Layer Name: Unmapped Water Device Points

 

Layer Description:

An Unmapped Water Device Point represents the vicinity of a water right withdrawal or diversion, not the actual location. Unmapped water right device points are illustrated by the use of “centroids.” Centroids represent the center point of the Public Land Survey System subdivision where a water right withdrawal or diversion is located. The Public Land Survey System is a grid system covering most of the United States which is composed of townships and sections. Generally speaking, a Township is an area composed of 36 sections (6 by 6), each of them approximately one square mile in size.

The accuracy of a typical centroid will depend on whether the centroid represents the center of the Section (640 acres), Quarter Section (160 acres) or Quarter-Quarter Section (40 acres) of a described water right location. For example, if a water right withdrawal location is only known to fall within Township 20N, Range 3E and Section 10, the centroid will represent the center point of a roughly square area 640 acres in size, within which also is the point of withdrawal or location. In this case, the distance between the centroid and the actual water right location may be hundreds or even several thousand feet. If the centroid represents the center of a quarter or quarter-quarter Section, the distance between the centroid and actual location will, on average, be reduced. In all cases, however, centroids should not be construed as representing the actual location.

Like mapped Water Device Points, a centroid may be associated with one or more water-right documents, especially where multiple unmapped withdrawals located in the same legal subdivision. For example, three unmapped rights located in different locations within the NW quadrant of Section 5 will all be depicted using a single centroid at the center of that subdivision.

 

Source:

Washington State Department of Ecology – Water Resources Program

gwis.gwis_rw.D_Point2

 

Date:               Variable, Converted to Mapped Water Device Points on an Ongoing Basis

Input Scale:    Variable

Projection:      Washington State Plane, South Zone

Datum:            NAD 83 HARN

Units:              Feet