Water Evaluation and Planning system model for Central Valley waterbird habitat (WEAP-CVwh) and habitat projection and impacts analysis

Two publications describing models and methodology. Output from the WEAP-CVwh model is used to project through time the availability of habitats used by waterbirds in the Central Valley under water and land resources scenarios. For each specified scenario, WEAP-CVwh estimates projected available water supplies supporting agricultural and wetland habitats important for wintering waterbirds and water demands of all uses including for habitats in the Central Valley. In simulations of scenario impacts, the model achieves this objective while also accounting for projected changes in land resources (i.e., urbanization of agricultural land) upon which habitats depend. To produce the tool, a specific WEAP model (or “WEAP-CV”) (a water resource systems model) was adapted, which already has been developed for and represents the watershed hydrology and water demands of the Central Valley region. However, considerable work was required to adapt WEAP-CV to more accurately model habitats for wintering waterbirds (e.g., adding winter-flooded agricultural habitats that had not been represented, updating/correcting area of wetland habitats, distinguishing certain water supply sources not specifically represented, combining multiple land cover datasets in a Geographic Information System (GIS) to better calculate areas of various land cover classes at a finer spatial resolution, other changes), while accommodating a variety of scenarios we wished to examine. Model output are on a monthly time step and represent habitats at a spatial resolution accounting for the variation in habitat water sources. Subsequent to modeling scenarios using WEAP-CVwh, we used model output and other information to calculate availability of each habitat (hectares) as a function of modeled water supplies and demands and assumed crop harvest and habitat management practices pertaining to habitats. Projected available habitat was at a much finer spatial scale than hydrological basins used by the Central Valley Joint Venture (CVJV). Information on habitat availability is a key component used in biological models to evaluate future sustainability of goal waterbird populations in the Central Valley as established in current habitat conservation planning. Amounts and timing of available habitats supported by water supplies projected under specified scenarios was included in avian bioenergetics models (see Data Input- existing collections) to translate scenario impacts on water supplies and habitats into projected impacts on Central Valley wintering waterbirds through changes in their food supplies. Additional post-processing was required to produce spatially-explict maps of habitat areas required for use in the SWAMP avian bioenergetics model. The CVJV is a major conservation organization comprised of over 20 partner organizations, and since 1986, has facilitated most bird habitat conservation in the Central Valley. Adaptation and use of WEAP-CVwh-based scenario modeling tool and its output (deliverables) and integration with bioenergetics models will allow the CVJV to incorporate climate, urbanization, and water supply management impacts on waterbird habitats into its conservation planning (deliverable).