Modeled historical streamflow metrics for the contiguous United States and National Forest Lands

Available water supply varies greatly across the United States depending on topography, climate, elevation and geology. Forested and mountainous locations, such as national forests, tend to receive more precipitation than adjacent non-forested or low-lying areas. However, contributions of national forest lands to regional streamflow volumes is largely unknown. Using outputs from the Variable Infiltration Capacity hydrologic model, we calculated mean annual and mean summer (July and August) streamflow metrics based on total flow and flow from national forest lands for each 1:100,000 scale National Hydrography Dataset stream reach in the contiguous United States. Specifically, this data publication contains twenty-one comma-delimited ASCII text files (for different drainage areas and processing units across the United States) containing 1915-2011 mean annual flow and mean summer flow. These files also contain the mean annual and mean summer flows from National forest system (NFS) lands as well as the portion of total mean annual flow contributed by flow from NFS lands. These data provide insight into 1915-2011 hydrologic regimes and national forest contributions to total water yield and can be joined to a National Hydrography Dataset stream layer for spatial illustrations and studies.
The streamflow metrics dataset provides a high resolution, spatially explicit estimate of annual and summer flow volumes that can be used in more extensive studies of water quantity and water quality. In addition, the dataset highlights the relative importance of national forest lands to overall water quantity.