This dataset describes the location and characteristics of stream channel heads of three headwater watersheds in Clarksburg, Montgomery County, Maryland.

This dataset describes the location and characteristics of stream channel heads of three headwater watersheds in Clarksburg, Montgomery County, Maryland.

This dataset consists of flow direction rasters for each 4-digit Hydrologic Unit Code (HUC) area in Maine (0101, 0102, 0103, 0104, 0105, and 0106). The cell size of each raster is 10 meters, and the eight integer values indicate the predicted direction of flow based on direction of steepest drop. The flow direction rasters may be used along with the accompanying data layers in this data release to delineate watersheds within the HUC-4 areas.

This data release consists of 5390 streamflow gages within the conterminous United States that will serve as version 1.0 of streamflow benchmark locations for hydrologic model evaluation and benchmarking.

Drainage areas (or watersheds) were calculated for each stream segment in the National Hydrography Dataset High Resolution Plus Beta (NHD HR Plus Beta) using non-end junction points and the provided hydrologically enforced Digital Elevation Model (DEM). The DEM was used to create a flow direction raster. The pour points used were determined from junction points at each stream intersection excluding stream ends (i.e. channel heads are not included). Watershed calculations were automated using the ArcGIS "watershed" tool and then edited manually for accuracy. In western San Diego County (non-desert) there were 39,980 drainage areas calculated. The percent impervious in each watershed was calculated using the National Land Cover Dataset 2019 Impervious surface.

This digital dataset contains the name and location for the diversions from the surface-water network for the Central Valley Hydrologic Model (CVHM). The Central Valley encompasses an approximate 50,000 square- kilometer region of California. The complex hydrologic system of the Central Valley is simulated using the USGS numerical modeling code MODFLOW-FMP (Schmid and others, 2006b). This simiulation is referred to here as the CVHM (Faunt, 2009). Utilizing MODFLOW-FMP, the CVHM simulates groundwater and surface- water flow, irrigated agriculture, land subsidence, and other key processes in the Central Valley on a monthly basis from 1961-2003. The total active modeled area is 20,334 square-miles. The CVHM includes complex surface-water management processes. The hydrology of the present-day Central Valley and the CVHM model are driven by surface-water deliveries and associated groundwater pumpage. The Streamflow Routing Package (SFR1) is linked to MODFLOW-FMP to facilitate the simulated conveyance of surface-water deliveries. If surface- water deliveries do not meet the farm delivery requirement, the FMP invokes simulated groundwater pumping to meet the demand. The surface-water network represents a subset of the entire stream network in the valley. Even so, it covers about 3,000 kilometers of surface-water and is simulated using 208 stream segments that represent 2244 stream reaches, with 43 inflows and 66 diversion locations providing 64 routed and 41 non-routed deliveries. Most of these inflows are regulated by dams and most of the deliveries are conveyed through an extensive canal network. The routed deliveries are conveyed through the simulated surface-water network, while the non-routed delivery conveyance typically occurs through small canals or diversion ditches and are not directly simulated. Much of the surface-water diversion and delivery information was compiled by the California Department of Water Resources (DWR) for 21 water-balance subregions (WBSs) covering the valley floor (C. Brush, California Department of Water Resources, written commun., February 21, 2007). The CVHM is the most recent regional-scale model of the Central Valley developed by the U.S. Geological Survey (USGS). The CVHM was developed as part of the USGS Groundwater Resources Program (see "Foreword", Chapter A, page iii, for details).