Ecology finds that:

(1) The magnitude or variability of flows are important in maintaining the aquatic ecosystem that sustains both fish and other valuable resources. Criteria to limit total withdrawals of water from the Lower Skagit River were developed to protect the aquatic ecosystem in the region covered by this rule.

(2) To protect the estuary area below river mile 8.1 the duration of flow inundation of at least one foot of depth, in selected estuary habitat, can be reduced no more than ten percent from existing conditions from the date of enactment of this regulation. This criterion applies to the period of February through August to withdrawals from the Skagit River. Total withdrawals greater than eight hundred thirty-six cubic feet per second during that period will result in a greater than ten percent deviation from existing conditions and therefore would result in harm to the fisheries resources and aquatic ecosystem in the region covered by this rule.

(3) Protection of the aquatic ecosystem of the estuary in the months of September through January requires that the total withdrawals of water from the Skagit River not exceed 1/10 of the fifty percent exceedance flow for each month, based on the period of record (1/1/41 - 12/31/95) for the U.S. Geological Survey (USGS) stream gage on the Skagit River near Mt. Vernon, WA (Sta. #12-2005-00) in order to maintain channel morphology and other estuarine and riverine functions. This equates to a low point of eight hundred thirty cubic feet per second during the month of September. Total withdrawals greater than eight hundred thirty cubic feet per second during the month of September will not protect and preserve fish, wildlife and other environmental values and therefore would be harmful to fisheries resources and the aquatic ecosystem in the region covered by this rule in violation of chapter 90.54 RCW.

(4) The rules setting minimum flows in the Lower and Upper Skagit River (WRIA 3 and 4) (WAC 173-503-040) and finding certain waters available (WAC 173-503-050) are necessary to protect and preserve wildlife, fish, scenic, aesthetic and other environmental values.