In highly developed watersheds, many streams may fail to achieve desired biological condition and require management decisions to restore designated uses. Some management goals may be impractical due to limited resources, particularly in streams where large-scale changes on the landscape (e.g., urbanization) impose constraints on the upper limit of biological integrity. In 2018 a statewide landscape model was developed by the Southern California Coastal Water Research Project (SCCWRP) that predicted the ranges of likely scores for the macroinvertebrate-based bioassessment index (CSCI) within landscape constraints to prioritize management actions. The model provides a context for what is likely to be observed at a given site independent of an actual bioassessment score. With this approach, sites can be described as over- or under-scoring relative to an expectation that is typical for the observed level of landscape alteration.

To demonstrate the utility of landscape models, SCCWRP developed a visualization tool, the Stream Classification and Priority Explorer (SCAPE) , that compares observed bioassessment scores with modelled expectations and can rapidly identify reaches that are scoring better or worse than expected (Beck et al. 2019). Using the SCAPE tool, the San Gabriel River Regional Monitoring Program (SGRRMP) (including regulators, dischargers, stormwater agencies, and environmental advocates) identified regions in the watershed with consistent patterns in bioassessment scores relative to expectations. Based on these patterns, they prioritized different management actions for each region. Sites in both developed and undeveloped areas that scored below expectations were prioritized for restoration; in contrast, restoration was not a priority at developed sites where scores were low but within expected ranges. Sites scoring better than expected were prioritized for enhanced protection, as well as additional monitoring. Interactive tools that connect landscape models with observed data can help set management goals appropriate for stakeholder needs and likely constraints on biological integrity. These tools can easily be applied to other locations where biological data are used to assess environmental condition.

Please visit SCaPE to explore the management prioritization of stream reaches in the San Gabriel River watershed.

Marcus W. Beck, Raphael D. Mazor, Scott Johnson, Karin Wisenbaker, Joshua Westfall, Peter R. Ode, Ryan Hill, Chad Loflen, Martha Sutula, and Eric D. Stein, "Prioritizing management goals for stream biological integrity within the developed landscape context," Freshwater Science 38, no. 4 (December 2019): 883-898.