Fighting Urban Stream Syndrome in South OC through Integration of Water Use and Water Quality Data
The 2015 paper on Urban Stream Syndrome published in the Journal of Environmental Science & Technology defined it as a reduction in stream health associated with catchment urbanization. South Orange County has undergone significant and rapid urbanization over the last 30-plus years, and many of the once ephemeral streams now suffer from acute urban stream syndrome, with symptoms that include altered flow, morphology, water quality, and ecological health and function.
The regional MS4 permit adopted by the San Diego Regional Water Board in 2013, requires development of a water quality improvement plan (WQIP) for each watershed management area (WMA) within its jurisdiction. The County of Orange/OC Public Works led the development of the WQIP for the south Orange County WMA which was recently submitted to the San Diego Regional Water Board in early April of 2017 for review and approval. OC Public Works and the municipalities of south Orange County took a holistic, data-driven approach in determining the highest priority water quality conditions (HPWQCs) to be addressed. A massive amount of data on the chemical, physical, and biological condition of streams was synthesized using a water quality index (Canadian Council of Ministers of the Environment Water Quality Index) to identify segments in poor ecological health. Continuous flow monitoring was also performed at nearly 80 stormdrain outfalls for two week time periods during dry weather to help prioritize catchments contributing significant non-stormwater flows. At the end of the prioritization process, Unnatural Water Balance and Flow Regime emerged as one of three HPWQCs.
A challenge in addressing this HPWQC will be to know where to target implementation of the proposed strategies on a catchment scale. Potential strategies include source control, incentives, and educational measures to promote water conservation and reduction of unnatural flows into the MS4 and structural BMP retrofit strategies to divert and capture water at high priority outfalls, where appropriate.This presentation will detail an innovative partnership project between OC Public Works and a key water/wastewater agency in the south OC WMA – Moulton Niguel Water District (MNWD). The CA Data Collaborative, which does work for MNWD, is also a partner on the project, which is aiming to integrate water use data from customers with water quality and flow monitoring data collected by OC Public Works to help fill data gaps and inform where to most effectively apply strategies to address the Unnatural Water Balance and Flow Regime HPWQC.
A key goal of the project is to develop a web-based decision making tool affectionately being called the “Urban Drool Tool” that will showcase a relationship between storm drain outfall discharge and water use inefficiency. This relationship ideally will help lead help lead both agencies to smart, well-informed management decisions. For example, where there are catchments with high flows during dry weather and high water inefficiency, targeted enhanced water conservation education may be selected as a strategy for implementation by both agencies. If there are high flows at an outfall but low water inefficiency in that catchment, it may make more sense to divert flows to the sanitary sewer system for reuse than increase public education.
CodeLabOC, a volunteer group of coders who look for community projects to hone their coding skills, have been enlisted to help develop some of the web-based tools and applications that will support this data integration. This is an exciting collaborative effort that could become a model approach for other watersheds suffering from Urban Stream Syndrome, and we are excited to have an opportunity to share the details of the project and its approach with CASQA.
Amanda Aprahamian is an Environmental Resources Specialist with the County of Orange in California. She works in the Data Management section of OC Public Works’ Environmental Resources Service Area. Amanda earned her Bachelor of Science degree in Earth System Science from the University of California, Irvine while minoring in Civic and Community Engagement. With the County of Orange Amanda has focused on streamlining data management and work processes, while exploring meaningful ways to visualize and daylight County water quality and hydrological data.
Monobina Mukherjee is a Water Resources Analyst at Moulton Niguel Water District (MNWD). She has a PhD in Environmental Economics with a focus on water economics and policy from the University of California, Riverside. She has published on California water issues in different peer reviewed journals. As a Water Resources Analyst at MNWD she helps the Planning and Finance department of the district in their financial and water conservation decisions by analyzing their rates and water data with statistical models and data analytics.