Water Quality Improvement Projects (TMDLs) > WRIA 56 > Hangman Creek Area Multi-parameter Project

Water Quality Improvement Project
Hangman Creek Area:
Multi-parameter

Introduction

The Hangman Creek (also known as Latah Creek) watershed drains approximately 431,000 acres and spans across two states and four counties. More than 60 percent of the watershed resides in eastern Washington State (WRIA 56) while the remaining portion, including the headwaters, originates in the western foothills of the Rocky Mountains near Sanders, Idaho.  The major tributaries to Hangman Creek are Marshall Creek; California Creek; Spangle Creek; Rock Creek; Rattler Run Creek; and the Little Hangman Creek.

Water quality issues

Streams in the Hangman Creek watershed currently do not meet Washington state’s water quality standards for several reasons. Land use influences, (agriculture, impervious surfaces, timber harvest, roads, etc.) as well as stream channel and flood plain alterations over the last 100-years have contributed to “flashy” flow conditions, unstable stream banks, and substandard water quality.

Hangman Creek is also a majority tributary to the Spokane River. Ecology developed a plan to address low oxygen and high nutrients (phosphorus) in the Spokane River and Lake Spokane (Long Lake). Hangman Creek's contribution of nutrients and sediment to the Spokane River is important to this process. Efforts to reduce nutrients, especially phosphorus, in the Hangman Creek watershed will be necessary to address water quality issues in the Spokane River and Lake Spokane.

Why this matters

Water quality standards are designed to protect the beneficial uses of our streams and lakes. Beneficial uses can include irrigation, fishing, habitat, recreation (swimming, wading, and boating) and other uses. When a water body does not meet state standards, it is placed on the federal Clean Water Act’s 303(d) list of impaired water bodies. Information about the 303(d) list can be found on our Water Quality Assessments page.

Fecal coliform is a type of “bacteria” common in human and animal waste. It indicates that sewage or manure is entering a water body. As the level of fecal coliform increases the risk of people getting sick from playing or working in the water increases. Bacteria can get into our waters from untreated or partially treated discharges from wastewater treatment plants, from improperly functioning septic systems, and from livestock, pets and wildlife.

People can help keep bacteria out of the water. Properly collect, bag, and trash dog poop. Check your on-site sewage system to make sure it is maintained and working properly. Ensure livestock and manure are kept away from the water.

Water temperature influences what types of organisms can live in a water body. Cooler water can hold more dissolved oxygen that fish and other aquatic life need to breathe. Warmer water holds less dissolved oxygen. Many fish need cold, clean water to survive.

One way to cool water temperature is to shade the water body by adding or retaining streamside vegetation.

Turbidity is a measure of the clarity of the water. In the case of Hangman Creek most of its elevated turbidity comes from high levels of suspended fine sediments. These elevated suspended sediment levels are the result of streambank erosion, agricultural runoff, and other sources that wash off during rain and snowmelt. Pollutants such as fecal coliform bacteria and nutrients, like phosphorus, can hitch a ride with suspended sediments. Turbidity can also make a river or stream less transparent, resulting in greater solar absorption and higher stream temperatures.

Stream turbidity can be improved by controlling stormwater and agricultural runoff and by adding or maintaining vegetation on stream banks.

For more information on these parameters please see our impairments information page.

Status of the project

To address the water quality problems in the Washington portion of the watershed, Ecology and the Spokane County Conservation District worked together on a project called a Total Maximum Daily Load (TMDL). A TMDL, also known as a water quality improvement plan, is a common-sense, science-based approach to cleaning up polluted water so that it meets water quality standards. TMDLs established today also can help manage water quality on a watershed scale to prevent the loss of beneficial uses in the future. Beneficial uses can include irrigation, fishing, habitat, recreation (swimming, wading, and boating) and other uses.

In 2004, the Spokane County Conservation District (SCCD) applied for and was awarded a grant to develop the water quality improvement report or total maximum daily load (TMDL) for the Hangman Creek watershed. Since then, the SCCD and Ecology have worked together to study the watershed, work with the local community, and develop the improvement report. This effort addresses high levels of fecal coliform bacteria, high water temperatures, and high turbidity.

In 2004-2005, SCCD conducted monitoring to fill the data gaps needed to complete the TMDL analysis. The SCCD also formed a watershed advisory group to work on strategies to reduce the amount of pollution reaching the streams. The advisory group consists of people representing many different interests in the watershed, including agriculture; forestry; livestock production; and entities such as Spokane County; the city of Spokane; and the Coeur d’Alene Tribe. The advisory group met regularly to work on the water quality improvement plan (TMDL).

Ecology published the water quality improvement report for fecal coliform bacteria, high water temperatures, and turbidity in the Spring of 2009. Ecology and the SCCD reviewed all comments, revised the report, and published the final report in June 2009. The Environmental Protection Agency approved the report on September 29, 2009.

Since the approval of the TMDL, Ecology and the SCCD have been working with agencies and organizations to develop an implementation plan outlining what needs to occur to meet water quality targets in the watershed and various commitments to the effort. The draft implementation plan was available for public review and comment from February 15 to March 18, 2011. After addressing the comments received, Ecology published the final plan and sent a copy to EPA on May 13, 2011.

Hangman Creek also has dissolved oxygen and pH impairments which are typically the result of excess nutrients like nitrogen and phosphorus. Ecology collected water quality data on dissolved oxygen, pH, and nutrients in the watershed. This data will be used to develop a separate TMDL to address these parameters when resources become available. However, much of the implementation needed to address the original TMDL will also address nonpoint sources contributing to the dissolved oxygen and pH impairments. The nutrient water quality data will also be useful as we measure the progress toward meeting the phosphorus allocation set at the mouth by the Spokane River Dissolved Oxygen TMDL.

Technical information

Unless otherwise specified, the files below are Ecology publications.

Bacteria, temperature, turbidity (total suspended solids):

Hangman (Latah) Creek Watershed Fecal Coliform, Temperature, and Turbidity Total Maximum Daily Load - Water Quality Implementation Plan
www.ecy.wa.gov/biblio/1110012.html

Hangman (Latah) Creek Watershed Fecal Coliform, Temperature, and Turbidity Total Maximum Daily Load - Water Quality Improvement Report
www.ecy.wa.gov/biblio/0910030.html

Hangman Creek Watershed Water Quality Sampling - Quality Assurance Project Plan (QAPP) (Spokane Conservation District)
www.ecy.wa.gov/programs/wq/tmdl/HangmanCr/HangmanQAPPfinal.pdf

Hangman (Latah) Creek Water Sampling Data Summary - March 2005 (Spokane Conservation District)
www.ecy.wa.gov/programs/wq/tmdl/hangman_cr/wq_final_report040505.pdf

CDM's Final WARMF Model Report to Ecology
www.ecy.wa.gov/programs/wq/tmdl/hangman_cr/FinalMdlRptHangmanLatah011607.pdf

April 23, 2009 Public Meeting Presentation
www.ecy.wa.gov/programs/wq/tmdl/HangmanCr/042309Presentations.pdf

Dissolved oxygen, pH (nutrients):

Quality Assurance Project Plan: Hangman Creek Watershed Dissolved Oxygen and pH Total Maximum Daily Load Water Quality Study Design
www.ecy.wa.gov/biblio/0803117.html

Quality Assurance Project Plan: Hangman Hills Nutrient Loading Groundwater Study (Ecology publication)
www.ecy.wa.gov/biblio/1003116.html

Hangman Creek Watershed Dissolved Oxygen, pH, and Nutrients Total Maximum Daily Load (TMDL) Study: Data Summary
www.ecy.wa.gov/biblio/1103020.html

Related information

Back to top of page