City of Pomona, CA
Home MenuPedley Spreading Grounds Pond Enhancements Project
Project Description:
The Pedley Spreading Grounds (PSG) Pond Enhancements Project proposes targeted infrastructure improvements to increase stormwater capture, infiltration, and operational efficiency at the site.
Key elements of the Project include:
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Modifying an existing storm drain system along Mills Avenue to allow additional stormwater to flow into the PSG
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Regrading and deepening the existing basins to increase storage capacity and improve flow control
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Enhancing the facility’s ability to capture and infiltrate stormwater during moderate storm events
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Incorporating educational and park-related improvements near Chaparral Park to increase community awareness of water sustainability and stormwater management
Community Benefits:
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Increased Local Water Supply: Capturing and recharging stormwater helps reduce dependence on imported water.
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Improved Water Quality: The Project reduces pollutants in stormwater before they reach local rivers and the ocean.
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Drought Resilience: Enhancing groundwater recharge prepares the community for more frequent and severe drought conditions.
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Educational Opportunities: Planned park and educational features will help residents and students learn about water conservation and stormwater systems.
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Environmental Protection: Improved stormwater management supports healthier groundwater and surface water resources.
Project Timeline:
Site Background:
The project site is a key part of the City of Pomona's water and stormwater infrastructure. It is a multifunctional site featuring:
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Groundwater wells
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Drinking water treatment facility (Pedley Filtration Plant)
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Drinking water reservoirs
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Stormwater infiltration basins
The PSG features three infiltration basins that capture stormwater flows from adjacent neighborhoods through storm drain pipes, excess surface water flows from the San Gabriel mountains, and water flows from the water treatment facility. The captured waters percolate through the soil to replenish underground aquifers.
Funding Sources and Collaboration:
In 2020, the Project was awarded funding from the Los Angeles County Flood Control District's Safe, Clean Water Regional Program with the intent of diverting local urban runoff and deepening the basins underlying the PSG.
Additional support is provided through regional partnerships, including the East San Gabriel Watershed Management Group, Six Basins Watermaster, Kizh Nation, and Yuhaaviatam of San Manuel Nation. Special thanks to the City of Claremont, Claremont Unified School District, Chaparral Elementary School, and the California Botanic Gardens for their engagement and coordination throughout the project.