For purposes of this chapter, the following definitions shall be used:

"Allocation" means the designation of specific amounts of water for specific beneficial uses.

"Appropriation" means a beneficial use of waters of the state, authorized by and consistent with all applicable laws and regulations.

"Community water supplier" means an entity that supplies water for fifteen or more residential service connections or for providing residential use of water for a nonresidential population that is, on average, at least twenty-five people for at least sixty days a year.

"Consumptive use" means a use of water whereby there is diminishment of the amount or quality of the water source.

"Ecology" means the Washington state department of ecology.

"Environmental restoration project" or "ERP" means a project with a primary purpose of restoring salmonids, requiring a temporary use of water.

"Habitat-forming function" means a physical, chemical, or biological function that is necessary to create and maintain natural or desired habitat conditions that benefit fish and other aquatic life. Habitat forming functions include but are not limited to creating and maintaining the following: Channel migration, gravel and sediment transport, water quality, nutrients, large woody material recruitment, flood plain flows, and riparian habitat.

"Habitat-related action" means enhancing desirable riparian, stream, wetland, or flood plain functions and related biological, chemical, and physical processes.

"Instream flow" means a level of stream flow, established under chapters 90.03, 90.22, 90.54 and 90.82 RCW, necessary in perennial streams to preserve wildlife, fish, scenic, aesthetic, and other environmental and navigational values. The term instream flow is synonymous with "minimum flow" as used in chapters 90.03 and 90.22 RCW, "base flow" as used in chapter 90.54 RCW, and "minimum instream flow" as used in chapter 90.82 RCW.

"Interruptible use" means a type of water use that relies upon withdrawals on a periodic or seasonal basis that if interrupted would not cause substantial hardship or health or safety concerns, or that is highly unlikely to be interrupted during the expected period of use. For the purposes of this chapter, interruptible uses are subject to the instream flows set in WAC 173-528-060.

"Net stream flow depletion" means the total depletion of water from a subbasin that may be available for future use under the reservation set in this chapter. The net stream flow depletion equals the flow depletion that remains after performance of offsetting actions, and is available for use only after applicable conditions in WAC 173-528-110 have been met.

"Nonconsumptive use" means a type of water use where either there is no diversion or withdrawal from a source or where there is no diminishment of the amount or quality of the water source.

"Permit-exempt withdrawal" or "permit exemption" means a groundwater withdrawal exempted from permit requirements under RCW 90.44.050, but otherwise subject to surface and groundwater statutes and other applicable laws. For the purpose of this chapter, stockwater use does not include feedlots or other activities not related to normal grazing land uses.

"Planning unit" means the Salmon-Washougal and Lewis watershed planning unit, established under chapter 90.82 RCW, and all successors, formally designated by the Salmon-Washougal and Lewis watershed planning initiating governments.

"Public water system" means any system, excluding a system serving only one single-family residence and a system with four or fewer connections all of which serve residences on the same farm, providing piped water for human consumption, including any collection, treatment, storage, or distribution facilities under control of the purveyor and used primarily in connection with the system; and collection or pretreatment storage facilities not under control of the purveyor but primarily used in connection with the system.

"Regional supply area" means a defined area where ecology finds water to be available for future groundwater withdrawal. Regional supply areas are designated by WAC 173-528-090 or by order of ecology.

"Reservation" means a one time, finite allocation of water for future beneficial uses. For the purposes of this chapter, the reservation is not subject to instream flows set in WAC 173-528-060, nor to closures set in WAC 173-528-070. The reservation is senior to the instream flow water rights set in WAC 173-528-060.

"Water-related action" means an offsetting activity that provides a quantity of water during certain times and at certain places that essentially replaces water at or upstream of where a proposed water right would impact surface flow. Water-related actions include but are not limited to acquiring an active water right or donation of a water right to the trust water right program under chapter 90.42 WAC.

"Water right" means a right to make beneficial use of public waters of the state, including any water right established for instream flow purposes or a permit-exempt groundwater withdrawal.

"Watershed plan" means the Salmon-Washougal and Lewis watershed management plan, adopted on July 21, 2006, by the Clark, Cowlitz, and Skamania county commissioners.

"Withdrawal" means the extraction of groundwater, or the diversion of surface water for a beneficial use.