1.Drainage areas from the input datasets were subset of the Northern Appalachians ecoregion. For the U.S drainage areas intersect the ecoregion boundary were selected while for Canada drainage areas east of the St. Lawrence were selected.
2.The U.S. drainage areas were clipped to a county dataset from the BTS
3.The Canadian and clipped U.S. drainage areas were then unioned to create one data layer.
4.Overlaps between drainage areas were assigned to U.S drainage areas.
5.Gaps were filled and assigned to U.S drainage areas.
6.A unique drainage areas ID was assigned to each resulting drainage area in the field "DA_ID" and was based on the input drainage area.
All attributes from the input drainage area datasets are maintained in this combined drainage areas dataset.