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City of Los Angeles Proposition O BMP Optimization Water Quality Monitoring

CWE managed and coordinated eight wet-weather and seven dry-weather monitoring events over three years. These were conducted at up to 35 sites spread among 11 Proposition O BMP project locations.  Various sites provided additional safety challenges.  Assorted lakes, median strips, underground vaults, and vehicle traffic required special consideration and planning.  A coordinated safety/hazards approach was generated for each sampling location.

A Monitoring Plan and Quality Assurance Project Plan was generated to best optimize sample gathering and analysis.  Coordinating with the City of Los Angeles’ Environmental Monitoring Division (EMD), a standards process was established for sample collection, logging, delivery, processing, and analysis.

Monitoring includes analysis of constituents such as nutrients, metals, algae, bacteria, and pesticides.  Timing is very important when gathering samples.  Storm events move large amounts of runoff into public waterways.  Gathering samples during these events is critical.  Using strategic weather tracking, aided by regional forecasting, CWE planned and conducted multiple storm sampling events across many key locations.  Samples are drawn at specific time intervals during a storm event to best establish a bell curve of the concentration of the specific constituents.

Results were analyzed in comparison with applicable limitations due to Total Maximum Daily Loads (TMDLs), California Toxics Rule (CTR), the basin plan, and Municipal Separate Storm Sewer System (MS4) permit requirements. Results were utilized to assess Best Management Practice (BMP) functionality and effectiveness.  These are used to identify program challenges and accomplishments.  Coordinating with the City and other consultants, this analysis was used to create CWE’s final recommendations for future enhancements.

Project Tasks

Coordinate wet-weather and dry-weather monitoring events
Address safety hazards at monitoring sites
Generate Monitoring Plan and Quality Assurance Project Plan
Establish standards for sample collection, logging, delivery, processing, and analysis
Analyze constituents (nutrients, metals, algae, bacteria, pesticides)
Gather samples during storm events to establish a bell curve of constituent concentration
Compare results with applicable limitations (TMDLs, CTR, basin plan, MS4 permit requirements)
Assess BMP functionality and effectiveness
Identify program challenges and accomplishments
Create final recommendations for future enhancements (with City and other consultants)