Water Quality Improvement Project
Erie Lake Area:
Total Phosphorus


Erie Lake is located on Fidalgo Island in Skagit County, Washington. It is a shallow kettle lake carved by glacial activity. It receives water primarily by seasonal, intermittent runoff from several small drainage ways, as well as from shallow subsurface seepage. Erie Lake discharges to Campbell Lake.

Land use around the lake is a mixture of rural and residential. The watershed is in the Olympic Mountain rain shadow, and receives about 26 inches of rain yearly.

Water quality issues

Erie Lake, along with Campbell Lake, was listed on Washington State's 303(d) list for exceeding water quality standards for phosphorus. This violated the standards' beneficial uses, based on Phase I and Phase II restoration projects.

Erie Lake at sunset, Washington State.  Photo courtesy of Hank Lipchak via Flickr.

© Hank Lipchak, Flickr.


Why this matters

Excessive nutrient inputs to lakes provide aquatic plant and algae dominance, making lakes unsuitable for recreation or viewing enjoyment. Phosphorus is one of the nutrients. When it is discharged into a waterbody, like a lake, it fuels the growth of algae.

Excessive algae growth reduces water clarity, increases oxygen demand in the bottom sediments severely impacting coldwater aquatic habitat, and can, depending on the dominant algae present, pose a human health risk.

Status of the project

TMDL studies based on lake restoration plans for both Campbell and Erie lakes were submitted to the Environmental Protection Agency (EPA) by Ecology. EPA approved the TMDLs in 1997.

Alum treatments were applied to the lake for phosphorus control. Monitoring showed that the process was a success, but must be repeated on a recurring basis to maintain the water quality standard for aesthetics.

The TMDL studies on both Campbell and Erie lakes indicated restoration activities were successful, and the lakes were in compliance with the TMDL goals set for total phosphorus.

Technical information

Erie Lake Total Phosphorus Total Maximum Daily Load (Ecology publication)

Lake Campbell and Lake Erie Total Phosphorus Total Maximum Daily Load - Water Quality Effectiveness Monitoring Report (Ecology publication)

Quality Assurance Project Plan: Total Maximum Daily Load Effectiveness Monitoring Study: Lakes Erie and Campbell (Ecology publication)

Related information

WRIA 3: Lower Skagit-Samish Information (Water web site)


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Last updated September 2010
  Water Resource Inventory Area (WRIA) 3 map, Washington State.


WRIA: #3 (Lower Skagit-Samish)
County: Skagit

Water-body Name:
Erie Lake

Total Phosphorus

# of TMDLs: 1

Approved by EPA

Contact Info:
Tricia Shoblom
Phone: 425-649-7288
Email: Tricia.Shoblom@ecy.wa.gov

Northwest Region
Department of Ecology
3190 160th Ave. SE
Bellevue, WA 98008-5452