Canada1Water Model Boundaries, Drainage Basins and a High-Resolution Coastline

Accurate hydrological modeling is essential for effective water resource management, flood forecasting, and environmental conservation. The Canada1Water project seeks to develop a comprehensive hydrological model for Canada by integrating sub-watershed data from the NHN and NHD datasets. A key step in this process is the grouping of sub-watershed polygons into larger drainage basins and ensuring their alignment with stream networks using a high-resolution coastline. High resolution coastline vector polylines are contained within the NHN Geobase (Littoral) and USGS NHD (Flowline Ftype==566) but are fractured by sub-watershed working units. To best join stream mouths to coastlines or mask datasets like Digital Elevation Models by land or ocean, a high resolution coastline mask tool would be useful. Thus, the NHN Geobase Littoral and USGS NHD Flowline$Ftype==566 datasets were joined together into a single polygon and polyline shapefile. This shapefile can be subset into continental land masses (Canada1Water model parts) and offshore islands. 487 of 1499 NHN and 297 of 2230 NHD sub-watershed areas (8-digit) contain coastline polyline parts. Download the Full Dataset here: https://portal.canada1water.ca/#/c1w-downloads