Temporally Variable Land Cover Parameterizations for the USGS National Hydrologic Model

Abstract:

Land cover changes can have a substantive effect on hydrologic response. Although land cover can change over time, parameter values that describe aspects of land cover are typically held constant in hydrologic modeling applications. This is often not realistic for periods of simulation that exceed even a relatively short time span of a decade. To address this shortcoming during the development of the US Geological Survey (USGS) National Hydrologic Model (NHM), simulations of historical land cover conditions are used to derive annually-varying sequences of hydrologic modeling parameters to describe the USGS Geospatial Fabric (GF) Feature Set (https://www.sciencebase.gov/catalog/item/535eda80e4b08e65d60fc834). The GF is used by the NHM as the delineation of the modeling response units and routing network. The presentation will describe spatial and temporal trends in historical land cover and their impact on simulations of streamflow for the conterminous United States. It will also describe the prototype NHM workflow that is used to examine potential improvements in representation of non-stationarity in hydrologically important characteristics, which the authors seek to apply for both historical and future periods of simulation.