•  Carrier

In the western United States, watershed management is transitioning to an integrated process wherein stakeholders and engineers approach individual water and environmental projects as pieces of a puzzle, each dependent on the other for long-term success.

Where urban growth pressures coincide with limited water supply or major environmental conflicts, the ability to balance the built and natural environment has become a major obstacle to governmental and project permitting and decision making.

The Walla Walla Watershed Project represents a unique experiment in developing a sustainable water management strategy for the future while accommodating and protecting the quality of life.

Recognizing a Need

The Walla Walla urban growth area is the economic and commercial hub of this watershed—a region where agriculture, wineries, several American Indian Tribes, recreational opportunities and a city of about 40,000 thrive and are dependent on a limited supply of water.

In 1998 the Washington State Legislature enacted the Watershed Planning Act (HB2514), which authorized establishment of a local government-led planning unit to include all of the major watershed stakeholders. It included property owners, local governments, state and federal agencies, and tribal governments. The Act provided funding and authorization for establishment of a planning unit for each of the 62 watersheds in the state. The Walla Walla Watershed was a priority due to water use conflicts among irrigation users, municipal water suppliers and the endangered salmon and other fish in the basin. Many independent efforts to address these conflicts had been tried, unsuccessfully.

The planning process took place between 1999 and 2005, when the Walla Walla Watershed Planning Unit employed an integrated process to coordinate the input and needs of a multitude of stakeholders. The purpose was to form a comprehensive watershed plan for Water Resource Inventory Area (WRIA) 32. This required the Planning Unit to reach consensus on short- and long-term strategies addressing the built and the natural environment before the plan could be advanced to implementation. In many instances, perfect information and complete agreement was not possible, so an adaptive management plan for both out-of-stream water users and instream water managers was needed to create a shared approach that would meet future needs of the watershed.

Instream Flow Management

Seasonal low-flow conditions exist naturally in the Walla Walla basin. Summer peak demands exacerbate both the flow and water quality in the stream, resulting in degraded fish habitat conditions. Alternative out-of-stream water uses were also developed to modify demand during critical water use periods. Groundwater withdrawals from shallow aquifers also impact flows in certain areas.

To address these issues, the Planning Unit recommended new appropriation flows (NAF) for four management points. Each management point was selected on the basis of ability to physically measure flows from a sub-area of the watershed and at stream juncture locations that could also guide operational and management decisions related to the watershed plan.

Complicating the management plan was the lack of a clear understanding of the intent and objective of historical tribal treaties and agreements, and where tribes have federally backed authority to apply treaty management objectives. In some cases, the tribal reservations provide clarity of management locations; however, with migrating salmon and other fish, the entire watershed is part of the management strategy.

For example, part of the recommended management plan recognizes that an Indian reservation can be granted an allowance above the recommended NAF for “environmental enhancement storage projects” with consensus recommendation from the Confederated Tribes of the Umatilla Indian Reservation, the Planning Unit and initiating governments (with technical advice from the Snake River Regional Technical Team). In this manner, the plan recognized the status of the treaties without actually attempting to define them.

Another challenging water management issue was how to address historical, legal and traditionally conflicting water right management decisions without a lawsuit. The consensus plan, which provided for modifications to existing administrative stream closures in the basin that addressed all tributaries in WRIA 32, was based on where and when important life stages and species occur. Simply setting new appropriation flows and updating closures will not increase the amount of water available to support instream management objectives. Therefore, a “best solutions” approach was developed by the Planning Unit.

Additionally, more flow alone did not necessarily address temperature, timing or other fish management needs. Where applicable, riparian habitat modifications for stream temperature improvements and management and operational steps to reduce seasonal water withdrawals were identified and recommended to improve stream flows while still providing for out-of-stream needs. Each of the quality and quantity issues were collectively addressed by the Planning Unit and then alternative approaches were developed for testing and implementation.

Flow enhancement, timing of limited flow releases and the riparian habitat all are important to fish recovery and associated terrestrial species. To aid in the improved watershed objective, the Planning Unit developed preliminary flow enhancement targets at each management point to help regulate out-of-stream withdrawals to be achieved through a variety of voluntary measures. The measures included water-use efficiency, changes in crop types and, in some cases, elimination of water uses. Updated flow enhancement targets will be established over time.

Groundwater Management

The Planning Unit and major water users throughout the basin realize that better utilization of existing sources, and recharge and expansion of these sources, are the best long-term approaches for groundwater supplies. The following general strategies have been identified as the most applicable to the basin:

  • reduce demands via conservation, reuse and irrigation efficiencies;
  • enhance shallow alluvial aquifer and deeper basaltic aquifer recharge;
  • identify opportunities and streamline groundwater rights transfers, purchases and leases;
  • coordinate groundwater use and development regionally; and
  • improve understanding of surface/groundwater interaction through monitoring and regional hydrogeologic study.

Surface Water Quality Management
The primary goals of surface water management are ensuring the quality of public drinking water, protecting fish and supporting aquatic biota. This is an ongoing process based on continued accrual and analysis of new water quality monitoring data. As a result of updates to the Environmental Protection Agency’s Clean Water Act Section 303(d) list for Washington, water quality strategies in the watershed plan are expected to become more specific with completion of total maximum daily load studies and further public reviews.

To protect the surface water quality, the Planning Unit identified four focus areas for action within the realm of surface water quality management:

  • reduce non-point source pollution;
  • support and maintain point source programs;
  • improve watershed-wide information database; and
  • minimize detrimental impacts from water resource management.

General management actions are likely to include preventing and/or mitigating impacts from forest practices, agricultural land use and stormwater, as well as improving understanding of watershed problems and solutions through monitoring.

Groundwater Quality Management

Similar to the goals established for surface water, groundwater quality-related planning goals are to ensure the quality of public drinking water, protect fish and support aquatic biota. Based on overall planning goals and data limitations, the Planning Unit identified the following specific groundwater quality objectives:

  • improve watershed-wide information database;
  • clean up impacted groundwater supplies;
  • prevent future potential degradation of clean groundwater supplies; and
  • prevent further degradation of impacted groundwater supplies.

General management actions related to groundwater quality include assessing susceptibility of groundwater supplies to contamination, improving detection and monitoring of impacts, upgrading local wellhead protection programs, minimizing impacts of land-use activities by implementing technical management strategies, cleaning up sources of contamination and providing oversight for well decommissions to ensure compliance with safe practices.

Aquatic Habitat Management

The Walla Walla Sub-basin Plan serves as the basis for aquatic habitat management within WRIA 32. Additionally, the Snake River Salmon Recovery Plan, a regional effort to identify recovery goals for salmonids in the lower portion of the Snake River drainage, will be incorporated into the management strategy upon its completion.

The Sub-basin Plan includes a vision statement, working hypotheses, biological objectives and management strategies. Prioritized strategies include:

  • Imminent Threat. This includes passage barriers that might delay migration, fish screens and unscreened diversions that might entrain migrating fish or prevent passage, and dry-stream reaches that prevent passage or cause stranding.
  • Priority Areas. Includes stream reaches that, if allowed to further degrade, represent substantial decline in abundance, productivity and life-history diversity.

Conversely, if restored they show greater gains in abundance, productivity and life-history diversity when compared to other areas.

In addition to general regulatory, stakeholder education, conservation and flow management strategies, programs will be initiated to address habitat-specific goals such as controlling noxious weed populations; restoring perennial vegetation; improving riparian habitat; constructing pool and riffle habitat; and maintaining, relocating or eliminating forest, public and private roads in sensitive areas.

Management Plan
The Walla Walla River Watershed encompasses 1,758-mi2 in southeast Washington and northeast Oregon. WRIA 32 comprises 1,278- mi2of the Washington portion and is divided into five implementation zones for the purpose of the management plan

Basin-wide strategies were established for managing instream flows, groundwater quantity, surface and groundwater quality, and habitat management. With the completion of the Integrated Water Resources Management Plan, all stakeholders have assignments and the local communities now have a strategy designed to meet the economic, irrigated agriculture and municipal water supply needs for the long term. At the same time, the plan calls for enhancing and managing the instream resources required by the Endangered Species Act and broader environmental objectives. This is a true partnership among federal, tribal, state and local governments, with priorities being set by property owners and citizens of the watershed—giving the entire community a real and personal stake in ensuring its effective implementation.

Ben Floyd and Bob Wubbena, P.E., work at HDR Inc in Washington. Floyd can be reached at 509-546-2053, or This email address is being protected from spambots. You need JavaScript enabled to view it..