Water Quality Improvement Project
Fenwick Lake Area:
Total Phosphorus

© Kimberly Mallady.

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

In 1991, a comprehensive lake and watershed management plan was proposed for Fenwick Lake under EPA's Clean Lakes Program.  The proposal included a two-phased implementation approach to resolve the phosphorus issues in the lake.  Implementation plans included monitoring to evaluate the effectiveness of the assigned load allocations for phosphorus, as well as other parameters.  The second phase was scheduled to begin in December 1998.  Based on these plans, EPA approved a total maximum daily load (TMDL) for Fenwick Lake in January 1993.

Despite implementation actions, in 2002 Ecology monitoring determined that goals set by the TMDL were not being achieved.  The lake is currently on the 2008 water quality assessment as a category 5 (water cleanup plan required by the Clean Water Act).

Technical information

Fenwick Lake Total Phosphorus Total Maximum Daily Load (Ecology publication)
www.ecy.wa.gov/biblio/9310203.html

Effectiveness Monitoring for Total Phosphorus Total Maximum Daily Loads in Fenwick and Sawyer Lakes (Ecology publication)
www.ecy.wa.gov/biblio/0203054.html

Related information

Reducing Phosphorus Pollution to Improve Water Quality (Water Quality web site)
www.ecy.wa.gov/programs/wq/nonpoint/phosphorus/PhosphorusBan.html

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