MassGIS has adapted and modified the U.S. Geological Survey 1:100,000 Hydrography Digital Line Graph (DLG) quadrangle files to produce two layers:
* HYDRO100K_POLY - ponds and lakes
* HYDRO100K_ARC - streams and rivers
In ArcSDE the layers are named as listed above. In the BASIN library, the coverages are named HD100_<num> where <num> represents the tile unit of the basin index. Annotation features were also created.