National Wetlands Inventory (Arcs)

This polyline layer represents river and stream features as created by the National Wetlands Inventory (NWI) program, administered by the United States Fish and Wildlife Service. The NWI project was established to generate information about the characteristics, extent and status of the Nation's wetlands and deepwater habitats. This information is used by Federal, State, and local agencies, academic institutions, U.S. Congress, and the private sector. The Emergency Wetland Resources Act of 1986 directs the Service to map the wetlands of the United States. The Act also requires the Service to produce a digital wetlands database for the United States. The layer is named NWI_ARC. Also see the wetlands area layer NWI_POLY.

该折线要素层由美国鱼类及野生动物管理局（United States Fish and Wildlife Service）主管的国家湿地清查（National Wetlands Inventory, NWI）项目创建，用于表示河流与溪流地物。国家湿地清查项目的设立初衷是获取美国全国湿地及深水栖息地的特征、分布范围与现状信息。此类信息可供联邦、州及地方机构、学术机构、美国国会与私营部门使用。1986年《紧急湿地资源法案》（Emergency Wetland Resources Act of 1986）要求该局开展美国湿地的测绘工作，该法案同时要求该局构建美国全国数字化湿地数据库。该要素层命名为NWI_ARC，另可参阅湿地面状要素层NWI_POLY。