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Marin NHD Local

Marin NHD Local Resolution - documentation

Welcome to the reference documentation for Marin National Hydrography Dataset-Local Resolution. This site contains the detailed methods used to identify surface and near-surface flow features. This also includes some creeks.

Current work involves the delineation of western Marin County catchment areas from a seamless topographic-bathymetric surface. The surface has been analyzed for steepest descent flow paths after application of hydrologic enforcement features drawn with reference to the surface, orthoimagery, and some Public Works information for storm drain system features.

The Esri ArcGIS for Desktop extension ArcHydro was used to define catchment areas for all flow lines below 0.1 square km drainage, and these "100k square meter" catchments are being manually aggregated to clarify surface drainage areas for use as Watershed Boundary Dataset--Hydrologic Unit Code level 16 (HUC-16) features. Once defined and assigned conventional HUC names, these HUC-16 will be aggregated to HUC-14, and those will be aggregated to define new WBD HUC-12 extents.