Water Quality Improvement Project
November 2014 - Lake Whatcom water quality report published, submitted to
EPA for approval
Ecology completed the final water quality improvement study, known as the
Lake Whatcom is the primary drinking water source for about 100,000 people in
and around Bellingham. Ecology determined in 1998 that the lake fails to meet
water quality standards. The primary concern is low levels of dissolved oxygen
as a result of increased levels of phosphorous and fecal coliform bacteria
entering the lake.
Since 2002, Ecology has worked on a water quality improvement study called
the Lake Whatcom TMDL (total maximum daily load).
The final TMDL report concluded that in order to restore the health and
quality of the lake, approximately 87 percent of the current development around
the lake needs to be able to store and filter stormwater like a forest, and
bacteria levels in the most contaminated streams need to be reduced up to 96
The final report includes minor changes from the draft TMDL (2013) as well as
a response to comments. In addition, the report includes a conservative estimate
of the progress that has already been made by partners on meeting TMDL goals.
Ecology applauds these efforts to meet expectations of the TMDL before it is
The 2-volume water quality improvement report (WQIR) is sent to EPA for
- EPA will review the TMDL (up to 3 months, depending on level
of review determined necessary).
- EPA will send an approval letter when they are satisfied the
TMDL meets the requirements of the Clean Water Act.
- The requirements of the TMDL become official after the EPA
approval. In 2018, Ecology will issue the new permits for
discharge to Lake Whatcom, which will include the requirements
set forth by the TMDL.
Lake Whatcom is a large natural lake in Whatcom County. The northwest end of
the lake lies within the city of Bellingham, and 22 small watersheds drain into
the lake. Lake Whatcom serves as the drinking water source for about 96,000
people in the Bellingham area. The lake is popular for recreation, and the area
around it has become a popular place to live.
Water quality issues
The lake has been threatened by declining water quality and in 1998
was put on the state’s
list of polluted water bodies. The primary concern is low levels of
dissolved oxygen as a result of increased levels of phosphorous and
fecal coliform bacteria. A lack of oxygen threatens the survival of fish
and aquatic plants. In addition, too much phosphorous can create an
overgrowth of algae which can increase drinking water treatments costs
and may require the use of more treatment chemicals.
Stormwater is the primary vehicle for phosphorous. Roofs, roads, driveways
and lawns speed the flow of stormwater to the lake without the benefit of
filtering out the phosphorous. In undeveloped areas, stormwater is allowed to
slowly seep into the ground where it is filtered naturally before it reaches the
The problems in Lake Whatcom triggered a water quality improvement project,
the Lake Whatcom TMDL. From the beginning, the goal was to determine how much
pollution the lake can process and still achieve acceptable levels of oxygen (See
Why this matters
Phosphorus is the main cause of Lake Whatcom’s low-oxygen problem. Phosphorus
occurs naturally, but development increases phosphorus entering the lake in
stormwater. Computer predictions show the lake would meet state standards for
oxygen if there was 86 percent less development than existed in 2003. Since then, zoning laws have allowed more development in the watershed.
Sources: Runoff from bare soil and developed areas. Phosphorus occurs naturally in
soil and human and animal waste, and is added to some detergents.
Connection to algae and oxygen: Phosphorus feeds algae growth. Bacteria that
consume dying algae deplete the oxygen that fish and other aquatic life need to
survive. When oxygen levels are low, phosphorus is released from lake sediment
and re-enters the water, perpetuating the cycle. The dissolved oxygen levels in
Lake Whatcom fail to meet state water quality standards now, and they have the
potential to get much worse, making the problem much harder to fix.
Treatment of drinking water: Excess phosphorus creates larger algae blooms,
which require more treatment to make the water safe for drinking. That process
creates more trihalomethanes, a byproduct that some studies link to cancer.
Effect of development: Roofs, driveways and lawns interrupt the absorption
and filtration provided by forests and soils, instead sending phosphorus-laden
stormwater rushing to the lake. Communities must modify existing and future
development to create the same effect as removing development.
Fecal coliform bacteria originate in human and animal waste. Runoff carries
the bacteria from the ground and from failing septic systems into the lake. Eleven
tributaries feeding Lake Whatcom fail to meet state standards for fecal coliform
bacteria. The bacteria create a health risk for people who work or play in and
around the water.
Unless otherwise specified, the following documents are Ecology publications:
Lake Whatcom Watershed Total Phosphorus and Bacteria Total Maximum Daily
Loads: Volume 2. Water Quality Improvement Report and Implementation Strategy
Lake Whatcom Watershed Total Phosphorus and Bacteria Total Maximum
Daily Loads: Volume 1. Water Quality Study Findings
Dissolved Oxygen in Lake Whatcom/Trend in the Depletion of Hypolimnetic
Oxygen in Basin I 83-97
Quality Assurance Project Plan: Lake Whatcom TMDL Study
Quality Assurance Project Plan: Characterization of Groundwater Discharge to
Lake Whatcom Total Maximum Daily Load Groundwater Study
Lake Whatcom water quality still slipping, data shows
(The Bellingham Herald
article, March 17, 2011)
Ecology accepts plan for better protection of water quality in Lake Whatcom
(Ecology news release - March 11, 2011)
State rejects well drilling ban, approves county plan for Lake Whatcom
safeguards (The Bellingham Herald
article, March 11, 2011)
Focus on Lake Whatcom TMDL: Draft study identifies limits for Lake Whatcom
phosphorus and bacteria
Bellingham Petition to Amend WAC 173-501-060 and WAC 173-501-070
Ecology denial letter to Mayor of Bellingham
Whatcom County letter of commitment
April 29, 2011 response to Whatcom County’s list of proposed code
sections and development standards to be addressed
Whatcom County May 18, 2011
response to Ecology comments
Whatcom County July 18, 2011 notification of revised schedule
on new developments scheduled
Focus on Lake Whatcom: State working with
city, county to improve water quality protections for Lake Whatcom
Frequently Asked Questions on Ecology's
Petition Response: How Ecology′s alternative to the Lake Whatcom
petition will serve to protect the lake′s water quality
WRIA 1: Nooksack
Watershed Information (Water web site)
Back to top of page
Last updated May