For purposes of this chapter and subsequent regulations formulated for planning and management within individual water resource inventory areas, the following definitions shall be used:

(1) "Allocation" means the designating of specific amounts of the water resource for specific beneficial uses.

(2) "Appropriation" means the process of legally acquiring the right to specific amounts of the public water resource for application to beneficial uses.

(3) "Base flow" means a level of streamflow established in accordance with provisions of chapter 90.54 RCW required in perennial streams to preserve wildlife, fish, scenic, aesthetic, and other environmental and navigational values.

(4) "Beneficial uses" are uses of water for domestic, stock watering, industrial, commercial, agricultural, irrigation, hydroelectric power production, mining, fish and wildlife maintenance and enhancement, recreational, and thermal power production purposes, and preservation of environmental and aesthetic values, and all other uses compatible with the enjoyment of the public waters of the state.

(5) "Consumptive use" means use of water whereby there is a diminishment of the water source.

(6) "Department" means the Washington state department of ecology.

(7) "Hydrograph" is a graph showing the variations of streamflow (or stream discharge) with respect to time during a year as determined at a specific cross-sectional location on the stream.

(8) "Low flow" means those flow level limitations appearing as provisions on permits and certificates issued by the department, or its predecessors, prior to the effective dates of chapters 173-501 through 173-599 WAC.

(9) "Nonconsumptive use" is a type of water use where either there is no diversion from a source body, or where there is no diminishment of the source.

(10) "Perennial stream" means a stream the natural flow of which is normally continuous at any given location.

(11) "Stream management unit" means stream segments, reaches, or tributaries, each containing a control station, that are identified on stream reach maps in adopted water resource management program documents as units for defining base flow levels.

(12) "Water right" means a right to make beneficial use of public waters of the state.