NV5 has been supporting the City of San Diego with as-needed water quality technical support since 2014. Support has included providing regulatory technical reviews and issue papers for Phase I Municipal Permits and Statewide Regulations that may impact the City. NV5 supported the Chollas Creek Dissolved Metals Total Maximum Daily Load (TMDL) Monitoring and Reporting Program. Support on the TMDL Program has included quality assurance and report writing on the Chollas Creek Water Effects Ratio (WER), as well as monitoring and reporting support for the Chollas Creek TMDL Special Studies Program, . Report quality assurance and technical editing was provided for the Shelter Island Copper TMDL.
NV5 developed the Municipal Separate Storm Sewer System (MS4) Flow SystemTM to specifically help municipalities identify, assess, and eliminate non-stormwater flows in their storm drains. The web-enabled flow data system relies on ultra-sonic sensors, wireless data loggers and a customizable web portal.
As part of an on-going project, NV5 has been deploying this flow data system in more than 100 deployments since 2018 throughout the City of San Diego’s MS4 network to collect accurate measurements of real-time flow rates and trends to establish baseline flow conditions, measure the effectiveness of strategies implemented toward reducing or eliminating dry weather flows and estimate pollutant load reductions. Project staff are provided access to near real-time flow conditions via the web portal to evaluate flow patterns utilizing site-specific graphs and reports of the daily, weekly, and monthly flow patterns. The City’s staff use the data and statistics to determine when significant flows were occurring and to schedule dry weather flow observations for a higher probability of success at finding a meaningful source of the flow pattern. Once sites were sufficiently characterized or flows were eliminated, the equipment was easily removed and installed in a new location, providing scalability and coverage with relatively fewer instruments.
