Hangman Creek multi-parameter TMDL

We’re focusing efforts in Hangman Creek to identify, understand, and fix potential sources of pollution. The creek is a major tributary to the Spokane River and suffers from low oxygen, high nutrients, high temperatures, and too much sediment suspended in the water. Fish need cool, clean water and gravel on the creek bed for rearing and spawning.

Water quality problems

Hangman Creek has been identified as not meeting clean water requirements, according to our water quality assessments. Pollution problems include:

  • High temperature, nutrients, bacteria, and pH
  • Low dissolved oxygen
  • Too much sediment in the water column (turbidity)

Too many nutrients cause depletion of oxygen that fish and other aquatic life need to survive. Excess nutrients can also contribute to algae blooms downstream in the Spokane River and Lake Spokane that are harmful to human health.

What we are doing

Approximately $500 million has been invested in the Spokane River watershed to make improvements in urban areas that will reduce toxics and increase dissolved oxygen. Hangman Creek is a major tributary and we've committed to our partners to prioritize water quality improvement in the creek by: 

  • Completing a full analysis of the creek’s health including streamside vegetation and in-stream conditions.
  • Identifying, prioritizing, and fixing pollution problems.
  • Monitoring the creek’s health and tracking progress of improvements.
  • Developing an education and outreach program with our partners.

Nearly 80 percent of the land use is dominated by dryland farming so we're working with federal, state, and local partners to make on-the-ground improvements that benefit farms and Hangman Creek. More than $15 million is available in the greater Spokane River watershed, including Hangman, to address pollution from forested and working agricultural lands.

Landowners have responsibility under state law to prevent runoff from polluting and can prevent runoff by using best practices that keep soil and other pollution out of the creek. Conservation practices like direct seeding, low-disturbance tilling, and streamside plantings can help reduce soil erosion and prevent water pollution. 

Wastewater facilities

The City of Tekoa operates a wastewater treatment facility that discharges into Hangman Creek and has been working to upgrade and improve the aging system. Since 2005, the city has replaced more than 14,000 feet of sewer pipe to reduce groundwater influence that can overwhelm the system's ability to treat wastewater.

Also, we're studying the creek near the city to develop additional water quality requirements and allow Tekoa to appropriately plan for reducing nutrients in the wastewater.

Several other systems discharge into tributaries of Hangman Creek and must meet water quality standards:

Assessment and monitoring

Our scientists are studying Hangman Creek to gain a better understanding of it's slow streamflow, groundwater influence, and springtime runoff. These studies will help quantify how pollution influences the creek and the development of solutions for improving water quality. 

Staff also evaluate the creek by documenting streamside vegetation and land use practices that can cause pollution. Our team works with landowners to make on-the-ground improvements to reduce pollution sources primarily through financial and technical assistance programs. 

Ecology Prioritizes Hangman Creek Watershed Health after 2018 Settlement Agreement 

In 2018, Ecology and Spokane Riverkeeper signed the Agreement Between Washington Department of Ecology and Spokane Riverkeeper Relating to the Hangman Creek TMDL (Settlement Agreement). Spokane Riverkeeper sued EPA over the agency's approval of the 2009 Hangman Creek TMDL water cleanup plan, claiming the plan was inadequate and would not ensure water quality protection. Ecology joined settlement negotiations with EPA and the Riverkeeper. The parties worked to determine an agreed-upon path forward that strives to have both highly productive farms and a healthy Hangman Creek. The Settlement Agreement with the Riverkeeper requires Ecology to:

  • Complete a full analysis of the creek’s health including streamside vegetation and in-stream conditions;

  • Identify, prioritize and fix pollution problems;

  • Monitor the creek’s health and track progress of improvements; and

  • Develop and implement an education and outreach plan.

Related Settlement links