Op-Ed: The benefits of capturing stormwater
Our local groundwater supplies are critically important to the communities of La Cañada Flintridge, Altadena and Pasadena. On average, they comprise about half of our drinking water and usually are the cheapest source of supply. The current drought has impacted these groundwater levels, and they are at historic lows. Three retail utilities in our local communities have lost most or all of their groundwater well supplies. To solve this problem we need to capture more stormwater in the winter to replenish our local groundwater aquifers.
Los Angeles County Department of Public Works (Public Works) is currently planning two important projects in the Arroyo Seco Watershed that will directly and indirectly benefit the capture and reuse of stormwater flows. We urge the residents of our local communities to support Public Works in the timely implementation of both projects.
Stormwater in the Arroyo Seco Watershed is the primary source to replenish the basin. Currently, some stormwater can be spread into percolation ponds specifically designed to replenish the Raymond Basin aquifer. These ponds, located on the eastern edge of Hahamongna Park, are owned and maintained by the city of Pasadena. The majority of stormwater during normal and above-normal rainfall years however, is not percolated into the local aquifer. Once the water goes beyond these ponds, it can no longer be captured for use. It flows from Devils Gate Dam down the Arroyo into the L.A. River and then to the Pacific Ocean. Recently, Public Works held public meetings to discuss the Devil’s Gate to Eaton Water Conservation Project. The project plans to conserve the excess stormwater that would otherwise be released to the ocean by conveying some flows captured behind Devil’s Gate Dam to the Eaton Wash area through a pipeline. The project also outlines the possible construction of a facility that could pump excess stormwater back up to the higher-elevation spreading ponds in the Arroyo. Details concerning construction of this pump-back facility and appropriate cost-sharing require further vetting.
The addition of such a facility is of critical importance in retaining local water resources within the Monk Hill Sub-basin that serves the city of Pasadena and many of our local water providers. Coordination and cooperation of the city and local providers will be necessary to recondition those areas within the Arroyo that have historically been used for local water recharge. An ongoing commitment to operate and maintain those spreading areas will be necessary if we are to maximize conservation of our local water supplies.
Additionally, drastic changes since the Station fire due to an influx of debris flows hampers the ability of stormwater percolation in the Raymond Basin. Public Works seeks to remove a vast majority of accumulated sediment within the watershed through its Devil’s Gate Reservoir Sediment Removal and Management Project. The primary objective of the project is to maintain flood control capacity and safety. However, the removal of sediment will also provide a secondary essential benefit. It will allow recharge behind the dam increasing groundwater levels and water supply reliability in the area. Public Works has also committed to habitat protection and restoration with this project. Thus, the project will achieve co-equal goals of flood control and conservation and habitat restoration.
We all need to support these stormwater capture projects in our local watersheds for the integrated benefits they provide, especially concerning stormwater capture. We invite our residents to support Public Works for their vision and leadership in creative approaches to protecting our homes from flood and conserving more stormwater, our primary source of drinking water.
Submitted by: NINA JAZMADARIAN, general manager, Foothill Municipal Water District; JOHN BEDNARSKI, president, Las Flores Water Co.; LISA YAMASHITA-LOPEZ, general manager, Rubio Cañon Land & Water Assn.; MEL MATTHEWS, general manager, Kinneloa Irrigation District; DOUG CAISTER, general manager, La Cañada Irrigation District; ROBERT HAYWARD, general manager, Lincoln Avenue Water District; BOB FAN, general manager, Valley Water Co. and TIM FLYNN, general manager, Mesa Crest Water Co.