Clarks Creek: dissolved oxygen and sediment

Water quality issues

Clarks Creek flows year-round out of Maplewood Springs. Its tributaries flow primarily in the wet season. Clarks Creek is a salmon-bearing stream supporting chinook, coho, and chum salmon, steelhead, and cutthroat trout. 

Low dissolved oxygen levels, excess fine sediment and sand, and the overgrowth of elodea (Elodea nuttalii) create conditions in Clarks Creek that harm fish and their supporting habitat.

Also, Clarks Creek and its tributaries do not meet water quality standards for fecal coliform.

What we have done

We worked with a stakeholder group to develop a TMDL (water cleanup plan). The group was comprised of local residents and staff from Pierce County, City of Puyallup, Washington State University Puyallup, Washington State Department of Transportation, Puyallup Tribe of Indians, and the U.S. Environmental Protection Agency.

We held a formal public comment process on the draft TMDL. After addressing public comments, we submitted the plan to EPA for review. In May 2015, EPA approved the Clarks Creek Dissolved Oxygen and Sediment Total Maximum Daily Load Water Quality Improvement Report and Implementation Plan (WQIR-IP).

The Clarks Creek Water Quality Improvement Plan assigns the amount of pollution the creek can receive and still meet water quality standards. Any additional pollution needs to be reduced by an equivalent amount or eliminated to achieve clean water.

The plan lays out a framework for how stakeholders will track, monitor, and implement the water cleanup plan. It outlines what must be done, establishes a schedule, and guides corrective actions with adaptive management practices.

Status of the project

We are working with local communities to implement the TMDL. The pollution reductions should be achieved by 2035.

Why this matters

Fish and other aquatic life need oxygen dissolved in healthy water to “breathe” in order to survive. It is more difficult to transfer oxygen from water to blood than it is to transfer oxygen from air to blood. Therefore, it is critical that water contain an adequate amount of oxygen for this transfer to take place efficiently and sustain aquatic life. Oxygen is also necessary to help decompose organic matter in the water and bottom sediments, as well as for other biological and chemical processes.

Excess sediment loading contributes in a variety of ways to the dissolved oxygen problems in Clarks Creek. Sediment accumulation is an important factor in promoting dense growths of elodea that adversely impact dissolved oxygen concentrations. Elodea growth in turn slows flows in the creek, which worsens the problem of sediment accumulation and leads to flooding problems. Sediment loads may also contain elevated nutrient concentrations that promote plant and bacterial growth. Sediment can be improved by controlling stormwater runoff and by adding or maintaining vegetation on stream banks.