Percent of Non-Federal Area in Water, 1987
This map shows the spatial distribution of the nation's open surface water in 1987 as a percentage of non-Federal area within each 8- digit hydrologic unit. There were 49,893,600 acres of water in 1987. This includes Small Water and Census Water.
Cautions for this Product:
Use this map only to identify broad spatial trends.
Source: National Resources Inventory, 1997
NRI sample data are generally reliable at the 95% confidence interval for state and certain broad substate area analyses. Generally, analyses that aggregate data points by smaller geographic areas and/or more specific criteria result in fewer data points for each aggregation and therefore less reliable estimates. NRI maps reflect national patterns rather than site- specific information.
Aggregate Layer: 8 Digit Hydrologic Unit Areas with Federal Land
Other Layers Displayed: State
Includes water bodies at least 40 acres in size and perennial streams at least 1/8 mile wide. Also referred to as Large Water. [NRI-97]
Includes all land and water areas where the ownership is by private, municipal, county or parish, state, Indian tribal, individual trust, the Tennessee Valley Authority, or areas under temporary control of a Federal, state, county or municipal agency or government for foreclosure or nonpayment of taxes.
Small water bodies:
Inland bodies of water with a water surface area of less than 40 acres. This distinction is made by the U.S. Bureau of the Census. [NRI-97]
A Land cover/use category comprising water bodies and streams that are permanent open water. [NRI-97]
Product ID: 6022
Production Date: 1/25/01
Product Type: Map
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