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The Challenge
The Gates Canyon Stormwater Improvement Project sought to manage urban runoff from 105 acres of residential land in Calabasas, California. This area drains to Las Virgenes Creek, which is a tributary to Malibu Creek (and, ultimately, Santa Monica Bay), which have been listed as impaired due to nutrients and sedimentation, among other factors. In addition to improving water quality in the receiving streams, this project also aimed to reduce potable water demand. These conflicting objectives, coupled with the inconsistent and unpredictable nature of rainfall patterns in this area, posed a significant management challenge for the Los Angeles County Public Works.
The Solution
The Gates Canyon Park stormwater capture and reuse system utilizes continuous monitoring and adaptive control (CMAC) to meet water quality improvement and reuse objectives at a single facility. The system is configured to optimize the facility's storage capacity by constantly maintaining a reservoir of water for use as irrigation within the park while also reserving space for unexpected inflows. The CMAC system prevents overflows from the system by continuously monitoring the 72-hour weather forecast and preparing the system for predicted rain events. If a storm is predicted, the system will proactively drain water from the cistern by pumping it into a series of infiltration wells, making room for the incoming storm. If the cistern water level exceeds the target reservoir volume for any reason, it will also reactively pump out the excess water to maintain its target levels.
The Results
Since implementation, the CMAC-controlled capture and reuse system at Gates Canyon Park has demonstrated reliable performance. Recent data analysis indicates water usage for irrigation may average at least 5M gallons per year, and infiltration occurs as needed to provide storage space for incoming runoff. Ultimately, this project's success demonstrates how intelligent, forecast-informed control transforms static infrastructure into a dynamic, multi-benefit resource. This adaptive approach allows communities to turn the challenge of unpredictable rainfall from a liability into a valuable asset for both the public and the environment.
