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Combining Dynamic Assessment with Traditional Monitoring Approaches to Improve Understanding of NPS Pollution Impacts. William T. Stringfellow Sharon E. Borglin Gary M. Litton Jeremy S. Hanlon Mark S. Brunell University of the Pacific Environmental Engineering Research Program Stockton, CA.
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Combining Dynamic Assessment with Traditional Monitoring Approaches to Improve Understanding of NPS Pollution Impacts William T. StringfellowSharon E. BorglinGary M. LittonJeremy S. HanlonMark S. BrunellUniversity of the PacificEnvironmental Engineering Research ProgramStockton, CA
Outline • San Joaquin River • Geography • Dissolved oxygen impairment • Scientific Objectives for DO TMDL Project • Combining Monitoring & Science • Summary & Conclusions
Ecosystem Impairment Courtesy of Jones & Stokes
Algal load contributes to DO impairment Low DO barrier to fish migration Monitoring Identifies Problems
Research Objectives – DO Project • Understand algal growth processes in the San Joaquin River (SJR) • Conduct mass balance on algae and nutrients in the SJR • Understand how NPS discharges influence algal growth • Develop scientifically based management strategies (best management practices)
Unlimited Hypothesis • Algae growth is essentially unlimited • Nutrients are too high to control • Algae grow at constant rate down river • Control algal inoculum
Limited Hypothesis • Algae growth is limited • Algae reach a maximum carrying capacity • Reducing inoculum ineffective, algae grow back in river • Control limiting factor (nutrients)
Research Approach • Traditional monitoring • Intensive approach • Directed scientific studies • Sub-watershed studies • Lagrangian studies (unit flow tracking) • Stable isotopes for source identification • Modeling • Close link to monitoring & studies • Algal growth & water quality model
Chlorophyll BOD10 CBOD NBOD TOC/DOC Ammonia nitrogen Nitrate nitrogen Total nitrogen o-Phosphate Total phosphate Total iron Total suspended solids Volatile suspended solids Alkalinity pH Turbidity (NTU) Incident light Dissolved oxygen Specific conductivity Temperature Algae cell counts Stable isotopes Lipids Measurements - Grab Sample
Sub-Watershed Study Results • Nutrients and grazing are most important non-seasonal factors • Carbonate can be limiting • Nitrogen not limiting • Suspended minerals are a source of limiting nutrients for algal, independent of phosphates • Results suggest removal of sediments would limit suspended algae growth • Management based on unlimited model not recommended
Apply Lessons to Ecosystem Level Studies • New emphasis on zooplankton grazing impacts • Lipid signature and traditional (microscopic) methods • Improved measurement of inorganic carbon • Stable isotope analysis and increased sampling • Incorporation of pilot model parameters into larger river water quality model • Mineral solids and inorganic carbon
Summary & Conclusions • Monitoring data identified problem areas • Provided little useful information for institution of improvements • Scientific studies & modeling identifies cause & effect • Results from studies & modeling used to improve monitoring • Additional measurements