Screening Causal Assessment to Support Development of Biological Objectives and Prioritizing Implementation Actions
Recent statewide and regional efforts to develop emerging bio-integrity policies and regulations place more emphasis on the importance of cooperation and collaboration among stakeholders to develop methods that effectively incorporate biological data in water quality assessment and implementation programs. The San Diego Water Board has identified developing biological objectives as its highest priority in the current triennial review and the City of San Diego has been actively working with Board staff, as well as other organizations, in developing the technical underpinnings of a sound bioassessment and bio-objectives policy. As part of this process, the City and Tetra Tech have been developing a causal assessment screening tool (CAST) that can help quickly identify potential causes of biological impairment in southern California streams, including stormwater influenced channels. This presentation describes the CAST and will illustrate the workings of the tool using several sites in southern California. A key aspect of the CAST approach is a multivariate procedure for identifying different groups of comparator sites in the coastal ecoregion of southern California, which provides a more rigorous and informative comparison with which to evaluate potential stressors at a given site. This approach can include comparisons with known reference sites and can be used with or without land use factors in the analysis. In addition to using stressor-specific data for a given site or stream reach, the CAST uses previously developed screening information regarding channel modifications (e.g. channelized stream) and degree of perennial flow for stream reaches. The CAST also incorporates several important diagnostic tools previously developed such as stressor-specific species tolerance values for macroinvertebrates and algae (e.g., conductivity/total dissolved solids tolerance values) and species sensitivity distributions for certain chemicals (e.g., various pyrethroids). Future work, in collaboration with the San Diego Water Board, SCCWRP, and others will incorporate flow ecology stressor and diagnostics information and other enhancements, which will enable users to identify whether altered hydrology is a factor affecting biological condition and attainment of bio-objectives. The CAST is intended to be a key part of a larger recovery potential and restoration/protection prioritization tool, which not only identifies critical stressors present at a site or reach but also uses those results, along with surrounding land use and other information, to prioritize sites or reaches for restoration and/or protection. The development of the restoration/protection prioritization tool will require collaboration with multiple stakeholders and agencies to ensure that important socioeconomic, as well as ecological considerations are addressed.
Vicki Kalkirtz is a Senior Planner in the City of San Diego’s Transportation & Storm Water Department, Policy & Enforcement section. She has been working on storm water policy issues for 7 years, five with the City. Vicki holds a Bachelor of Science in Environment and Natural Resources from the University of Minnesota, a Master of Urban Planning in Land Use and Environmental Planning and a Master of Science in Natural Resources with a focus on Environmental Justice from the University of Michigan.
Mr. Boschen has more than 20 years of professional experience providing technical and program management support to federal, state, municipal, and local water resource agencies. He has extensive experience in the areas of stormwater management, water quality planning, stream and lake assessment, watershed/receiving water modeling studies, water quality and biological sampling, and wetland permitting. Mr. Boschen leads Tetra Tech’s TMDL, water quality, and watershed management support for municipalities in Southern California, EPA Region 9, the San Diego Water Board, and other organizations.