Gobernadora Multi-Purpose Basin

South Orange County, CA

PACE provided design services for the 26-acre Gobernadora Multi-Purpose Stormwater Treatment and Storage Project to recycle urban dry weather and stormwater runoff, provide greening and recreational opportunities, and create regional flood control benefits. The 11-acre upper basin and 16-acre lower basin work in tandem to improve water quality in Gobernadora Creek and reclaim water for non-potable use and groundwater recharge. Capturing and treating urban runoff and storm flows also reduces downstream erosion and sedimentation.

The system is successful due to its dynamic hydraulic operating system incorporating automated controls that can respond to both low flow and high storm flow conditions in the creek. Operational flexibility is facilitated through multiple hydraulic systems, including a dry weather nuisance runoff diversion structure featuring a rubber inflatable dam system to divert flows into natural water quality treatment and infiltration cells, an elevated side weir to capture storm flows for peak flow storage, a secondary rubber dam for large flood flow water level control, sedimentation basin and fine straining, disinfection, and a pump station to transport treated flows for recycled water applications.

The system accommodates a projected 350 to 800 acre-feet of dry weather flow recovery and provides storm flow detention up to the 100-year storm event. The high-quality precedents and practices used have allowed the basin to serve as a prototype for other areas with similar urban runoff and storm flow difficulties within the Santa Margarita Water District, the southern California region, and throughout the State.

Key Features:

• Hydrology, hydraulics, sediment analyses
• Diversion structures
• Side weirs / spillways
• Multiple interconnected basins
• Flood detention
• Groundwater infiltration
• Water quality treatment
• Accurate construction cost estimates
• Operations and Maintenance manuals