Watershed Assessments, Plans and Water Right Decisions


When lawmakers passed the Watershed Planning Act (RCW 90.82), they stated that the primary purpose of the statute was "…to develop a more thorough and cooperative method of determining the current water situation in each water resource inventory area of the state and to provide local citizens with the maximum possible input concerning their goals and objectives…"

The Department of Ecology expects that watershed plans will define each water resource inventory area’s (WRIA) preferred future for water management. At a minimum, this means the plans will address the water quantity issues required by law (RCW 90.82.070). Planning units are also encouraged to address water quality and habitat within the plan.

Watershed assessments

A central element of planning under the Watershed Planning Act is an assessment of how much water is available and how much is being used and/or needed in the watershed. A "water balance," also known as a water budget, is a key piece of a watershed assessment. If the assessment indicates there is sufficient water for instream uses, including fish, and that there is additional water available for desired growth, then Ecology will use that information as part of the basis for making water-right permit decisions for growth.

Watershed assessment minimum requirements

To develop a clear direction for the future, each plan will need to include the results from its watershed assessment. The Watershed Planning Act requires at a minimum:

While not required, it may be very useful to evaluate the likely effect of future development on groundwater recharge, aquifer sustainability, baseflows to streams, and senior water rights.

Functions of a watershed assessment

A well-developed watershed assessment has a number of important uses:

Choices and tradeoffs in funding a watershed assessment

Watershed groups have a number of choices and tradeoffs to make in structuring their watershed assessments. These may include cost, level of detail, level of confidence in the results, and comprehensiveness. For example, choices may include:

The sub-basins and the level of detail selected will affect where water rights decisions can be made based on the watershed assessment.

Watershed assessments and water rights decisions

Before a water right is granted, each water right application must meet four statutory tests:

While there is no prescribed or single approach to conducting watershed assessments, a watershed assessment can be very useful in addressing the water availability test and, perhaps, one or more of the other three tests for a water right. The relative contribution that watershed assessments can make toward water rights decision-making varies and depends on the following factors:

The watershed assessment can identify areas where water is available, or may potentially be available for appropriation and thus warrant additional analysis. The watershed assessment may rule out a category of water right applications from a particular source (e.g., applications from a closed river system, including applications in hydraulic continuity with the river system). High-quality and detailed assessment information, along with strong local agreement reflected in an adopted watershed plan, will speed up water-right decision-making and reduce the potential for legal challenges to water rights decisions.

Watershed plans

The adopted watershed plans and the assessments produced through the planning process are expected to provide information that helps make future water-rights decisions. It is Ecology’s hope that each planning unit will identify how water will be managed and cared for within the WRIA and will serve as an expression of public interest in making future water-rights decisions.

The plan must also provide strategies for increasing water supplies in the management area, which may include but are not limited to:

The objective of these strategies is to supply water in sufficient quantities to satisfy the minimum instream flows for fish and to provide water for future out of stream uses.

Obligations and expectations

Once plans are approved by local planning units and participating state agencies, Ecology will: