Development of a Stream Restoration and Protection Prioritization Tool
Statewide and regional efforts are ongoing to develop Bio-integrity policies and regulations that effectively incorporate biological data in water quality assessment and implementation programs. The San Diego Regional Water Quality Control Board has identified developing biological objectives as its highest priority in the current Basin Plan Triennial Review and the City of San Diego (City) has been actively working with Board staff and other organizations to develop the technical underpinnings of a sound bioassessment and bio-objectives policy. As part of that effort, the City is developing a Restoration and Protection Prioritization (RPP) Tool to help identify stream segments where restoration or protection activities are likely to provide significant improvements in ecological condition. The RPP framework incorporates stressor information, predictive assessments of biological condition, and the latest science on recovery potential to identify high priority sites for restoration or protection. Stressor information is provided by the Causal Assessment Screening Tool (CASTool) that was recently developed by the City to help rapidly identify potential causes of biological impairment in southern California waterbodies, including stormwater-influenced stream segments. The CASTool indicates those stressor(s) that are likely causes of biological impairment at a site, or which could affect a biologically unimpaired site. Stressor information from the CASTool is summarized as a score of stressor intensity, which is added to a recovery potential score and the Biological Condition Gradient (BCG) level to calculate an overall score for Potential for ecological uplift at a site. Biological potential focuses on improvements to the benthic macroinvertebrate community and can be determined using either actual biological data for a site or using modeled data based on the statewide California Stream Condition Index (CSCI). A score for potential Threats, using future population estimates and land use changes at or near the site, and a score for Opportunities (potential co-benefits, linkages with ongoing stormwater planning activities, watershed planning, and socio-economic considerations) are incorporated with the Potential score to calculate an overall RPP index score. The RPP Tool includes connectivity of the site to nearby upstream or downstream unimpaired benthic macroinvertebrate assemblages (using either actual or modeled biological information), environmentally sensitive areas, areas with native aquatic species vulnerability, and multi-habitat planning areas to help determine priorities for restoration and protection. EPA’s EnviroAtlas and SanGIS/SANDAG regional GIS data layers are used to obtain current data. The RPP Tool incorporates the ability for the user to weight the various input factors differently in order to provide flexibility and to support waterbody-specific goals and objectives. By running the RPP Tool for many candidate sites, RPP index scores can be compared among all the sites to support planning efforts that are focused on stream restoration and protection goals. Although the RPP Tool (and the companion CASTool) were developed to support City watershed planning and implementation efforts, these tools include the spatial extent of the Southern California Stormwater Monitoring Coalition (SMC) region and can be extended to support other regions of the state. Examples will be presented illustrating how sites can be prioritized to support stormwater planning and effective use of resources to achieve beneficial ecological outcomes.
Vicki Kalkirtz is a Senior Planner with the City of San Diego, Transportation & Storm Water Department, and supports stormwater policy initiatives and planning efforts.
Clint Boschen is a Principal Scientist and Director with Tetra Tech based in San Diego. He received a Bachelor’s degree in Biology from Virginia Tech and a Master’s degree in Aquatic Biology from Florida State University. Clint has over 23 years’ experience providing TMDL, water quality, and watershed management support throughout California and across the U.S.
Dr. Jerry Diamond has been working with the City of San Diego on sediment quality issues, bacteria recreational water quality criteria, biological objectives, and most recently, web-based analytical tools for screening causes of biological impairment and for supporting restoration and protection priorities.