4.9 HYDROLOGY AND WATER QUALITY

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1 The Project site is located within the jurisdiction of the Santa Ana Regional Water Quality Control Board (RWQCB). Water quality information for this Subsection was obtained from the Santa Ana RWQCB s Santa Ana River Basin Water Quality Control Plan (updated June 2011) and the Integrated Regional Water Management Plan (IRWMP) for the Santa Ana River Watershed (also referred to as One Water One Watershed, dated November 16, 2010), prepared by the Santa Ana Watershed Project Authority (SAWPA). These documents are herein incorporated by reference and are available for public review at the physical locations and website addresses given in EIR Section 7.0, References. Information in this Subsection also relies on Water Quality Management Plan reports prepared by Hall & Foreman, Inc., which are included as Technical Appendix I2 (Hall & Forman, 2015a) and Technical Appendix I3 (Hall & Foreman, 2015c) to this EIR, respectively. With respect to hydrology, the analysis in this Subsection is based on a report prepared by Hall & Forman, Inc., titled, Preliminary Hydrology Report Watson Industrial Park-Phase II, dated February 2015, and included as Technical Appendix I1 to this EIR (Hall & Forman, 2015b). The Project site is located within Subarea 2 of the Chino Agricultural Preserve Area Storm Drain Master Plan (updated December 2007). Hydrology information in this Subsection, therefore, also was obtained from the Chino Master Drainage Plan (Chino, 2007), which is herein incorporated by reference and available for public review at physical location and website address given in EIR Section 7.0, References EXISTING CONDITIONS A. Regional Hydrology The Project site is located in the Santa Ana River watershed, which drains a 2,650 square-mile area and is the principal surface flow water body within the region (SAWPA, 2014, Ch. 3). The Santa Ana River rises in Santa Ana Canyon in the southern San Bernardino Mountains and runs southwesterly across San Bernardino, Riverside, and Orange Counties, where it discharges into the Pacific Ocean at the City of Huntington Beach. The total length of the Santa Ana River and its major tributaries is approximately 700 miles (SAWPA, 2014, Ch. 3). The Project site s location within the Santa Ana River Watershed is depicted on Figure 4.9-1, Santa Ana River Watershed Map. B. Site Hydrology Figure 4.9-2, Existing Conditions Hydrology Map, illustrates the drainage pattern of the Project site under existing conditions. As illustrated on Figure 4.9-2, storm water runoff from the western portion of the Project site drains across the subject property in a southwesterly direction as sheet flow before discharging from the property at its western boundary (existing Baker Avenue alignment and proposed future alignment of Van Vliet Avenue) and its southwestern corner (Remington Avenue). Storm water runoff from the north-central and northeastern portions of the Project site drain across the property in a southerly direction as sheet flow before collecting in existing wastewater basins(dairy ponds) adjacent to the southern Project site boundary (near the future alignment of Page 4.9-1

2 WATSON I NDUSTRIAL PARK 4.9 H YDROLOGY AND W ATER Q UALITY ( ' & % 15 Big Bear Lake 330 Claremont Upland 210 Rancho Cucamonga Pomona La Habra Heights LEGEND City Boundary Parcels Placentia Agriculture Light Industrial Airport Related ' ( & % Medium Density Residential Grand Terrace Loma Linda Redlands ( ' & % _ [ Yucaipa 10 ' ( & % Calimesa 15 Riverside Norco Moreno Valley 60 Westminster Corona ( ' & % Villa Park Orange Perris Santa Ana Tustin Irvine 133 Newport Beach City of Ontario Zoning (AG) Specific Plan (Ag Preserve) Lake Elsinore Hemet Canyon Lake Costa Mesa 73 S-P - Specific Plan 74 R-1 - One-Family Dwellings City of Eastvale Zoning I-P - Industrial Park San Jacinto 22 Huntington Beach A-2 - Heavy Agriculture Beaumont 405 Open Space Recreational Low Density Residential 30 Garden Grove ( ' & % Airport Development Zone Anaheim 5 Stanton City of Chino Zoning Public Colton 91 Cypress Los Alamitos 215 Highland Yorba Linda La Palma Project Boundary ' ( & % Fullerton San Bernardino 60 Chino Hills Brea Fontana Chino 71 La Habra PROJECT SITE 10 Ontario ' ( & % # Montclair Rialto Lake Forest ' ( & % 15 Laguna Woods Office Commercial Source(s): RCTLMA (2014), SANBAG (2013) Figure Miles Lead Agency: City of Chino SANTA ANA RIVER WATERSHED MAP SCH No Page 4.9-2

3 4.9 HYDROLOGY AND WATER QUATLITY Source(s): Hall & Foreman, Inc. ( ) Figure NOT TO SCALE Lead Agency: City of Chino EXISTING CONDITIONS HYDROLOGY MAP SCH No Page 4.9-3

4 Hellman Avenue) and discharging off-site. Storm water runoff from the southerly portion of the Project site drains westerly to the aforementioned wastewater basins along the southern Project site boundary. Under existing conditions, peak storm water runoff volumes on the Project site during the 100-year storm event are projected to be cubic feet per second (cfs) (Glauser, 2014). C. Master Drainage Plan The Project site is located within the boundary of the Storm Drain Master Plan for Subarea 2 of the Chino Agricultural Preserve Area (which corresponds with the boundaries of The Preserve Specific Plan Area). The Storm Drain Master Plan was prepared by the City of Chino to identify masterplanned drainage and flood control facilities that are needed to safely convey storm water runoff generated within The Preserve Specific Plan area upon full buildout. The Storm Drain Master Plan identifies a public storm drain line traveling beneath the Project site and along Remington Avenue to the Cucamonga Creek Channel (Chino, 2007, Figure 3). This facility has not been constructed under existing conditions. As described in EIR Subsection 3.3.4, and as detailed in the Project s preliminary hydrology report (Technical Appendix I1), the Project would not construct this facility; but, alternatively, proposes to construct a 72-inch storm drain pipe segment beneath Hellman Avenue (between Remington Avenue and Kimball Avenue); construct a flow diversion structure at the southwest corner of the Project site (at Remington Avenue); and replace an existing 54-inch storm drain pipe beneath Hellman Avenue with a 72-inch storm drain pipe (between Remington Avenue and Autumn Path Street). As part of the implementing actions required by the Project, the Applicant will update the City s Storm Drain Master Plan to reflect the revisions to the storm drain infrastructure as proposed by the Project (refer to EIR Subsection 4.14 for additional information). D. Flooding and Dam Inundation According to the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) No C9375H, dated August 28, 2008, the Project site is not located within a special flood hazard area subject to inundation by the 1-percent annual flood (100-year flood). However, a portion of the Project site is designated by FEMA as being prone to some degree of flooding during rare storm events. The eastern and western portions of the Project site are located within FEMA Flood Zone X (Shaded). Flood Zone X (Shaded) is generally correlated with areas of moderate flood hazard (greater than 0.2-percent annual-chance), usually consisting of the area between the limits of the 100-year and 500-year floods. Zone X (Shaded) also is used to designate base floodplains of lesser hazards, such as areas protected by levees from 100-year flood, or shallow flooding areas with average depths of less than one (1) foot or drainage areas less than one (1) square mile. The central portion of the Project site is located within FEMA Flood Zone X (Unshaded), which is generally correlated with areas of minimal flood hazard (outside of the 0.2-percent annual-chance floodplain). The Cucamonga Creek Channel, which is located approximately 0.40 mile east of the Project site, is designated by FEMA as a provisionally accredited levee. The FEMA FIRM for the Project area is depicted on Figure 4.9-3, FEMA Flood Insurance Map Panel No C9375H. Page 4.9-4

5 C I T Y O F C H I N O C I T Y O F O N T A R I O GROVE AVE COMET AVE MERRILL AVE REMINGTON AVE KIMBALL AVE Source(s): Eagle Aerial (2013), ESRI, SANBAG SB County (2014), SB County (2014) ,000 2,000 Feet EDISON AVE WALKER AVE PINE AVE BAKER AVE PROJECT SITE HELLMAN AVE CITY OF CHINO VINEYARD AVE CITY OF EASTVALE MERRILL (VACATED) REMINGTON AVE Figure FEMA FLOOD INSURANCE MAP PANEL NO C9375H Page CARPENTER AVE S.B.C.F.C.D. 65TH ST LEGEND ARCHIBALD AVE City Boundary Flood Zone A Flood Zone X

6 In addition, the Project site is in the vicinity of the Prado Dam, which is located approximately 6.0 miles southwest of the subject property. According to the City of Chino General Plan Figure SAF-3, 566 Foot Prado Dam Inundation Area, the Project site is not subject to dam inundation hazards associated with the potential failure of the Prado Dam (Chino, 2010a). E. Water Quality The California Porter-Cologne Water Quality Control Act (Section ( Water Quality ) et seq., of the California Water Code), and the Federal Water Pollution Control Act Amendment of 1972 (also referred to as the Clean Water Act (CWA)) require that comprehensive water quality control plans be developed for all waters in the State of California. In order to accomplish this, the California State Water Resources Control Board divided the state into planning regions and the present system of nine Regional Water Quality Control Boards (RWQCBs). The Project site and vicinity are located in the Santa Ana River watershed, which is within the purview of the Santa Ana RWQCB. The Santa Ana RWQCB s Santa Ana River Basin Water Quality Control Plan is the governing water quality plan for the region, which sets forth goals and objectives for protecting water quality within the region (Santa Ana RWQCB, 2011). The Cucamonga Creek Channel receives storm water drainage flows generated within the Project site and the surrounding area. Water from the Cucamonga Creek Channel flows to downstream reaches of the Santa Ana River and, ultimately, the Pacific Ocean. The Cucamonga Creek Channel is classified as an impaired water body, and has been placed on the CWA s Section 303(d) list of impaired waters because of excessive concentrations of two (2) pollutants ( Pollutants of Concern ), including pathogens and metals (Hall & Forman, 2015a, p. 3-4). F. Groundwater The City of Chino is underlain by groundwater resources associated with the Chino Groundwater Basin. The City of Chino s Water Utility, a sub-agency of the Inland Empire Utilities Agency (IEUA), relies on groundwater resources from this groundwater basin for a portion of their total water supply. According to the Chino Basin Watermaster, groundwater elevations beneath the Project site occur at elevations between approximately 550 feet AMSL, indicating that groundwater beneath the site occurs approximately 90 to 120 feet below the ground surface during the spring (CBWM, 2013, Exhibit 2). The Project site contains three active water wells and two abandoned water wells (Liliburn, 2013, pp. 9-13; Northgate, 2014e, pp. 9-13). No public wells or public water systems are located within a one mile radius of the Project site (Liliburn, 2013, p. 16). G. Applicable Policies and Regulations Federal Policies and Regulations The Federal Water Pollution Control Act (also known as the Clean Water Act (CWA)) is the principal federal statute that addresses water resources. The statute employs a variety of regulatory Page 4.9-6

7 and non-regulatory tools to reduce direct pollutant discharges into waterways, finance municipal wastewater treatment facilities, and manage polluted runoff. The broad goal is to restore and maintain the chemical, physical, and biological integrity of the nation s waters so that they can support the protection and propagation of fish, shellfish, and wildlife and recreation in and on the water. The CWA requires all states to conduct water quality assessments of their water resources and identify water bodies that do not meet water quality standards. The Environmental Protection Agency (EPA) publishes recommended water quality criteria. States are not required to adopt the exact criteria, but state standards must be approved by the EPA and provide the same level of protection as EPA s standards. In California, water quality standards are established by the nine RWQCBs. The Project site is located in the Santa Ana region, and the Santa Ana RWQCB s Santa Ana River Basin Water Quality Control Plan (Santa Ana RWQCB, 2011) is applicable to the Project site and vicinity. The provisions of the CWA applicable to the proposed Project are as follows, which also apply to all construction sites of over one acre in size: CWA Section 401 requires federal agencies to obtain a Water Quality Certification from states, territories, and Indian tribes before issuing permits that would result in increased pollutant loads to a water body. A Section 401 certification can be issued only if increased pollutant loads would not cause or contribute to exceedances of water quality standards; and CWA Section 402 authorizes the National Pollutant Discharge Elimination System (NPDES) permit program that covers point sources of pollution discharging to a water body. The NPDES program also requires operators of construction sites one acre or larger to prepare a Storm Water Pollution Prevention Plan (SWPPP) for construction activities and obtain authorization to discharge storm water under an NPDES construction storm water permit. The NDPES program also requires certain land uses (e.g., industrial uses) to prepare a SWPPP for operational activities and to implement a long-term water quality sampling and monitoring program, unless an exemption has been granted. On April 1, 2014, the California State Water Resources Control Board adopted an updated new NPDES permit for storm water discharge associated with industrial activities (referred to as the Industrial General Permit ). The new Industrial General Permit, which is more stringent than the existing Industrial General Permit, becomes effective on July 1, State Policies and Regulations The California Water Code (including the Porter-Cologne Water Quality Control Act (Division 7)) is the principal law regulating water quality in California. The Porter-Cologne Water Quality Control Act establishes a comprehensive program to protect water quality and the beneficial uses of water, and applies to both surface and groundwater. As mentioned above, the State Water Resources Control Board adopts statewide water quality control plans and its nine RWQCBs are required to Page 4.9-7

8 develop and adopt regional water quality control plans ( basin plans ) that conform to state water quality policy. As mentioned above, the Project site is located in the Santa Ana region. As such, the Santa Ana RWQCB s Santa Ana River Basin Water Quality Control Plan is applicable to the Project site; it designates beneficial uses of water bodies to be protected and establishes water quality objectives. Local Policies and Regulations Chapter (Storm Water Drainage System Regulations) of the City of Chino Municipal Code requires the City to participate as a "Co-permittee" under the NPDES permit program to accomplish the requirements of the CWA. Pursuant to this chapter, the City is required to participate in the improvement of water quality and comply with Federal requirements for the control of urban pollutants to storm water runoff BASIS FOR DETERMINING SIGNIFICANCE The proposed Project would result in a significant impact to hydrology and water quality if the Project or any Project-related component would: 1. Violate any water quality standards or waste discharge requirements; 2. Substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level (e.g., the production rate of pre-existing nearby wells would drop to a level which would not support existing land uses or planned uses for which permits have been granted); 3. Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner which would result in substantial erosion or siltation on- or off-site; 4. Substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, or substantially increase the rate of surface runoff in a manner which would result in flooding on- or off-site; 5. Create or contribute runoff which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff; 6. Otherwise substantially degrade water quality; 7. Place housing within a 100-year floodplain, as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map; 8. Place within a 100-year flood hazard area structures which would impede or redirect flood flows; 9. Expose people or structures to a significant risk of loss, injury or death involving flooding, including flooding as a result of the failure of a levee or dam; or Page 4.9-8

9 10. Expose people or structures to a significant risk of loss, injury or death involving inundation by seiche, tsunami, or mudflow IMPACT ANALYSIS Threshold 1: Would the Project violate any water quality standards or waste discharge requirements? A. Construction related Water Quality Impacts Construction of the proposed Project would involve demolition, clearing, grading, paving, utility installation, building construction, and landscaping activities, which would generate potential water quality pollutants such as silt, debris, chemicals, paints, and other solvents with the potential to adversely affect water quality. As such, short-term water quality impacts have the potential to occur during construction of the Project in the absence of any protective or avoidance measures. Pursuant to the requirements of the Santa Ana RWQCB and the City of Chino, the Project would be required to obtain a NPDES Municipal Stormwater Permit for construction activities. The NPDES permit is required for all projects that include construction activities, such as clearing, grading, and/or excavation, which disturb at least one (1) acre of total land area. In addition, the Project would be required to comply with the Santa Ana RWQCB s Santa Ana River Basin Water Quality Control Program. Compliance with the NPDES permit and the Santa Ana River Basin Water Quality Control Program involves the preparation and implementation of a SWPPP for construction-related activities. The SWPPP will specify the Best Management Practices (BMPs) that the Project would be required to implement during construction activities to ensure that all potential pollutants of concern are prevented, minimized, and/or otherwise appropriately treated prior to being discharged from the subject property. Examples of BMPs that may be utilized during construction include, but are not limited to, sandbag barriers, geotextiles, storm drain inlet protection, sediment traps, rip rap soil stabilizers, and hydroseeding. Mandatory compliance with the SWPPP would ensure that the proposed Project does violate any water quality standards or waste discharge requirements during construction activities. Therefore, water quality impacts associated with construction activities would be less than significant and no mitigation measures would be required. B. Post-Development Water Quality Impacts Storm water pollutants commonly associated with the land uses proposed by the Project (i.e., light industrial/warehouse) include bacterial indicators, metals, nutrients, pesticides, toxic organic compounds, sediments, trash/debris, and oil and grease. Based on current receiving water impairments (pursuant to the CWA s Section 303(d) list), the Project s pollutants of concern are pathogens and metals. To meet the requirements of the City s NPDES permit and in accordance with City of Chino Municipal Code Section , the Project would be required to prepare and implement a Water Quality Management Plan (WQMP), which is a site-specific post-construction water quality Page 4.9-9

10 management program designed to address the pollutants of concern of a development project via BMPs. Implementation of the WQMP ensures the on-going protection of the watershed basin. The Project s Preliminary WQMPs, prepared by Hall & Foreman, are included as Technical Appendices I2 and I3 to this EIR. As identified in Technical Appendix I2, the proposed Project is designed to include on-site structural source control BMPs consisting of water quality/detention, as well as operational source control BMPs (including but not limited to: the installation of water-efficient landscape irrigation systems, storm drain system stenciling and signage, and implementation of a trash and waste storage areas) to minimize, prevent, and/or otherwise appropriately treat storm water runoff flows before they are discharged from the site and minimize the release of pollutants of concern. As identified in Technical Appendix I3, the Project s proposed off-site improvements (i.e., Hellman Avenue extension) would incorporate vegetated swales and biofiltration systems to minimize and/or otherwise appropriately treat storm water runoff flows before they discharged into the City s storm drain system. Compliance with the WQMPs would be required as a condition of Project approval (pursuant to Municipal Code Section ) and long-term maintenance of onsite water quality features would be required to ensure their long-term effectiveness. Therefore, water quality impacts associated with long-term operational activities would be less than significant. In addition to the WQMP, the NDPES program also requires certain land uses (e.g., industrial uses) to prepare a SWPPP for operational activities and to implement a long-term water quality sampling and monitoring program, unless an exemption has been granted. On April 1, 2014, the California State Water Resources Control Board adopted an updated new NPDES permit for storm water discharge associated with industrial activities (referred to as the Industrial General Permit ). The new Industrial General Permit, which is more stringent than the existing Industrial General Permit, becomes effective on July 1, Once the new NPDES Industrial General Permit becomes effective on July 1, 2015, the Project would be required to prepare a SWPPP for operational activities and implement a long-term water quality sampling and monitoring program or receive an exemption. Because the permit is dependent upon the operational activities of the buildings, and the Project s future building occupants and their operations are not known at this time, details of the SWPPP (including BMPs) or potential exemption to the SWPPP operational activities requirement cannot be determined at this time. However, based on the requirements of the NPDES Industrial General Permit, it is anticipated that the Project s mandatory compliance with all applicable regulations would further reduce potential water quality impacts during long-term operation. Based on the foregoing analysis, the Project would not violate any water quality standards or waste discharge requirements during long-term operation. Impacts would be less than significant. Page

11 Threshold 2: Would the Project substantially deplete groundwater supplies or interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level (e.g., the production rate of pre-existing nearby wells would drop to a level which would not support existing land uses or planned uses for which permits have been granted)? No potable groundwater wells are proposed by the Project. In addition, the Project would abandon all active and inactive water wells located on the Project site (a CDA well is located on the northeast corner of Remington Avenue and Van Vliet Avenue, which is not a part of the proposed Project and will remain in place). The conversion of the Project site s overlying agricultural water rights would allow the City of Chino Water Utility to apply for additional groundwater production credit through an Agricultural Land Use Conversion. The City s water utility relies on local potable groundwater as a source of its water supply (in addition to imported water from the Metropolitan Water District of Southern California, desalted water, and recycled water) (Chino, 2003a, p ). Therefore, because the Project proposes to abandon the existing wells on the Project site, the existing overlying agricultural pool rights associated with those wells could be transferred to the public purveyor, resulting in a potential increase to the Chino Water Utility s water rights. For a detailed discussion of water supply and demand, refer to Subsection 4.14, Utilities and Service Systems. Accordingly, implementation of the proposed Project would not substantially deplete groundwater supplies and its impact to groundwater supplies would be less than significant. Development of the Project would increase impervious surface coverage on the property, which would in turn reduce the property s ability to infiltrate surface water into the Chino groundwater basin. A majority of the groundwater recharge in the Chino groundwater basin occurs in the northern portion of the Basin, north of the City of Chino, within percolation basins located throughout San Bernardino County (Chino, 2010b p ; CBWM, 2006). The Project is located in the southern portion of the Chino groundwater basin and would not physically impact any of the major groundwater recharge facilities in the Basin and, therefore, would not result in substantial, adverse effects to local groundwater levels. Additionally, the Project would install 15 water quality/detention basins, nine underground infiltration chambers, and approximately 33 acres of permeable landscape areas to maximize the percolation of on-site storm water runoff into the groundwater basin. Accordingly, buildout of the Project with these design features would not interfere substantially with groundwater recharge. For the reasons stated above, the Project would neither substantially deplete groundwater supplies nor interfere substantially with groundwater recharge such that there would be a net deficit in aquifer volume or a lowering of the local groundwater table level. Impacts would be less than significant. Page

12 Threshold 3: Would the Project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner which would result in substantial erosion or siltation on- or off-site? The Project site does not contain a stream or river and no streams or rivers are located in close proximity to the property. Storm water discharged from the Project site is directed to the Cucamonga Creek Channel, an engineered drainage channel located 0.4-mile to the east of the Project site. Therefore, implementation of the Project has no potential to alter the course of a stream or river. The proposed Project would alter existing ground contours of the Project site, which would result in changes to the site s existing drainage patterns; however, storm water runoff discharged from the Project site would follow a similar overall pattern across the Project site and would ultimately discharge into the Cucamonga Creek Channel as occurs under existing conditions (Hall & Forman, 2015a, p. 4-6). Storm water from the western-most portion of the Project site would be conveyed via storm drain facilities within Remington Avenue while the remainder of flows would be conveyed via a proposed 72-inch storm drain pipe within Hellman Avenue before ultimately discharging into the Cucamonga Creek Channel, similar to existing conditions (Hall & Forman, 2015b p. 3-1). The postdevelopment drainage characteristics of the Project site are illustrated on Figure 4.9-4, Proposed Conditions Hydrology Map. The Project proposes to construct an integrated system of underground storm drain pipes, catch basins, drainage swales, and water quality/detention basins to capture on-site storm water runoff flows, convey the runoff across the site, and treat the runoff with BMPs to minimize the amount of water-borne pollutants carried from the Project site. As summarized in the Project s WQMP (refer to Technical Appendices I2 and I3), the proposed Project BMPs, including the water quality/detention basins, are effective at removing sediment from storm water runoff (Hall & Forman, 2015a, n.p.). Compliance with the WQMP would be required as a condition of Project approval (pursuant to Municipal Code Section ) and long-term maintenance of on-site water quality features would be required to ensure their long-term effectiveness. The BMPs included in the WQMP will also address hydrologic conditions of concern through structural and programmatic requirements designed to both reduce and treat erosion and sedimentation concerns as they relate to potential runoff from the Project site (specifically BMP S3, S4, S5, and S6). Therefore, storm water runoff flows leaving the Project site would not carry substantial amounts of sediment. Because the Project would retain the site s general drainage pattern and because all on-site storm water runoff would be treated by BMPs designed to remove sediment, the Project would not result in substantial erosion or siltation on- site or off-site. In fact, replacement of the existing on-site dairy operations with the proposed Project would reduce erosion and sedimentation compared to existing conditions because the addition of paved surfaces and landscaping on the subject property would substantially reduce the area of bare, uncovered soils on the subject property and proposed water quality treatment BMPs would remove sediment from storm water runoff before it is discharged from the property. Impacts would be less than significant. Page

13 4.9 HYDROLOGY AND WATER QUATLITY - PHASE II Source(s): Hall & Foreman, Inc. ( ) NOT SCALE TO Lead Agency: City of Chino - PHASE II Figure PROPOSED CONDITIONS HYDROLOGY MAP SCH No Page

14 Threshold 4 Would the Project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, or substantially increase the rate or surface runoff in a manner which would result in flooding on- or off site? As discussed above under Threshold 3, the Project site does not contain a stream or river. Therefore, implementation of the Project has no potential to result in flooding on- or off-site due to the alteration of the course of a stream or river. In both the pre- and post-development conditions (long-term), all storm water runoff from the Project site would ultimately discharge into the Cucamonga Creek Channel. Under existing conditions, storm water is discharged from the Project site as sheet flow to the west (toward Remington Avenue) or to the south (toward Hellman Avenue), where runoff is captured by existing storm drains and routed to the Cucamonga Creek Channel. Under proposed, post-development conditions, all Project storm water runoff flows would continue to be conveyed west along Remington Avenue or south along Hellman Avenue, via a combination of existing and proposed storm drain facilities, before discharging into the Cucamonga Creek Channel, similar to existing conditions. Under post-development conditions, the Project would discharge approximately 150 cfs of storm water runoff from the subject property during the 100-year storm event, a decrease of approximately 63-percent as compared to existing conditions (Hall & Forman, 2015b, p. 5-2; Glauser, 2014). As previously described in Subsection 4.9.1C, the Project site is located within the Storm Drain Master Plan for Subarea 2 of the Chino Agricultural Preserve Area but proposes alterations to the Storm Drain Master Plan s planned storm drain network to accommodate new on-site and modified off-site storm drain facilities. The Project proposes to construct a 72-inch storm drain pipe segment beneath Hellman Avenue (between Remington Avenue and Kimball Avenue); construct a flow diversion structure at the southwest corner of the Project site (at Remington Avenue); and replace an existing 54-inch storm drain pipe beneath Hellman Avenue with a 72-inch storm drain pipe (between Remington Avenue and Autumn Path Street). The proposed storm drain improvements would have sufficient capacity to accommodate and convey storm water runoff flows generated by the Project and would convey the expected future storm water runoff flows associated with buildout of the surrounding area to a similar or better degree than the facilities originally planned by the Storm Drain Master Plan (Hall & Forman, 2015b, pp , 5-1). Based on the foregoing information, the Project would not result in flooding on- or off-site due to substantial alterations to the existing drainage pattern of the Project site or surrounding area or due to the introduction of substantial, unanticipated storm water flows. Impacts would be less than significant. Page

15 Threshold 5 Would the Project create or contribute runoff which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff? As discussed above under Threshold 4, proposed storm drain improvements have sufficient capacity to convey storm water runoff generated by the Project. In addition, Project implementation would not increase storm water flows from the Project site as compared to existing conditions and would not exceed the planned capacity of the Storm Drain Master Plan for Subarea 2 of the Chino Agricultural Preserve Area (as modified and supplemented by the Project). Accordingly, the Project would not create or contribute runoff which would exceed the capacity of any planned storm water drainage system, and impacts would be less than significant. As discussed under the analysis of Threshold 1, the proposed Project would be required to comply with a future SWPPP and the Project s WQMP (Technical Appendices I2 and I3), which identify required BMPs to be incorporated into the Project to ensure that near-term construction activities and long-term post-development activities of the proposed Project would not result in substantial amounts of polluted runoff. Therefore, with mandatory compliance with the Project s SWPPP and WQMP, the proposed Project would not create or contribute substantial additional sources of polluted runoff, and impacts would be less than significant. Threshold 6 Would the Project otherwise substantially degrade water quality? There are no conditions associated with the proposed Project that could result in the substantial degradation of water quality beyond what is described above in the responses to Thresholds 1, 3, and/or 5. Accordingly, no additional impacts would occur and mitigation is not required. Threshold 7 Would the Project place housing within a 100-year floodplain, as mapped on a federal Flood Hazard Boundary or Flood Insurance Rate Map or other flood hazard delineation map? The Project Applicant does not propose housing. Therefore, there is no potential for the Project to place housing within a 100-year flood hazard area. No impact would occur as a result of the Project. Threshold 8 Would the Project place within a 100-year flood hazard area structures which would impede or redirect flood flows? According to FEMA s FIRM No C9375H, the Project site is not located within a 100-year flood hazard zone (FEMA, 2014). Accordingly, the Project would not place structures which could impede or redirect flood flows within a 100-year flood hazard area. No impact would occur. Page

16 Threshold 9 Would the Project expose people or structures to a significant risk of loss, injury or death involving flooding, including flooding as a result of the failure of a levee or dam? The Project site is located approximately 0.4-mile west of a levee (i.e., Cucamonga Creek Channel); however, FEMA s FIRM No C9375H does not identify the Project as being located within an area subject to substantial flood hazards as a result of failure of the Cucamonga Creek Channel (FEMA, 2014). The Project site is located approximately 6.0 miles northeast of the Prado Dam; however, according to the City of Chino General Plan, the Project site is not located in an area subject to flooding hazards in the event of failure of the Prado Dam (Chino, 2010a, Figure SAF-3). Accordingly, the Project would not expose people or structures to a significant risk of loss, injury, or death involving flooding, including flooding as a result of the failure of a levee or dam. No impact would occur. Threshold 10 Would the Project cause inundation by seiche, tsunami, or mudflow? The Pacific Ocean is located more than 30 miles from the Project site; consequently, there is no potential for the Project site to be impacted by a tsunami. The Project site is not located near any steep hillsides and there are no steep hillsides present on the subject property; therefore, there is no potential for the site to be adversely affected by mudflow. The site is also not subject to flooding hazards associated with a seiche because the nearest large body of surface water (Lake Matthews, located approximately 12.0 miles southeast of the Project site) is too far away from the subject property to impact the property with a seiche. Accordingly, implementation of the Project would not expose people or structures to a significant risk of loss, injury, or death involving inundation by seiche, tsunami, or mudflow. No impact would occur CUMULATIVE IMPACT ANALYSIS The cumulative impact analysis considers construction and operation of the proposed Project in conjunction with other development projects in the vicinity of the Project site and resulting from full General Plan buildout in the City of Chino and surrounding areas. The analysis of potential cumulative impacts to hydrology and water quality is divided into six general topics of discussion by combining the Thresholds of Significance (listed above in Subsection 4.9.2) into groupings of like topics, as follows: 1) water quality (Thresholds 1 and 6); 2) groundwater supply and recharge (Threshold 2); 3) erosion and siltation (Threshold 3); 4) flood hazards (Thresholds 4, 7, 8, and 9); 5) storm water drainage system capacity (Threshold 5); and 6) other hazards (Threshold 10). A. Water Quality During Project construction, the proposed Project and any other project under construction or land use that generates water quality pollutants within the 2,650 square-mile Santa Ana River watershed would have the potential to result in a cumulative water quality impact, including erosion and sedimentation. Pursuant to the requirements of the State Water Resources Control Board and the Santa Ana RWQCB, all construction projects that disturb one (1) or more acres of land area are required to obtain a NPDES permit and obtain coverage for construction activities. In order to obtain Page

17 coverage, an effective site-specific SWPPP is required to be developed and implemented for all development projects. The SWPPP must identify potential on-site pollutants and identify and implement an effective combination of erosion control and sediment control measures to reduce or eliminate discharge of pollutants to surface water from stormwater and non-stormwater discharges. In addition, the Project and all cumulative developments would be required to comply with the Santa Ana RWQCB s Santa Ana River Basin Water Quality Control Program. With compliance to these mandatory regulatory requirements, the Project s contribution to water quality impairments during Project construction would be less than cumulatively considerable and mitigation is not required. As discussed in detail under the analysis of Threshold 1, a Project-specific WQMP has been prepared to identify pollutants of concern within the Project site s watershed and to identify specific BMPs to address those pollutants in Project-related storm water discharge under long-term operational conditions. Compliance with the WQMP would be required as a condition of Project approval pursuant to Municipal Code Section Other developments within the watershed would similarly be required to prepare site-specific WQMPs and to incorporate BMPs into site design as necessary to ensure that runoff does not substantially contribute to existing water quality violations. With implementation of the Project as designed, including the proposed water quality/detention basins and underground infiltration chambers, and mandatory compliance to the Project s WQMP (Technical Appendices I2 and I3), the Project s storm water runoff would not contribute to a violation of water quality standards or waste discharge requirements or exacerbate an existing violation. Accordingly, the Project s long-term operational impacts to water quality would be less than cumulatively considerable and no mitigation would be required. B. Groundwater Supply and Recharge As discussed under the analysis of Threshold 2, the Project does not propose to install any potable groundwater wells. The Project would abandon all active and inactive water wells located on the Project site and the pumping rights associated with these wells would revert to the City of Chino s Water Utility. The City s water utility relies on local potable groundwater as a source of its water supply; therefore, the abandonment of the wells on the Project site and the additional pumping rights granted to the City would increase the Chino Water Utility s water supply. For these reasons, the proposed Project would not deplete groundwater supplies, and would therefore have no potential to have a cumulatively considerable adverse impact to groundwater supplies. Although the proposed Project would increase the amount of impervious surfaces on site, the Project includes 15 water quality/detention basins, nine underground infiltration chambers, and approximately 33 acres of permeable landscape areas to maximize the percolation of on-site storm water runoff into the groundwater basin. Furthermore, most of the groundwater recharge in the Chino groundwater basin occurs in the northern portion of the basin, within designated (i.e., protected) groundwater recharge basins. The Project is located in the southern portion of the basin and would not adversely affect any designated groundwater recharge basin; therefore, there is no potential for the Project to have a cumulatively considerable adverse impact to groundwater recharge. (CBWM, 2013, Exhibit 3) Page

18 Based on these factors, the proposed Project would not result in cumulatively considerable impacts associated with depletion of groundwater supplies or substantial interference with groundwater recharge. C. Erosion and Siltation As discussed under the analysis of Threshold 3, the Project s proposed drainage plan would generally maintain the existing drainage patterns of the local area. Additionally, all on-site runoff would be treated by the Project s BMPs, which were selected for their ability to remove sediment from storm water runoff. Accordingly, due to the design of the proposed Project, there is less than significant potential for the Project to make a cumulatively considerable impact associated with substantial alterations to the existing drainage pattern of the site or area which could result in substantial erosion or siltation on- or off-site. D. Flood Hazards As discussed under the analysis of Threshold 4, the proposed Project would generally maintain the existing drainage pattern of the site and the proposed Project would not affect the course of any streams or rivers. In addition, the Project s proposed storm water drainage system is designed to ensure that peak flood volumes are reduced in comparison to those that occur under existing conditions and can be safely accommodated by existing, proposed, and planned master-planned storm drain facilities. Accordingly, because the Project would not increase flooding potential either on or off the site, the Project would have a less than significant cumulatively considerable impact associated with flooding. As discussed under Threshold 7, the Project does not involve the construction of residential uses, nor would the Project increase flood hazards on off-site properties such that residential structures could be impacted by floods. Accordingly, the Project has no potential to contribute to cumulative impacts associated with flooding of residential properties. As discussed under the analysis for Threshold 8, the Project site is not subject to substantial flood hazards and implementation of the Project would not impede or redirect flood flows such that downstream properties would be affected. Accordingly, the Project has no potential to make a cumulatively considerable contribution to flood hazard impacts. As discussed under the analysis of Threshold 9, the Project site is not subject to flood hazards associated with failure of a levee or dam. As such, the Project has no potential to contribute to cumulative impacts associated with such failures. E. Stormwater Drainage System Capacity As discussed under the analysis of Threshold 5, the Project s proposed storm drain improvements would have sufficient capacity to accommodate and convey storm water runoff flows generated by the Project and would convey the expected future storm water runoff flows associated with buildout Page

19 of the surrounding area to a similar or better degree than the facilities originally planned by the Storm Drain Master Plan. All development projects in the Chino Agricultural Preserve Area are required to demonstrate that storm drain capacity is available to service their anticipated flows. As such, cumulative impacts would be less than significant and the proposed Project s contribution of flows would thus be less than cumulatively considerable. F. Other Hazards The Project site is not subject to hazards associated with seiches, tsunamis, or mudflows. There are no components of the proposed Project that would increase the potential for seiches, tsunamis, or mudflows. Accordingly, the Project has no potential to make a cumulatively considerable contribution to these types of impacts SIGNIFICANCE OF IMPACTS BEFORE MITIGATION Threshold 1: Less-than-Significant Impact. The proposed Project would not violate any water quality standards or waste discharge requirements on a direct or cumulative basis. The Project is required to prepare a SWPPP to address construction-related water quality issues, and is required to comply with a site-specific WQMP and its associated BMPs. Threshold 2: Less-than-Significant Impact. The Project proposes no potable water wells and would not substantially impact the availability of potable groundwater in the Project area. The abandonment of existing wells on-site and their water rights would result in an increase in availability of potable groundwater in the Project vicinity. Threshold 3: Less-than-Significant Impact. The proposed Project would maintain the existing general drainage pattern of the site and would not result in substantial erosion or siltation on- or offsite. Threshold 4: Less-than-Significant Impact. The proposed Project would not significantly increase flood hazards and would not result in a substantial increase in the rate of surface runoff in a manner that would result in increased flood hazards on- or off-site. Threshold 5: Less-than-Significant Impact. The proposed Project would not create or contribute runoff which would exceed the capacity of existing or planned stormwater drainage systems, nor would the Project provide substantial additional sources of polluted runoff. Threshold 6: No Impact. There are no other components of the proposed Project with a potential to substantially degrade water quality. Threshold 7: No Impact. The proposed Project does not involve the construction of housing and is not located within a 100-year flood hazard area. Therefore, the Project would not place housing within a 100-year flood hazard area. Page

20 Threshold 8: No Impact. The proposed Project is not located within a 100-year flood hazard area, and would not result in the construction of new structures within a 100-year flood hazard area which could impede or redirect flood flows. Threshold 9: Less-than-Significant Impact. The proposed Project would not expose people or structures to a significant risk of loss, injury or death involving flooding, including flooding as a result of the failure of a levee or dam. Threshold 10: No Impact. The Project site is not subject to hazards associated with seiches, tsunamis, or mudflow MITIGATION Impacts would be less than significant; therefore, mitigation is not required. Page