Stafford Dam Adjustable Spillway Gate (ASG)

One of the alternatives that ranked high in the 2022 Study was increasing storage capacity in Stafford Lake using a “Spillway Notch Slide Gate” now referred to as the Stafford Dam Adjustable Spillway Gate (ASG) project. This project focuses on Stafford dam’s downstream spillway control notch that measures 10-feet wide by 3-feet tall. Installation of an adjustable gate across this notch would allow the District to store an additional 3 feet of water in Stafford Lake, which equates to approximately 726 acre-feet (236 million gallons) of increase storage volume. This volume of water could then be treated at the District’s nearby Stafford Treatment Plant (STP) during the plant’s operational period in the months when the District faces its peak demands. District staff began preliminary planning work on the ASG project in August 2022 and identified a project roadmap that included preliminary California Environmental Quality Act (CEQA) work, dam stability and seepage analysis, concrete spillway assessment, hydrologic and hydraulic analysis, potential need for revised inundation mapping, biological field surveying, review of water rights, environmental permitting, full CEQA clearance, design, bidding, and construction phases.