Water Supply, Use, and Treatment
Lake Whatcom is the source of water for approximately half of Whatcom County residents. The majority of these residents obtain water from the City of Bellingham however there are a number of others that also obtain water from the lake or watershed (e.g. groundwater) including:
- Lake Whatcom Water and Sewer District;
- A number of other small public water systems (less than 15); and
- Approximately 250 households that draw water directly from the lake.
The lake also supplies water to two fish hatcheries. A kokanee hatchery is located at the south end of the lake next to Brannian Creek. At the north end of the lake, water is taken from a discharge pipe in Basin 1 and transported to a hatchery at Whatcom Falls Park.
The water stored in Lake Whatcom supports these demands. It is fed by two separate watersheds — the watershed surrounding Lake Whatcom and the watershed surrounding the Middle Fork of the Nooksack River. As illustrated in the figures below, a dam on the Middle Fork of the Nooksack River diverts water from the Deming Glacier on Mt. Baker to Lake Whatcom. The water travels in a tunnel through Bowman Mountain and then 9.5 miles underground to Mirror Lake where water slows down to allow fine sediment to settle out. From there it continues down Anderson Creek to the south end of Lake Whatcom. The dam and diversion system are operated by the City of Bellingham and can be opened or closed depending on the needs.
One of the increasingly important considerations in operating the diversion is fish and instream needs in the Middle Fork. It is important to ensure that as water is diverted into Lake Whatcom, consideration is given to fish needs in their various life stages in the Middle Fork.
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Middle Fork Diversion Dam
Lake Level Management
Manipulating the diversion and control dams allows the City of Bellingham to adjust lake levels. Minimizing the fluctuations in lake level is important for supplying a consistent drinking water supply, even during the dry months of the year. Controlling lake levels also prevents lakeshore homes and properties, as well as homes and businesses along Whatcom Creek, from being flooded. The legal maximum lake level for Lake Whatcom was established by the Whatcom County Superior Court in 1953 at 314.94 feet.
The lake level is controlled not only by how much water is diverted from the Middle Fork, but also by a control dam located at the head of Whatcom Creek. This dam helps to prevent flooding of the creek as well as maintaining the water level of the lake itself.
Water Intakes and Treatment
The two major intake structures in the lake that supply water for domestic, commercial, and industrial uses are for the City of Bellingham and Lake Whatcom Water and Sewer District.
City of Bellingham
The City of Bellingham treatment plant serves residents of Bellingham as well as five neighboring water districts and one tribal nation.
The City of Bellingham withdraws water from Basin 2 through a 1200-foot wooden pipeline that leads to the screenhouse at Whatcom Falls Park. At the screenhouse, large removable screens catch the “big stuff” before the water continues on to the water plant for treatment. Suspended rocks, plants, and other debris are examples of items filter out of the water by the large screens. Treatment of the water begins at the screenhouse with prechlorination to aid the filtration process.
Before the water reaches the treatment facilities, a portion is directed towards uses other than drinking water. The Georgia Pacific Corporation currently uses about five million gallons of water a day, piped directly to their plant on Bellingham Bay through a separate pipeline. The water for Georgia Pacific’s paper processing is untreated except for a small amount of chlorine added in the screenhouse.
The water designated for treatment enters a series of six multi-media filters, then a clearwell and finally into a contact reservoir where it is chlorinated and treated with soda ash (sodium carbonate) to raise the pH and prevent corrosion of the pipes and system.
The City of Bellingham operates a state certified laboratory that performs compliance testing for the plant, and process control testing for each unit process. State certified plant operatores are on duty 24 hours a day to monitor and control the treatment process. The plant is fully automated and has a state-of-the-art computer system that provides operators with accurate and up-to-date information. For more information about the City's laboratory and monitoring programs contact the Laboratory Supervisor, Peg Wendling, at (360) 676-7689 or pwendling@cob.org.
Water District
The Lake Whatcom Water and Sewer District withdraws water out of Basin 3 to serve residents in Sudden Valley, Geneva, and portions of North Shore and South Bay.
The Water District’s treatment process is similar to that of the City of Bellingham, but utilizes four multi-media filters and reaches a maximum output of 825 gallons per minute or 50,100 gallons per day.
