation, the MS4 outfall and receiving water may only have hydraulic connectivity during extremely wet storm events. The precipitation intensities of the monitoring year (see Section 8.3) do not represent extremely wet conditions. As part of a conservative assessment, the WQOs associated with existing San Gorgonio River beneficial uses are applied to Ramsey Street Storm Drain wet weather data. Although the Basin Plan also identifies a potential MUN beneficial use for the San Gorgonio River, wet weather flows from the Ramsey Street Storm Drain MS4 outfall station generally evaporate and/or infiltrate without reaching the San Gorgonio River receiving water. The potential MUN WQOs are not applied to the Ramsey Street Storm Drain MS4 outfall station. CVSC Beneficial Uses: FRSH; REC-1; REC-2; WARM; WILD; and Preservation of rare, threatened, or endangered species (RARE). The CVSC is the 25-mile long constructed, downstream extension of the Whitewater River channel between Washington Street in La Quinta and the north shore of the Salton Sea. As described in Section A of the 2013 Permit, the lower 17-mile reach of the CVSC is the only surface waterbody in the WWR with perennial flow; these flows are dominated by effluent from NPDES-permitted POTW discharges, rising groundwater, and agricultural return flows. The CVSC at Avenue 52 Bridge (719CVS884) receiving water station is located downstream from the Valley Sanitation District (VSD) wastewater treatment plant (WWTP), a permitted discharge to the CVSC. All dry weather samples collected from the CVSC at Avenue 52 Bridge receiving water station represent background conditions within the CVSC. The Avenue 52 Storm Drain (719AVE785) is located downstream from the CVSC at Avenue 52 Bridge receiving water station. The Avenue 52 Storm Drain (719AVE785) is offset approximately 190 feet from the CVSC, and this distance is sandy-bottomed and heavily vegetated. Based on the beneficial uses designated in the Basin Plan, the applicable WQOs for the WWR, including ph, DO, and bacterial indicators, are presented in Table 8-9. E. coli is the only bacterial indicator required to be monitored in accordance with the 2008 MS4 Permit MRP, and, therefore, is the only bacterial indicator WQO presented in Table 8-9. For the MS4 outfall stations, the identified WQOs are those that apply to the receiving waters into which the MS4 outfall discharges. 8-23

31 Table 8-9: Applicable Basin Plan WQOs by Monitoring Station Water Quality Objectives (WQOs) Monitoring Station Receiving Water Dissolved E. coli (singlesample maximum) (Station ID) for Analysis ph Oxygen (DO) Ramsey Street Storm Drain San Gorgonio (a) 8.0 mg/l 400 MPN/100mL (719RMS782) (COLD) (REC-1) Avenue 52 Storm Drain CVSC (b) 5.0 mg/l 400 MPN/100mL (719AVE785) (WARM) (REC-1, REC-2) Portola Avenue Storm Drain (719POR817) Washes (Ephemeral Streams) (c) mg/l 2,000 (c) (d) (WARM) MPN/100mL (REC-2) (c) Upper Whitewater River at Canyon 8.0 mg/l 400 MPN/100mL Whitewater River Road Crossing (719WWT813) (COLD) (e) (REC-1, REC-2) CVSC at Avenue 52 Bridge CVSC (b) 5.0 mg/l 400 MPN/100mL (719CVS884) (WARM) (REC-1, REC-2) MPN most probable number (a) Based on historical observation, flow from this outfall station is not anticipated to have reached the receiving water. (b) The CVCS is owned by the CVWD, which prohibits public access to these facilities, making recreational activities illegal. (c) These beneficial uses are "intermittent" and considered only when sufficient flow exists. (d) Per Basin Plan Table 2-3, footnote 7, a WARM beneficial use, if any, will be determined by the Regional Board on a case-by-case basis. (e) A WARM beneficial use is "intermittent" and considered only when sufficient flow exists. The WQOs for DO when both WARM and COLD beneficial uses apply is 8.0 mg/l. The MUN beneficial use is only applicable to the Upper Whitewater River at Canyon Road Crossing receiving water station, which only flows during extremely wet storm events (flash flood conditions). The MUN WQOs are presented in Table Table 8-10: Potentially Applicable Basin Plan WQOs MUN Beneficial Use only Monitoring Station (Station ID) Upper Whitewater River at Canyon Road Crossing (719WWT813) (b) Total Arsenic 50 µg/l Water Quality Objectives (WQOs) for MUN Beneficial Use (a) Total Barium 1,000 µg/l Total Cadmium 10 µg/l Total Chromium 50 µg/l Total Lead 5.0 µg/l Total Mercury 2.0 µg/l Nitrate as Nitrogen 10 mg/l Total Selenium (a) Select priority pollutants also have MUN associated WQOs; only constituents of concern (Table 8-8) are identified. (b) No flow was observed at Golf Center Parkway during the monitoring year; therefore, no samples were collected. 50 µg/l 8-24

32 8.6.3 ILLICIT CONNECTION/ILLEGAL DISCHARGE ELIMINATION MS4 Outfall Dry Weather IC/ID Monitoring The three MS4 outfall stations are required to be monitored quarterly during dry weather to investigate for evidence of non-typical flow and water quality conditions. Dry weather IC/ID MS4 outfall monitoring was conducted in accordance with the schedule presented in Section MS4 outfall stations are summarized and mapped in Table 8-6 and Figure 8-2, respectively. When sufficient flow is present at an MS4 outfall station, bacteriological samples were collected along with field parameters and flow. Based on the results of quarterly IC/ID monitoring, follow-up investigations may be necessary if parameters are outside of normal range, non-typical flow or water quality conditions are evidenced, and/or if an IC/ID is suspected. If an IC/ID incident is discovered within a Permittee's jurisdiction, that Permittee is notified to conduct a follow-up investigation (see Section ) Complaint Calls In the event that a Permittee has received a complaint call, the Permittee should determine the jurisdiction responsible for the follow-up actions (see Section ), as based on the location described by the complaint report, and notify the appropriate point of contact as referenced in the QAPP (Vol. II of the CMP). For complaints falling within a Permittee's jurisdiction, it is recommended that their respective internal enforcement protocols be followed, or the Enforcement and Compliance Response Procedures (Section 1.7 of the WWR Stormwater Management Plan [SWMP]) may be utilized as guidance Follow-Up Investigations and Actions In the event that quarterly monitoring results indicate the need for follow-up IC/ID investigations, the Permittee having jurisdiction will follow their local procedures, as necessary, as follow-up actions for quarterly dry weather MS4 outfall monitoring, including Permittee outfall inspections and field reconnaissance, as necessary. Permittee Administrative and Legal Procedures are also contained in the Permittees' individual SWMP or other local Permittee procedures. If not a permitted discharge, Permittee staff enforce respective Stormwater Ordinances; the Enforcement and Compliance Response Procedures (SWMP Section 1.7), may be utilized as guidance. These actions continue until the discharger is able to obtain a permit from the Regional Board and the discharge is determined to be acceptable by the Permittees. In order to provide further guidance to the Permittees, the July 2014 WWR CMP (Volume V) contains additional procedures and recommendations to assist in the response to a potential IC/ID. 8-25

33 EVENTS Dry weather and wet weather monitoring was conducted in the WWR during the monitoring year as summarized in Table All storm events with at least 0.1 inch average total rainfall within a 24-hour period, and the QPS used to evaluate wet weather mobilization are also summarized in Table The total amount of rain shown is an average calculated from the daily precipitation at each precipitation gauging station listed in Attachment B. The July 20, 2012, September 4, 2013, and May 22, 2014 storm events were local precipitation events. The QPSs and measured precipitation amounts vary significantly between individual stations due to the topography of the WWR (Table 8-11). The Thermal QPS precipitation station is located in closest proximity to the Portola Avenue Storm Drain and Avenue 52 Storm Drain MS4 outfall stations and the CVSC at Avenue 52 Bridge receiving water station. During the monitoring year, only the August 26, hour QPS for the Thermal precipitation station met the wet weather mobilization criteria. The Beaumont QPS precipitation station is located closest to the Ramsey Street Storm Drain MS4 outfall station. The QPS forecasts for Beaumont, California were greater than for Thermal, California and generally met the wet weather mobilization criteria. Table 8-11: Monitoring Event Summary and Wet Weather Data Ramsey Street Storm Drain (719RMS782) Avenue 52 Storm Drain Outfall (719AVE785) Portola Avenue Storm Drain (719POR817) Upper Whitewater River at Canyon Road Crossing (719WWT813) CVSC at Avenue 52 Bridge(719CVS884) QPS at Thermal, CA (a) 6 hr (in) / 24 hr (in) QPS at Beaumont, (a) (b) CA 6 hr (in) / 24 hr (in) Avg. Total Rain (in) (c) Date Wet Weather Events 08/26/2013 X X X 0.22 / / (4) 10/09/2013 X 0.01 / / (2) 11/21/2013 X 0.11 / / (3) 05/22/2014 X * X * 0 / / (0) Other Storm Events 07/20/2013 No Data No Data 0.31 (2)* 09/04/2013 No Data No Data 0.35 (3)* 02/26-03/03/ / / (6) ** Dry Weather Events (including quarterly IC/ID monitoring) 07/31/2013 VNS 08/20/2013 VNS VNS X 09/24/2013 X 12/17/213 VNS VNS X 02/25/2014 VNS VNS X 03/12/2014 VNS 05/29/2014 VNS 06/11/2014 VNS VNS X 8-26

34 Notes for Table 8-11 X - Sampled. VNS - Visited not sampled. Site was dry or there was insufficient flow for sample collection. * - Localized precipitation. ** - Multiple days of precipitation. QPS indicated heavy precipitation after initial 24 hours. (a) Storm event mobilization criteria for typical wet weather conditions, as defined in the 2013 QAPP, ranges from 0.3-inch to 0.5-inch in six / 24 hours. QPS meeting these mobilization criteria are presented in bold font. (b) This precipitation station is used to evaluate storm event mobilization criteria for Ramsey Street Storm Drain MS4 outfall station. QPS meeting the District's mobilization criteria are presented in bold font. (c) Cumulative depth of rain in inches for entire storm using daily average for five precipitation gauging stations. The storm duration (number of days with a daily average precipitation greater than zero) is shown in parentheses. Dry Weather MS4 Outfall IC/ID Monitoring Dry weather IC/ID MS4 outfall monitoring was conducted at Ramsey Street Storm Drain MS4 outfall station on July 31, 2013, December 17, 2013, March 12, 2014 and May 29, Although a "trickle" of flow was observed at the Ramsey Street Storm Drain MS4 outfall station during two site visits, all dry weather events were classified as VNS because observed dry weather flows were insufficient for field parameter measurement and E. coli sample collection. Low flows observed at the Ramsey Street Storm Drain MS4 outfall station during dry weather events evaporated and/or infiltrated without impacting receiving water beneficial uses. Dry weather IC/ID MS4 outfall monitoring was conducted at the Portola Avenue Storm Drain MS4 outfall station on August 20, 2013, September 24, 2013, December 17, 2013, February 25, 2014 and June 11, During the August 20, 2013 site visit, dry weather monitoring and IC/ID visual assessment had to be postponed because the MS4 outfall was inaccessible due to significant vegetation (+12 feet in height) growing on top of the cement apron, and the first dry weather event for this MS4 outfall station was rescheduled. Field parameter measurements and E. coli samples were collected from the Portola Avenue Storm Drain MS4 outfall station on September 24, 2013 (1.46 cubic feet per second [cfs]) and December 17, 2013 (trickle). As documented by field photos, the receiving water (Whitewater River wash [ephemeral stream]) was heavily vegetated during the monitoring year and appeared to be dry during non-storm periods. Per the Basin Plan, for this segment of the Whitewater River receiving water the designated beneficial uses are applicable only when there is the presence of flow capable of sustaining their use. Therefore, the dry weather flows observed at the Portola Avenue Storm Drain MS4 outfall station, which evaporated and/or infiltrated in the dry riverbed, did not impact the receiving water. 8-27

35 Dry weather IC/ID MS4 outfall monitoring was conducted at the Avenue 52 Storm Drain MS4 outfall station on August 20, 2013, December 17, 2013, February 25, 2014 and June 11, No flow was observed during these dry weather events. Field parameter measurements and E. coli samples were not collected, and all four events were classified as VNS. Wet Weather MS4 Outfall Monitoring Wet weather monitoring was conducted at the Ramsey Street Storm Drain MS4 outfall station on October 9, 2013 and November 21, Field parameters were measured and samples were collected and analyzed for E. coli and constituents of concern. The Ramsey Street Storm Drain is tributary to Smith Creek, which is a tributary of the San Gorgonio River (i.e., the receiving water with beneficial uses and WQOs used for comparison in this document). Due to approximately three miles of dry ephemeral stream between the receiving water and the MS4 outfall, there is only hydraulic connectivity during extremely wet storm events. Although the Banning precipitation station recorded 0.85 inch (October 9-10, 2013), the average regional precipitation (0.25 inch, Attachment B) and measured flow (5.9 cfs) indicate that this does not represent an extremely wet storm event. The Banning precipitation station recorded 0.18-inch (November 21-24, 2013, Attachment B). Flow at the Ramsey Street Storm Drain MS4 outfall station was measured to be 0.46 cfs. Also, conditions in the WWR during the monitoring year were dry (61% below normal precipitation, Table 8-4). Therefore, wet weather flows sampled at the Ramsey Street Storm Drain MS4 outfall station likely evaporated and/or infiltrated before reaching the San Gorgonio River; therefore not impacting the receiving water beneficial uses. Wet weather monitoring was conducted at the Portola Avenue Storm Drain MS4 outfall station on August 26, As documented in field notes and site photos, a localized storm cell (0.27 inch at Cathedral City gauge, Appendix B) created sufficient storm surge to clear vegetation observed a week prior as blocking the MS4 outfall. Field parameters were measured, and samples were collected and analyzed for E. coli and constituents of concern. A flow of 0.85 cfs was recorded at the MS4 outfall station at the time of sampling. No other storm events that occurred during the monitoring year met the CMP mobilization criteria. Wet weather monitoring was conducted at the Avenue 52 Storm Drain MS4 outfall station on August 26, 2013 and May 22, Field parameters were measured, and samples were collected and analyzed for E. coli and constituents of concern. Flow could not be measured at the MS4 outfall during the August 26, 2013 wet weather event because debris and vegetation deposited by the storm made access and flow measurement infeasible. The May 22, 2014 wet weather event (11.06 cfs) was caused by a local storm cell above the CVSC receiving water. Zero precipitation was measured at the regional precipitation gauging stations (Attachment B). 8-28

36 Dry Weather Receiving Water Monitoring Dry weather receiving water monitoring was conducted at the CVSC at Avenue 52 Bridge receiving water station on August 20, 2013 and February 25, Field parameters were measured, and samples were collected and analyzed for E. coli and constituents of concern. It is important to note that the CVSC Avenue 52 Bridge receiving water station is located upstream of the Avenue 52 Storm Drain MS4 outfall station; therefore, dry weather samples collected at the receiving water station characterize background conditions in the CVSC and predominately represent permitted flows from the VSD WWTP. An additional dry weather event (June 11, 2014) was conducted at the CVSC at Avenue 52 Bridge receiving water station in error. Field parameters were measured and samples were collected and analyzed for E. coli and constituents of concern. Results for the third dry weather event have been presented in this document but these extra data are not discussed in detail. The data have been incorporated into the long-term trend analysis. Wet Weather Receiving Water Monitoring No flow was observed at Golf Center Parkway during the monitoring year; therefore, no wet weather samples were collected at the Upper Whitewater River at Canyon Road Crossing (reference) receiving water station. Wet weather receiving water monitoring was conducted at the CVSC at Avenue 52 Bridge receiving water station on August 26, 2013 and May 22, Field parameters were measured, and samples were collected and analyzed for E. coli and constituents of concern. As documented in field photos from August 26, 2013, wet weather flow traveled downstream through multiple shallow streams that braided across the width of the receiving water channel. Although samples and field parameters were collected using a bucket, the mudflats made the site inaccessible for stream rating and flow measurement. Flow of cfs was measured at the CVSC at Avenue 52 Bridge receiving water station during the May 22, 2014 wet weather event. It is important to note that the CVSC Avenue 52 Bridge receiving water station is located upstream of the Avenue 52 Storm Drain outfall; therefore, wet weather samples collected at the receiving water station characterize background conditions for the CVSC (i.e., NPDES-permitted POTW discharges, rising groundwater, and agricultural return flows [2013 Permit, Section A, Findings]) SUMMARY OF ANALYTICAL DATA AND RESULTS The Basin Plan establishes WQOs applicable to receiving waters in the WWR for a number of pollutants. For receiving water stations, the water quality data can be compared directly to the respective WQOs for each receiving water. The WQOs apply to the receiving waters and do not apply directly to discharges of urban runoff to receiving waters (i.e., MS4 outfalls). As a general means of assessing whether individual MS4 outfalls may be contributing to changing receiving water conditions, water quality data from samples collected at MS4 outfall stations also were compared to WQOs for their respective receiving water's reach. 8-29

37 Table 8-12 presents a summary of the MS4 outfall station monitoring data, and Table 8-13 presents a summary of the receiving water monitoring data. Concentrations of pollutants that exceed applicable, monitoring station-specific WQOs are indicated in bold font. Constituents with estimated results due to detections above the laboratory method detection limit (MDL) but below the reporting limit (RL) are presented in Table 8-12 and Table 8-13 as detected not quantified (DNQ). Not reported/not required (NR) has been used to indicate station-parameters not required by the 2008 MS4 Permit. Several samples underwent additional analyses (i.e., total hardness, as well as several nutrients and dissolved phase metals) not required by the 2008 MS4 Permit during the monitoring year. These additional analytical results are presented in gray font at the bottom of Table 8-12 and Table 8-13 for references purposes only. These data have not been discussed further in this document. Where nitrate results were reported by the analytical laboratory as nitrate (NO3 - ) rather than as nitrate as nitrogen (N), both the original laboratory reported value and the calculated result were reported. Table 8-14 presents the additional dry weather monitoring data collected at the CVSC at Avenue 52 Bridge receiving water station on June 11, These data were collected in error and have been provided for references purposes only. The results for this additional dry weather event have been incorporated into the long-term dataset for integrated analyses (Section 8.7) but otherwise have not been discussed further in this document. The MS4 outfall and receiving water data were also evaluated by graphing the water quality results over time ("time series" plots) to illustrate trends relative to the pertinent WQOs. Graphical summaries of the water quality data from analysis of samples collected between 1993 and 2014 from the WWR are provided as Attachment D (electronic version only). The results are also provided in tabular form in Attachment E (electronic version only). 8-30

38 Constituent Bacteriological Table 8-12: Concentrations of Monitored Constituents WWR MS4 Outfall Stations Units E. Coli MPN/100mL Basin Plan WQO (a) 400 (REC-1) 2,000 (REC-2) 719RMS AVE POR817 Ramsey Street Storm Drain Avenue 52 Storm Drain Portola Avenue Storm Drain Wet Event Wet Event Wet Event Wet Event Dry Event Dry Event Wet Event 10/9/ /21/2013 8/26/2013 5/22/2014 9/24/ /17/2013 8/26/ ,000 (REC-1) 5,000 (REC-1) >1,600 (REC-1) 49,000 (REC-1) Field Measurements ph ph units Dissolved Oxygen (DO) mg/l 5 (WARM) (COLD) (b) (COLD) (COLD) (WARM) (WARM) (WARM) Specific Conductance µs/cm Temperature Celsius Turbidity NTU Other General Parameters Total Dissolved Solids (TDS) mg/l NR NR 300 Metals Arsenic µg/l (c) 1.8 DNQ(0.5) NR NR ND Barium µg/l (c) NR NR 39 Cadmium µg/l (c) 0.57 ND DNQ(0.99) 0.84 NR NR ND Chromium, Total µg/l (c) NR NR ND Lead µg/l (c) 41 DNQ(0.9) NR NR DNQ(1.5) Mercury µg/l (c) DNQ(0.1) ND ND ND NR NR ND Selenium µg/l (c) ND ND ND 2 NR NR ND Nutrients Ammonia-Nitrogen mg/l. 1.5 DNQ(0.062) NR NR 0.28 Total Kjeldahl Nitrogen mg/l NR NR 3.9 Nitrate as Nitrogen (N) mg/l Ω NR NR 3.1 Nitrite as Nitrogen (N) mg/l. DNQ(0.07) ND 0.16 DNQ(0.046) NR NR 0.11 Total Nitrogen (calculation) mg/l NR NR 7.11 Orthophosphorus mg/l NR NR 0.15 Total Phosphorus mg/l /0.68* NR NR 0.33 CONSTITUENTS NOT REQUIRED BY THE 2008 MS4 PERMIT Total Hardness ** mg/l NR NR NR NR NR Hexavalent Chromium ** µg/l. NR DNQ(0.87) NR NR NR NR NR Trivalent Chromium ** µg/l. NR DNQ(0.43) NR NR NR NR NR Arsenic, Dissolved ** µg/l. DNQ(0.6) DNQ(0.6) NR NR NR NR NR Barium, Dissolved ** µg/l NR NR NR NR NR Cadmium, Dissolved ** µg/l. ND ND NR NR NR NR NR Total Chromium, Dissolved ** µg/l NR NR NR NR NR Lead, Dissolved ** µg/l. DNQ(0.7) DNQ(0.2) NR NR NR NR NR Mercury, Dissolved ** µg/l. ND ND NR NR NR NR NR Selenium, Dissolved ** µg/l. ND ND NR NR NR NR NR Nitrite + Nitrate as Nitrogen (N) ** mg/l. NR NR NR 4.2 NR NR NR Nitrite as NO2 ** mg/l. NR NR NR 0.15 NR NR NR Nitrate as NO3 ** mg/l. NR NR NR 18 NR NR NR 79,000 (REC-2) 8-31

39 Notes for Table 8-12 Bold text indicates an exceedance of the applicable Basin Plan water quality objective (WQO). DNQ Detected not quantified. Indicates that the constituent was detected below the reporting limit (RL). The concentration was not quantified. Values in parentheses are estimated. ND Not-detected. Indicates constituent was not detected above the method detection limit (MDL). NR Not required. Sampling not required under the 2008 MS4 Permit, Order No. R , NPDES Permit No. CAS Ω - Result calculated from laboratory reported result for Nitrate as NO3 (California Department of Health, 2014). * - Analysis performed by two laboratories. Left value is from Babcock Laboratories, right value is from Coachella Valley Water District (CVWD) Water Quality Laboratory. ** - Sampling of this constituent is not required under the 2008 MS4 Permit, Order No. R , NPDES Permit No. CAS (a) The Basin Plan WQO is dependent upon beneficial use and varies by monitoring station. (b) The Basin Plan WQOs for washes (ephemeral streams) only apply to Portola Avenue Outfall if the receiving water is the flowing. Flow was documented in the wash, ephemeral stream receiving water adjacent to this MS4 outfall station during the 08/26/2013 wet weather event. (c) The potential WQOs associated with the potential MUN beneficial use for the Ramsey Street Storm Drain MS4 outfall station have not been applied. 8-32

40 Table 8-13: Concentrations of Monitored Constituents WWR Receiving Water Stations 719CVS884 Constituent Units Basin CVSC at Avenue 52 Bridge Plan WQO (a) Dry Event Dry Event Wet Event Wet Event 8/20/2013 2/25/2014 8/26/2013 5/22/2014 Bacteriological E. Coli MPN/ mL (REC-1) ,000 4,600 Field Measurements ph ph units Dissolved Oxygen (DO) mg/l 5 (WARM) Specific Conductance µs/cm Temperature Celsius Turbidity NTU Other General Parameters Total Dissolved Solids (TDS) mg/l. NS Metals Arsenic µg/l. ND ND Barium µg/l Cadmium µg/l. ND ND ND DNQ(0.17) Chromium µg/l. DNQ(1.9) DNQ(3.8) Lead µg/l. DNQ(0.62) DNQ(1.1) Mercury µg/l. ND ND ND ND Selenium µg/l. ND ND ND 2.1 Nutrients Ammonia-Nitrogen mg/l Total Kjeldahl Nitrogen (TKN) mg/l Nitrate as Nitrogen (N) mg/l Ω Ω Nitrite as Nitrogen (N) mg/l Orthophosphorus mg/l Total Nitrogen (calculation) mg/l Total Phosphorus mg/l. 1.9/1.9* /2.08* CONSTITUENTS NOT REQUIRED BY THE 2008 MS4 PERMIT Arsenic, Dissolved ** µg/l. NR ND NR NR Barium, Dissolved ** µg/l. NR 44 NR NR Cadmium, Dissolved ** µg/l. NR ND NR NR Chromium, Dissolved ** µg/l. NR DNQ(4.9) NR NR Lead, Dissolved ** µg/l. NR DNQ(0.3) NR NR Mercury, Dissolved ** µg/l. NR DNQ(0.055) NR NR Selenium, Dissolved ** µg/l. NR DNQ(1.6) NR NR Nitrite + Nitrate as N** mg/l. 4.7 NR NR 4.4 Nitrite as NO2 ** mg/l. 3.3 NR NR 2.2 Nitrate as NO3 ** mg/l. 16 NR NR

41 Notes for Table 8-13: Bold text indicates an exceedance of the applicable Basin Plan water quality objective (WQO). DNQ - Detected Not Quantified. Indicates that the constituent was detected below the reporting limit (RL). The concentration was not quantified. Values in parentheses are estimated. ND - Indicates constituent was not detected above the method detection limit (MDL). NR - Constituent not sampled. Sampling not required under the 2008 MS4 Permit, Order No. R , NPDES Permit No. CAS NS - Not sampled. * - Sampling of this constituent not required under the 2008 MS4 Permit, Order No. R , NPDES Permit No. CAS ** - Analysis performed by two laboratories. Left value is from Babcock Laboratories, right value is from Coachella Valley Water District (CVWD) Water Quality Laboratory. Ω - Result calculated from laboratory reported result for Nitrate as NO 3 (California Department of Health, 2014). (a) The Basin Plan WQO is dependent upon beneficial use and varies by monitoring station. 8-34

42 Table 8-14: Concentrations of Monitored Constituents Additional Dry Weather Event at CVSC at Avenue 52 Bridge Receiving Water Station 719CVS884 Constituent Units Basin Plan WQO (a) CVSC at Avenue 52 Bridge Dry Event 6/11/2014 Bacteriological E. Coli MPN/100mL 400 (REC-1) 170 Field Measurements ph ph units Dissolved Oxygen (DO) mg/l 5 (WARM) 4.72 Specific Conductance µs/cm Temperature Celsius Turbidity NTU Other General Parameters Total Dissolved Solids (TDS) mg/l. 600 Metals Arsenic µg/l. DNQ(1.5)/DNQ(1.4)* Barium µg/l. 49/50* Cadmium µg/l. ND/ND* Chromium µg/l. DNQ(4.4)/DNQ(2.5)* Lead µg/l. DNQ(0.45)/DNQ(0.59)* Mercury µg/l. ND/ND* Selenium µg/l. ND/DNQ(1.6)* Nutrients Ammonia-Nitrogen mg/l. 20 Total Kjeldahl Nitrogen (TKN) mg/l. 24 Nitrate as Nitrogen (N) mg/l Nitrite as Nitrogen (N) mg/l Orthophosphorus mg/l. 1.9 Total Nitrogen (calculation) mg/l Total Phosphorus mg/l. 2.3 Notes for Table 8-14: Bold text indicates an exceedance of the applicable Basin Plan water quality objective (WQO). DNQ Detected Not Quantified. Indicates that the constituent was detected below the reporting limit (RL). The concentration was not quantified. Values in parentheses are estimated. ND Not detected. Indicates constituent was not detected above the method detection limit (MDL). * Analysis performed by two laboratories. Left value is from Babcock Laboratories, right value is from Coachella Valley Water District (CVWD) Water Quality Laboratory. (a) The Basin Plan WQO is dependent upon beneficial use and varies by monitoring station. 8-35

43 The monitoring year is characterized as dry (e.g., 61% below normal precipitation, see Table 8-4) for the WWR as a whole. There is very limited hydraulic connectivity between MS4 outfall stations and downstream receiving waters. Due to these dry conditions, hydraulic connectivity would only be expected during extremely wet storm events. As discussed in Section 8.3, monitored wet weather events did not qualify as extremely wet storm events. The results presented in Table 8-12 and Table 8-13 are summarized and qualified as follows: Samples were collected at the Ramsey Street Storm Drain MS4 outfall station on October 9, 2013 (wet weather) and November 21, 2013 (wet weather). The ph levels measured were within the WQO range during both wet weather events. The DO concentration measured in the November 21, 2013 sample was slightly less than the COLD WQO. E. coli results measured during both wet weather events were greater than the REC-1 WQO. Wet weather flows sampled at the Ramsey Street Storm Drain MS4 outfall station likely evaporated and/or infiltrated along the three miles of ephemeral stream, prior to reaching the San Gorgonio River receiving water (the receiving water with beneficial uses and WQOs used for comparison in this document) and, therefore, did not impact beneficial uses of the receiving water. Samples were collected at the Portola Avenue Storm Drain MS4 outfall station on August 26, 2013 (wet weather), September 24, 2014 (dry weather), and December 17, 2013 (dry weather). No flow was observed in the Whitewater River wash (ephemeral stream) adjacent to the MS4 outfall station during monitored dry weather events; therefore, the WQOs were not applied because sampled flows evaporated and/or infiltrated without impacting beneficial uses of the receiving water. During the August 26, 2013 wet weather event, stormwater flows cleared vegetation blocking the MS4 outfall, therefore the WQOs were applied to this data. Measured ph and DO levels were within applicable WQO ranges. The E. coli result was greater than the REC-2 WQO, but it is unknown if there were impacts to the intermittent beneficial uses. Based on the dry conditions in the WWR during the monitoring year, it is likely that the low flow (0.85 cfs) sampled at the Portola Avenue Storm Drain MS4 outfall station evaporated and/or infiltrated within the ephemeral wash even if it did reach the receiving water. Samples were collected at the Avenue 52 Storm Drain MS4 outfall station on August 26, 2013 (wet weather) and May 22, 2014 (wet weather). DO and ph levels measured at the Avenue 52 Storm Drain MS4 outfall station during sampled wet weather events were within the WQO ranges. E. coli results were greater than the REC-1 WQO. Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. The CVSC is owned and operated by the CVWD, which prohibits public access to these facilities, making recreational activities unlikely. Therefore, the monitoring data do not imply impact to beneficial uses in the CVSC because these beneficial uses would not be realized. Samples were collected at the CVSC at Avenue 52 Bridge receiving water station on August 20, 2013 (dry weather), August 26, 2013 (wet weather), February 25, 2014 (dry weather) and May 22, 2014 (wet weather). The ph levels measured were within the 8-36

44 WQO range during all dry weather and wet weather events. The DO concentrations measured in the August 20, 2013 dry weather sample and the August 26, 2013 wet weather sample were less than the WARM WQO. E. coli results were greater than the REC-1 WQO during monitored wet weather events only. The CVSC is owned and operated by the CVWD, which prohibits public access to this facility, making recreational activities highly unlikely. This assumption is supported by the difficulty field teams had accessing flowing water in the CVSC receiving water during wet weather monitoring activities. The CVSC at Avenue 52 Bridge receiving water station is located upstream of the Avenue 52 Storm Drain MS4 outfall station. Dry weather flows generally characterize permitted discharges from the VSD WWTP, and wet weather flows represent background conditions within the CVSC. Therefore, the monitoring data do not imply impact to beneficial uses in the CVSC. Summarized below are the water quality data for each field parameter measured or detected in a sample above the laboratory RL, or flagged as greater than a WQO during the monitoring year. Attachment F describes the importance of these constituents to urban runoff water quality and the types of industries within the WWR that are likely to discharge them in their waste streams. An analysis of the constituents that have not been detected in samples collected from the period of record, including constituent results with estimated values (DNQ results), is presented in Table 8-12 and Table 8-13 and further discussed in Attachment G. Constituents or compounds that have not been detected in the WWR monitoring program period of record also are listed in Attachment G. Ammonia as Nitrogen (N) (#1051) (constituent of concern) The Basin Plan does not specify a numeric WQO for ammonia. Dry Weather Dry weather monitoring for ammonia was not required at the MS4 outfall stations. Ammonia was detected above the RL in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (14 and 20 milligrams per liter [mg/l]). The February 24, 2014 dry weather sample measured the highest ammonia concentration (20 mg/l) of the monitoring year. These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Ammonia was detected above the MDL in all five wet weather samples collected at the three MS4 outfall stations, with results ranging from an estimated mg/l (DNQ result) to 2.2 mg/l. The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Ammonia wet weather results 8-37

45 for the CVSC at Avenue 52 Bridge receiving water station, the station characterizing background water quality conditions in the CVSC, were above the RL (2.2 and 15 mg/l). These results were lower than measured at the downstream MS4 outfall station (0.34 and 2.2 mg/l). Arsenic (#1070, total; #1071, dissolved) (constituent of concern) In accordance with Table L-1 of the 2008 MS4 Permit, total phase metals are constituents of concern and required to be monitored for permit compliance. Extra analytical results for dissolved arsenic presented in Table 8-12 and Table 8-13 are for reference purposes only. The Basin Plan specifies a numeric WQO for total arsenic for MUN beneficial uses. Based on historical observation and aerial photography, it is unlikely that Ramsey Street Storm Drain MS4 outfall station had hydraulic connectivity to the San Gorgonio River receiving water during the monitoring year. Wet weather flows sampled at this MS4 outfall station during monitoring activities likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water, due to the soil type and distance to the receiving water (approximately three miles). Therefore, the WQOs associated with the potential MUN beneficial use (e.g., drinking water source) have not been applied to the water quality data from the Ramsey Street Storm Drain MS4 outfall station. Dry Weather Dry weather monitoring for total arsenic was not required at the MS4 outfall stations. Total arsenic was not detected (ND) in either of the dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station. These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather The wet weather sample collected from the Portola Avenue Storm Drain MS4 outfall station had a ND result for total arsenic, and therefore did not impact the intermittent beneficial uses of the receiving water. Total arsenic was detected above the MDL in both wet weather samples collected at the Ramsey Street Storm Drain MS4 outfall station, with results ranging from an estimated 0.5 µg/l (DNQ result) to 1.8 µg/l. Wet weather flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Total arsenic wet weather results for the CVSC at Avenue 52 Bridge receiving water station, the station characterizing background water quality conditions in the CVSC, were above the RL (3.1 and 7.2 µg/l). Wet weather results at the downstream MS4 outfall were similar (0.8 and 6.3 µg/l). Bacterial Indicators; E. coli (#1077) (constituent of concern) (REC-1 WQO E. coli = 400 most probable number (MPN)/100 milliliters (ml), REC-2 WQO E. coli = 2,000 MPN/100mL) During the monitoring year, the E. coli REC-1 WQO was applied to the Avenue 52 Storm Drain outfall and Ramsey Street Storm Drain MS4 outfall stations and the CVSC at Avenue 52 Bridge receiving water station. The E. coli REC-2 WQO was only applied to the wet weather data collected at the Portola Avenue Storm Drain MS4 outfall station. 8-38

46 Dry Weather Dry weather E. coli samples were collected at the Portola Avenue Storm Drain MS4 outfall station, on September 24, 2013 and December 17, E. coli was detected above the RL at concentrations for both dry weather samples. Dry weather flows sampled at the Portola Avenue Storm Drain evaporated and/or infiltrated in the absence of flow in the receiving water and, therefore, did not impact beneficial uses of the ephemeral wash receiving water. The WQO was not applicable. E. coli was detected above the RL (350 and 1.8 MPN/100mL) in dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station. These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather All five wet weather samples collected at the MS4 outfall stations had E. coli results above applicable WQOs. The highest E. coli result quantified during the monitoring year, 79,000 MPN/100mL, was from the August 26, 2013 sample collected at the Portola Avenue Storm Drain MS4 outfall station. This wet weather flow (0.85 cfs) likely evaporated and/or infiltrated from the ephemeral streambed without impacting the intermittent beneficial uses of the receiving water. E. coli results at the Ramsey Street Storm Drain MS4 outfall station were above the REC-1 WQO (23,000 and 5,000 MPN/100mL). Wet weather flows sampled at the MS4 outfall station likely evaporated and/or infiltrated within ephemeral tributaries and did not reach the San Gorgonio River receiving water. There were no impacts to beneficial uses. The E. coli wet weather results for the Avenue 52 Storm Drain MS4 outfall station included an estimated level of >1,600 MPN/100mL (August 26, 2013) and measured level of 49,000 MPN/100mL (May 22, 2014). E. coli was also detected above the REC-1 WQO in wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (33,000 and 4,600 MPN/100mL). The CVSC is owned and operated by the CVWD, which prohibits public access to these facilities, making recreational activities unlikely. Barium (#1090, total; #1088, dissolved) (constituent of concern) In accordance with Table L-1 of the 2008 MS4 Permit, total phase metals are constituents of concern and required to be monitored for permit compliance. The extra analytical results for dissolved barium presented in Table 8-12 and Table 8-13 are for reference purposes only. The Basin Plan specifies a numeric WQO for total barium for MUN beneficial uses. Based on historical observation and aerial photography, it is unlikely that Ramsey Street Storm Drain MS4 outfall station had hydraulic connectivity to the San Gorgonio River receiving water during the monitoring year. Wet weather flows sampled at this MS4 outfall station during monitoring activities likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water, due to the pervious soils and distance to the receiving water (approximately three miles). Therefore, the WQOs associated with the potential MUN beneficial use (e.g., drinking water source) have not been applied to the water quality data from the Ramsey Street Storm Drain MS4 outfall station. 8-39

47 Dry Weather Dry weather monitoring for total barium was not required at the MS4 outfall stations. Total barium was detected above the RL in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (38 and 57 μg/l). These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Total barium was detected above the RL in all five wet weather samples collected at the three MS4 outfall stations, with concentrations ranging from 29 µg/l to 450 µg/l. The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Total barium was detected above the RL in both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (420 and 140 µg/l). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Total barium concentrations at the receiving water station were greater than at the MS4 outfall station during the first sampled storm event and visa versa during the second storm event. Cadmium (#1145, total; #1148, dissolved) (constituent of concern) In accordance with Table L-1 of the 2008 MS4 Permit, total phase metals are constituents of concern and required to be monitored for permit compliance. The extra analytical results for dissolved cadmium presented in Table 8-12 and Table 8-13 are for reference purposes only. The Basin Plan specifies a numeric WQO for total cadmium for MUN beneficial uses. Based on historical observation and aerial photography, it is unlikely that Ramsey Street Storm Drain MS4 outfall station had hydraulic connectivity to the San Gorgonio River receiving water during the monitoring year. Wet weather flows sampled at this MS4 outfall station during monitoring activities likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water, due to the soil type and distance to the receiving water (approximately three miles). Therefore, the WQOs associated with the potential MUN beneficial use (e.g., drinking water source) have not been applied to the water quality data from the Ramsey Street Storm Drain MS4 outfall station. Dry Weather Dry weather monitoring for total cadmium was not required at the MS4 outfall stations. Total cadmium was ND for both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station. 8-40

48 Wet Weather The August 26, 2013 sample from the Portola Avenue Storm Drain MS4 outfall station and the November 21, 2013 sample from the Ramsey Street Storm Drain MS4 outfall station had a ND result for total cadmium. These ND results did not impact the beneficial uses of the receiving waters. The October 9, 2013 wet weather sample collected from the Ramsey Street Storm Drain MS4 outfall station had a total cadmium result above the RL (0.57 µg/l). This wet weather flow likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). The total cadmium RL applied for the August 26, 2013 and May 22, 2014 wet weather events differed by an order of magnitude (2.0 to 0.25 µg/l, respectively). At the Avenue 52 Storm Drain MS4 outfall station, total cadmium concentrations were 0.99 µg/l (DNQ estimated concentration) and 0.84 µg/l, respectively. At the CVSC at Avenue 52 Bridge receiving water station, total cadmium concentrations were ND and 0.17 µg/l (DNQ estimated concentration), respectively. The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Chromium (#1180, total; #1181, dissolved) (constituents of concern) In accordance with Table L-1 of the 2008 MS4 Permit, total phase metals are constituents of concern and required to be monitored for permit compliance. The extra analytical results for dissolved chromium presented in Table 8-12 and Table 8-13 are for reference purposes only. The Basin Plan specifies a numeric WQO for total chromium for MUN beneficial use. Based on historical observation and aerial photography, it is unlikely that Ramsey Street Storm Drain MS4 outfall station had hydraulic connectivity to the San Gorgonio River receiving water during the monitoring year. Wet weather flows sampled at this MS4 outfall station during monitoring activities likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water, due to the soil type and distance to the receiving water (approximately three miles). Therefore, the WQOs associated with the potential MUN beneficial use (e.g., drinking water source) have not been applied to the water quality data from the Ramsey Street Storm Drain MS4 outfall station. Dry Weather Dry weather monitoring for total chromium was not required at the MS4 outfall stations. Total chromium was detected above the RL in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (15 and 53 μg/l). These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather The wet weather sample collected from the Portola Avenue Storm Drain MS4 outfall station had a ND result for total chromium and therefore did not impact the intermittent beneficial uses of the receiving water. Total chromium was detected above the RL in both wet weather samples collected at the Ramsey Street Storm Drain MS4 outfall station (17 and 1.3 µg/l). Wet weather flows sampled at the Ramsey Street Storm Drain MS4 outfall station likely evaporated and/or 8-41

49 infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Total chromium was detected above the RL in both wet weather samples collected at the Avenue 52 Storm Drain MS4 outfall station (36 to 52 µg/l). Sampled wet weather flows at the MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Total chromium was detected above the RL in both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (53 and 15 µg/l). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Dissolved Oxygen (DO) (#1435) (field parameter) During the monitoring year, the DO COLD WQO of 8.0 mg/l was applied to the Ramsey Street Storm Drain MS4 outfall station and the DO WARM WQO of 5.0 mg/l was applied to the Avenue 52 Storm Drain outfall. The WARM WQO was only applied to the wet weather data collected at the Portola Avenue Storm Drain MS4 outfall station. Dry Weather The field parameter DO was measured during both dry weather IC/ID monitoring events at the Portola Avenue Storm Drain MS4 outfall station (8.83 mg/l to 9.05 mg/l). Dry weather flows sampled at the Portola Avenue Storm Drain evaporated and/or infiltrated in the absence of flow in the receiving water and, therefore, did not impact beneficial uses of the ephemeral wash receiving water. The WQO was not applicable. The August 20, 2013 dry weather DO measurement at the CVSC at Avenue 52 Bridge receiving water station (2.78 mg/l) was below the WQO minimum concentration of 5.0 mg/l. The February 25, 2014 DO measurement (5.1 mg/l) met the minimum WQO criteria. These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather DO was measured at the MS4 outfall stations during all five monitored wet weather monitoring events at the MS4 outfall stations. The DO concentration measured at the Portola Avenue Storm Drain MS4 outfall station during wet weather (7.6 mg/l) was above the minimum WQO criteria and therefore did not impact the intermittent beneficial uses of the receiving water. Although the DO concentration measured at the Ramsey Street Storm Drain MS4 outfall station (7.31 mg/l) during the November 21, 2013 wet weather event was below the WQO minimum criteria, the wet weather flow sampled likely evaporated and/or infiltrated within ephemeral tributaries and did not reach the San Gorgonio River receiving water. As a result, the reduced DO concentration did not result in impacts to beneficial uses. The October 9, 2013 DO measurement at the Ramsey Street Storm Drain MS4 outfall station was within the WQO range. The DO concentrations measured at the Avenue 52 Storm Drain MS4 outfall station during wet weather events (6.55 and 8.25 mg/l) were greater than the WQO minimums criteria and did not result in impacts to the beneficial uses of the CVSC. 8-42

50 The August 26, 2013 dry weather DO measurement at the CVSC at Avenue 52 Bridge receiving water station (1.2 mg/l) was below the WQO minimum concentration of 5.0 mg/l. The May 22, 2014 DO measurement (5.03 mg/l) met the minimum WQO criteria. Lead (#1290, total; #1287, dissolved) (constituent of concern) In accordance with Table L-1 of the 2008 MS4 Permit, total phase metals are constituents of concern and required to be monitored for permit compliance. The extra analytical results for dissolved lead presented in Table 8-12 and Table 8-13 are for reference purposes only. The Basin Plan specifies a numeric WQO for total lead for MUN beneficial uses. Based on historical observation and aerial photography, it is unlikely that Ramsey Street Storm Drain MS4 outfall station had hydraulic connectivity to the San Gorgonio River receiving water during the monitoring year. Wet weather flows sampled at this MS4 outfall station during monitoring activities likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water, due to the soil type and distance to the receiving water (approximately three miles). Therefore, the WQOs associated with the potential MUN beneficial use (e.g., drinking water source) have not been applied to the water quality data from the Ramsey Street Storm Drain MS4 outfall station. Dry Weather Dry weather monitoring for total lead was not required at the MS4 outfall stations. Total lead was detected above the MDL in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (estimated DNQ results of 0.62 and 1.1 μg/l). These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Total lead concentrations measured in all five wet weather samples collected at the three MS4 outfall stations were above the MDL, ranging from an estimated concentration 0.9 µg/l (DNQ result) to a measured result of 41 mg/l. The highest and lowest total lead concentrations were measured at the Ramsey Street Storm Drain MS4 outfall station. The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Total lead was detected above the RL in both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (36 and 7.8 µg/l). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Total lead concentrations at the 8-43

51 receiving water station were greater than at the MS4 outfall station during the first sampled storm event and visa versa during the second storm event. Mercury (#1310 total; #1316 dissolved) (constituent of concern) In accordance with Table L-1 of the 2008 MS4 Permit, total phase metals are constituents of concern and required to be monitored for permit compliance. The extra analytical results for dissolved mercury presented in Table 8-12 and Table 8-13 are for reference purposes only. The Basin Plan specifies a numeric WQO for total mercury for MUN beneficial uses. Based on historical observation and aerial photography, it is unlikely that Ramsey Street Storm Drain MS4 outfall station had hydraulic connectivity to the San Gorgonio River receiving water during the monitoring year. Wet weather flows sampled at this MS4 outfall station during monitoring activities likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water, due to the soil type and distance to the receiving water (approximately three miles). Therefore, the WQOs associated with the potential MUN beneficial use (e.g., drinking water source) have not been applied to the water quality data from the Ramsey Street Storm Drain MS4 outfall station. Dry Weather Dry weather monitoring for total mercury was not required at the MS4 outfall stations. Total mercury was ND in both of the dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station. Wet Weather The concentrations of total mercury were ND in wet weather samples collected from the Portola Avenue Storm Drain and Avenue 52 Storm Drain MS4 outfall stations. At the Ramsey Street Storm Drain MS4 outfall station, total mercury results were ND and DNQ (0.1 µg/l estimated concentration). These results do not indicate impact to receiving water beneficial uses. Total mercury was ND for both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station. These results do not indicate impact to receiving water beneficial uses. Nitrate as Nitrogen (N) (#1340) (constituent of concern) The Basin Plan specifies a numeric WQO for nitrate for MUN beneficial uses. Based on historical observation and aerial photography, it is unlikely that Ramsey Street Storm Drain MS4 outfall station had hydraulic connectivity to the San Gorgonio River receiving water during the monitoring year. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station during the monitoring activities likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water, due to the soil type and distance to the receiving water (approximately three miles). Therefore, the WQOs associated with the potential MUN beneficial use (e.g., drinking water source) have not been applied to the water quality data from the Ramsey Street Storm Drain MS4 outfall station. 8-44

52 Dry Weather Dry weather monitoring for nitrate was not required at the MS4 outfall stations. Nitrate was detected at concentrations above the RL in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (3.61 and 3.4 mg/l). The result for the August 20, 2013 dry weather event was calculated for nitrate as N (3.61 mg/l) from the laboratory reported value for nitrate as NO3 (16 mg/l) using the methodology defined by the California Division of Drinking Water (California Department of Health, 2014). These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Concentrations of nitrate collected during wet weather at the three MS4 outfall stations were above the RL, with concentrations ranging from 1.1 to 4.3 mg/l. The result for the May 22, 2014 dry weather event at the Avenue 52 Storm Drain MS4 outfall station was calculated for nitrate as N (4.07 mg/l) from the laboratory reported value for nitrate as NO3 (18 mg/l) using the methodology defined by the California Division of Drinking Water (California Department of Health, 2014). The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Nitrate was detected above the RL in both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (4.3 and 3.61 mg/l). The result for the May 22, 2014 wet weather event was calculated for nitrate as N (3.61 mg/l) from the laboratory reported value for nitrate as NO3 (16 mg/l) using the methodology defined by the California Division of Drinking Water (California Department of Health, 2014). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Nitrate results were similar at the two monitoring stations. Nitrite as Nitrogen (N) (#1345) (constituent of concern) The Basin Plan does not specify a numeric WQO for nitrite. Dry Weather Dry weather monitoring for nitrite was not required at the MS4 outfall stations. Nitrite was detected above the RL in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (0.39 and 0.67 mg/l). These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). 8-45

53 Wet Weather Wet weather nitrite concentrations at the Ramsey Street Storm Drain station were ND or DNQ (0.07 mg/l, estimated concentration). The May 22, 2014 wet weather sample from the Avenue 52 Storm Drain outfall station was DNQ for nitrite (0.046 mg/l, estimated concentration). These results do not indicate impact to receiving water beneficial uses. Nitrite concentrations in two samples collected during wet weather monitoring were measured above the RL (0.16 mg/l at the Avenue 52 Storm Drain; 0.11 mg/l at the Portola Avenue Storm Drain). The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Nitrite was detected above the RL in both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (0.39 and 0.67 mg/l). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Concentrations at the receiving water station were greater than at the MS4 outfall station. Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Nitrite results were similar at the two monitoring stations. Nitrogen, Total Kjeldahl (TKN) (#1360) (constituent of concern) The Basin Plan does not specify a numeric WQO for TKN. Dry Weather Dry weather monitoring for TKN was not required at the MS4 outfall stations. The concentration of TKN was detected above the RL in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (17 and 20 mg/l). These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather TKN concentrations in wet weather samples collected at the three MS4 outfall stations were above the RL in all five samples, with concentrations ranging from 2.2 mg/l to 8.9 mg/l. The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. TKN was detected above the RL in both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (8.2 and 20 mg/l). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Concentrations at the receiving water station were greater than detected at the MS4 outfall station. 8-46

54 Nitrogen (total) (#1355) (constituent of concern) The Basin Plan does not specify a numeric WQO for total nitrogen. Dry Weather Dry weather monitoring is not required for nutrients and, therefore, the total nitrogen concentration was not calculable for the MS4 outfall stations. Total nitrogen was calculated for both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (21.6 and 23.8 mg/l). These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Assessment of wet weather data for the three MS4 outfall stations included calculation of total nitrogen concentrations for all five samples, with concentrations ranging from 3.3 mg/l to mg/l. The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Total nitrogen concentrations were calculated for wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (12.9 and 24.3 mg/l). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Concentrations at the receiving water station were greater than detected at the MS4 outfall station. ph (# 1705, field; #1710, lab) (field parameter) The Basin Plan specifies a ph range of 6.0 to 9.0 ph units as the WQO for ph. Dry Weather ph was measured in the field for both dry weather samples collected at Portola Avenue Storm Drain MS4 outfall station (8.0 to 8.3 ph units). All ph measurements were within the WQO range. ph was measured in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (7.3 and 7.5 ph units). All dry weather ph measurements were within the WQO range. Wet Weather Wet weather ph measurements at the three MS4 outfall stations ranged between 7.27 ph units to 7.6 ph units. All wet weather ph measurements were within the WQO range. ph was measured in both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (7.2 and 7.38 ph units). All ph measurements were within the WQO range. 8-47

55 Phosphorus, Ortho (#1480) (constituent of concern) The Basin Plan does not specify a numeric WQO for orthophosphorus. Dry Weather Dry weather monitoring for orthophosphorus was not required at the MS4 outfall stations. The concentration of orthophosphorus was measured above the RL in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (5.83 and 1.8 mg/l). These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Orthophosphorus concentrations measured in samples collected during wet weather monitoring at the three MS4 outfall stations were above the RL in all five samples, with results ranging from 0.11 mg/l to 2.09 mg/l). The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Orthophosphorus concentrations measured in wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (0.39 and 6.36 mg/l). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Orthophosphorus concentrations at the receiving water station were greater than detected at the MS4 outfall station. Phosphorus (total) (#1485, total; #1490, dissolved) (constituent of concern) The Basin Plan does not specify a numeric WQO for total phosphorus. Dry Weather Dry weather monitoring for total phosphorus was not required at the MS4 outfall stations. Concentrations of total phosphorus were detected above the RL in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (1.9 to 2.2 mg/l). The sample collected on August 20, 2013 was independently analyzed by two laboratories; the total phosphorus concentration (1.9 mg/l) reported by both of the laboratories. These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Total phosphorus was measured in samples collected during wet weather events for the three MS4 outfall stations, with concentrations ranging from 0.18 mg/l to 3.7 mg/l. The wet weather sample collected at the Avenue 52 Storm Drain outfall station on May 22, 2014 was analyzed by 8-48

56 two laboratories and similar total phosphorus concentration reported (0.68 and 2.6 mg/l). The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Total phosphorus concentrations measured in wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station were above the RL, with reported results ranging from 2.08 mg/l to 3.2 mg/l. The sample collected on May 22, 2014 was independently analyzed by two laboratories and similar total phosphorus concentration reported (2.08 and 2.5 mg/l). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Total phosphorus concentrations were similar at the two monitoring stations. Selenium (#1520, total; #1521, dissolved) (constituent of concern) In accordance with Table L-1 of the 2008 MS4 Permit, total phase metals are constituents of concern and required to be monitored for permit compliance. The extra analytical results for dissolved selenium presented in Table 8-12 and Table 8-13 are for reference purposes only. The Basin Plan specifies a numeric WQO for total selenium for MUN beneficial uses. Based on historical observation and aerial photography, it is unlikely that Ramsey Street Storm Drain MS4 outfall station had hydraulic connectivity to the San Gorgonio River receiving water during the monitoring year. Wet weather flows sampled at this MS4 outfall station during monitoring activities likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water, due to the soil type and distance to the receiving water (approximately three miles). Therefore, the WQOs associated with the potential MUN beneficial use (e.g., drinking water source) have not been applied to the water quality data from the Ramsey Street Storm Drain MS4 outfall station. Dry Weather Dry weather monitoring for total selenium was not required at the MS4 outfall stations. Total selenium concentrations measured in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station were ND. These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Total selenium was ND at the Portola Avenue Storm Drain MS4 outfall station and the Ramsey Street Storm Drain MS4 outfall station. These results do not indicate impact to receiving water beneficial uses. The total selenium RL applied for the August 26, 2013 and May 22, 2014 wet weather events differed (5.0 to 1.0 µg/l, respectively). At the Avenue 52 Storm Drain MS4 outfall station and the CVSC at Avenue 52 Bridge receiving water station, total selenium concentrations were ND 8-49

57 during the first wet weather event. During the May 22, 2014 wet weather event, total selenium was detected above the RL (2.0 µg/l at the MS4 outfall station; 2.1 µg/l at the receiving water station). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Specific Conductance (#1200) (field parameter) The Basin Plan does not specify a numeric WQO for specific conductance. Dry Weather The two dry weather measurements of specific conductance from the Portola Avenue Storm Drain MS4 outfall station ranged from 741 microsiemens per centimeter [µs/cm] to 1,088 µs/cm. Due to the dry conditions in the WWR during the monitoring year, these sampled dry weather flows likely evaporated and/or infiltrated without reaching the receiving waters. There were no impacts to beneficial uses. Specific conductance was measured in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (1,100 µs/cm and 1,210 µs/cm). These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Specific conductance was measured at the three MS4 outfall stations during wet weather events, with concentrations ranging from 143 µs/cm to 732 µs/cm. Conductance was lower during wet weather events compared to the dry weather events. The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Specific conductance was measured in both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (899 µs/cm and 1,084 µs/cm). These dry weather measurements represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Temperature (#1655) (field parameter) The Basin Plan does not specify a numeric WQO for temperature. Dry Weather The two dry weather measurements of temperature from the Portola Avenue Storm Drain MS4 outfall station ranged from 21.3 Celsius to 25.1 Celsius. Due to the dry conditions in the WWR during the monitoring year, all dry weather flows monitored likely evaporated and/or infiltrated without reaching the receiving waters. There were no impacts to beneficial uses. 8-50

58 Temperature was measured in both dry weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (19.9 and 28 Celsius). These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Temperature was measured at the three MS4 outfall stations during wet weather events, with levels ranging from Celsius to 27.6 Celsius. The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Temperature was measured in both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (22.9 and 25.6 Celsius). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. TDS (Total Dissolved Solids) (#1625) (constituent of concern) The Basin Plan does not specify a numeric WQO for TDS. Dry Weather Dry weather monitoring for TDS was not required at the MS4 outfall stations. TDS concentrations were measured above the RL in the February 25, 2014 dry weather sample collected at the CVSC at Avenue 52 Bridge receiving water station (740 mg/l). Due to a recording error, TDS was not included on the chain of custody submitted to the laboratory during the August 20, 2013 dry weather event and not analyzed for this constituent. These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather TDS concentrations were measured above the RL in all five wet weather samples collected at the three MS4 outfall stations, ranging from 140 mg/l to 360 mg/l. The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. TDS concentrations were measured above the RL in both wet weather samples collected at the CVSC at Avenue 52 Bridge receiving water station (640 and 800 mg/l). The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. TDS concentrations at the receiving water station were greater than detected at the MS4 outfall station. 8-51

59 Turbidity (#1690, field; #1695, lab) (field parameter) The Basin Plan does not specify a numeric WQO for turbidity. Dry Weather The two dry weather measurements of turbidity from the Portola Avenue Storm Drain MS4 outfall station ranged from 3.2 nephelometric turbidity units (NTU) to 5.4 NTU. Due to the dry conditions in the WWR during the monitoring year, all dry weather flows monitored evaporated and/or infiltrated without reaching the receiving waters. There were no impacts to beneficial uses. Dry weather turbidity measurements conducted at the CVSC at Avenue 52 Bridge receiving water station ranged from 8.7 NTU and 26.1 NTU. These dry weather results represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Turbidity was measured in wet weather samples collected at the three MS4 outfall stations, with results ranging from 100 NTU to 1,000 NTU. The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water (three miles downstream). Sampled wet weather flows at the Avenue 52 Storm Drain MS4 outfall station may have been sufficient to reach flows observed in the CVSC receiving water. Turbidity wet weather field measurements in samples collected at the CVSC at Avenue 52 Bridge receiving water station ranged from 9.9 NTU to 1,700 NTU. The receiving water station is located upstream of the MS4 outfall station and characterizes background conditions in the CVSC. Turbidity concentrations at the receiving water station were greater than at the MS4 outfall station during the first sampled storm event and visa versa during the second storm event. Never or Seldom Detected Constituents Attachment G lists constituents or compounds that have not been detected at any monitoring station during the 1996, 2001, or 2008 MS4 Permit monitoring periods. In accordance with the 2008 MS4 Permit, MDLs are based on State Water Resources Control Board (SWRCB) minimum levels, if applicable and depending on laboratory capability. The monitoring year was the first that SWRCB minimum levels for detection limits were required under the 2008 MS4 Permit. As a result, previous data may have had lower or higher MDLs, based on methods of analysis and laboratory capability. Analytical methods listed in Attachment C are provided as requested methods and may not represent the methods actually used by the laboratory, as provided on the table of monitored parameters, also available in Attachment C. 8-52

60 8.7 INTEGRATED ANALYSIS An integrated analysis in accordance with reporting requirements C and D of the MRP is presented in the subsections below. Applicable WQOs were determined based on the beneficial uses, HUC, and receiving water of each monitoring station (see Table 8-9 and Table 8-10, above). Although the WQOs apply only to reaches of receiving waters and do not directly apply to MS4 discharges to receiving waters (as measured at the MS4 outfalls), the comparisons of MS4 outfall station monitoring results to WQOs are provided to fulfill MRP requirements and to determine whether MS4 discharges may potentially contribute to water quality exceedances in the receiving waters. This Monitoring Annual Report applied WQOs to each monitoring station as described in Section WATER QUALITY PARAMETERS MEASURED OUTSIDE THE NORMAL RANGE Provision L.12.C of the 2008 MS4 Permit requires the Permittees to identify monitoring event sample results that are outside the normal ranges for specific parameters based on historical water quality data. Provision L.12.C of the 2008 MS4 Permit labels this analysis as "acute water quality problems." An acute water quality problem as used in the MRP does not align with the technical use of the term (i.e., related to water toxicity) in state regulations. The discussion presented below does not include an analysis of water toxicity, cannot link water quality results with toxicity, and does not necessarily indicate a determination of an actual water quality problem. To avoid misinterpretation, the label, "acute water quality problem" has not been used in this document. This document fulfills reporting requirement C through a discussion of constituents above the WQO for identification of results outside the normal range based on historical data, as discussed below. Individual parameter results for samples collected during the monitoring year are discussed in Section The data are included in the graphs and tables in Attachment D and Attachment E, respectively. The majority of the water quality constituents measured during the monitoring year did not exceed WQOs. Where constituents did exceed WQOs, those exceedances did not occur during all sampling events. Exceedances of applicable WQOs include the following: E. coli results exceeded the applicable REC-1 and REC-2 WQOs for all wet weather samples collected from the CVSC at Avenue 52 Bridge receiving water station and the three MS4 outfall stations. Due to the dry conditions in the WWR during the monitoring year, the wet weather MS4 outfall discharge likely evaporated and/or infiltrated within ephemeral tributaries. Also, site conditions (e.g., difficult site access, fencing, etc.) made recreational activities highly unlikely. The DO concentrations measured at the CVSC at Avenue 52 Bridge receiving water station during the August 20, 2013 dry weather event and the August 26, 2013 wet weather event were below the WARM WQO minimum criteria (5.0 mg/l). This result reflects background conditions (i.e., permitted discharges from the VSD WWTP) because the receiving water station is located upstream of the point where the Avenue 52 Storm Drain outfall discharges to the CVSC. The November 21, 2014 wet weather sample from the Ramsey Street Storm Drain MS4 outfall station had a DO concentration less than the 8-53

61 COLD WQO minimum criteria (8.0 mg/l). Flow from the Ramsey Street Storm Drain likely evaporated and/or infiltrated within ephemeral tributaries, never reaching the San Gorgonio River receiving water. In accordance with Reporting Requirement C, a normal range analysis was conducted for parameters with water quality exceedances during the monitoring year, including E. coli and DO. The normal range analysis was based on historical water quality data (e.g., monitoring data collected through the monitoring year). Data collected in subsequent years will allow the Permittees to provide a better definition of what constitutes a normal range for a particular constituent as measured in the WWR. The definition of normal range and, therefore, constituents flagged for being measured outside the normal range, will continue to evolve as the WWR monitoring program continues to collect additional data. E. coli: WWR Historical Range and Historical Mean Results Samples collected in the WWR have been analyzed for E. coli since Descriptive E. coli statistics, including the annual and overall range, are included in Attachment E. Given the limited total number of samples collected due to arid conditions within the WWR and the high variability for stormwater runoff samples, the historical range and historical mean calculated for each monitoring station are descriptive. As more data become available, these descriptive statistics will change. The historical range and historical mean E. coli results for each MS4 outfall and receiving water station are presented in Table The overall historical means (combined dry weather and wet weather results) for E. coli for the Avenue 52 Storm Drain outfall station and the CVSC at Avenue 52 Bridge receiving water station are 3,526 MPN/100mL and 1,084 MPN/100mL, respectively (an order of magnitude greater than the REC-1 WQO of 400 MPN/100mL). The overall historical mean for E. coli for the Ramsey Street Storm Drain MS4 outfall station is 6,240 MPN/100mL (an order of magnitude greater than the REC-1 WQO of 400 MPN/100mL). The overall historical mean for E. coli for the Portola Avenue Storm Drain MS4 outfall station is 2,934 MPN/100mL. Table 8-15: Normal Range for E. coli (Constituent of Concern) Monitoring Station (Station ID) Ramsey Street Storm Drain (719RMS782) Avenue 52 Storm Drain (719AVE785) Upper Whitewater River at Canyon Road Crossing (719WWT813) Portola Avenue Storm Drain (719POR817) CVSC at Avenue 52 Bridge (719CVS884) Dry Weather Wet Weather Overall Normal Normal Mean Mean Mean Range Range N (MPN/ N (MPN/ (MPN/ (MPN/ (MPN/ 100mL) 100mL) 100mL) 100mL) 100mL) 1 N/A N/A 9 ND 23,000 5,711 6, , ,000 30,000 7,100 3,526 No flow was observed at Golf Center Parkway during the monitoring year; therefore, no samples were collected. 11 ND ,700 17,000 6,747 2, (a) ,000 2,061 1,

62 Notes for Table 8-15: Normal range for E. coli data through the monitoring year. N/A Not applicable. Insufficient data has been collected to establish a normal range and historical mean value. ND Not detected. N Sample size. (a) E. coli monitoring data collected by the Regional Board in support of the CVSC Bacterial Indicator TMDL (February-September 2003) fall within this normal range. E. coli in the Whitewater River Receiving Water The Portola Avenue Storm Drain MS4 outfall station is tributary to a wash in the Whitewater River, and the receiving water was dry during monitored dry weather events, therefore, the intermittent REC-2 WQO did not apply due to a lack of flow in the receiving water. Dry weather E. coli concentrations were greater than the dry weather historical mean concentration (507 MPN/100mL). E. coli concentrations were within the normal range. Flow sampled at the Portola Avenue Storm Drain evaporated and/or infiltrated in the absence of flow in the receiving water and, therefore, did not impact intermittent beneficial uses. The E. coli concentration for the August 26, 2013 wet weather sample from the Portola Avenue Storm Drain MS4 outfall station (79,000 MPN/100mL) was greater than the upper limit of the normal range (17,000 MPN/100mL) and exceeded the REC-2 WQO. The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. E. coli in the San Gorgonio River Receiving Water All dry weather events at the Ramsey Street Storm Drain MS4 outfall station were VNS for the monitoring year; therefore, a normal range analysis could not be completed. The wet weather sample collected at the Ramsey Street Storm Drain MS4 outfall station on October 9, 2013 had an E. coli concentration (23,000 MPN/100mL) equal to the upper limit of the normal range. The November 11, 2013 E. coli concentration (5,000 MPN/100mL) was within the normal range and less than the historical mean concentration. Flows sampled at the Ramsey Street Storm Drain MS4 outfall station also likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water. E. coli in the CVSC Receiving Water No dry weather samples were collected at the Avenue 52 Storm Drain MS4 outfall station during the monitoring year because the MS4 outfall was dry (VNS) during all dry weather site visits. The E. coli concentration for the February 25, 2014 dry weather sample collected at the CVSC at Avenue 52 Bridge receiving water station (1.8 MPN/100mL) is an order of magnitude smaller than the lower limit of the normal range (79 MPN/100mL). The dry weather E. coli concentration for August 20, 2013 was within the normal range and less than the historical mean concentration. These dry weather monitoring data reflects background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). 8-55

63 The E. coli concentration for the August 26, 2013 wet weather sample from the Avenue 52 Storm Drain MS4 outfall station was approximated by the laboratory (>1,600 MPN/100mL); therefore, the exact relationship of this sample result with the historical normal range cannot be determined. The E. coli concentration for the wet weather sample from the upstream CVSC at Avenue 52 Bridge receiving water station (33,000 MPN/100mL) was approximately five times greater than the upper limit of the normal range (7,000 MPN/100mL). The May 22, 2014 wet weather sample from the Avenue 52 Storm Drain MS4 outfall station had an E. coli concentration (49,000 MPN/100mL) that was greater than the upper limit of the normal range (30,000 MPN/100mL). At the upstream receiving water station, E. coli levels were within the normal range (200-7,000 MPN/100mL). E. coli levels for all wet weather samples collected from the CVSC MS4 outfall and receiving water stations during the monitoring year exceeded the REC-1 WQO. The CVSC at Avenue 52 Bridge receiving water station is located upstream of the Avenue 52 Storm Drain MS4 outfall station, and therefore the MS4 outfall does not contribute to the DO concentration at the CVSC receiving water station. The wet weather monitoring data for the receiving water station reflect background conditions of the CVSC. Dissolved Oxygen (DO): WWR Historical Range and Historical Mean Results Field measurements of DO concentrations have been conducted at the Ramsey Street Storm Drain MS4 outfall station since DO was measured at all other monitoring stations starting in the monitoring year. Descriptive statistics of the DO concentration, including the annual and overall range, are included in Attachment E. The historical range and historical mean DO concentrations for each monitoring station are presented in Table The overall historical means (combined dry weather and wet weather results) for DO for the Avenue 52 Storm Drain MS4 outfall station and CVSC at Avenue 52 Bridge receiving water station are 7.44 mg/l and 5.02 mg/l, respectively (greater than the WARM WQO minimum criteria of 5.0 mg/l). The overall historical mean DO concentration for the Ramsey Street Storm Drain MS4 outfall station is 9.05 (greater than the COLD WQO minimum criteria of 8.0 mg/l). The overall historical mean DO concentration for the Portola Avenue Storm Drain MS4 outfall station is 9.07 mg/l. Table 8-16: Normal Range for Dissolved Oxygen (DO) (Field Parameter) Monitoring Station (Station ID) Avenue 52 Storm Drain (719AVE785) CVSC at Avenue 52 Bridge (719CVS884) Portola Avenue Storm Drain (719POR817) Upper Whitewater River at Canyon Road Crossing (719WWT813) Ramsey Street Storm Drain (719RMS782) Dry Weather Wet Weather Overall Normal Normal Mean Mean Mean N Range N Range (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) No flow was observed at Golf Center Parkway during the monitoring year; therefore, no samples were collected

64 Notes for Table 8-16: N/A Not applicable. There is insufficient data to establish a normal range and historical mean value. ND Not Detected. N Sample size. DO in the Whitewater River Receiving Water The Portola Avenue Storm Drain MS4 outfall station is tributary to a wash in the Whitewater River, and the receiving water was dry during monitored dry weather events, therefore, the intermittent WARM WQO did not apply due to a lack of flow in the receiving water. Dry weather DO measurements were within the normal range. Flow sampled at the Portola Avenue Storm Drain evaporated and/or infiltrated in the absence of flow in the receiving water and, therefore, did not impact intermittent beneficial uses. Although the August 26, 2013 wet weather DO measurement for the Portola Avenue Storm Drain MS4 outfall station (7.4 mg/l) was slightly below the normal range, DO was greater than the WARM WQO minimum criteria (5.0 mg/l). The low flow sampled at the Portola Avenue Storm Drain MS4 outfall station (0.85 cfs) likely evaporated and/or infiltrated without impacting the intermittent beneficial uses of the receiving water. DO in the San Gorgonio River Receiving Water All dry weather events at the Ramsey Street Storm Drain MS4 outfall station were VNS for the monitoring year; therefore, a comparison to the normal range could not be completed. The DO measurements for both wet weather samples from the Ramsey Street Storm Drain MS4 outfall station were within the normal range. The November 21, 2013 result of 7.31 mg/l was below the COLD WQO minimum criteria (8.0 mg/l). Flows sampled at the Ramsey Street Storm Drain MS4 outfall station likely evaporated and/or infiltrated within ephemeral tributaries prior to reaching the San Gorgonio River receiving water. DO in the CVSC Receiving Water No dry weather samples were collected at the Avenue 52 Storm Drain MS4 outfall station during the monitoring year because the MS4 outfall was dry (VNS) during all dry weather site visits. The August 20, 2013 dry weather sample from the at the CVSC at Avenue 52 Bridge receiving water station had a DO concentration (2.78 mg/l) slightly below lower limit of the normal range. This sample concentration was also below the WARM WQO minimum criteria (5.0 mg/l). The February 25, 2014 dry weather DO measurement was within the normal range and was above the WQO minimum criteria. These dry weather monitoring data reflects background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). The DO measurements for both wet weather samples from the CVSC at Avenue 52 MS4 outfall station were within the normal range and above the WARM WQO minimum criteria. At the CVSC at Avenue 52 Bridge receiving water station, the August 26, 2013 wet weather DO concentration (1.2 mg/l) was less than the lower limit of the normal range (2.75 mg/l) and below the WQO minimum criteria (5.0 mg/l). The May 22, 2014 wet weather DO measurement was within the normal range and met the WQO minimum criteria. These wet weather monitoring data reflect background conditions of the CVSC receiving water. 8-57

65 8.7.2 MANN-KENDALL LONG-TERM TREND ANALYSIS Provision L.12.D of the 2008 MS4 Permit requires the Permittees to identify long-term trends in stormwater and receiving water quality. Graphical summaries of the water quality data collected between 1993 and 2013 are provided as Attachment D to this Monitoring Annual Report (electronic version only). The number of samples collected was limited due to arid conditions. In addition, the typical high variability of the quality of stormwater samples limits the Permittees' ability to identify statistically significant trends from the monitoring data. The historical monitoring data were analyzed for statistically significant trends using a nonparametric Mann-Kendall test for linear trend. The Mann-Kendall trend analysis was conducted on the historical monitoring datasets as follows: Wet weather trends were run for all MS4 outfall and receiving water stations. Identification of long-term dry weather trends for the MS4 outfall stations is not required by the 2008 MS4 Permit and is not presented here. The data were organized by station, date of collection, and type of monitoring event (dry weather or wet weather). Historical parameters for which monitoring has been discontinued and parameters with fewer than three years of data were excluded from this trend analysis. The data were screened for parameters monitored during the monitoring year and assessed to determine the proportion of results below the MDL for each parameter (i.e., ND results). Parameters with more than 50% ND results were removed from the trend analysis because they do not meet the assumptions of the Mann-Kendall analysis (Mann, 1945; Kendall, 1975). For parameters with 49% ND results or less, a numeric value equal to half the RL was assigned to ND results. The nonparametric Mann-Kendall test for linear trend was used to evaluate whether the parameter had increased or decreased significantly since the start of monitoring, based on a 95% confidence level (e.g., a 5% probability of obtaining a test statistic, or a p-value of less than 0.05). Trend results were QA/QCed in the context of the period of record. Where recent ND results appeared to drive a trend (e.g., half the RL was greater than historically reported results), the data were re-analyzed using the MDL as the numeric value for ND results. If the trend could not be confirmed through this re-assessment, the trend was considered invalid and not presented in Table 8-17 or Table Sen's slope, a non-parametric estimator of the magnitude of the change in parameter concentration over time (Sen, 1968), was calculated for parameters with statistically significant trends. Sen's slope could only be calculated if the proportion of samples assessed below the MDL (i.e., ND results) was less than 15% (Sen, 1968). 8-58

66 Mann Kendall Trends Dry Weather Dry weather monitoring is not required at the Upper Whitewater River at Canyon Road Crossing receiving water station, and the site was dry for the duration of the monitoring year. Statistically significant long-term dry weather trends identified for the CVSC at Avenue 52 Bridge receiving water station are presented in Table Three nutrients, including nitrite (pvalue of 0.022), TKN (p-value of ) and total nitrogen (p-value of 0.016), were found to have statistically significant dry weather trends indicating increasing concentrations in the water column. The magnitude of these trends range from 0.03 mg/l per year (nitrite) to 1.0 mg/l per year (TKN and total nitrogen). Total nitrogen is a calculated value based on other nitrogenbased nutrients. These dry weather trends reflect background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Table 8-17: Mann-Kendall Long-Term Dry Weather Water Quality Trends Monitoring Station (Station ID) CVSC at Avenue 52 Bridge (719CVS884) ND Not detected Parameter Trend p-value ND Percent Sen's Slope Nitrite as Nitrogen (N) up % Total Kjeldahl Nitrogen (TKN) up % 1.00 Total Nitrogen up %

67 Mann-Kendall Trends Wet Weather During the monitoring year, no samples were collected at the Upper Whitewater River at Canyon Road Crossing receiving water station and no trend analysis was performed. Statistically significant long-term trends for wet weather constituent concentrations measured in samples from the MS4 outfall stations and CVSC at Avenue 52 Bridge receiving water station are presented in Table Wet weather trends differed between monitoring stations, and more trends were found for the MS4 outfall stations than in the CVSC receiving water. Five statistically significant wet weather trends were identified for the Ramsey Street Storm Drain MS4 outfall station. The three statistically significant decreasing trends for total metals (barium - p-value of 0.006; chromium - p-value of 0.029; lead - p-value of 0.001) indicate decreasing concentrations in the water column with time and therefore water quality improvement. The decreasing trend for DO (p-value of 0.039) has a magnitude of -0.2 mg/l per year. An increasing trend for temperature (p-value of 0.018) was also observed. Based on historical observations, wet weather flows sampled at the Ramsey Street Storm Drain MS4 outfall station likely evaporate and/or infiltrate within miles of dry ephemeral tributaries prior to reaching the San Gorgonio River receiving water without impacting beneficial uses. Three statistically significant wet weather trends were identified for the Portola Avenue Storm Drain MS4 outfall station, including increasing trends for temperature (p-value of 0.038) and turbidity (p-value of 0.032) and a decreasing trend for DO (p-value of 0.009). The magnitude of the DO trend is mg/l per year. The monitoring year result (7.4 mg/l) represents the lowest DO measurement to date at this MS4 outfall station; however, the results are greater than the WARM WQO minimum criteria (5.0 mg/l). Wet weather flows generally evaporate and/or infiltrate in the ephemeral receiving water without impacting intermittent beneficial uses. Nine statistically significant wet weather trends were identified for the Avenue 52 Storm Drain MS4 outfall station. Increasing trends for total phosphorus (p-value of 0.030) and turbidity (pvalue of 0.011) were observed, but there are not water quality criteria available to evaluate these trends. The decreasing trend for DO (p-value of 0.014) has a magnitude of mg/l per year. During the monitoring year, both wet weather DO measurements met the WARM WQO (5.0 mg/l), which indicates that this trend does not signify a likely risk to the beneficial uses of the CVSC from DO. Similarly, the increasing trends for total metals, including total arsenic (p-value of 0.038), total barium (p-value of 0.030), total chromium (pvalue of 0.024), and total lead (p-value of 0.038), and the decreasing trend for ph (p-value of 0.030), are relatively low in magnitude, and therefore, may indicate only a slight change in water quality. A statistically significant increasing trend for specific conductance (p-value of 0.019) was observed for the CVSC at Avenue 52 Bridge receiving water station. 8-60

68 Table 8-18: Mann-Kendall Long-Term Wet Weather Water Quality Trends Monitoring Station (Station ID) Avenue 52 Storm Drain (719AVE785) Portola Avenue Storm Drain (719POR817) Ramsey Street Storm Drain (719RMS782) CVSC at Avenue 52 Bridge (719CVS884) ND Not detected Parameter Trend p- value ND Percent Sen's Slope Arsenic, Total up % 5.73E-04 Barium, Total up % Chromium, Total up % Dissolved Oxygen (DO) down % Lead, Total up % Nitrate as Nitrogen (N) up % ph down % Total Phosphorus up % Turbidity up % Dissolved Oxygen (DO) down % Water Temperature up % Turbidity up % Barium, Total down % - Chromium, Total down % - Dissolved Oxygen (DO) down % Lead, Total down % Water Temperature up % Specific Conductance up % ANALYSIS OF MANN-KENDALL LONG-TERM TRENDS IN RELATION TO WQO EXCEEDANCES Provision L.12.D of the 2008 MS4 Permit requires the Permittees to identify and analyze longterm trends in stormwater and receiving water quality. Provision L.12.D of the 2008 MS4 Permit identifies this as an analysis for signs of "chronic water quality problems." Similar to the discussion for Section 8.7.1, the label "chronic water quality problem" as used in the MRP does not align with the technical use of the term (i.e., related to water toxicity) in state regulations. The discussion presented below does not relate water quality and water toxicity, nor do the longterm trends identified in Table 8-17 and Table 8-18 indicate a determination of an actual water quality problem. For the purposes of this document, the label "chronic water quality problem" is not used, but rather the descriptive guidance in the 2008 MS4 Permit is applied. The Permittees used the following definition to determine parameters for which analysis is appropriate: "A constituent for which a given waterbody frequently experiences exceedances of receiving water WQOs, or for which there is an established TMDL for a particular waterbody." 8-61

69 Most of the water quality constituents measured during the monitoring year did not exceed WQOs in either receiving water or MS4 outfall stations. For those constituents that had an exceedance of the WQOs in the monitoring year (E. coli and DO), Table 8-19 lists the total number of WQO exceedances since , the first monitoring year of the 2008 MS4 Permit. (Note that the monitoring year is also when E. coli sampling began in the WWR. See Attachment E.) Since no samples were collected at the Upper Whitewater River at Canyon Road Crossing receiving water station during the monitoring year or the previous years, a similar analysis for this receiving water station has not been provided. Table 8-19: Total Number of Samples (n) and Percent (%) Results Above the Basin Plan WQOs for Parameter E. coli Dissolved Oxygen (DO) Monitoring WQO Station ID DRY WET OVERALL n % Exceed n % Exceed n % Exceed 719AVE MPN/ 8 13% 9 100% 17 59% 719CVS mL 12 8% 9 89% 21 43% 719POR817 (a) 12 N/A 8 63% WWT813 N/A 0 N/A RMS MPN/ 100mL (b) 1 100% 10 80% 11 82% 719AVE % 9 0% 21 5% 5 mg/l 719CVS % 9 44% 22 64% 719POR817 (a) 16 N/A 8 0% WWT813 N/A 17 N/A RMS782 8 mg/l (b) 8 38% 16 38% 24 38% N/A Not applicable. (a) The WQOs for washes (ephemeral stream) only apply to Portola Avenue Storm Drain MS4 outfall station if sufficient flow exists. Flow was observed in the receiving water adjacent to the MS4 outfall station during monitorable wet weather events but not during dry weather events. WQOs were only applied to wet weather monitoring data. (b) This COLD WQO is for the San Gorgonio River receiving water, which is located several miles downstream of the Ramsey Street Storm Drain MS4 outfall station. 8-62

70 E. coli in the CVSC Receiving Water Dry Weather Since 2008, only one dry weather sample (13%, Table 8-19) from the Avenue 52 Storm Drain MS4 outfall station has had E. coli levels above the REC-1 WQO. The MS4 outfall station was dry (VNS) during IC/ID dry weather monitoring events of the monitoring year. The City of Coachella has constructed a dry well to divert dry weather flows from the Avenue 52 Storm Drain and this system appears to be operating as designed. There were no dry weather impacts to the beneficial uses of the CVSC receiving water during the monitoring year, and the historic data suggest that existing BMPs are protective of water quality. There were no dry weather exceedances of the REC-1 WQO at the CVSC at Avenue 52 Bridge receiving water station during the monitoring year. Since 2008, there has only been one dry weather WQO exceedance (8%, Table 8-18) and one dry weather result equal to the WQO. The Mann-Kendall analysis did not find statistically significant increasing or decreasing trends for E. Coli. Data from CVSC at Avenue 52 Bridge receiving water station represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Wet Weather Since 2008, all nine of the wet weather samples from the Avenue 52 Storm Drain MS4 outfall station and eight of nine wet weather samples from the CVSC at Avenue 52 Bridge receiving water station have had E. coli concentrations above the REC-1 WQO (Table 8-18). The Mann- Kendall analysis did not find statistically significant increasing or decreasing trends for E. Coli for either of these stations. Data from CVSC at Avenue 52 Bridge receiving water station represent background conditions in the CVSC (i.e., permitted discharges from the VSD WWTP). Starting in January 2013, monthly E. coli monitoring and site photo documentation was conducted at the Avenue 52 Storm Drain MS4 outfall station (Coachella Site 3) as outlined in the 2012 QAPP and Bacterial Indicator Monitoring Plan for Outfalls Entering the CVSC. The results of this monitoring are reported to the Regional Board by the City of Coachella on a quarterly basis. E. coli in the Whitewater River Receiving Water Dry Weather The Portola Avenue Storm Drain MS4 outfall station is tributary to a wash in the Whitewater River and the receiving water was dry during monitored dry weather events, therefore, the intermittent REC-2 WQO did not apply due to a lack of flow in the receiving water. Flow sampled at the Portola Avenue Storm Drain likely evaporated and/or infiltrated in the absence of flow in the receiving water and, therefore, did not impact intermittent beneficial uses. Wet Weather During the period of record, five wet weather samples had E. coli levels greater than REC-2 WQO, including the August 26, 2013 wet weather sample (63%, Table 8-19). The Mann- Kendall analysis did not find statistically significant trends for E. Coli for this monitoring station. Generally, wet weather flows sampled at the Portola Avenue Storm Drain evaporate and/or 8-63

71 infiltrate into the adjacent wash and suggests that these results do not impact the intermittent beneficial uses of the receiving water. E. coli in the San Gorgonio River Receiving Water Dry Weather No dry weather samples were collected at the Ramsey Street Storm Drain MS4 outfall station during the monitoring year. Historically, the Ramsey Street Storm Drain has no flow during dry weather and monitored flows likely evaporated and/or infiltrated within ephemeral tributaries and did not reach the San Gorgonio River receiving water. Wet Weather During the period of record, eight wet weather samples collected at the Ramsey Street Storm Drain MS4 outfall station had E. coli concentrations greater than the REC-1 WQO (80%, Table 8-19), including both wet weather samples from the monitoring year. There are no statistically significant long-term trends for E. coli for this monitoring station. Wet weather flows monitored at this MS4 outfall generally evaporate and/or infiltrate within ephemeral tributaries and did not reach the San Gorgonio River receiving water. DO in the CVSC Receiving Water Dry Weather Since 2008, dry weather DO concentrations the Avenue 52 Storm Drain MS4 outfall station have fallen below the WARM WQO minimum criteria once (8%, Table 8-19). The MS4 outfall station was dry during IC/ID dry weather monitoring events of the monitoring year, suggesting that the dry weather installed at this location is diverting dry weather flows. What minimal flow may remain evaporates and/or infiltrates within the 190 feet of sandy-bottomed, heavily vegetated channel prior to reaching the surficial waters of the CVSC. Since 2008, dry weather DO measurements at the CVSC Avenue 52 Bridge receiving water station have been less than the minimum WARM WQO criteria at least once each monitoring year, including during the August 20, 2013 dry weather event. Cumulatively DO measurements have been below the WQO for 77% of dry weather samples (Table 8-19). The Mann-Kendall trend analysis did not identify a statistically significant long-term dry weather trend for DO. Data from the CVSC at Avenue 52 Bridge receiving water station represent the background conditions in the CVSC, which consists of permitted discharges from the VSD WWTP. Wet Weather Since 2008, there have been no wet weather exceedances of the WQO for DO at the Avenue 52 Storm Drain MS4 outfall station. The lowest DO measurement at the Avenue 52 Storm Drain MS4 outfall station (6.55 mg/l) was recorded on August 26, The Mann-Kendall analysis observed a statistically significant decreasing trend at this MS4 outfall station, indicating that wet weather DO concentrations are moving in the direction of the WQO minimum criteria at a rate of mg/l per year. 8-64

72 Since 2008, four wet weather DO measurements in samples from the CVSC Avenue 52 Bridge receiving water station have been less than the minimum WARM WQO criteria (44%, Table 8-19), including the August 26, 2013 sample. No statistically significant long-term wet weather trends were observed for DO at the receiving water station. Data from the CVSC at Avenue 52 Bridge receiving water station represent the background conditions in the CVSC. DO in the Whitewater River Receiving Water Dry Weather The Portola Avenue Storm Drain MS4 outfall station is tributary to a wash in the Whitewater River and the receiving water was dry during monitored dry weather events, therefore, the intermittent REC-2 WQO did not apply due to a lack of flow in the receiving water. Flow sampled at the Portola Avenue Storm Drain evaporated and/or infiltrated in the absence of flow in the receiving water and, therefore, did not impact intermittent beneficial uses. Wet Weather Although the Mann-Kendall analysis found a statistically significant decreasing wet weather trend for DO measurements at the Portola Avenue Storm Drain MS4 outfall station, none of the wet weather samples collected to date have had DO measurements below the WARM WQO minimum criteria. Generally, wet weather flows from the Portola Avenue Storm Drain evaporate and/or infiltrate into the wash without impacting the intermittent beneficial uses. DO in the San Gorgonio River Receiving Water Dry Weather No dry weather DO measurements were recorded at the Ramsey Street Storm Drain MS4 outfall station during the monitoring year. Historically, the Ramsey Street Storm Drain has no flow during dry weather and monitored flows evaporated and/or infiltrated within ephemeral tributaries and did not reach the San Gorgonio River receiving water. Wet Weather During the period of record, six wet weather samples collected at the Ramsey Street Storm Drain MS4 outfall station have had DO measurements below the COLD WQO minimum criteria (38%, Table 8-19), including the November 21, 2014 sample. A statistically significant decreasing long-term trend was observed for DO, indicating that wet weather DO concentrations are moving in the direction of the WQO minimum criteria at a rate of mg/l per year. Wet weather DO measurements have been below the COLD WQO (8.0 mg/l) more frequently during recent monitoring year compared to the start of the 2008 MS4 Permit period and greater period of record (Attachments D and E). Wet weather flows monitored at the Ramsey Street Storm Drain MS4 outfall station generally evaporate and/or infiltrate within ephemeral tributaries and did not reach the San Gorgonio River receiving water IDENTIFICATION OF POTENTIAL URBAN SOURCES The only approved TMDL within the WWR is the CVSC Bacterial Indicator TMDL, which was approved by USEPA on April 27, Bacterial indicators are naturally occurring (McKee, 1978) and are commonly found in environmental samples. Coliform organisms are intestinal 8-65

73 bacteria that are excreted from humans, mammals, amphibians, and birds. They are also found primarily in the non-fecal forms on fibrous and vegetable matter in surface waters. Bacterial indicators may indicate the potential presence of contamination by human waste. However, the urban areas within the WWR are relatively new and have modern municipal separate sanitary sewer systems and waste water treatment systems. Human waste associated with septic tanks or leaking sanitary sewer systems are not likely sources of bacterial indicators in urban runoff in the WWR. However, transients living in the CVSC and improper management of human waste in tribal lands in the watershed tributary to the CVSC have been identified as potential sources of the bacterial indicators. Additionally, non-human anthropogenic sources of bacterial indicators are common within the urban environment, most notably waste from pets and other domestic animals. Also, urban areas may promote increases in the levels of bacterial indicators from natural sources. For example, increased impervious areas may allow wild animal waste and bird droppings to wash into an MS4 facility instead of infiltrating into soil. Vegetation also promotes increases in wildlife populations, which results in increased animal excrement. The City of Coachella has constructed three dry weather diversions to capture urban runoff within the City limits before it reaches the CVSC. These systems appear to have virtually eliminated dry weather urban runoff as a source of bacterial indicators to the CVSC EVALUATION OF THE EFFECTIVENESS OF EXISTING BMPS Bacterial Indicators E. coli Bacterial indicators are the only parameter for which there is a TMDL within the WWR. Several Permittee programs, including IC/ID detection, industrial and commercial facility inspection programs, new development requirements, and public education, have been proposed to address potential urban sources of E. coli. The Permittees reviewed these programs as part of the Permit renewal process to ensure they adequately addressed potential urban sources of bacterial indicators. These new programs were initiated on June 15, 2009 and were in effect during the monitoring year. The District and the City of Coachella have continued to evaluate methods to address potential urban contribution to the bacterial indicator impairment of the CVSC. The City of Coachella conducted a special study to identify and eliminate IDs within MS4 drainages directly tributary to the CVSC. The goal of this evaluation was to eliminate dry weather sources of flow to the CVSC. The City continues to work with the other sources of dry weather runoff to eliminate or reduce their discharges to the MS4. The City of Coachella also partnered with a storm drain BMP manufacturer to install and evaluate catch basin filter inserts designed to reduce nutrients and bacterial indicators in MS4 facility flows prior to reaching the CVSC. The City of Coachella redirected discharges from the MS4 facilities to dry wells, which appears to have eliminated urban runoff as a source of bacterial indicators to the CVSC. The City of Coachella has partnered with other desert agencies to develop an Integrated Watershed Management Plan (IWMP), which is expected to eventually provide additional funding for the City's proposed BMP alternatives. 8-66

74 The Permittees will continue to use IC/ID and public education outreach to focus on pollutants that may be contributed by urban runoff. In addition, the implemented Water Quality Management Plans (WQMPs) for new development and significant redevelopment will address potential urban sources of pollution, including E. coli (City of Coachella, 2005). As monitoring data from the Low Impact Development (LID) Testing and Demonstration Facility become available, the effect of this program may be quantified (Section 8.8.2). Other Parameters in the WWR The performance of existing BMPs in the WWR may be compared to the documented performance of various BMP systems. For example, a 2004 study conducted by Caltrans evaluated eight different types of BMPs installed at facilities across California (Caltrans, 2004). The maximum and minimum BMP effluent concentrations from the study for several parameters evaluated as part of the WWR monitoring program are presented in Table These effluent concentrations are similar to studies sponsored by product vendors when evaluating the percent reduction achieved by implementation of designed BMP technologies. The monitoring year total lead results are below the BMP effluent concentrations. Historical data for nutrients (Attachments D and E) also show that these parameters have frequently been measured at concentrations below the concentration range listed in Table This generally suggests that treatment control BMPs may not be able to significantly improve the quality of urban runoff associated with these parameters. Table 8-20: Currently Available Treatment Control BMP Technology Effluent Concentrations for Select WWR Monitoring Program Parameters 2004 Caltrans BMP Effluent Concentration Ranges Parameter Minimum Maximum Lead, total 2 µg/l 35 µg/l Nitrogen, total 2.1 mg/l 3.2 mg/l Total Kjedahl Nitrogen (TKN) 1.2 mg/l 2.4 mg/l Nitrate as NO mg/l 1.1 mg/l Phosphorus, total 0.2 mg/l 0.9 mg/l Orthophosphorus 0.1 mg/l 0.5 mg/l 8-67

75 8.8 SPECIAL STUDIES AND REGIONAL ACTIVITIES During the monitoring year, the Permittees, individually or jointly, participate in the regional activities and special studies as described below DESERT TASK FORCE As a Principal Permittee, the District conducts certain activities to coordinate the efforts of the Permittees and facilitate compliance with the 2008 MS4 Permit, and transition to the 2013 MS4 Permit requirements. One of these activities is chairing monthly meetings of the Permittees' NPDES Advisory Committee, the Desert Task Force LID DEMONSTRATION FACILITY The District, on behalf of all Permittees in Riverside County, constructed a LID Testing and Demonstration Facility at the District's headquarters in Riverside. Construction of this $2.5 million project commenced in February 2011 and construction was completed in October The facility formally opened on May 14, The LID Integrated Management Plan Testing and Demonstration Facility will be used to monitor the performance of LID features in the field, to illustrate LID features in training workshops, and to assist in the development of technical guidance regarding LID features. The 15-acre facility included the following: Converting 8,400 square feet of existing asphalt pavement and base to new porous asphalt pavement and new porous concrete pavement with subdrain systems. Revising the parking circulation layout to reduce impervious asphalt and eliminate over 600 lineal feet of concrete curb, gutter and storm drain in favor of a vegetated infiltration swale. Constructing two raised flow-through planters and one landscape filter basin that may double as 'rain garden' educational displays. Replacing two-thirds of the facility's turf with drought tolerant landscaping and efficient irrigation systems, designed in accordance with the County's Water Efficient Landscape Ordinance. Deepening an existing infiltration basin to facilitate positive drainage for the LID features. Constructing 10 monitoring vaults with flow and water quality monitoring equipment. The BMPs were designed based on the current state of science and specifically incorporated mechanisms to allow both inflow and effluent water quality and flow volume measurements. The results of the study will be used to establish water quality treatment effectiveness and numeric criteria for crediting flow reductions to developments that implement these BMPs. Monitoring at the facility was implemented during the monitoring year in accordance with the approved LID Monitoring Plan and QAPP. Flow data and influent and effluent samples from BMPs were sampled once, during the February 28, 2014 wet weather event. Flow data was collected for two additional wet weather events on November 21, 2013 and December 7,

76 This monitoring data has been submitted to the SMC's overarching LID BMP evaluation project. Additional wet weather monitoring is planned for the fiscal year CALIFORNIA STORMWATER QUALITY ASSOCIATION California Stormwater Quality Association (CASQA) is composed of stormwater quality management organizations and individuals, including cities, counties, special districts, industries, and consulting firms throughout the state. It was formed in 1989 to recommend approaches to the SWRCB for stormwater quality management in California. In this capacity, CASQA has assisted and continues to assist the SWRCB with the development and implementation of the stormwater permitting programs. All Permittees are members of CASQA. The Permittees attend CASQA's quarterly meetings and the annual conferences, as their availability and priorities allow. District staff have participated in various subcommittees, including the Legislative, Monitoring and Science, Pesticides, and Conference subcommittees. Jason Uhley and Darcy Kuenzi of the District staff currently serve as Co-chairs to the Legislative Committee. Mr. Uhley was formerly a member of the CASQA Board of Directors and has previously served as Treasurer. The CASQA 2013 Annual Report is included as Attachment H. The Permittees have contributed to representative participation in the Pyrethroid Re-Evaluation Stakeholder Meeting (PRSM) process with the California Department of Pesticide Regulation (DPR) and other stakeholders for the monitoring year. The Permittees also have provided support for the ongoing work of CASQA's Pesticides Committee, "CASQA Pestcom," with DPR to develop surface water protection regulations to mitigate the effects of pyrethroid pesticides in urban waterways, and the ongoing efforts of CASQA to improve USEPA pesticide environmental effects assessments through the pesticide registration review process CVSC BACTERIAL INDICATOR TMDL Regional Board staff have coordinated with the Permittees to develop a TMDL to address bacterial indicator impairment of recreational beneficial uses in the CVSC receiving water. The perennial portion of the CVSC, which begins at the VSD outfall (Indio) and continues to the Salton Sea, is a 303(d)-listed body for bacterial indicators. Only a portion of the perennial CVSC lies within the WWR the portion beginning near the VSD outfall (Indio), approximately the southern portion of the unincorporated area of Mecca. On June 17, 2010, the Regional Board approved an amendment to their Basin Plan to establish the CVSC Bacterial Indicator TMDL, which subsequently received final approval from the SWRCB on July 19, 2011, the Office of Administrative Law on February 2, 2012, and finally the USEPA, on April 27, The approved Basin Plan amendment specifies waste load allocations (WLAs) for point sources including the City of Coachella (the only WWR MS4 Permittee named as a responsible party), Caltrans, VSD WWTP, Coachella Sanitary District WWTP, and Mid-Valley Water Reclamation Plant; as well as load allocations (LAs) for agricultural runoff, Federal and tribal lands, and septic systems. 8-69

77 On October 8, 2012, the Regional Board provided notification to responsible parties that Phase I implementation of the TMDL had been initiated. The CVSC Bacterial Indicator TMDL implementation plan is divided into two phases. Phase I actions take three years to complete, and focus on monitoring to assess individual contributions of bacteria to CVSC from each identified source. Each party was given 90 days from the date of notification by the Regional Board to develop and submit respective Quality Assurance Project Monitoring Plans (QAPMPs), which would describe their monitoring activities. The City of Coachella submitted the first draft of its QAPMP, "QAPP and Bacterial Indicator Monitoring Plan for Outfalls Entering the CVSC" to the Regional Board on January 8, 2013 (City of Coachella, 2013). Regional Board and City of Coachella staff conducted a site walk in the CVSC on March 14, 2013, prior to the submittal of the second draft QAPMP. The City of Coachella's final QAPMP was subsequently approved by the Regional Board on May 9, 2013 and marks the start date of the City's three-year Phase I monitoring program. As a proactive measure, the City of Coachella completed construction of drywell diversions at each of their three outfalls to the CVSC, thereby eliminating the City's dry weather discharges to the channel. However, in accordance with its QAPMP and Phase I of TMDL implementation, the City performs monthly monitoring at each of these outfalls, and gathered monitoring data is provided to the Regional Board on a quarterly basis. The Regional Board will use data gathered by all responsible parties during Phase I to assess contributions of bacterial indicators from anthropogenic sources to the CVSC. Per the TMDL implementation plan, Phase I implementation will determine whether bacterial indicator WQOs have been achieved, sources of bacterial indicator pollution have been identified, and whether additional actions are required to meet the WQOs for Phase II (within 7 years of the end of Phase I) SOUTHERN CALIFORNIA STORMWATER COALITION As Principal Permittee for the three MS4 Permit compliance programs in Riverside County, the District participates in the SMC, a regional monitoring consortium. The SMC is a regional monitoring consortium which consists of southern California agency members. The consortium includes SCCWRP, the Los Angeles, Santa Ana, and San Diego Regional Water Quality Control Boards, Principal Permittees in Southern California (Counties of Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Ventura), the cities of Los Angeles, San Diego, and Long Beach, as well as Caltrans and the State Board. The overall goal of the RWMP is to increase the compliance and effectiveness of existing NPDES monitoring programs by integrating information among agencies to achieve a large-scale assessment of the watershed condition. Additionally the program focuses on improvement of stormwater monitoring science, development and improvement of monitoring standards and techniques, coordination among data collection programs, and evaluation of the effects of stormwater discharges to receiving waters. The SMC's research plan for is currently under development. The SMC Annual Reports may be viewed and/or downloaded at: Additional information regarding completed SMC Projects may be viewed and/or downloaded at: These projects include the following: Stormwater Research Needs in California 8-70

78 Phase I Hydromodification Study Design of Regional Bioassessment Program Low Impact Development Manual for Southern California Barriers to Low Impact Development Study Southern California Monitoring Coalition 2014 Research Agenda SOUTHERN CALIFORNIA WATER COMMITTEE The Southern California Water Committee is a non-profit, non-partisan, public education partnership dedicated to informing Southern Californians about their water needs and the State's water resources. It is a cooperative effort of business, government, water agencies, agriculture, and public interests. The District contributes $15,000 per year as part of Riverside County's support of the committee. The Committee has a Water Quality Task Force dedicated to promoting water conservation. No specific special studies benefitting the Permittees were conducted by the Southern California Water Committee during the monitoring year. 8-71

79 8.9 PROGRAM ACCOMPLISHMENTS AND RECOMMENDATIONS FOR FUTURE The Permittees' recommended future monitoring actions and updates to monitoring protocols are provided in this section. The Permittees will continue to revise their local programs based on these recommendations, as necessary, to fulfill the requirements of the Permit PROGRAM ACCOMPLISHMENTS Overall, receiving water conditions appear protective of the majority of the beneficial uses of the WWR due to the implementation of monitoring programs, as follows. IC/ID Program Dry weather water quality impacts associated with urban runoff from the MS4 is limited given that the IC/ID program quarterly investigations generally find MS4 outfall stations are dry, ponded, or have insubstantial flow for sample collection (i.e., VNS results). Sampleable flow during the dry weather monitoring activities was limited to one of three MS4 outfall stations. BMP and TMDL Programs The City of Coachella has constructed three dry weather diversions for their MS4 facilities that previously discharged into the CVSC, including a diversion upstream of the Avenue 52 Storm Drain MS4 outfall station. As mentioned previously, this MS4 outfall station was VNS during quarterly IC/ID dry weather site visits conducted during the monitoring year. Monitoring at this MS4 outfall station is no longer required under the 2013 MS4 Permit, in part, because dry weather urban runoff has been successfully diverted from the CVSC receiving water. The District, on behalf of all Permittees in Riverside County, constructed the LID Testing and Demonstration Facility at the District's headquarters in Riverside. Monitoring at the facility was implemented during the monitoring year. Flow data and influent and effluent samples from BMPs were sampled once during wet weather and flow data was collected for two additional storm events. The results of this monitoring will be used to establish water quality treatment effectiveness and numeric criteria for crediting flow reductions to developments that implement these BMPs. Additional wet weather monitoring is planned for the fiscal year YEAR PROGRAM Recommendations for the improvement and implementation of the WWR monitoring program during the monitoring year include: Implementation of Provisions under the 2013 MS4 Permit and MRP: The draft 2011 WWR Monitoring Plan (CMP Volume V) was finalized in July 2014 to reflect the lessons learned in the last few years and to include the most current monitoring program requirements based on the 2013 MS4 Permit. Starting in the monitoring year, the 8-72

80 Permittees will implement the programmatic changes required by the 2013 MS4 Permit using the monitoring program guidance in the WWR Monitoring Plan. Monitoring Program Receiving Water Monitoring MS4 Outfall Monitoring Regional Monitoring Programs Table Monitoring Year Monitoring Program Monitoring Frequency Sampling Requirement Monitoring Stations Type Required Wet Flow Weather (a) Once annually Field Parameters (a) CVSC at Avenue 52 Constituents of Concern (a)(b) Bridge (719CVS884) Dry Weather Wet Weather Dry Weather / IC/ID Twice annually Flow (a) Field Parameters (a) Twice annually Constituents of Concern (a)(b) Visual Observations Field Parameters (a) Four timer per E. coli (a) year (quarterly) IC/ID Flow-up As-needed Investigations As stated under individual monitoring programs. Ramsey Street Storm Drain (719RMS782) Portola Avenue Storm Drain (719POR817) (a) Samples will only be collected if the site is flowing. (a) Constituents of concern are listed in Table 1-3 of the WWR Monitoring Plan (CMP Volume V), and generally include E. coli, nutrients, total metals (expanded list), and other parameters (expanded list includes methyleneblue activated substances (MBAS), oil and grease and ethylene-glycol). Implementation of Program-Specific Laboratory Standards to the Maximum Extent Practicable: During the monitoring year, the RLs used by the contract laboratory changed between monitoring events. The trend analysis methodology was revised to evaluate for trend validity. During future trend analysis, consideration must be given to changes in RLs over time in order to avoid identifying false trends driven by a change in analytical methodology or reporting. Updates to 2013 QAPP (CMP Volume II) resulted in the development of a master list of analytical constituents, along with SWRCB minimum levels and SWAMP target RLs to be used by the contract laboratory. Additionally, the Permittees will meet with the laboratory consultant to review the monitoring year requirements to prevent issues experienced in the past regarding laboratory QA/QC reporting and report turnaround timeliness. Key Program Changes: Key changes to the monitoring programs for the monitoring year being incorporated to address new requirements of the 2013 MS4 Permit include: Monitoring at fewer monitoring stations (i.e., two MS4 outfall stations and one receiving water station); Sample analysis for an expanded list of constituents of concern; and 8-73

81 Better documentation of conditions at MS4 outfall stations in order to distinguish samples representing discharges to surface receiving waters from small flows that evaporate and/or infiltrate prior to reaching the receiving water; Better documentation of observations of connectivity to flowing receiving waters during wet and dry weather sampling; and Streamlining the Monitoring Annual Report to focus on assessment of monitoring data required under the 2013 permit period. (Long-term trend analyses are only required during the monitoring year; Period of record attachments will focus on 2013 water quality parameters.) OTHER EFFORTS DURING THE YEAR A significant amount of resources have been dedicated towards the implementation of the WWR monitoring programs described herein. However, the Permittees have also committed to additional monitoring and assessment programs related to pollutants in the Whitewater River watershed. These programs include: Supporting monitoring programs being implemented by the Permittees to investigate elevated levels of bacterial indicators in the CVSC. The Monitoring Annual Report will provide an update on the status of planning, reporting, and monitoring efforts associated with CVSC Bacterial Indicator TMDL. Testing the effectiveness of LID BMPs contained in District's LID BMP Design Manual through the District's monitoring station testing and demonstration facility. The Permittees recognize the importance of consistency of monitoring protocols throughout the Southern California region and shall continue to actively participate in efforts put forth by the SMC. These additional efforts are implemented either directly by Permittee staff, or through fiscal contributions to regional efforts that facilitate implementation the programs. These programs represent an additional fiscal and staff commitment to ensuring the protection of beneficial uses in the Whitewater River Watershed. No additional monitoring beyond the above programs is currently recommended. 8-74

82 8.10 REFERENCES California Regional Water Quality Control Board, Colorado River Basin Region. Waste Discharge Requirements for Discharges from the Municipal Separate Storm Sewer System (MS4) Within the Whitewater River Watershed. Order No. R NPDES No. CAS Adopted May 21, California Regional Water Quality Control Board, Colorado River Basin Region. Waste Discharge Requirements for Discharges from the Municipal Separate Storm Sewer System (MS4) Within the Whitewater River Watershed. Order No. R NPDES No. CAS Adopted June 20, California Department of Health, Information for Public Drinking Water Systems Converting Nitrate-N and Nitrate as NO3. Accessed on October 1, ate-nandnitrate-no3.pdf California Department of Transportation, BMP Retrofit Pilot Program Final Report. January California Regional Water Quality Control Board, Colorado River Basin Region Total Maximum Daily Load and Implementation Plan for Bacterial Indicators, Coachella Valley Stormwater Channel. May 16, California Regional Water Quality Control Board, Colorado River Basin. Water Quality Control Plan for the Colorado River Basin Region , amended June, Center for Watershed Protection. Illicit Discharge Detection and Elimination: A Guidance Manual for Program Development and Technical Assessments. October City of Coachella Water Quality Management Plans (WQMPs) for New Development and Significant Redevelopment. City of Coachella QAPP and Bacterial Indicator Monitoring Plan for Outfalls Entering the CVSC. Final. May 9, 2013 Cozad, Daniel Forest Burned, Filter Broken Water Quality Suffers After Fires, California Forests. Winter 2004, pp Coachella Valley Water District Final Report: Urban Water Management Plan. December Coachella Valley Water District Implementation Plan for Bacterial Indicators in the CVSC. December

83 GeoSyntec Consultants, et al Urban Stormwater BMP Performance Monitoring: A Guidance Manual for meeting the National Stormwater BMP Database Requirements. April Available at: November Last visited 11/19/12. Kendall Rank Correlation Methods, Fourth Edition. Charles Griffin, London. Mann Non-Parametric tests against trend. Econometrica. 13: McKee, et. al., Editors Water Quality Criteria, Second Edition. California State Water Resources Control Board Publication No. 3-A Revised Meixner, el. al Wildfire Impacts on Water Quality. Southwest Hydrology. September/October 2004 issue, pp Riverside County Flood Control and Water Conservation District. Section 8 Whitewater River Region Monitoring Annual Report Fiscal Year January 15, Riverside County Flood Control and Water Conservation District Consolidated Program for Water Quality Monitoring. Revised May Riverside County Flood Control and Water Conservation District. Hydrology Manual. April Riverside County Flood Control and Water Conservation District. Whitewater River Region Stormwater Management Plan. Revised January, Sawyer, et al. Chemistry for Environmental Engineering, 4 th Ed.. McGraw-Hill, Inc Sen Estimates of the Regression Coefficient Based on Kendall's Tau. Journal of the American Statistical Association. 63: Southern California Stormwater Monitoring Coalition (SMC). Model Monitoring Program for Municipal Separate Storm Sewer Systems in Southern California, A report from the Stormwater Monitoring Coalition's Model Monitoring Technical Committee. August State Water Resources Control Board CWA Section 303(d) List of Water Quality and Limited Segment. Colorado Basin Regional Water Quality Control Board State Water Resources Control Board. Policy for Implementation of Toxics Standards for Inland Surface Waters, Enclosed Bays, and Estuaries of California. California Environmental Protection Agency Southern California Coastal Water Research Project Effects of Southern California Wildfires on Stormwater Metals and PAHs. SCCWRP Presentation to member agencies. January

84 Southern California Coastal Water Research Project Southern California Monitoring Coalition Laboratory Intercalibration. Surface Water Ambient Monitoring Program (SWAMP). Quality Assurance Management Plan. last visited January SWAMP. SWAMP Data Management Plan. Chemistry Template. April 13, U.S. Department of the Interior GeoMAC Wildfire Information U.S. Environmental Protection Agency. MS4 Program Evaluation Guidance. USEPA Office of Wastewater Management. EPA-833-R January U.S. Environmental Protection Agency. NPDES Storm Water Sampling Guidance Document. EPA 833-B July (U.S. Forest Service Wildfires and Water Quality Protection on National Forests in California. EPA Groundwater and Source Water Protection Conference Presentation. May U.S. Geological Survey TWRI Book 9. Chapter A4: Collection of Water Samples, p. 18. August, U.S. Geological Survey Preliminary Analytical Results for Ash and Burned Soils from the October 2007 Southern California Wildfires, Open File Report pp

85 Attachment A Glossary WWR Monitoring Annual Report

86 Section 8 Attachment A ABBREVIATIONS AND ACRONYMS 2008 MS4 Permit Order No. R , NPDES Permit No. CAS MS4 Permit Order No. R , NPDES Permit No. CAS AGR agricultural beneficial use Babcock E.S. Babcock & Sons, Inc. Basin Plan Water Quality Control Plan for the Colorado River Basin BMP best management practice CASQA California Stormwater Quality Association cfs cubic feet per second CMP Consolidated Monitoring Program COLD cold freshwater habitat beneficial use County County of Riverside CVSC Coachella Valley Stormwater Channel CVWD Coachella Valley Water District District Riverside County Flood Control and Water Conservation District DNQ detected not quantified DO dissolved oxygen DPR Department of Pesticide Regulation ELAP Environmental Laboratory Accreditation Conference FRSH freshwater replenishment beneficial use GWR groundwater recharge beneficial use HUC hydrologic unit code IC/ID illicit connection/illicit discharge IWMP Integrated Watershed Management Plan LA load allocation LID low impact development MDL method detection limit mg/l milligrams per liter ml milliliter MPN most probable number MRP Monitoring and Reporting Program MMP Model Monitoring Program Monitoring Year July 1 to June 30 MS4 municipal separate storm sewer system MUN municipal beneficial use N nitrogen NA not analyzed ND not detected NELAP National Environmental Laboratory Accreditation Conference NR not reported/not required NPDES National Pollutant Discharge Elimination System NTU nephelometric turbidity unit NWS National Weather Service Permittees Collectively, the District, County of Riverside, CVWD, and incorporated Cities of Riverside County within the Whitewater River Basin POTW publicly owned treatment works POW hydropower generation beneficial use PRSM Pyrethroid Re-Evaluation Stakeholder Meeting QA/QC quality assurance/quality control QAPP Quality Assurance Project Plan A-1

87 Section 8 Attachment A QPF QPS RARE REC-1 REC-2 Regional Board RL RNA ROWD SWMP SMC SAR SAWPA SCCWRP SMR SSO SWRCB TDS TKN TMDL μg/l µs/cm UAA URMP USEPA VNS VSD WARM WILD WLA WQBEL WQMP WQO WWR WWTP quantitative precipitation forecast quantitative precipitation statement preservation of rare, threatened, or endangered species beneficial use water contact recreation beneficial use non-contact water recreation beneficial use California Regional Water Quality Control Board, Colorado River Basin Region reporting limit requested not analyzed Report of Waste Discharge Storm Water Management Plan Southern California Monitoring Coalition Santa Ana Region Santa Ana Watershed Project Authority Southern California Coastal Water Research Project Santa Margarita Region site-specific objective State Water Resources Control Board total dissolved solids total Kjeldahl nitrogen total maximum daily load micrograms per liter microsiemens per centimeter use attainability analysis Urban Runoff Management Program United States Environmental Protection Agency visited not sampled Valley Sanitary District warm freshwater habitat beneficial use wildlife habitat beneficial use waste load allocation water quality-based effluent limitation Water Quality Management Plan water quality objective Whitewater Region wastewater treatment plant A-2

88 Section 8 Attachment A COMMONLY USED TERMS IN THE WWR ANNUAL REPORT Additional terms and definitions may be found in the Glossary of Commonly Used Terms (CMP Volume VI). bacterial indicator Bacterial indicator species used to indicate potential contamination with human waste. One bacterial indicator (E. coli) is sampled under the WWR monitoring program. beneficial use The uses of water necessary for the survival or well-being of man, plants, and wildlife. These uses of water serve to promote tangible and intangible economic, social, and environmental goals. "Beneficial Uses" of the waters of the State that may be protected include, but are not limited to, domestic, municipal, agricultural and industrial supply; power generation; recreation; aesthetic enjoyment; navigation; and preservation and enhancement of fish, wildlife, and other aquatic resources or preserves. Existing beneficial uses are uses that were attained in the surface or groundwater on or after November 28, 1975; and potential beneficial uses are uses that would probably develop in future years through the implementation of various control measures. "Beneficial Uses" are equivalent to "Designated Uses" under federal law. [California Water Code Section 13050(f)]. constituent of concern Parameters commonly associated with urban runoff in the WWR defined in Table L-1 of the 2008 MS4 Permit. Monitoring for constituents of concern is required by the 2008 MS4 Permit. CVSC Bacterial Indicator TMDL Coachella Valley Stormwater Channel CVSC Bacterial Indicator Total Maximum Daily Load TMDL dry weather event Site visit and monitoring event where samples are collected of non-wet weather event flows during the dry season. Dry weather events are generally 72 hours or more after the last recorded precipitation event. Dry weather events may be referred to in report tables as "dry events." dry season/ dry weather June 1st through September 30th of each year, unless specifically defined otherwise in an applicable TMDL implementation plan. impairment Where water quality conditions are not adequate to support all designated existing or potential beneficial uses of a waterbody. intermittent beneficial use Beneficial uses which are dependent on and occur only when sufficient flow exists. major outfall In general, a major outfall is an MS4 outfall that discharges from a single pipe with an inside diameter of 36 inches or more, or its equivalent (discharge from a single conveyance other than circular pipe which is associated with a drainage area of more than 50 acres). It is also commonly referred to as a Major MS4 Outfall. A-3

89 Section 8 Attachment A Monitoring Annual Report Whitewater River Region Monitoring Annual Report, a report on annual monitoring activities, a part of the Annual Report. monitoring year Period of monitoring beginning on July 1st and ending on June 30th in a given year. MS4 outfall station Municipal separate storm sewer system outfall monitoring station used to represent urban runoff from the WWR. ph An expression of the intensity of the basic or acidic condition of a liquid. priority pollutant USEPA priority pollutants defined in Attachment D of the 2008 MS4 Permit. Monitoring of priority pollutants is required once during the permit period. receiving water station Receiving water monitoring station used to represent the WWR. stormwater Per 40 CFR (b)(13), means storm water [or stormwater] runoff, snowmelt runoff and surface runoff and drainage. Surface runoff and drainage pertains to runoff and drainage resulting from precipitation events. urban runoff In general, urban runoff includes those discharges from residential, commercial, industrial, and construction areas within the respective permit area and excludes discharges from open space, feedlots, dairies, publically owned treatment works (POTWs), and farms and agricultural fields. Urban runoff discharges consist of stormwater and non-stormwater surface runoff from drainage sub-areas with various, often mixed, land uses within all of the hydrologic drainage areas that discharge into the Waters of the U.S. In addition to urban runoff, the MS4s regulated by the MS4 permits receive flows from open space, agricultural activities, agricultural fields, state and federal properties, and other non-urban land uses not under the control of the Permittees. The quality of the discharges from the MS4s varies considerably and is affected by, among other things, past and present land use activities, basin hydrology, geography and geology, season, the frequency and duration of storm events, and the presence of past or present illegal and allowed disposal practices and illicit connections. The Permittees lack legal jurisdiction over stormwater discharges into their respective MS4 facilities from agricultural activities, California and federal facilities, utilities and special districts, Native American tribal lands, wastewater management agencies and other point and non-point source discharges otherwise permitted by or under the jurisdiction of the Regional Board. The Regional Board recognizes that the Permittees should not be held responsible for such facilities and/or discharges. Similarly, certain activities that generate pollutants present in urban runoff are beyond the ability of the Permittees to eliminate. water quality objective Water quality objectives (WQO) are water quality criteria required to be compared to water quality monitoring results, per the 2008 MS4 Permit. WQOs are referred to in this report as WQOs identified in the Basin Plan and beneficial uses. water quality standards In general these are the beneficial uses (e.g., swimming, fishing, municipal drinking water supply, etc.,) of water and the WQOs necessary to protect those uses. A-4

90 Section 8 Attachment A wet weather event Site visit and monitoring event where samples of wet weather event flows are collected during the wet season. Wet weather events may be referred to in report tables as "wet events." wet season/ wet weather There is no defined wet season in the WWR. In many Regions, the wet season is defined as October 1st through May 31st each year, unless defined otherwise in a TMDL implementation plan. A-5

91 Attachment B Monitoring Station Descriptions and Daily Rainfall for the Monitoring Year WWR Monitoring Annual Report

92 Table B-1 summarizes the sample history for the receiving water and MS4 outfall monitoring stations monitored in the Whitewater Region (WWR). Table B-1 identifies all monitoring stations required to be monitored under the 2008 MS4 Permit, distinguishing between stations that will no longer be required under the 2013 MS4 Permit and stations for which monitoring will continue. Table B-1 also identifies historic monitoring locations that are no longer required to be monitored under the permit. Land use maps and descriptions of monitoring stations are presented in this Attachment, below. Table B-2 provides the total daily rainfall for each of the five precipitation gauging stations within the WWR used to derive average annual rainfall statistics and provide historical context for monitoring events conducted at MS4 outfall and receiving water monitoring stations. Daily rainfall totals are for 24-hour intervals ending at 08:00 of the date indicated. The monthly sum row represents the total rainfall per month by precipitation gauging station. The cumulative total row represents cumulative annual totals for the monitoring year. 8-B1

93 Monitoring Year X Table B-1. WWR Sample Collection Summary by Monitoring Station 2008 & 2013 MS4 Permit Required 2008 MS4 Permit Stations^ Historical Monitoring Stations* Monitoring Stations 719RMS POR817 ± 719CVS AVE WWT MWW CCW TCW PCW815 MS4 Outfall MS4 Outfall Receiving Water MS4 Outfall Receiving Water Receiving Water Receiving Water Receiving Water Receiving Water HUC HUC HUC HUC HUC HUC HUC HUC HUC X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X HUC - Hydrologic unit code. Describes the watershed subarea in which each respective monitoring station drains. ^ The 2013 MS4 Permit does not require monitoring at these MS4outfall and receiving water stations in the monitoring year. * Historical receiving water monitoring stations are not required to be monitored under the 2008 MS4 Permit. ± The receiving water and associated beneficial uses for individual monitoring stations are used to identify and determine the applicability of water quality objectives (WQOs). Not all applicable receiving waters are listed in the Basin Plan (i.e., Portola Avenue Storm Drain MS4 outfall station); the most applicable receiving water and associated beneficial uses/ WQOs are used for comparison purposes. 8-B2

94 Day Banning Palm Springs Desert Hot Springs Table B-2: Daily Rainfall for Monitoring Year (inches) * July August September Desert Desert Rancho Cathedral Palm Rancho Cathedral Palm Avg. Banning Hot Avg. Banning Hot Mirage City Springs Mirage City Springs Springs Springs Sum Total Rancho Mirage Cathedral City Avg. 8-B3

95 Day Banning Palm Springs Desert Hot Springs Table B-2: Daily Rainfall for Monitoring Year (inches) * (continued) October November December Desert Desert Rancho Cathedral Palm Rancho Cathedral Palm Avg Banning Hot Avg Banning Hot Mirage City Springs Mirage City Springs Springs Springs Sum Total Rancho Mirage Cathedral City Avg 8-B4

96 Day Banning Palm Springs Desert Hot Springs Table B-2: Daily Rainfall for Monitoring Year (inches) * (continued) January February March Desert Desert Rancho Cathedral Palm Rancho Cathedral Palm Avg Banning Hot Avg Banning Hot Mirage City Springs Mirage City Springs Springs Springs Sum Total Rancho Mirage Cathedral City Avg 8-B5

97 Day Banning Palm Springs Desert Hot Springs Table B-2: Daily Rainfall for Monitoring Year (inches) * (continued) April May June Desert Desert Rancho Cathedral Palm Rancho Cathedral Palm Avg Banning Hot Avg Banning Hot Mirage City Springs Mirage City Springs Springs Springs Sum Total * Note that precipitation data from these gauges during this storm may not be suitable for daily storm totals but are suitable for storm totals and yearly totals. Rancho Mirage Cathedral City Avg 8-B6

98 The following Legend applies to all Land Use Maps presented in this Attachment. 8-B7

99 Station Name: Ramsey Street Storm Drain, Banning Site #: 719RMS782 Location: Latitude Longitude Elevation Thomas Bros Pg Classification: Receiving Water: 33 55' 30.7" N ' 30.6" W 2,285 ft 722 D3 Outfall Smith Creek Sampling Frequency: 2 Wet Weather 2 Dry Weather Directions to the site: Drive east on the 60 Freeway from the District office. Connect with the eastbound I-10 Freeway. Exit at Hargrave Street in Banning going north. Turn right on Ramsey Street and drive just past Hathaway Street. Look toward the right for a culvert just north of the I-10 Freeway and collect the sample just south of Ramsey Street. Other notes: During dry and wet weather, park just south of Ramsey Street and just east of the culvert on the empty lot. A pole sampler and/or the poly scoop can be used to gain a sample safely. The site can be accessed by walking down a small slope and collecting the sample while standing on a concrete pad. 8-B8

100 Station 719RMS782 - Ramsey Street Storm Drain, Banning Total drainage area: acres Land uses: Land Use Percent (%) Agricultural 0.00 Commercial 4.29 Exempt Public Properties 7.49 Industrial 1.32 Preserves Open Space Parks & Recreation 0.94 Rural Residential Streets Urban Residential B9

101 Station Name: Upper Whitewater River at Canyon Road Crossing (before Trout Farm) Site #: 719WWT813 Location: Latitude Longitude Elevation Thomas Bros Pg Classification: Receiving Water: 33 59' 01.5" N ' 10.0" W 2,135 ft. 694I1 Receiving Water Whitewater River Sampling Frequency: 2 Wet Weather only when regional stormwater flows are flowing at Golf Center Parkway in Indio. Directions to the site: Drive east on the 60 Freeway from the District office. Connect with the eastbound I-10 Freeway. Exit at "Whitewater Cutoff" off-ramp. Turn left at the end of the off-ramp and go over the I-10 Freeway (heading north). Turn left on Whitewater Canyon Road and drive about 4 to 5 miles to its crossing with the Whitewater River. Other notes: This station is located outside of the Whitewater River Region and represents the Upper Whitewater River. The tributary watershed to this station originates in San Bernardino County. For both dry and wet weather, if there is water to sample, it is recommended to use a pole sampler with a poly scoop to gain water samples safely. 8-B10

102 Station 719WWT813 - Upper Whitewater River at Canyon Road Crossing (Before Trout Farm) Total drainage area: 32, acres (9, acres within Riverside County boundary) Land uses (within Riverside County): Land Use Percent (%) Agricultural 0.00 Commercial 0.00 Exempt Public Properties Industrial 0.00 Preserves Open Space 2.22 Parks & Recreation 0.36 Rural Residential 0.00 Streets 0.00 Urban Residential B11

103 Station Name: Avenue 52 Storm Drain (Outfall) Site #: 719AVE785 Location: Latitude Longitude Thomas Bros Pg Classification: Receiving Water: 33 40' 17.4" N ' 56.4" W 5471F7 Outfall Coachella Valley Stormwater Channel Sampling Frequency: 2 Wet Weather 2 Dry Weather Directions to the site: From CVWD's Coachella office, drive east on Avenue 52 to a sandy, dirt access road on the south side of the road, just before the Avenue 52 Bridge. The outfall is on the southwest bank of the CVSC, just south of the Avenue 52 Bridge. 8-B12

104 Station 719AVE785 Avenue 52 Storm Drain Total drainage area: acres Land uses: Land Use Percent (%) Agricultural Commercial 0.69 Exempt Public Properties Industrial 3.12 Preserves Open Space Parks & Recreation 1.31 Rural Residential 9.90 Streets 6.52 Urban Residential B13

105 Station Name: Coachella Valley Storm Channel (CVSC) at Avenue 52 Bridge Site #: 719CVS884 Location: Latitude Longitude Thomas Bros Pg Classification: 33 o 40' 20.9" N 116 o 08' 57.8"W 5471 F7 Receiving Water Receiving Water: Stormwater Channel Coachella Valley Sampling Frequency: 2 Wet Weather 2 Dry Weather Directions to the site: From CVWD's Coachella office, drive east on Avenue 52 until you reach the Avenue 52 Bridge just west of the State Highway 86S Expressway. During dry weather sampling, drive to a sandy access road on the south side of the road on the west side of the Avenue 52 Bridge. Descend down southwest bank of CVSC to the pilot channel and collect samples directly beneath the south side of the bridge. During wet weather sampling, lower sampling equipment from the Avenue 52 Bridge with a rope to the pilot channel to collect samples. Traffic control may be necessary. Exercise discretion during high flow events! 8-B14

106 Station 719CVS884 Coachella Valley Storm Channel (CVSC) at Avenue 52 Bridge Total drainage area: 814, acres (703, acres within Riverside County boundary) Land uses: Land Use Agricultural Commercial Exempt Public Properties Industrial Preserves Open Space Parks & Recreation Rural Residential Streets Urban Residential Percent (%) B15

107 Station Name: Portola Avenue Storm Drain (Outfall), Palm Desert Site #: 719POR817 Location: Latitude Longitude Thomas Bros Pg Classification: Receiving Water: 33 o 44' 16.8"N 116 o 22' 24.6"W 818 G6 Outfall Whitewater River Sampling Frequency: 2 Wet Weather 2 Dry Weather Directions to the site: Take I-10 east to the Monterey exit and turn south on Monterey Avenue. Turn east on Country Club Drive. Turn south on Portola Avenue. The outfall is on the southeast side of the Portola Avenue Bridge on the south bank of the Whitewater River. Access to the collection point is through a gate located at the southeast side of the bridge, down concrete steps to the top of the outfall. The collection point is the discharge of the west culvert of the outfall right before it enters the concrete apron leading to the Whitewater River. For wet weather samples, it is recommended to use a pole sampler with a poly scoop to obtain water samples safely. 8-B16

108 Station 719POR817 Portola Avenue Storm Drain, Palm Desert Total drainage area: acres Land uses: Land Use Percent (%) Agricultural 0.00 Commercial 3.28 Exempt Public Properties 2.25 Industrial 0.00 Preserves Open Space 4.47 Parks & Recreation Rural Residential 0.58 Streets Urban Residential B17