The City of Bellingham manages the
amount of water stored in the Lake Whatcom Reservoir in order to ensure that an adequate
supply of drinking water is available throughout the year. A control dam at
the head of Whatcom Creek, (the only stream flowing out of the Lake Whatcom
provides a mechanism for managing the surface level of the lake and therefore
the amount of water stored in the lake. Four primary factors influence the
city’s lake level management strategy.
1. Maximum Surface Elevation
The maximum surface elevation of the lake was set by a court order in the
1960’s. When the lake reaches the court-set maximum surface elevation, the
city must open the gates on the control dam and spill as much water as
possible to avoid flooding lakeside properties.
2. Water Availability
The amount of water that is available for storage and treatment. The
amount available for storage is determined as much by when it rains as it is
by how much it rains in the Lake Whatcom Watershed. The second part of the
availability equation is the timing and amount of water available from the
Middle Fork diversion.
3. Drinking Water Demand
The demand for drinking water is based on how much water is consumed by
City residents and businesses. Although this varies from year to year the
daily drinking water consumption for the past 35 years has stayed at about
10 million gallons a day.
4. Salmon Habitat
The fourth primary factor influencing lake management is the outflow into
Whatcom Creek. Controlling the amount of water flowing into Whatcom Creek is
necessary as we attempt to provide healthy habitat for Chinook salmon and
other fish using the stream. NOAA Fisheries, a federal agency, has listed
Puget Sound Chinook on the Endangered Species Act list as a Threatened
Together these four operating constraints present a complex set of
management options that are considered and incorporated into the strategy
for managing the Lake Whatcom Reservoir.