WatershedWatershed ManagementManagement ImprovementsImprovements inin thethe ChinoChino BasinBasin

PREPARED FOR:

Chino Basin Water Conservation District 4594 San Bernardino Street Montclair, 91763

Associates 13620 Metropolis Avenue, Suite 110 Fort Myers, Florida 33912 O 239.204.5300 F 866.398.2426 JUNE 2018 FINAL REPORT www.waterscienceassociates.com

Watershed Management Improvements in the Chino Basin

PREPARED FOR:

Chino Basin Water Conservation District 4594 San Bernardino Street Montclair, California 91763

Roger Copp Senior Water Resource Modeler

JUNE 2018 FINAL REPORT W. Kirk Martin, P.G. 79 Principal Hydrogeologist

Associates

TABLE OF CONTENTS

SECTION A INTRODUCTION AND BACKGROUND ...... 1 SECTION B ASSESSMENT OF EXISTING WATERSHED MANAGEMENT ...... 3 SECTION C PLANNED FUTURE IMPROVEMENTS ...... 6 SECTION D CONFLUENCE REGIONAL WATER RESOURCE PROJECT CONCEPTUAL DESIGN ...... 7 SECTION E WATER QUALITY BENEFITS OF THE CONFLUENCE REGIONAL WATER RESOURCE PROJECT ...... 12 SECTION F ADDITIONAL PROJECTS TO CAPTURE AND RECHARGE STORMWATER...... 13 SECTION G RECOMMENDATIONS ...... 14 SECTION H REFERENCES ...... 16

FIGURES

Figure 1 Map of the Chino Basin ...... 2 Figure 2 Recharge Basins in the Chino Basin ...... 3 Figure 3 Estimated Streambed Iniltration in the Chino Basin and Increased Recharge Resulting from Recharge Master Plan ...... 4 Figure 4 Measured Water Levels in the Brooks Recharge Basin ...... 8 Figure 5 Measured Water Leves in Montclair Recharge Basins 1, 2, and 3 ...... 9 Figure 6 Estimated Capture Volumes for the Proposed Confluence Project and Total Annual Flow for Chino Creek at Schaeffer Ave...... 10 TABLES

Table 1 Summary of Flows Captures by the Confluence Project ...... 7 Table 2 Water Quality Benefits Associated with the Confluence Project ...... 12

APPENDICES

Appendix A Water Quality Analysis for the Confluence Water Storage Project Table A-1 Average Concentrations of Water Quality Constituents for Chino Creek at Central Ave...... A-2 Figure A-1 Measured Fecal Coliform Levels vs Flow for Chino Creek at Central Ave...... A-2 Figure A-2 Measured Electrical Conductivity vs Flow for Chino Creek at Central Ave...... A-2 Figure A-3 Measured Total Suspended Solids vs Flow for Chino Creek at Central Ave...... A-3 Figure A-4 Measured Nitrate Nitrogen for Chino Creek at Pine Ave...... A-3

Appendix B Proposed Water Quality Monitoring Program Table B-1 Information on Sampling Locations ...... B-1 Table B-2 Proposed Water Quality Constituents for Analysis ...... B-1 Figure B-1 Map of Sampling Stations ...... B-2

SECTION A INTRODUCTION AND BACKGROUND Water Science Associates conducted a planning level assessment of existing and proposed watershed management efforts in the Chino Basin with the objective of recommending additional projects that will have the potential to increase groundwater recharge, reduce salt content in the Chino Basin aquifers, and improve water quality. This effort was conducted for the Chino Basin Water Conservation District (CBWCD).

The Chino Basin is located primarily in San Bernardino County in east of Los Angeles County, north of the , and includes the cities of Upland, Montclair, portions of Rancho Cucamonga, Ontario, Eastvale, Chino, , Norco, Pomona, and others. The sphere of influence for CBWCD includes portions of Upland north of I-210, portions of Rancho Cucamonga north of I-210 and east of I-15, and Fontana. The Chino Basin is bounded by the Cucamonga Basin and the to the north, the Rialto-Colton Basin to the northeast, the chain of the Jurupa, Pedley, and La Sierra Hills to the southeast, the Temescal Basin to the south, the Chino and Puente Hills to the southwest, and the San Jose Hills and Pomona and Claremont Basins to the northwest as shown in Figure 1.

The Chino Basin has experienced years of land use changes that have reduced groundwater recharge, extracted groundwater for agricultural and public water supply, and introduced contaminants such as total dissolved solids (TDS) and nitrate-nitrogen in the aquifer (Wildermuth Environmental and Black & Veatch, 2001; Wildermuth, 2015). These activities have reduced groundwater levels in the basin and contributed to land subsidence in portions of the basin by more than seven feet along with ground fissuring (Wildermuth Environmental, Inc., 2017a). In September 2000, the Superior Court of the State of California approved the Peace Agreement and authorized the implementation of the Chino Basin Optimum Basin Management Program to protect and enhance the safe yield of the Chino Basin. The Peace Agreement II of 2007 is an update to the original agreement (CBWM, 2013). Prior to and following the Peace Agreement, numerous projects have been implemented to increase groundwater recharge while minimizing excess TDS concentrations in the groundwater of the Chino Basin. The CBWCD involved in a Four Party Agreement and has worked collaboratively with Chino Basin Watermaster, San Bernardino Control District, and Utilities Agency to develop and implement a recharge master plan that was developed in 2007 and is updated every five years. Due to the extent of water challenges in the Chino Basin, a detailed summary of legal and engineering activities related to the Peace Agreement and the Recharge Master Plan will not be provided in this report. Additional information can be obtained by reviewing the References section of this report.

The following tasks were completed as part of this project: • Assessment of existing watershed management efforts within the Chino/San Antonio Basins • Evaluation of watershed management efforts currently being planned and/or constructed by Chino Basin watershed management agencies, such as the Chino Basin Watermaster (CBWM), Inland Empire Water Utilities Agency (IEUA), City of Pomona, Monte Vista Water District (MVWD), San Bernardino County, Santa Ana Watershed Protection Authority (SAWPA), Metropolitan Water District of Southern California (SCMWD), and the Chino Basin Desalter Authority. • Assist Wagner & Bonsignore in development of a conceptual design of a water storage facility on a 15.76-acre property recently purchased by the CBWCD which is located at the junction of Chino and San Antonio Creeks south of Riverside Drive in unincorporated

1 San Bernardino County, CA. This property is referred to herein as the Confluence Regional Water Resource Project or the Confluence Project. • Identify potential water quality benefits of the Confluence Project and recommend a monitoring program for the project. • In addition to the Confluence Project, evaluate the potential for additional capture and recharge of basin flows that will reduce the overall salt content of the aquifers of Chino Basin.

The assessment of existing and proposed recharge efforts within Chino Basin provides a basis for the conceptual design of the proposed Confluence Regional Water Resource Project.

Figure 1 – Map of the Chino Basin (Source: Wildermuth et.al., 2010)

2 SECTION B ASSESSMENT OF EXISTING WATERSHED MANAGEMENT The Parties to the Peace Agreement have been working collaboratively to implement recommended recharge projects. Reports such as the 2013 Amendment to the 2010 Recharge Master Plan Update (Wildermuth Environmental, Inc., 2013) provide details on implementation progress and status reports are provided weekly (e.g. IEUA, 2018) and semi-annually (Wildermuth Environmental, Inc., 2017b). The 2013 Amendment to the 2010 Recharge Master Plan Update describes existing spreading basins (see Figure 2), enhancements to improve recharge basin performance, and recharge via aquifer storage and recovery (ASR).

Lower Cucamonga Basins

Figure 2 – Recharge Basins in the Chino Basin (Source: Wildermuth Environmental, 2013)

One of the unintended consequences of water resources development projects from the 1950’s through the 1990’s was a loss of groundwater recharge due to concrete lining of San Antonio, Chino, Cypress, Cucamonga, Deer, Day, and San Sevaine Creeks. Historically, runoff from the

3 San Gabriel mountains flowed south into the alluvial deposits of the Chino Basin and infiltrated through the coarse sediments in the upper Chino Basin. As shown in Figure 3, recharge projects implemented from the 2002 Recharge Master Plan have done much to replace that infiltration. Additional groundwater recharge is anticipated from projects that are planned for implementation as defined in the 2013 Amendment.

Blue bars indicate estimated recharge from stormwater, red bars indicate recharge due to 2002 Recharge Master Plan improvements

Figure 3 – Estimated Streambed Infiltration in the Chino Basin and Increased Recharge Resulting from Recharge Master Plan (Source: State of the Basin Report, 2016)

Recharge water is supplied by stormwater capture, recycled water from within the Chino Basin, and imported water from a number of sources including Metropolitan Water District of Southern California (SCMWD) which provides water from the State Water Project (SWP) and Colorado River Aqueduct (CRA). One problem with imported water is that the cost of water from SCMWD has increased three-fold in recent years (Table 2-9, 2013 Amendment), and water availability in recent years is less certain. Because CRA water has high TDS levels (Wildermuth et al, 2010), it is not permitted to be used for recharge in the Chino Basin. Recent studies indicate that SCWMD will only be able provide water in 3 out of 10 years, which is substantially less than historical availability rates of 7 of 10 years (2013 Amendment, p 4-4). The potential decrease in water availability from external sources highlights the need to maximize capture of local water from within the Chino Basin. Accordingly, the Chino Basin Facilities Improvement Project (CBFIP) is focused on enhancing capture of stormwater and recycled water (Wildermuth Environmental, Inc., 2013). Improvements to recharge basins implemented as part of the CBFIP have been made since 2005 to improve groundwater recharge with an objective of recharging 130,000 AFY.

The improvements to date have totaled $50,000,000 and yielded over $52,000,000 of water into the Chino Basin over the seven years between 2005/06 and 2011/12 (page 4-2 2013 Amendment). The Chino Basin monitored and/or estimated actual recharge rate for FW 2005/06 through FW 2011/12 was 30,182 AFY, substantially less than the initial objective of 130,000 AFY.

4 Actual recharge rates at a number of basins between 2005-2006 and 2011-2012 were lower than planned due to compaction or clogging of basin surface with fine sediments or biological growth, including Banana, Brooks, Dedez, Eley, Etiwanta Debris, Hickory, Jurupa, Lower Day, Montclair, Upland, and Victoria. Recharge rates matched or exceeded planned rates for basins that are in the upstream portions of sub-watersheds including 7th and 8th Street, College Heights, RP3, Turner, and San Sevaine.

The 2013 RMPU contained recommendations to improve 10 recharge facilities and an implementation plan for their planning, design, and construction. Since completion of the 2013 RMPU, the IEUA and CBWM have entered into agreements to plan, design, and construct five of the recommended facility improvements (Wildermuth, 2018). The 2018 RMPU currently underway is evaluating a number of approaches to increase recharge

Aquifer Storage and Recovery (ASR) is a technology that is used across the U.S. and ASR wells are owned by the Monte Vista Water District (MVWD) and the City of Chino in Montclair. Treated SWP water is injected at four MVWD wells during the seven-month period of October through April. Typical injection rates are 3,500 AFY with a maximum of 5,400 AFY. Because of pricing changes for SWP-supplied water, the stored waters are not recovered for subsequent treatment and delivery to MVWD customers due to cost considerations.

5 SECTION C PLANNED FUTURE IMPROVEMENTS Improvements are underway to improve basin infiltration rates and/or water delivery rates. Examples include maintenance activities to remove fine sediments that have accumulated in the recharge basins, grading to increase detention time in the basins, improvements to the Wineville Basin and construction of a pipeline to convey additional water to basins with high infiltration rates, such as an additional pump station to convey water from the San Sevaine channel to the RP3 basins. The Montclair basins 1 and 2 have additional infiltration capacity (pers. comm., Andy Campbell, IEUA, 2018) that could be realized if additional flows can be directed to those basins from either Montclair Basin 4, additional recycled water, and/or stormwater captured from San Antonio Creek downstream of the Brooks basin.

The 2016 State of the Basin report evaluated groundwater levels at numerous wells for the period of 1977 through 2016 and the analysis indicates that groundwater levels are decreasing in the eastern portion of the basin due to groundwater production rates exceeding the rates of groundwater recharge in recharge basins. These findings are consistent with modeling conducted for the CBWM that show declines in groundwater storage due to continued increases in urban water supply demand (Wildermuth Environmental, Inc., 2015). “The projected decline in groundwater levels and storage through 2044 would be less if a combination of stored water and wet-water recharge (see definition in next sentence) were used to meet future replenishment obligations.” (page 7-20). Stored water is groundwater that was not pumped from the aquifer, and wet-water recharge is water recharged from imported water sources. Additional stormwater recharge, when available, is needed to: • offset increasing groundwater production • minimize the risk of reductions of imported water • provide recharge water that has lower concentrations of TDS and nitrate-nitrogen

The 2018 update to the recharge master plan is currently in preparation (pers. Comm. Mark Wildermuth, 2018). This plan includes a number of proposed improvements to capture stream flows in the southern portions of the Chino Basin and pump the captured water upstream to basins such as San Sevaine, Upland, and Montclair Basins 1 & 2 that have higher infiltration rates.

IEUA, the City of Pomona, and Monte Vista Water District evaluated introduction of water to Montclair Basins 1 and 2 to recharge the surficial aquifer with the objective of mitigating land subsidence southwest of the Montclair recharge basins (Carollo, 2016). The source waters are the City of Pomona recycled water combined with water pumped from Spadra Well 19. The City of Pomona recycled water plant and Spadra Well 19 are located approximately 5 miles west of the Chino Basin. Alternative 2a consists of advanced treatment of 3.5 MGD with surface spreading in the Montclair Basins 1 and 2 and was the top ranked alternative. The advanced treatment process includes membrane filtration, reverse osmosis, and ultraviolet advanced oxidation process with peroxide (UV/AOP). US/AOP treatment is able to oxidize certain constituents or chemical of emerging concern such as certain endocrine disrupting compounds, pharmaceutical, and personal care products, and other microconstituents such as 1.4-dioxane and NDMA. The treated water will be conveyed via a new pump stations and approximately 6-7 miles of new force main. The estimated capital cost for this alternative is $64,498,000 with an annual operating cost of $2,245,250. The annual cost over a 30-year period is $1,460/AF. This alternative is being evaluated in greater detail by IEUA.

6 SECTION D CONFLUENCE REGIONAL WATER RESOURCE PROJECT CONCEPTUAL DESIGN The CBWCD purchased a 7.4-acre parcel of land in Chino, CA that is located just upstream of the confluence of Chino and San Antonino Creeks. The land was acquired to further the goals of the CBWCD, which are to protect the Chino Groundwater Basin in order to guarantee that current and future water needs will be met (http://www.cbwcd.org/204/Our-Mission). Studies were initiated in 2017 to evaluate hydrology of Chino and San Antonio Creeks and hydrogeology of the property (Wagner & Bonsignore 2018a and 2018b). Following the Wagner & Bonsignore evaluations, initial planning work was conducted as part of this project by Water Science Associates and Wagner & Bonsignore for the Confluence Project to determine the best possible use of the property to capture flows from Chino and San Antonio Creeks and to utilize the captured water in a beneficial manner to achieve the goal of balancing groundwater withdrawals and recharge in the Chino Basin. The team determined the most appropriate use of the site by addressing the following questions:

1. What is the percolation capacity of the site? Borings were drilled at three locations on the proposed site (Wagner & Bonsignore, 2018b). In addition, published regional geologic mapping information was evaluated. The on-site boring logs indicate alluvial soils consisting of layers of sand, silt, clay, and gravel. Layers of fat clay and sandy clay were encountered between the depths of 23 to 41 feet, and sandstone and claystone were encountered at depths of 50 to 60 feet. Based on the regional geologic information and the borings, it was concluded that the site would have low recharge rates (0.05 ft/day).

2. Are there sufficient flows in Chino and San Antonio Creeks that can be diverted into the Confluence Project site? Analysis of USGS flow data for Chino Creek at Schaefer Avenue (located 0.85 miles south of the Confluence Project site) indicates that there is an average of more than 2,200 acre-feet of basin runoff that can be diverted to the site. This analysis excluded OC59 flows and was adjusted for drainage area. Table 1 indicates that the percentage of flows during the dry season between 2010 and 2017 ranges from 4 to 28%. The analysis conducted as part of this project suggests that the site is suitable to be used as a water storage facility.

Table 1 – Summary of Flows Captured by the Confluence Project Avg Flow, AF/day Wet/Dry Season Statistics Water Year May-Sept Oct-Apr Wet/Dry % Dry Weather Flow 2010-2011 1.42 6.42 4.5 18% 2011-2012 1.81 4.56 2.5 28% 2012-2013 1.16 3.41 2.9 25% 2013-2014 1.19 3.18 2.7 27% 2014-2015 0.55 3.64 6.6 13% 2015-2016 0.16 4.02 25.8 4% 2016-2017 0.47 5.65 12.1 8% Note: Wet season is defined as the period between October and April. Statistics based on estimated flow deliveries from Chino and San Antonio Creeks to the proposed Confluence Project. OC59 flows were excluded.

7 3. Can the water be used beneficially in the local area surrounding the Project site? There are a number of IEUA recycled lines that are located downstream of the Project site, and stored water from the project site could be delivered by gravity for introduction into those recycled pipelines. However, based on discussions with IEUA, the existing available supply of recycled water from the Carbon Canyon Water Reclamation Facility exceeds the demand for recycled water during the winter when most flows are available from the Confluence Project, therefore adding flows from the Confluence Project site to the recycled lines would increase treated wastewater discharges to the Prado Reservoir. Therefore, the stored water in the Confluence site currently cannot be used beneficially to enhance the recycled water program. Water demand is forecasted to increase in the City of Pomona, and once demand increases, the Confluence Project outflows could be conveyed via the existing pipeline through Chino Hills and Diamond Bar to the City of Pomona. However, this pipeline route is more than five miles in length and requires inter- local agreements with Los Angeles County, the Rowland Water District, and the Walnut Valley Water District. This option may be feasible in the future; however it cannot be relied upon at the current time.

4. Can the water be pumped north to recharge basins adjacent to San Antonio Creek in Montclair and Upland and is there capacity in those basins to accept the water? The recharge basins upstream of the Confluence Project include the Brooks Basin and Montclair Basins 1, 2, 3, and 4 in the City of Montclair, the Upland Basin and the College Heights East and West Basins in the City of Upland. Engineering analyses conducted by Wagner & Bonsignore indicate that it is feasible to pump water from the Confluence Project up to the Brooks and/or Montclair Basins. Measured water level data for the Brooks and Montclair Basins was obtained from the CBWM (data is collected by IEUA, and was condensed by CBWM) and is presented in Figures 4 and 5. The Brooks basin does not normally have available capacity, but there is excess capacity in Montclair Basin 2 which has infiltration rates in the range of 1.5 ft/day.

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Brooks Measured Water Depth Max Depth Brooks

Figure 4 – Measured Water Levels in the Brooks Recharge Basin

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MC2 MC1 MC3 Max Depth MC 1&2 Max Water Depth MC3

Figure 5 – Measured Water Levels in Montclair Recharge Basins 1, 2, and 3

5. Does the Confluence Project provide a water quality benefit to the Middle Santa Ana River Watershed? The TMDL for the MSAR has a pollutant reduction goal of 37 billion CFU/day (San Bernardino County FCD, 2011). Construction and operation of a water storage facility on the Confluence Project site would reduce bacterial loads to the MSAR, therefore there is a water quality benefit to this project. In addition, diversion of water from Chino and San Antonio Creeks would reduce nitrogen, suspended solids, and heavy metals loads to the Prado Reservoir.

6. Is additional recharge needed in Management Zone MZ1? The 2013 Amendment to the 2010 Recharge Master Plan (Wildermuth Environmental, 2013) indicates that the CBWM appropriative water right permit from the State Water Resources Control Board Permit No. 21225 allows for diversion of 68,500 AFY of surface water for recharge in the Chino Basin. Recharge over the past six years has averaged approximately 11,000 AFY, therefore additional recharge is needed. Also, ground subsidence is persisting in northwest portion of Management Zone 1 (MZ1) of the Chino Basin, which includes the area southwest of the Montclair Recharge basins (2016 State of the Basin Report). Therefore, transferring water from the Confluence Project site uphill to the Montclair Basins is highly beneficial.

As listed above, the Confluence Project can capture runoff from Chino and San Antonio Creeks that will reduce pollutant loads to the Prado Reservoir, and the best option for beneficial use of the captured flows is conveyance upstream to the Brooks and Montclair recharge basins via a new force main. The following discussion highlights the key components of the initial conceptual design.

The Confluence Project is located at the confluence of Chino and San Antonio Creeks south of Riverside Drive and east of the Chino Valley Freeway. Because of storm drain inputs from Pomona that enter both Creeks south of the Brooks Basin, there is available runoff that can be captured in the Confluence Project. While the conceptual design is on-going, the current plan is to have a two-cell off-line water storage area with an invert elevation of 710 feet and a maximum water elevation of 730 feet. Inflow pipelines will allow for inflows from Chino and San Antonio Creeks. Pneumatically-actuated gates (Obermeyer gates) will be raised during storm events and will allow for gravity inflows into the Confluence Basin. Pump stations will convey flows into the Confluence Basin once water levels in the Basin reach water levels in the creeks. The pump station capacity will be 25 cfs for each creek and will convey the runoff into the Basin up to an

9 approximate elevation of 729 feet. The first cell of the Confluence Project is intended for initial settling of coarse sediments, and the second cell will be for polishing. A portion of the water stored in the basin is anticipated to percolate at a low rate of 0.05 feet/day, and a 7.5-cfs pump station will be constructed to convey water up along the San Antonio Creek to Montclair Basin #2. Montclair Basin #2 is 13.5 acres and has a storage volume of 258 AF. Utilizing data from IEUA, maximum reported recharge for all four Montclair basins was 155 AF/day (IEUA, 2018). The outlet of Montclair Basin #2 will be reconfigured to maximize groundwater recharge.

There are significant water recharge and water quality benefits that will result from this project. Studies conducted by IEUA have confirmed that the Montclair Basins capture more than 90% of the annual flow from the San Antonio Creek watershed upstream of the Montclair Basins. Because there are numerous storm drain outfalls to San Antonio Creek and Chino Creek upstream of the junction of these two creeks, the Confluence Project is well-suited for additional capture of runoff from the City of Pomona, Montclair, and Claremont that enters the creeks downstream of the Montclair and Brooks recharge basins.

Analysis of USGS flow data for Chino Creek gage (located just south of the Confluence Project) indicates that substantial amounts of water can be captured by the Confluence Project. Figure 6 presents a comparison of the combined annual runoff from Chino Creek downstream of the Confluence Project to captured flows in the Confluence Project. Using USGS flow data from 1999 through 2017, the basin can capture an average of approximately 2,200 AFY (range = 900 – 3,700 AFY). The captured flow represents an average of 37% of the annual runoff volume from Chino Creek at Schaeffer Avenue (range = 13 – 100%). If only flows during wet weather events are captured, the annual capture volume will decrease to approximately 1,500 AFY.

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Annual Total Runoff, Chino Creek Captured Flow

Figure 6 – Estimated Capture Volumes for the Proposed Confluence Project and Total Annual Flow for Chino Creek at Schaeffer Ave

Figure 6 indicates that a significant percentage of the annual runoff from Chino and San Antonio Creeks is not captured during the wet years of 1999, 2000. 2003-2005, 2010, 2011, and 2016. An analysis of December 2010 illustrates the challenge of capturing stormwater in recharge basins. The flows during December 16-23, 2010 ranged from 15 – 844 cfs, yielding a combined runoff volume of more than 5,000 AF. The Confluence Project proposed storage capacity is 140 AF, and with a maximum inflow pump capacity of 50 cfs, the basin will be filled in 1.4 days. Combined flows for Chino and San Antonio Creeks were less than 50 cfs 96.3% during the period

10 of 1/1/1999 and 9/30/2017. Because most of the flows are less than 50 cfs, the inflow pump stations will operate at full capacity for less than 4% of the time, or 253 days out of the 6,848 days between 1/1/1999 and 9/30/2017. Accordingly, it will not be cost effective to construct a basin that can capture all of the runoff from Chino and San Antonio Creeks, and it is definitely not cost effective to construct pump stations that can capture all of the runoff. A detailed value engineering analysis has not been completed for the Confluence Basin storage and inflow capacity, therefore it is possible that some adjustments may need to be made to the proposed project. Regardless, analyses conducted to date suggest that the Confluence Project can provide significant hydrologic benefits to the Chino Basin.

11 SECTION E WATER QUALITY BENEFITS OF THE CONFLUENCE REGIONAL WATER RESOURCE PROJECT Since the captured flows are removed from the surface water flows from the Chino Creek watershed, the pollutant removal rate for water quality pollutants such as bacteria and Total Suspended Solids (TSS) will be in the range of 37% of the annual load (see Table 2 for pollutant load capture information). Water quality data were reviewed for a monitoring station on Chino Creek at Central Avenue, which is downstream from the outfall from the Carbon Canyon Water Reclamation Facility. A limited amount of data was also obtained from the East San Gabriel Valley Watershed Management Group (ESGV), which has conducted stormwater sampling in a storm drain that is located under Ficus Street that enters Chino Creek just downstream of Riverside Drive (personal communication, J. Abelson, Stantec, 2018). The data suggest that total dissolved solids levels decrease with increasing flow rates, which is consistent with other studies in the region (See Appendix A for additional information). TDS levels measured in storm drain stormflow discharges to Chino Creek south of Riverside Drive and upstream of the Confluence Project are less than 50 mg/l, while groundwater TDS concentrations in the southern portion of the Chino Basin are in the range of 500 to 2,000 mg/l (Wildermuth Environmental, 2017b).

Available water quality data for coliform bacteria, TSS, and nitrate-nitrogen do not suggest significant trends in concentration as a function of flow, therefore it is appropriate to use average concentrations to calculate load reductions. Based on measured levels for Chino Creek at Central Avenue of E. coli, a bacteria indicative of contamination from human waste, the captured bacterial load is 3% of the calculated load from Chino Creek (load calculated using concentration data from Central Avenue and flow data from the USGS gage at Schaeffer Avenue). Therefore, it is possible that the Confluence Project can reduce annual bacterial inputs to the Prado Reservoir by 3%. Additional monitoring of bacteria closer to the Confluence Project will likely indicate that the proposed storage project may have a more significant impact on bacterial pollutant loads to the Prado Reservoir.

Table 2 – Water Quality Benefits Associated with the Confluence Project Constituent Unit Concentration Average Load Range TSS Mg/l 10.5 64,570 lb/yr 26,311 – 104,851 Bacteria MPN/100 ml 1,378 1.1 billion CFU/da 0.43 – 1.71 Note: concentrations are from different locations and may not be representative of concentrations for Chino and San Antonio Creeks at the Confluence Project site.

12 SECTION F ADDITIONAL PROJECTS TO CAPTURE AND RECHARGE STORMWATER The Confluence Project is an example of how stream flows can be successfully captured and used beneficially to achieve the goals of the Peace Agreement. There are numerous other locations where similar efforts are likely feasible. Two potential projects are highlighted in this section.

The Grove Avenue Basin is located east of the Confluence Project and receives runoff from a poorly drained area of Ontario, CA (see Figure 2 for the location of existing recharge and flood control basins). It is located south of Riverside Drive and west of Grove Avenue. Grove Avenue acts as a river during heavy rains with rapidly flowing water that fills the road. There are concerns regarding storing additional water in the Grove Avenue Basin due to concerns regarding safety of the southeastern portion of the basin. If those embankment safety concerns cannot be resolved, additional land should be considered for acquisition adjacent to the Grove Avenue Basin.

Cucamonga Creek south of the Ontario Airport has high wet season flows and steady baseflow (the baseflow is primarily from recycled water sources). The Lower Cucamonga East and West Basins are located on either side of Cucamonga Creek south of Chino Avenue. These basins are owned by the San Bernardino County Flood Control District were designed for flood control of large runoff events and are rarely used to capture small and mid-size runoff events. The CBWM has evaluated these basins as a possible location for temporary storage of stormwater. Due to low percolation rates at this site, recharge is not feasible. A pipeline has been evaluated to pump the water north to the San Sevaine Basins (see Figure 2 for location) for recharge (Wildermuth Environmental, 2013). This is a project that could be implemented in a similar manner to the Confluence project. The Lower Cucamonga Basins are located 2.2 miles down-gradient from the Grove Avenue Basins, and water could flow via gravity from Grove Avenue to the Lower Cucamonga Basins for subsequent delivery via the proposed force main to the San Sevaine Basins.

13 SECTION G RECOMMENDATIONS The following recommendations are offered for consideration by CBWCD: • The proposed project will be able to capture a significant percentage of annual runoff from Chino and San Antonio Creeks, and the diversion of the flows from those creeks could potentially provide significant benefits to multiple stakeholders. • Recharge at the Confluence project site will be limited; therefore the stored water should be utilized elsewhere. • Treatment of the capture flows using low-tech stormwater treatment methods is recommended to reduce TSS levels. • Current demand of recycled water in the vicinity of the Confluence project site is less than available supplies during the November to March period when the Confluence Project will typically be able to provide water. Therefore, at this point in time the captured flows should be pumped upstream to existing recharge basins along the San Antonio Creek for groundwater recharge. • The water should be pumped to Montclair Basin #2 which has high recharge rates. The groundwater recharge at that location is up-gradient from areas of subsidence southwest of the Montclair recharge basins. • It may be possible to recharge pumped flows in the Brooks Basin, however information from IEUA indicates that the Brooks Basin may not have storage capacity during some periods. In addition, studies conducted for the IEUA indicate that the area of subsidence is north of the Brooks Basin (Carollo, 2016). • Pre-treatment is recommended for inflows from Chino and San Antonio Creeks. The portion of the property that abuts Riverside Drive directly south of South Reservoir Street is an ideal location for a grassed buffer conveyance that can serve as a forebay to the main area of the project. • Additional treatment may be appropriate at the south end of the project site. A 0.6-acre sand filter with under-drains would provide effective removal of TSS. Annual average accumulations of 1-inch (82 CY) of sediment should be expected in the sand filter. Maintenance of the sand filter would likely be required approximately once every year or two. • The water quality benefits associated with the Confluence Project should contribute to the overall goal of reducing pollutant loads to the Prado Reservoir. The Confluence Project provides groundwater recharge at an equivalent annual cost of $850/AF. Water quality benefits are in the range of $55/lb TN and $29/lb TSS. The equivalent annual cost is calculated over a 20-year period and includes construction cost, O&M cost, and an O&M inflation rate of 3.5%. • Flow and water quality sampling is recommended to establish baseline water quality and hydrologic benefits, and the sampling should continue for 3 -5 years after project initiation to document actual benefits associated with this project. Coordination of the sampling program and analysis of project performance with local universities is recommended. A proposed water quality monitoring program is presented in Appendix B. • CBWCD should maintain a database of measured water levels in the Montclair and Brooks recharge basins to confirm availability of recharge capacity. CBWCD already has access to the SCADA water level data that is collected by IEUA, therefore maintaining this database should not involve significant effort. • This type of project is recommended for Cucamonga Creek using the existing Lower Cucamonga Basins as the initial storage area. This evaluation should be coordinated with on-going analysis being conducted by CBWM.

14 • Additional storage should be evaluated in the vicinity of the Grove Avenue Basin. Grove Avenue acts as a river during heavy rains with rapidly flowing water that fills the road. There are concerns regarding storing additional water in the Grove Street Basin due to concerns regarding safety of the southeastern portion of the basin. If those embankment safety concerns cannot be resolved, additional land should be considered for acquisition adjacent to the Grove Avenue Basin. Flows from the Grove Avenue Basin can be delivered via gravity to the Lower Cucamonga Basins for subsequent force main delivery to recharge basin in the upper reaches of Cucamonga, Day, or San Sevaine Creeks. Pipeline delivery of runoff from the southern portion of the Chino Basin upstream to recharge basins with high infiltration rates is currently being considered by CBWM.

15 SECTION H REFERENCES Carollo, 2016. Feasibility Study of Recycled Water Interconnections Between City of Pomona, Monte Vista Water District, and Inland Empire Utilities Agency, Final Report, June, 2016.

Chino Basin Watermaster, 2015. Chino Basin Subsidence Management Plan.

IEUA, 2018. IEUA RW GWR O&M Plan for Week Beginning Feb 12, 2018.

San Bernardino County Flood Control District, 2011. San Bernardino County Comprehensive Bacteria Reduction Plan, submitted to the California Regional Water Quality Control Board, Santa Ana Region, Report submitted by CDM to the San Bernardino County FCD.

Stantec, 2018. Personal communication with Jon Abelson, Stantec, consultant working for the San Gabriel Valley Watershed Management Group, April 11, 2018.

U.S. Department of the Interior Bureau of Reclamation, 2012. Colorado River Basin Water Supply and Demand Study.

Wagner & Bonsignore, 2018a. Peliminary Hydrologic Analysis, Su Hai Property Site Investigation, Chino and San Antonio Creeks Diversion and Recharge Project, prepared 2/5/18 for CBWCD.

Wagner & Bonsignore, 2018b. Preliminary Soil and Geologic Feasibility Study, Chino and San Antonio Creeks Diversion and Recharge Project, Su Hai Property – 3359 Riverside Drive, Chino. Prepared for the Chino Basin Water Conservation Distric, January 4, 2018.

Wildermuth Environmental, 2013. 2013 Amendment to the 2010 Recharge Master Plan Update, Prepared for Chino Basin Watermaster and Inland Empire Utilities Agency.

Wildermuth Environmental, Inc. 2015. 2013 Chino Basin Groundwater Model Update, Recalculation of Safe Yield Pursuant to the Peace Agreement, prepared for the Chino Basin Watermaster.

Wildermuth Environmental, Inc., 2017a. Task 3 and Task 4 of the Work Plan to Develop a Subsidence Management Plan for the Northwest MZ-1 Area: Development and Evaluation of Baseline and Initial Subsidence-Management Alternatives, Oct. 19, 2017 draft Technical Memorandum to the Ground-Level Monitoring Committee, Chino Basin Watermaster.

Wildermuth Environmental, Inc., 2017b. 2016 State of the Basin Report, June, 2017, prepared for the Chino Basin Watermaster.

Wildermuth Environmental, Inc., 2018. Section 4 of the 2018 RMPU, draft section under review.

Wildermuth Environmental, Inc. and Black & Veatch, 2001. Optimum Basin Management Program, Recharge Master Plan, prepared for the Chino Basin Watermaster.

Wildermuth Environmental, Black & Veatch, Wagner & Bonsignore, Sierra Water Group, prepared for the Chino Basin Water Master, Chino Basin Water Conservation District, and Inland Empire Utilities Agency, 2010. 2010 Recharge Master Plan Update, Prepared for the Chino Basin Watermaster, June 2010.

16

APPENDIX A WATER QUALITY ANALYSIS FOR THE CONFLUENCE WATER STORAGE PROJECT

APPENDIX A – WATER QUALITY ANALYSIS FOR THE CONFLUENCE WATER STORAGE PROJECT

Measured water quality data for Chino Creek at Central Avenue (4.7 miles downstream of the Confluence Project) were provided by Santa Ana Watershed Project Authority (SAWPA) that included measured flows, bacteria (Fecal Coliform and E. coli), total suspended solids (TSS) and electrical conductivity. Nitrate-nitrogen data was available for Chino Creek at Pine Avenue, which is 2.6 miles downstream of Central Avenue. Vegetation is evident in Chino Creek at Central Avenue, and Chino Creek has a natural channel cross section at Pine Avenue that is within the backwater of . Due to the long distance between the proposed Confluence Project at the two monitoring locations on Chino Creek, it is expected that pollutant concentrations may be different. Figure A-1 presents measured Fecal Coliform levels as a function of flow. Table A-1 presents average levels of Fecal Coliform, E. coli, TSS, and electrical conductivity for flow less than 5 cfs and for greater than 5 cfs. There is no apparent relationship between Fecal Coliform levels and flow due to two samples with high levels at low flows. High Fecal Coliform levels at low flows generally indicates transient populations utilizing creek channels for temporary shelter. Due to the high variability of Fecal Coliform levels for low flows, average levels for the two flow classes are relatively similar. Figure A-2 presents electrical conductivity (a parameter related to Total Dissolved Solids) as a function of flow. Generally, conductivity decreases with increasing flow. TSS concentrations vs flow are presented in Figure A-3, and the data indicate high variability at low flows and no apparent trends with increasing flow. Nitrate nitrogen data for Chino Creek at Pine Avenue at the upstream end of the Prado Reservoir are presented in Figure A-4 indicate some seasonal variability with lower concentrations during the summer.

The East San Gabriel Valley Watershed Management Group (ESGV Group) is conducting monitoring of wet weather flows for the Cities of Claremont, La Verne, Pomona, and San Dimas. That sampling program includes collection of stormwater samples from the Fiscus Street stormdrain that discharges to Chino Creek downstream of Riverside Drive. The monitoring program has collected composite stormwater samples for three events between July 2016 and June 2017. The average TSS concentration for the stormdrain was 47 mg/l, which is higher than the data for Chino Creek at Central Avenue. The average Electrical Conductivity for the three samples was 61 uS/cm, less than 10% of the measured values in Chino Creek at Central Ave.

The available electrical conductivity data for Chino Creek at Central Avenue and the ESGV Group sampling of the Fiscus storm drain indicate lower concentrations at higher flows. Data that has been reviewed to date suggest that average values of TSS, nitrogen, and bacteria should be used to calculate pollutant load reductions. Additional data collection is recommended for Chino Creek and San Antonio Creek near the proposed Confluence Project to determine if wet weather flows have lower TDS concentrations, and if so, the target flow range to capture for subsequent aquifer recharge. Also, TSS, bacteria, and nitrate-nitrogen concentrations in the vicinity of the proposed Confluence Project should be better quantified.

A-1

Chino Creek at Central Ave, Fecal Coliform vs Flow 40,000 35,000 30,000 25,000 20,000 15,000 10,000 5,000 Fecal Fecal Coliform MPN/100 ml 0 0 100 200 300 400 500 600 700 800 900 1,000 Flow, cfs

Figure A-1 – Measured Fecal Coliform Levels vs Flow for Chino Creek at Central Ave

Table A-1 – Average Concentrations of Water Quality Constituents for Chino Creek at Central Ave Avg FC Avg E. coli TSS Elec cond, MPN/100 ml MPN/100 ml mg/l us/cm Flow less than 5 cfs 1,648 1,033 10 936 Flow more than 5 cfs 1,992 1,378 11.2 797

Chino Creek at Central Ave, 801MSC7 1400

1200

1000

800

600

400 Conductivity, us/cm Conductivity,

200

0 0 20 40 60 80 100 120 140 Flow, cfs

Figure A-2 – Measured Electrical Conductivity vs Flow for Chino Creek at Central Ave

A-2

Chino Creek at Central Ave, 801MSC7 40

35

30

25

20

TSS, mg/l TSS, 15

10

5

0 0 20 40 60 80 100 120 140 Flow, cfs

Figure A-3 – Measured Total Suspended Solids vs Flow for Chino Creek at Central Ave

Nitrate-Nitrogen, Chino Creek at Pine Ave 16

14

12

10

8 mg/l 6

4

2

0 1/1/06 1/1/07 1/1/08 12/31/08 12/31/09 12/31/10 12/31/11 12/30/12

Figure A-4 – Measured Nitrate-Nitrogen for Chino Creek at Pine Avenue

A-3

APPENDIX B PROPOSED WATER QUALITY MONITORING PROGRAM

APPENDIX B – PROPOSED WATER QUALITY MONITORING PROGRAM

The Confluence Regional Water Resource Project is a proposed off-line storage basin in unincorporated San Bernardino County located at the confluence of Chino and San Antonio Creeks that is being developed by the Chino Basin Water Conservation District. A conceptual design is being prepared by Wagner & Bonsignore with assistance from Water Science Associates. The Confluence Project will capture flows during wet and dry periods for initial stormwater treatment within the Project site. Outflows from the Project site will be conveyed via force main upstream along the San Antonio Creek to the Montclair Recharge Basins. As part of the design criteria for planned system improvements, additional data are needed on stormwater quality and flows. A general water quality monitoring strategy is provided herein. Additional information on the conceptual design is in preparation.

There are some water quality data available for Chino Creek at Central Avenue for TSS, TDS, Fecal Coliform, and E. coli. Additionally, flows in Chino Creek have been measured at Central Avenue for most stormwater events. However, because Central Avenue is downstream from the Confluence Project site and water quality transformations occur in the concrete channel, the data is not considered representative of that passes by the Project site. In reviewing measured data from the USGS gaging stations, flows in San Antonio Creek and Chino Creek are often very low to non-existent. Because of the infrequency of significant runoff events, this sampling program should be conducted with the objective of getting as much data as possible for each monitored event.

There are also some streamflow data available for San Antonio Creek at a USGS gaging station located just upstream of the Confluence Project site at Riverside Avenue. Analysis of this data indicates that measurable runoff associated with wet weather events is experienced relatively infrequently, ranging from one to 10 events per wet season. In San Antonio Creek, there were 10 events for the 2012 – 2013 season (a wet year) that exceeded a peak flow of 20 cfs, with one event that had a peak flow of 62 cfs, and one event with a peak flow of 178 cfs.

Water quality data obtained from the California Regional Water Quality Control Board Santa Ana Region, Santa Ana Water Project Authority and the City of Pomona for Chino Creek, San Antonio Creek, and Cucomonga Creek indicate that TDS concentrations decrease with increasing discharge. Storm water quality data collected by Stantec for the East San Gabriel Valley Watershed Management Group for the stormdrain indicated in Figure A-1 indicates TDS concentrations are below 5- mg/l, substantially lower than for dry weather concentrations in Chino Creek at Central Ave. Because groundwater TDS levels are rising in the Chino Basin, the water quality monitoring program proposed in this plan focuses on determining the quality of wet weather flows in Chino and San Antonio Creeks. Because fecal coliform is the parameter of concern in the Santa Ana River Watershed, special attention will be paid to sample collection techniques that are appropriate for determination of bacterial levels in the creeks. The following monitoring program is proposed:

• Establishment of two automatic monitoring stations on Chino and San Antonio Creeks at locations south of a storm drain outfall to Chino Creek (see Table 1 and Figure 1). Metal housings and metal conduit for sample collection tubing will be installed from the top of bank to the channel inverts. The location of the stations shall be set in a location that is closest to the channel point that has the greatest depth when channel water depths are less than one foot. o The sampling equipment shall be Teledyne ISCO portable sampler model 6712 or approved equal.

B-1 o One-liter individual bottles shall be utilized to allow for analysis of multiple samples during events.

• Depending on the local site considerations, the sampling locations may need to be moved slightly up or downstream depending on site-specific conditions.

• During the first stormwater two events, three manual grab samples shall be collected from the storm drain on Chino Creek downstream of Riverside Drive and analyzed for the water quality constituents shown in Table 2 below. To the extent possible, water depths and velocities will be measured at the outfall. This storm drain is 9 feet in diameter, and the invert elevation is 714.5 ft.

• For the two monitoring stations (one each on Chino and San Antonio Creeks) the following sampling protocols should be followed: o Power will be supplied by a deep-cycle marine battery with a solar charger to recharge the battery. o Flow measurement shall be Teledyne ISCO flow meter Model 730 with bubbler water level record or approved equal. The bubbler tube will have to be attached to the bottom of the metal conduit. o Automatic samplers shall be set to initiate sampling at a critical depth (most likely 0.1 or 0.2 feet), and samples will be collected hourly until water depths drop below the critical depth (this will be finalized in the field). o Samples from the automatic sampler will be analyzed for TDS, TSS, Total Phosphorus, nitrate, ammonia, and Total Kjeldahl Nitrogen. Five samples shall be selected for analysis that represent first flush, rising limb, peak flow, and recession limb of the hydrograph. o Where possible, field staff will deploy to measure channel flow during larger events where water depths exceed three feet. If possible, approximately 5 measurements will be needed during high depth periods. Velocity measurements are needed at a minimum of 10 points across the channel unless an acoustic doppler velocity meter is used that measures velocities across the entire channel width.

• Flow measurements will be required for Chino Creek to establish a water depth/flow rating curve. Measurement of flow in Chino Creek will be very challenging. In-channel velocities prevent field crews from measuring flows in the channel using a wading rod. Turbulent flows complicate flow measurement using Price AA meters or acoustic doppler velocity meters. Close coordination with CBWCD will be required prior to finalizing the flow measurement strategy for Chino Creek.

• The San Antonio gaging station bubbler water levels can be correlated to water depths and flows at the San Antonio Creek USGS gaging station located at Riverside Avenue.

• Monitoring will continue until results are available for 10 events.

• Manual grabs (5 per event) will be collected in sterilized containers for bacterial analysis (FC and E. coli). Microbial Source Tracking using Source Molecular of three samples per event will be analyzed for two human and one dog source to determine the source of the bacterial contamination.

• Arrangements will be made with the laboratory to process Fecal Coliform and E. coli samples if the runoff events take place during the weekend so that the six-hour holding time is not exceeded.

B-2 • Rainfall shall be measured during the events using a tipping bucket rain gage at the San Antonio Creek monitoring station.

Manual sampling for the parameters listed above is recommended once per month.

Table B-1 – Information on Sampling Locations Location Channel Low Top of Channel Inv., ft Chord, ft Headwall or Width, ft sidewall, ft Chino Creek Site 710 N/A 724.5 39.6 San Antonio Creek Site 713.1 N/A 726.2 30

Table B-2 – Proposed Water Quality Constituents for Analysis Parameter Method of Sampling Total Dissolved Solids Automatic sampler, discreet bottle Total Suspended Solids Automatic sampler, discreet bottle Nitrate-Nitrogen Automatic sampler, discreet bottle Total Kjeldahl Nitrogen Automatic sampler, discreet bottle Total Phosphorus Automatic sampler, discreet bottle Fecal Coliform bacteria Garb sample, sterile bottle E. coli bacteria Garb sample, sterile bottle Microbial Source Tracking Garb sample, sterile bottle

Flow, stage, and water quality data and field procedures shall be analyzed after each event to identify any challenges in sample collection, such as clogging of intakes, battery failure, probe failures, vandalism, or challenges in obtaining accurate depth and flow measurements. Flow data collected in the San Antonio automatic sampler shall be compared to flow data at the USGS gaging station, and significant differences in estimated flows shall be investigated. Plots of pollutant concentration vs flow shall be prepared using all sample results collected to date. The results of this data analysis shall be provided to CBWCD twice during each wet season in a brief technical memorandum. An annual report shall be provided that presents measured rainfall, water quality data and flows, computed storm volumes, and pollutant loads for each event for TSS, TP, and TN. Volume-weighted mean TDS concentrations should be presented as well as geometric mean fecal coliform and E. coli levels. The annual report shall also provide the results of the Microbial Source Tracking.

B-3

Figure B-1 – Map of Sampling Stations

B-4