An expansion right is an expanded use of a groundwater right located within a CGWA where the expanded use occurred after the designation of the CGWA and is in violation of mandatory permit requirements. Groundwater is deemed to be unavailable to fill expansion rights unless a management program exists which will, within a time period acceptable to the director of IDWR, limit average annual water withdrawals from the aquifer designated in the CGWA to no more than the average annual recharge to the aquifer. Expansion rights may be curtailed if the director of IDWR determines that an adequate management program does not exist within two years after the completion of a general adjudication.
A number of CGWA expansion rights were decreed within the Oakley Fan and Raft River CGWAs as part of the Snake River Basin Adjudication (SRBA). The SRBA was completed as of August 25, 2014. IDWR will provide notice to the holders of CGWA expansion rights about the requirements of Idaho Code § 42-1416B.
Idaho Code § 42-1416B - Claim for Expanded Use in Critical Groundwater Area — Determination of Water Availability