Skip to main content

Public Utilities

Other Special Study Projects

The City of San Diego has been actively working on, collaborating with other researchers or agencies, or supporting a large number of important special projects or enhanced ocean monitoring studies over the past 15+ years. Many of these projects were identified as the result a scientific review of the City’s Ocean Monitoring Program and environmental monitoring needs for the region that was conducted by a team of scientists from the Scripps Institution of Oceanography (SIO) and several other institutions, as well as in consultation with staff from the Regional Water Board, USEPA, SCCWRP and others. Such special studies represent a unique mechanism to focus monitoring efforts on specific questions as defined in the model monitoring program that was developed for large ocean dischargers in southern California. Links to workplans, final reports, etc, for some of these projects are provided below.

San Diego Moored Observation System Pilot Study

This project was designed to begin examining the dynamics of the receiving waters off San Diego in the vicinity of the Point Loma Ocean Outfall (PLOO) via a system consisting of moored temperature loggers (thermistor strings) and Acoustic Doppler Current Profilers (ADCPs). The thermistors enabled tracking of the thermocline, including its dynamics and strength, while the ADCPs measured currents to determine the major modes of circulation near the outfall. These static moorings were subsequently incorporated into the City’s Plume Tracking Monitoring Program (see below).

Point Loma Ocean Outfall Plume Behavior Study

This project was designed to determine the characteristic fates of the PLOO wastewater plume in the coastal waters off Point Loma using a combination of observational and modeling approaches. The study was successfully completed in 2012 and resulted in several important conclusions and recommendations. The City is currently in the process of implementing the major recommendations of this study via the Plume Tracking Monitoring Program (see below).

Plume Tracking Monitoring Program

This project addresses recommendations that the City should improve monitoring of the fate and behavior of wastewater discharged to the ocean via the SBOO and PLOO (see PLOO Plume Behavior Study above). The project involves the deployment of real-time oceanographic mooring systems (RTOMS) at the terminal ends of the PLOO and SBOO to provide real time data on ocean conditions, and the deployment of a remotely operated towed vehicle (ROTV) in conjunction with the RTOMS to enhance the collection of water quality data in order to provide higher resolution maps of plume dispersion and location via adaptive sampling. Additional details are available in the workplan approved by the Regional Water Board on April 25, 2018. The PTMP project is expected to significantly enhance the City’s environmental monitoring capabilities in order to address current and emerging issues relevant to the health of San Diego’s coastal waters, including plume dispersion, subsurface current patterns, ocean acidification, hypoxia, nutrient sources, and coastal upwelling. Results from this project have subsequently become integrated into the City’s Biennial Receiving Waters Monitoring Reports.

Sediment Toxicity Monitoring

This project started with a 3-year pilot study implemented as a new joint regulatory requirement for the Point Loma and South Bay outfall regions in 2015. Findings for the 2016–2018 pilot study were summarized in a final project report that included recommendations for continued sampling through 2023. The findings are now being utilized as part of a Sediment Quality Triad Assessment alongside analyses of sediment chemistry and macrofaunal community data to provide a snapshot of the region’s sediment quality and benthic community structure.

San Diego Sediment Mapping Study

This represents a two-phased project conducted in collaboration with SCCWRP in which sampling was conducted in 2004 for Phase 1 and in 2012 for Phase 2. Phase 1 was designed to estimate spatial variance in sediment quality and benthic infauna community condition over an area spanning both the PLOO and SBOO monitoring regions (>400 km2). In contrast, the goal of Phase 2 was to utilize an optimal resolution (spacing) of sample sites derived in part from Phase 1 results to generate a completed map of sediment chemistry conditions within a more restricted 30 km2 area surrounding the PLOO. The findings for Phase 1 and the preliminary results from Phase 2 were included as a summary report in Appendix C.4 of City of San Diego’s 2015 NPDES Permit Renewal Application and 301(h) Modifications - Point Loma Ocean Outfall. A more comprehensive final project report is planned.