FROM: James D. Herberg, General Manager
Originator: Kathy Millea, Director of Engineering
SUBJECT:
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REGIONAL URBAN RUNOFF DIVERSION OPTIMIZATION STUDY
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GENERAL MANAGER'S RECOMMENDATION
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RECOMMENDATION:
Information Item.
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BACKGROUND
The Orange County Sanitation District (OC San) accepts dry weather urban runoff flows from local agencies to improve water quality at beaches and Newport Bay. OC San’s Dry Weather Urban Runoff Diversion Program allows the diversion of up to 10 million gallons per day (MGD) of dry weather urban runoff. OC San has issued 21 Dry Weather Urban Runoff Permits with a total capacity of 6 MGD. These diversions are owned and operated by local agencies, including the City of Huntington Beach, the City of Newport Beach, OC Public Works, and Irvine Ranch Water District.
In addition to improving water quality, another potential benefit is increased water availability for recycling. This additional flow may be needed should future wastewater flows decrease due to more stringent indoor water conservation standards. Reduced wastewater flows could free up system capacity both in the OC San collection and treatment systems to accept additional urban runoff diversions. It is critical that diversions of urban runoff do not cause operational problems in the collection system or treatment plants. The program is carefully managed under a permit-based system that regulates the volume and quality of runoff being diverted into the collection system to prevent spills, treatment process upsets, ocean discharge permit violations, biosolids contamination, or impacts to the Groundwater Replenishment System.
RELEVANT STANDARDS
• Comply with environmental permit requirements
• Maintain collaborative and cooperative relationships with regulators, stakeholders, and neighboring communities
• Meet volume and water quality needs for the GWRS
PROBLEM
OC Public Works must address water quality impacts caused by urban runoff under Municipal Separate Storm Sewer System (MS4) regulatory requirements. In addition, OCWD may need additional flows for GWRS in the future due to reduced wastewater flows at OC San. These problems and OC San’s capacity to accept additional urban runoff flows have not been comprehensively studied.
PROPOSED SOLUTION
Collaborate with OCWD and OC Public Works to conduct a comprehensive engineering study to identify feasible opportunities for OC San and OCWD to accept additional dry and wet weather runoffs within the existing capacities of both agencies’ infrastructure.
ATTACHMENT
The following attachment(s) may be viewed on-line at the OC San website (www.ocsan.gov) with the complete agenda package:
• Presentation