The U.S. Geological Survey (USGS), in cooperation with the Louisiana Department of Transportation, prepared hydro-conditioned geographic information systems (GIS) layers for use in the Louisiana StreamStats application. These data were used within peak flow and low flow regression equations for Louisiana. This dataset consists of flow accumulation rasters for each 8-digit Hydrologic Unit Code (HUC) area in Louisiana, one of the layer types needed to delineate watersheds within the HUC-8 areas, merged into a single dataset. The 54 HUCs represented by this dataset are 03180004, 03180005, 08030100, 08040202, 08040205, 08040206, 08040207, 08040301, 08040302, 08040303, 08040304, 08040305, 08040306, 08050001, 08050002, 08050003, 08060100, 08070100, 08070201, 08070202, 08070203, 08070204, 08070205, 08070300, 08080101, 08080102, 08080103, 08080201, 08080202, 08080203, 08080204, 08080205, 08080206, 08090100, 08090201, 08090202, 08090203, 08090301, 08090302, 11140201, 11140202, 11140203, 11140204, 11140205, 11140206, 11140207, 11140208, 11140209, 11140304, 11140306, 12010002, 12010004, 12010005, and 12040201.

The U.S. Geological Survey (USGS), in cooperation with the Louisiana Department of Transportation, prepared hydro-conditioned geographic information systems (GIS) layers for use in the Louisiana StreamStats application. These data were used within peak flow and low flow regression equations for Louisiana. This dataset consists of digital elevation model rasters for each 8-digit Hydrologic Unit Code (HUC) area in Louisiana, one of the layer types needed to delineate watersheds within the HUC-8 areas, merged into a single dataset. The 54 HUCs represented by this dataset are 03180004, 03180005, 08030100, 08040202, 08040205, 08040206, 08040207, 08040301, 08040302, 08040303, 08040304, 08040305, 08040306, 08050001, 08050002, 08050003, 08060100, 08070100, 08070201, 08070202, 08070203, 08070204, 08070205, 08070300, 08080101, 08080102, 08080103, 08080201, 08080202, 08080203, 08080204, 08080205, 08080206, 08090100, 08090201, 08090202, 08090203, 08090301, 08090302, 11140201, 11140202, 11140203, 11140204, 11140205, 11140206, 11140207, 11140208, 11140209, 11140304, 11140306, 12010002, 12010004, 12010005, and 12040201.

The U.S. Geological Survey (USGS), in cooperation with the Louisiana Department of Transportation, prepared hydro-conditioned geographic information systems (GIS) layers for use in the Louisiana StreamStats application. These data were used within peak flow and low flow regression equations for Louisiana. This dataset consists of flow direction rasters for each 8-digit Hydrologic Unit Code (HUC) area in Louisiana, one of the layer types needed to delineate watersheds within the HUC-8 areas, merged into a single dataset. The 54 HUCs represented by this dataset are 03180004, 03180005, 08030100, 08040202, 08040205, 08040206, 08040207, 08040301, 08040302, 08040303, 08040304, 08040305, 08040306, 08050001, 08050002, 08050003, 08060100, 08070100, 08070201, 08070202, 08070203, 08070204, 08070205, 08070300, 08080101, 08080102, 08080103, 08080201, 08080202, 08080203, 08080204, 08080205, 08080206, 08090100, 08090201, 08090202, 08090203, 08090301, 08090302, 11140201, 11140202, 11140203, 11140204, 11140205, 11140206, 11140207, 11140208, 11140209, 11140304, 11140306, 12010002, 12010004, 12010005, and 12040201.

Two maps, compiled at 1:1,000,000 scale, depict mean annual runoff, precipitation, and evapotranspiration in the part of the United States east of Cleveland, Ohio and north of the southern limit of glaciation. The maps are mutually consistent in that runoff equals precipitation minus evapotranspiration everywhere. The runoff map is based on records of streamflow from 503 watersheds in the United States and southernmost Canada, adjusted to represent 1951-80 and supplemented by records of precipitation at 459 stations. Precipitation at each station was partitioned into point estimates of runoff and evapotranspiration, which were constrained such that the evapotranspiration estimates varied smoothly across the region and decreased with increasing latitude and altitude, and the runoff estimates were consistent with measured runoff from nearby watersheds. A point estimate of runoff was allowed to equal mean runoff in a nearby watershed, or to be somewhat higher (or lower) if a compensating departure from mean watershed runoff could be inferred in distant parts of the watershed on the basis of altitude or regional trends. Then, precipitation contours were drawn to parallel runoff contours but differ from them by the magnitude of nearby estimates of evapotranspiration. These maps may slightly underrepresent mean precipitation and evapotranspiration in areas of high relief because most precipitation stations in such areas are in valleys. These 3 coverages were used to produce Open-File Report 96-395. Additional information about methodology can be found in this report

This dataset provides numerical and categorical descriptions of 48 basin characteristics for 956 basins with observed streamflow information at U.S. Geological Survey (USGS) streamflow-gaging stations. Characteristics are indexed by National Hydrography Dataset (NHD) version 2 COMID (integer that uniquely identifies each feature in the NHD) and USGS station number for streamflow-gaging station. The variables represent mutable and immutable basin characteristics and are organized by characteristic type: physical (5), hydrologic (6), categorical (12), climate (6), landscape alteration (7), and land cover (12). Mutable characteristics such as climate, land cover, and landscape alteration variables are reported in decadal increments (for example, average percent forest for the decade 1950-1959, 1960-1969, etc). The majority of basin characteristics in this dataset were calculated using divergence-routing methods and are often referred to as “network-accumulated”. This method uses a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the values derived from the reach catchment scale (Schwarz, G.E., and Wieczorek, M.E., 2018, Database of modified routing for NHDPlus version 2.1 flowlines: ENHDPlusV2_us: U.S. Geological Survey data release, https://doi.org/10.5066/P9PA63SM ). In four instances, values are also provided for the entire catchment above a site and area designated using the “CAT_” prefix.

This dataset provides numerical and categorical descriptions of 48 basin characteristics for 9,314 ungaged basins coinciding with 12-digit hydrologic unit code (HUC12) pour points that drain to the Gulf of Mexico. Characteristics are indexed by National Hydrography Dataset (NHD) version 2 COMID (integer that uniquely identifies each feature in the NHD) and HUC12 identifying number. The variables represent mutable and immutable basin characteristics and are organized by characteristic type: physical (5), hydrologic (6), categorical (12), climate (6), landscape alteration (7), and land cover (12). Mutable characteristics such as climate, land cover, and landscape alteration variables are reported in decadal increments (for example, average percent forest for the decade 1950-1959, 1960-1969, etc). The majority of basin characteristics in this dataset were calculated using divergence-routing methods and are often referred to as “network-accumulated”. This method uses a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the values derived from the reach catchment scale (Schwarz, G.E., and Wieczorek, M.E., 2018, Database of modified routing for NHDPlus version 2.1 flowlines: ENHDPlusV2_us: U.S. Geological Survey data release, https://doi.org/10.5066/P9PA63SM ). In four instances, values are also provided for the entire catchment above a site and area designated using the “CAT_” prefix.

The southeastern United States was modeled to produce historical and potential future simulations of streamflow statistics using the Precipitation Runoff Modeling System (PRMS) as part of the study documented in LaFontaine and others (2019). Hydrologic simulations using one observation-based historical climate dataset (Maurer and others, 2002), 13 used historical climate simulations using statistically downscaled general circulation model (GCM) output from the Coupled Model Intercomparison Project (CMIP5), and 45 used potential future climate simulations using statistically downscaled CMIP5 GCMs for four representative concentration pathways were used for the computation of 52 hydrologic statistics of streamflow using output data files from each simulation. Output files for the simulations include: 1) historical annual values of each statistic for each HRU and stream segment for the period 1952-2010 for the observation-based simulation, 1952-2005 for the 13 GCM-based historical simulations, and 2045-2075 for the 45 GCM-based future simulations, 2) PRMS summary output files with daily time step basin-averaged output variables for the period 1950-2010 for the observation-based simulation, 1950-2005 for the 13 GCM-based historical simulations, and 2006-2099 for the 45 GCM-based future simulations. The first year of the PRMS summary output files should be ignored due to model initiation. LaFontaine, J.H., Hart, R.M., Hay, L.E., Farmer, W.H., Bock, A.R., Viger, R.J., Markstrom, S.L., Regan, R.S., and Driscoll, J.M., 2019, Simulation of Water Availability in the Southeastern United States for Historical and Potential Future Climate and Land-Cover Conditions: U.S. Geological Survey Scientific Investigations Report, 2019-5039, 83 p., https://doi.org/10.3133/sir20195039. Maurer, E.P., Wood, A.W., Adam, J.C., Lettenmaier, D.P., and Nijssen, B., 2002, A long-term hydrologically based dataset of land surface fluxes and states for the conterminous United States: Journal of Climate, v. 15, no. 22, p. 3237–3251, accessed September 24, 2017, at https://doi.org/10.1175/1520-0442(2002)015<3237:ALTHBD>2.0.CO;2.

These tabular data sets represent mean monthly precipitation (millimeters) data from 800-meter PRISM data for the years 2016 and 2017 compiled for two spatial components of the NHDPlus version 2 data suite (NHDPlusv2) for the conterminous United States; 1) individual reach catchments and 2) reach catchments accumulated upstream through the river network. This dataset can be linked to the NHDPlus version 2 data suite by the unique identifier COMID. The source data for mean monthly precipitation (Celsius) from 800-meter PRISM data was produced by the PRISM Group at Oregon State University. Units are degrees Celsius. Reach catchment information characterizes data at the local scale. Reach catchments accumulated upstream through the river network characterizes cumulative upstream conditions. Network-accumulated values are computed using two methods, 1) divergence-routed and 2) total cumulative drainage area. Both approaches use a modified routing database to navigate the NHDPlus reach network to aggregate (accumulate) the metrics derived from the reach catchment scale. (Schwarz and Wieczorek, 2018).