Rethinking Riverine Habitat Quality: Integrated Systems Modeling to Improve Watershed Habitat Management and Decision Making

Session H2: Water Resources Management and Planning - Modeling and Software for Improving Decisions and Engaging Stakeholders

River restoration and conservation projects use habitat quality indicators (e.g., Habitat Suitability Index) to monitor and quantify changes of one or a few habitat attributes (e.g. instream flow, bank stability, and flood regime). A more integrated approach representing broader watershed habitat components requires rethinking riverine habitat quality. Systems models provide decision makers with tools to quantify and understand interconnections between different habitat components. They help predict and account for potential changes in hydrologic, ecological, and management variables in water systems. Applying systems models in restoration practice requires developing and applying new and robust habitat quality indicators that capture dynamic hydrologic and ecological changes in a watershed system with minimal data-collection effort. We have developed a Watershed Habitat Performance (WHP) indicator, measured in unit area, which quantifies habitat suitability for watershed priority species. The WHP sums four sub-indicators representing the four main foci of restoration that vary spatially and temporally: aquatic life, riparian areas, floodplain zones, and impounded wetlands. The systems model maximizes watershed habitat performance by adjusting decision variables that effect the four sub- indicators. These variables include water depth, flow, re-vegetation, nonnative vegetation control, and control of river bank erosion. The optimization is subject to constraints such as water rights delivery requirements, infrastructure capacity, mass balance, and limited water availability and financial budget for management. We apply this integrated approach to the Lower Bear River, Utah to show how to better manage water to improve habitat quality, environmental watershed services, and support local efforts to secure water for wetlands and riparian areas. We demonstrate the WHP model along one segment of the river at two different time periods. Preliminary results show that the model captures different management actions which are reflected in the value of the WHP. Systems models can help make planning and monitoring river restoration more effective by allocating scarce resources to improve habitat quality.