An instream flow rule establishes a water right for instream resources. The water right has a seniority date established at the time the rule is finally issued. So an instream flow rule would be a junior water right to all water currently being put to beneficial use via a permit, certificate, claim or permit-exempt well. Those senior water rights will not be affected by the junior right established in the instream flow rule.
However, instream flow rules also deal with water availability. If water is determined to be unavailable in some parts of a watershed, the instream flow rule may contain regulatory limits on the use of new water, including the issuance of new water rights or the use of permit-exempt wells. When necessary, the limits placed on new water use by instream flow rules have been developed based on local needs to protect fish while providing support for people and their communities.