Below-ground urban stormwater networks (BUSNs) and reservoirs are two common types of infrastructure for flood mitigation or prevention. However, there lack of a tool to examine their relative impacts on floods across the watershed, regional, and larger scales. We developed a watershed-scale, physically based model called Model for Scale Adaptive River Transport – urban, denoted as MOSART-Urban, that explicitly represents both BUSNs and reservoirs. For MOSART-urban simulates surface runoff from impervious urban areas into below-ground urban stormwater networks (BUSNs). BUSNs and street networks are coupled through street inlets, i.e., water can flow from streets to BUSNs and vice versa (overflow). BUSN data are usually not available to the public. We thus derive BUSNs using a novel algorithm based on graph theory and ubiquitous street network, topographic, and land use/land cover datasets. MOSART-Urban represents each reservoir with a unique operation rule curve derived from its upstream hydroclimatic conditions and downstream water demand data. Upon successful validation of MOSART-urban against the observed daily streamflow data at multiple USGS gauges, we conduct a small set of numerical experiments to isolate the individual, and combined effects of BUSNs and reservoirs on flood peaks across the water, regional, and national scales.
