Columbia Basin Project Water Rights

As part of the policy development process, we are seeking comment on a draft of the policy.

The policy describes Ecology’s interpretation of the 2024 amendment to RCW 90.03.380(1), which exempts Reclamation water right change applications from the annual consumptive quantity evaluation when seeking to increase the irrigated acreage within the CBP. The policy does not apply to other federal authorizations or state-issued water rights.

Read the draft policy: Draft Columbia Basin Project Water Rights Policy and Interpretive Statement

Background

Under RCW 90.03.380, the greatest amount of water that can be changed for spreading purposes is the net of total diversion and/or withdrawal from the water source minus the total quantity of return flows over a given year. This is known as the annual consumptive quantity (ACQ) test, which prevents any potential impairment of other water users due to enlargement of the water right’s consumptive use. 

However, Reclamation’s water use within the Columbia Basin Project is unique in the state. The water supplied with these water rights is considered “artificial” supply resulting from major infrastructure projects. Unlike all other water users in the state, Reclamation has the right to recapture and reuse these return flows. As a result, there is no risk of impairment due to enlargement from irrigated acreage changes to Reclamation’s water rights. For this reason, the Legislature amended RCW 90.03.380 in 2024 to provide the ACQ exemption for Reclamation’s water right portfolio within the Columbia Basin Project.