Regional Water Supply Planning

Local, state, and tribal partners (in the Puget Sound region of Washington State) working together to develop lawful pragmatic tools to address water supply planning issues.

Maps and Documents




Muckleshoot Indian Tribe
Washington Department of Ecology
Washington Department of Fish and Wildlife
Washington Department of Health
Public Health - Seattle & King County
King County
Pierce County
City of Auburn
Suburban Cities Association
Cascade Water Alliance
Cedar River Water and Sewer District
Lakehaven Utility District
Seattle Public Utilities
Tacoma Public Utilities
Woodinville Water District
Shared Strategy for Puget Sound
Center for Environmental Law & Policy
Washington Environmental Council
King County Business Community

Note -- members of the Cascade Water Alliance are the cities of Bellevue, Kirkland, Issaquah, Redmond, and Tukwila, and the Covington Water District, the Skyway Water and Sewer District, and the Sammamish Plateau Sewer and Water District.

flyer -- Regional Water Supply Planning, May 2006This Web page is also available in a print version format, May 2006 (pdf, 175 KB).

Regional Water Supply Planning

Multiple agencies and organizations working together to develop data, information and pragmatic tools to assist in water resource and supply planning activities in the region.

Multiple agencies and organizations are voluntarily participating in a regional water supply planning process for the purpose of identifying, compiling information on, and discussing many of the key issues that relate to or may affect water resources of the region. The goal is to develop the best available data, information, and pragmatic tools that the participants may use, at their discretion, to assist in the management of their respective water systems and resources, and in their water supply planning activities. Information developed by each technical committee is advisory only and development of that information in no way expands or limits the authority of any entity. All information generated will be shared among all those interested in receiving it. The planning process is not required by statute, but is expected to provide useful data that may support other processes that any participant may use to address water resource and water supply issues. Each of the participants is free to accept or reject the results of this process.

A regional water supply planning process (planning process) now under way is an effort to develop substantive technical information regarding current and emerging water resource management issues in and around King County. The planning process is generally guided by a Planning Framework developed in October 2005. The Framework outlines a multi-year schedule for studying water resource conditions and management approaches related to meeting the combined needs of water for people and fish from all available sources, including reclaimed water and conservation. In addition, the planning process is exploring the potential impact of climate change on water planning, as well as small water system issues and problems. Efforts of this planning process will produce analyses, information and potential projects which may be used in future water planning activities.

Who is participating?

The planning process was initiated as a result of a February 2005 Memorandum of Understanding (MOU) on water resource and water supply planning between King County and the Cascade Water Alliance – a group of eight local governments and special purpose districts in King County. King County initiated the planning process by inviting a large group of stakeholders to participate on a Scoping Committee. The participating entities included the Muckleshoot Indian Tribe, three state agencies (Departments of Ecology, Health, and Fish and Wildlife), City of Seattle, City of Auburn, King County Council, Tacoma Public Utilities, Cedar River Water and Sewer District, Lakehaven Utility District, Woodinville Water and Sewer District, Seattle-King County Public Health, Shared Strategy for Puget Sound, Washington Environmental Council, King County Department of Natural Resources and Parks, and Cascade Water Alliance.

From the Scoping Committee emerged a Framework for a regional planning process that would be led by a Coordinating Committee. This committee’s membership was expanded beyond the membership of the initial Scoping Committee to include Pierce County, a business community representative, another environmental organization, and an elected official from the membership of the Suburban Cities Association. The Coordinating Committee reviews, oversees, and coordinates a number of studies, analyses, and projects that will produce new information useful for water planning activities.

The Scoping Committee also selected a subset of the broader Coordinating Committee to serve as an Executive Committee to manage the logistical and procedural functions of the planning process.

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What is the expected outcome of the planning process?

The work of this planning process is expected to produce information and recommendations in seven topic areas: water demand forecast, water supply assessment, climate change impacts, reclaimed water, tributary stream flows, source exchange strategies, and small water systems.

In recognition of the Central Puget Sound Water Suppliers' Forum (Forum) (external link) commitment to update earlier work, two of the topic areas, regional demand forecast and water supply source alternatives, are to be led by the Forum. The Demand Forecast Committee is expected to develop the best available information on future municipal water demands to assist in making more informed decisions on future water supplies; it will include a projection of future municipal water needs in King, Snohomish, and Pierce counties, and will likely include a range of forecasts with differing assumptions (e.g., different levels of conservation). The supply alternatives effort will provide an inventory and assessment of municipal water supply sources that might be used to meet future water supply needs within King, Pierce, and Snohomish counties, and develop multiple supply scenarios to meet any shortfall between projected demands and existing supplies. This work will build upon earlier work done by the Forum in the 2001 Water Supply Outlook. The work products from these efforts will be provided to the Coordinating Committee for use in the planning process.

In addition to the Supply and Demand committees, there are five technical committees being overseen by the Coordinating Committee on each of the remaining study areas. They include:

  • Climate Change—assessing climate change impacts on water demand, water supplies and instream flows
  • Reclaimed Water—assessing the use, cost, and benefit of reclaimed water as a feasible source of supply for non-potable purposes
  • Source Exchange Strategies—identifying, evaluating, and helping develop voluntary projects for the replacement or supplementation of water supply sources that have been shown to adversely affect salmon runs with water from supply sources with less impact on salmon runs
  • Tributary Streamflow—identifying the location and ranking priority of flow-impaired tributary streams that are evaluated to most benefit from flow restoration in order to help maintain and recover salmon runs
  • Small Water Systems—addressing public health, resource management, and planning problems associated with the creation of new small water systems, failing small water systems, and associated well issues.

Each of the technical committees will produce reports and recommendations based on best science available on elements that could be included in water planning processes in the region. For example, King County and Cascade Water Alliance expect to use the technical work to create a Coordinated Water System Plan. Utilities in the region will have additional information on reclaimed water to use in their planning.

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How is the process being funded?

King County, City of Seattle, Cascade Water Alliance, and Washington Department of Ecology are all contributing to funding facilitation of the process. In addition, the Central Puget Sound Water Suppliers' Forum (external link) is funding work on the regional demand forecast and analysis of municipal water supply source alternatives as described earlier. Other entities are funding their own participation on the various committees.

For additional information, contact one of the agencies who are funding this effort:

Steve Hirschey
King County

Judi Gladstone
City of Seattle

Rick Kirkby
Cascade Water Alliance

Andrew Dunn
Washington Department of Ecology


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