ALISO CREEK WATERSHED RUNOFF MANAGEMENT PLAN WATER QUALITY DATA ASSESSMENT 2013 ANNUAL REPORT ORANGE COUNTY STORMWATER PROGRAM

Transcription

1 ALISO CREEK WATERSHED RUNOFF MANAGEMENT PLAN WATER QUALITY DATA ASSESSMENT 2013 ANNUAL REPORT ORANGE COUNTY STORMWATER PROGRAM

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3 Contents 1.0 Introduction Watershed Setting and BMPs BMP Monitoring Aliso Creek Monitoring Aliso Beach Monitoring Bacteria Trends Aliso Creek & Bacteria TMDLs Future Direction... 9 Appendices A Aliso Creek Directive Revised Monitoring Program 2013 Bacteria Test Results and Data Analysis Methods B Aliso Creek Watershed Beneficial Uses and Water Quality Objectives for Recreation Water Quality Data Assessment ii

4 1.0 Introduction This 2013 Annual Report includes the status of ongoing corrective actions, monitoring, assessment, and environmental research efforts for fecal indicator bacteria (FIB) and associated pathogens in Aliso Creek and downstream Aliso Beach (Figure 1). Findings are based upon over a decade of study including current efforts by the Orange County Stormwater Program s watershed partners (County of Orange, Orange County Flood Control District, and the cities of Aliso Viejo, Laguna Beach, Laguna Hills, Laguna Niguel, Laguna Woods, Lake Forest, and Mission Viejo) to implement provisions in Orange County municipal stormwater National Pollutant Discharge Elimination System (NPDES) permit R (Directive G, Aliso Creek Watershed Runoff Management Plan). Figure 1. Aliso Creek water sample being collected for FIB analysis as part of monitoring efforts by the Orange County Stormwater Program watershed partners. Watershed Setting and BMPs - A discussion on the watershed and water quality efforts; BMP Monitoring - An assessment of what Best Management Practices (BMPs) are working best to address stormdrain FIB loads; Aliso Creek Monitoring - Improvements in Aliso Creek bacterial water quality; Aliso Beach Monitoring - How FIB sources at the beach may be different than upstream; Bacteria Trends - The current drought and what that has meant for water quality in Aliso Creek; and Aliso Creek and Bacteria TMDLs Future Direction - Direction of efforts to identify sources of FIB contamination and define water quality objectives protective of beneficial uses but accounting for natural sources of bacteria. A description of data analysis methods and a detailed stationby-station analysis of monitoring program data collected as part of the current Aliso Creek Directive Revised Monitoring Program is provided in Appendix A. Appendix B includes an overview of California water quality objectives established for recreational water bodies and designated beneficial uses of water bodies within the Aliso Creek Watershed. In an effort to better clarify findings and present a complete picture of the state of the Creek and the factors affecting its water quality, specifically FIB, this year s report is divided under the following sectional themes: Water Quality Data Assessment 1

5 2.0 Watershed Setting and BMPs The Aliso Creek Watershed is located in southern Orange County approximately 50 miles south of Los Angeles and 65 miles north of San Diego. Aliso Creek drains a long, narrow coastal canyon with its headwaters in the Cleveland National Forest and ultimately discharges to the Pacific Ocean at Aliso Beach in the City of Laguna Beach. In the late 1800s the agricultural community of El Toro was one of the earliest modern settlements in the Watershed. Land uses included livestock grazing and orange and avocado groves. In the 1960s agricultural and ranch activities began to be replaced with residential and commercial development (Figure 2). Today the Watershed is largely developed with mixed residential and commercial land uses (Figure 3). National forest and County wilderness park areas comprise the largest remaining undeveloped land area in the upper and lower portion of the watershed. Figure 2: Historical agricultural land uses (1938) and current developed conditions at Aliso Creek and 5 Freeway (2013). Figure 3: Current developed (orange) and undeveloped (green) areas within the Aliso Creek Watershed. Approximately 67% of the watershed is now developed. Remaining undeveloped areas include primarily protected national forest and regional park land in the upper and lower portion of the watershed. Watershed urbanization has been accompanied by an increase in pollutant loads to Aliso Creek. Water quality, particularly FIB contamination, has been a priority issue for the Aliso Creek Watershed dating back to the late 1990s. Since that time numerous efforts have been made to understand and reduce sources of FIB to Aliso Creek and improve water quality (Figure 4). Since 2000, Aliso Creek Watershed water quality monitoring program and improvement efforts have exceeded $23 million (Figure 5). Water Quality Data Assessment 2

6 What are fecal indicator bacteria (FIB) and are they harmful? Identifying disease-causing organisms (pathogens) in surface water is difficult, time-consuming and costly. Therefore, FIB are used as indicators to determine the likelihood that harmful viruses and other pathogens may be present in water bodies. These bacteria normally occur in the intestines of all warm-blooded animals and Fecal Coliform Colonies are excreted in high numbers in feces but can also be found naturally in soils and decaying vegetation. There is no ideal indicator group of FIB, so testing is done for several groups including fecal coliforms and enterococci. Most strains of bacteria within these groups are not pathogenic themselves, but a strain of E. coli, a fecal coliform bacteria, is a pathogen. How do FIB and pathogens get into creeks and other water bodies? FIB can come from a variety of sources throughout the watershed including pet waste, trash, sewage spills, septic tanks (very few remaining in Orange County), animal manure fertilizers, natural sources such as bird and wildlife feces and decaying plant material. These bacteria can also re-grow and multiply in the environment unassociated with pathogen levels, making the use as indicators of water quality problematic. During wet weather, storm runoff picks up the bacteria and associated pathogens off of the land and carries them into creeks and other recreational waters. During dry weather, groundwater seepage and nuisance flows from urban land use activities such as car washing or lawn irrigation provide transport. Figure 4. Timeline of Key Aliso Creek Water Quality Efforts County receives Clean Water Act Section 205(j) grant to conduct Aliso Creek water quality studies. County initiates focused Aliso Creek water quality monitoring investigations on FIB contamination. Aliso Creek 205(j) Water Quality Planning Study Report completed laying out framework for water quality improvement. San Diego Water Board issues Directive to the County and watershed cities to continue to investigate and refine plan to address FIB contamination within Aliso Creek. Monitoring program expanded to weekly bacterialogical testing at all major stormdrain outfalls to Aliso Creek (over 100 monitoring stations throughout the watershed). Laguna Niguel source investigation finds non-human origin of FIB in J03P02 stormdrain. Constructed wetlands completed in J05 channel as mitigation for Laguna Hills Community Center project. J01P28 Media Filter and UV Light Disinfection Treatment System constructed to treat drainage from Aliso Viejo Town Center area. Wetland Capture and Treatment project completed to clean runoff from Laguna Niguel J03P02 stormdrain. South Orange County Integrated Regional Water Management Plan (IRWMP) developed with focus on water quality and restoring watershed biological diversity. J01P08 subwatershed irrigation controller pilot study in Lake Forest shows meaningful reductions in stormdrain flow. Aliso FIB monitoring program revised to focus on the summer when concentrations in the watershed are at their highest. Watershed wide SmarTimer Edgescape Evaluation Project (SEEP) study on benefits of enhanced irrigation controllers and landscape retrofits to reduce irrigation runoff and pollutant loads. Channel restoration project completed in segment of J04 (Narco) channel in Laguna Niguel achieves significant FIB reductions. San Diego Water Board adopts FIB Total Maximum Daily Load (TMDL) for south Orange County including Aliso Creek, its tributaries and Aliso Beach. Aliso Creek Watershed Comprehensive Load Reduction Plan (CLRP) developed identifying watershed BMPs needed to meet FIB TMDLs. Water Quality Data Assessment 3

7 An Aliso Creek Watershed Comprehensive Load Reduction Plan (CLRP) has been developed ( =712) focusing on four structural BMP categories to reduce bacteria and other watershed pollutant loads: Treatment Systems - Examples include sand filters, cartridge media filters and disinfection treatment, such as ozone or Ultraviolet (UV) light. Dry weather diversions are also included in this category where stormdrain flow is diverted to the sanitary sewer for treatment. Wetlands/Channel Restoration - Wetland treatment systems have shown proven reductions in bacteria, metals and other pollutants. Channel restoration enhances a stream s natural capacity to absorb pollutant loads and restores riparian habitat. Landscape Retrofits - Examples include weather-based irrigation controllers (aka SmarTimers), edgescaping where existing irrigated lawn area along the edge of a sidewalk, street curb, driveway, etc. is replaced with lower impact landscaping and permeable ground covering, and other irrigation improvements to improve water efficiency and reduce runoff. Catch Basin Retrofits - Examples include debris gates and in line baskets or filters. Debris gates are designed to keep trash out of stormdrains and within reach of street sweepers. In line baskets capture and retain trash pollutants for later removal while catch basin filters screen out finer pollutants such as metals, silt, and hydrocarbons. Figure 5: Map of current Aliso Creek Watershed BMP projects. A complete list of current and proposed watershed BMPs can be found in the Aliso Creek Watershed Comprehensive Load Reduction Plan (CLRP) Water Quality Data Assessment 4

8 3.0 BMP Monitoring The current bacteria monitoring program in the Aliso Creek Watershed focuses on six high-priority drains/bmp evaluation sites and a series of status and trends sites in Creek receiving waters (see Appendix A for a detailed description of the current monitoring program and data results). The six sites were selected to document the relative effectiveness of different BMPs, which in turn has helped guide BMP implementation in the watershed. Of the BMPs being implemented, wetlands and channel restoration projects have resulted in the highest consistent bacteria reductions (Figures 6 and 7). How Wetlands Remove Bacteria Bacteria attached to soil particles in the water settle by gravity and sink to the bottom where they are trapped by plant matter and sediment Wetland plants release compounds into the soil that have an anti-biotic effect, slowing bacteria growth Exposure to ultraviolet rays in sunlight kills bacteria Predatory microscopic animals called protozoans feed on bacteria in the water Acidic water chemistry in a wetland is detrimental to bacterial growth Figure 6. Dry weather bacteria reductions at high-priority drains. Reductions are based upon comparison of summer 2001 and 2013 stormdrain data for tested fecal coliform and enterococci bacteria. Drain Key Watershed BMP Effort Reduction in Bacteria Concentration J05 Wetland 96.7% J04 Channel Restoration 91.5% J07P02 Catch Basin Filters 76.4% J01P08 Landscape Irrigation 47.2% Controllers J06 Catch Basin Screens 34.6% J01P28 UV and Media Filter Treatment System 97.2%* *Reduction based upon 2013 treatment system performance data for FIB. The J01P28 treatment system was offline for maintenance 1 of the 4 months monitored in summer 2013 resulting in a 0% reduction at the drain during this period. Graphic courtesy of the City of Laguna Niguel Figure 7. The J04 Narco channel restoration project (above) has shown consistent bacteria reductions since completion in 2007 while the J01P28 UV and media filter treatment system (right) has been subject to maintenance issues. Water Quality Data Assessment 5

9 4.0 Aliso Creek Monitoring Since 2003 there has been a dramatic reduction in FIB concentrations in Aliso Creek (Figure 8). The most notable improvements have occurred in the lower portion of the watershed which has the highest potential for recreation use and related concerns about potential human health impacts (Figure 9). Figure 9. Monitoring station CTPJ01 in the lower Aliso Creek watershed. Although swimming, kayaking, and other water contact activities are currently not allowed, the lower watershed has the highest potential for future recreational use. In 2013 Aliso Creek monitoring site CTPJ01, located 1-mile inland from Aliso Beach, met water contact recreation (i.e. swimming) water quality objectives for fecal coliform bacteria for the second summer in a row and for the fifth time in the last six years (see Appendix B for a discussion on Aliso Creek Watershed beneficial uses and bacteria water quality objectives for recreation). Although bacteria concentrations at CTPJ01 did exceed the more stringent enterococci geomean objective (33 CFU/100ml) concentrations were very close (seasonal geomean of 45 cfu/100ml) and have remained consistently low over the last five years (Figure 10). Figure 10. FIB concentrations at Aliso Creek monitoring site CTPJ01 have significantly declined and now meet recreational water quality objectives (WQOs) for fecal coliform. Figure 8. Lower Aliso Creek Watershed summer bacteria concentrations based upon monitored Creek segments. (Summer 2013 seasonal geomean and geomean WQOs) Water Quality Data Assessment 6

10 5.0 Aliso Beach Monitoring Reductions in FIB concentrations in Aliso Creek waters should result in water quality improvements at the mouth of the Creek and in the surfzone. However, since 2003, water quality at the Creek mouth and in beach waters appears disconnected from the improving conditions in Aliso Creek (Figure 11). In fact summer surfzone FIB concentrations have remained consistently low despite fluctuations in Aliso Creek. Some of this disconnect may be explained by the periodic opening and closing of the Creek mouth to the ocean but it does not explain that over the last five years FIB concentrations at the Creek mouth (ACM1) have been higher than a mile upstream in the watershed (CTPJ01). Although a golf course adjoins the Creek in this segment there are no major stormdrain inputs (Figure 12). Additional data is being collected to investigate FIB sources along the lower 1-mile of Aliso Creek. Initial data Figure 11. Despite reductions upstream in the watershed (CTPJ01) bacteria concentrations at the Aliso Creek mouth (ACM1) and in the surfzone (ACM1d) have remained unchanged. Figure 12. Monitoring stations along the lower 1-mile of Aliso Creek and at Aliso Beach and recent geomeans of station enterococci concentrations. collected in October 2013 from a new monitoring station (AC- CCR) has been inconclusive as a larger data set is needed. Although the golf course has not been eliminated as a potential source, FIB regrowth in sediments and feces from birds that congregate at the shoreline are believed to be localized contributing sources (Figure 13). Figure 13. Seagulls along the shoreline of Aliso Beach. A single bird dropping can contain billions of FIB. Water Quality Data Assessment 7

11 6.0 Bacteria Trends (July-June) marked the second straight year of below average rainfall in Orange County and the Aliso Creek Watershed. Excluding the rainy season of where a 10- inch storm event comprised the majority of the rain received, there has been below average rainfall in the watershed for eight straight years (Figure 14). The lack of rain has not been isolated to Orange County. After a record dry year in a California-wide drought was declared in June 2008 and recently again in January Figure 14. Rainfall received at the Sulphur Creek dam in Laguna Niguel Regional Park (July 1975 June 2013). Figure 15. Aliso Creek flow rate and bacteria loads at CTPJ01 monitoring station in the lower Aliso Creek Watershed. Figure 16. Estimated dry weather flow reductions at high-priority stormdrains based upon 2007 and 2013 summer monitoring data. Coinciding with these drought conditions has been a reduction in water in Aliso Creek and also bacteria loads (Figure 15). The observed declines are likely attributable to several contributing factors. One notable change has been reductions in flow at stormdrains. Since 2007 there has been 50-76% reduction in flow at measured drains (Figure 16). This reduction is due to a decrease in groundwater inputs and watershed water conservation efforts. Recent BMP efforts have focused on stormdrain flow reduction including retrofitting landscaped areas to prevent over irrigation and enhance infiltration (see Other related water conservation efforts have been implemented by local water districts, including restricted watering days during drought periods and tiered water rate structures. These measures decrease runoff to the stormdrain system and the conveyance of bacteria and other pollutants. Water Quality Data Assessment 8

12 7.0 Aliso Creek and Bacteria TMDLs Future Direction The Orange County Stormwater Program s Aliso Creek Watershed bacteria monitoring program has focused on collecting data to determine the effect of BMPs at stormdrains during dry weather and evaluate improvements in downstream receiving waters. Data shows there has been a considerable decrease in bacteria loads from stormdrains (Figure 17) and concentrations within Aliso Creek receiving waters (Figure 10). Future monitoring efforts as described in the Aliso Creek Watershed CLRP will be expanded to include wet weather monitoring and series of special studies to fill data gaps for compliance with watershed bacteria Total Maximum Daily Loads (TMDLs). Figure 17. Summer bacteria loads at Aliso Creek high-priority stormdrain monitoring sites. In 2010 the San Diego Regional Water Quality Control Board adopted bacteria TMDLs for Aliso Creek, its tributaries, and Aliso Beach seeking to restore and protect recreational Figure 18. Aliso Creek single sample maximum (SSM) and geomean (GM) water quality objective exceedance rate vs. TMDL allowable exceedances rates and exceedance rates in reference creek systems. Exceedance Rate Enterococci WQO Monitoring Station Aliso Creek (CTPJ01) Creek Mouth (ACM1) Aliso Beach (ACM1d) Water Quality Objective Summer 2013 Aliso Dry Weather TMDLs OC & SD Reference Creeks SSM 30% 0% 34.1% GM 100% 0% 71% SSM 64% GM 100% SSM 6% GM 0% beneficial uses of these water bodies. The TMDLs define needed bacteria load reductions from the stormdrain system and receiving water bacteria concentration numeric targets based upon recreational water quality objectives. To account for natural sources of a bacteria (i.e. decaying vegetation, fecal matter from birds and other wildlife, etc.) the TMDLs allow for an exceedance frequency of bacteria numeric targets. A 22% allowable exceedance frequency is currently used for Aliso Creek Watershed samples collected during wet weather conditions. This is based upon Los Angeles County bacteria TMDLs which used data from a natural reference watershed beach (Leo Carrillo) to establish a permissible exceedance rate. No allowable exceedance frequency is currently in place for samples collected during dry weather. Initial data collected from an ongoing Orange and San Diego County reference watershed study suggests that the dry weather exceedance rate for natural creeks is not 0% as reference creeks systems have exceeded the enterococci geomean water quality objective by 71% (Figure 18). Based upon the study findings, Water Quality Data Assessment 9

13 when complete, it is expected that adjustments to the bacteria TMDLs will be needed. Future watershed special studies are also being planned to isolate bacteria sources using a toolbox of source tracking techniques. These include sewer infrastructure dye testing to ensure no leaks to the stormdrain system and receiving waters, bacteria DNA testing (microbial source tracking) to determine whether bacteria in the Creek and at the beach are from a human fecal origin, and possible direct testing for viruses and other pathogens to define a more accurate assessment of health risk to recreation users marked another year of improvement for the Aliso Creek Watershed and the state of Creek is considerably healthier than when monitoring and BMP efforts began in the 1990s. Despite noteworthy progress, more work is needed to continue to identify and control bacteria sources, evaluate water quality objectives, and meet TMDL targets. Using DNA to Identify Bacteria Sources New microbial Baby Beach source tracking (MST) methods rely on DNA sequencing to identify bacteria strains unique to different animal species. Recent MST testing conducted at Baby Beach in Dan Point Harbor consistently found the presence of DNA unique to bacteria in the intestinal track of dogs. This has prompted harbor staff to take additional measures to ensure enforcement of their no dogs on the beach policy. Water Quality Data Assessment 10