Hangman (Latah)
Creek Watershed Planning Project
Water Quality
Hangman Creek is a watershed
suffering from significant human disturbance over the last 100-years. Land use
influences,
including agricultural production, installation of impervious surfaces, timber harvesting, and road development, as well as stream channel and flood plain alterations,
contribute to highly variable flow
conditions, unstable stream banks, and substandard water
quality. The creek is often described
as
one
of the most degraded
waterbodies in eastern Washington State.
The federal Clean Water Act (CWA) requires states to identify waters not meeting federal or state water quality standards. Section 303(d) of the CWA requires Washington State to prepare a list of all surface waters in the state for which beneficial uses - such as agriculture, drinking, recreation, and aquatic habitat - are impaired by pollutants. Section 303(d) also specifies pollutants of concern under the Clean Water Act. Waters failing to meet water quality standards for any or all of these pollutants are placed on a 303(d) list by the Washington State Department of Ecology.
Hangman (Latah) Creek has been identified by the Department of Ecology as not achieving state water quality standards for several factors, including fecal coliform, dissolved oxygen, turbidity, ammonia, pH and temperature. Recent monitoring has identified several other water quality problems not specifically addressed under Section 303(d) of the Clean Water Act, including sediment load, low flows and total phosphorus.
Hangman Creek is suspected
to be the largest contributor
of bedload and suspended sediment to the Spokane River.
The majority
of the bedload portion of the sediment load is transported
downstream and deposited behind the Nine Mile
Dam. The suspended sediments continue through the dam’s
bypass system and settle out in Lake Spokane.
The Spokane County Conservation District, in cooperation with the Washington State Department of Ecology and local residents, is conducting a planning process to address water quality concerns in Hangman Creek. The planning process is known as a Water Quality Improvement or Total Maximum Daily Load (TMDL) project. The project involves identifying the type, amount, and source of water quality problems, and recommending practices to reduce the impacts of pollutants and improve the water quality of the Hangman Creek watershed.
< return to the Summary of Findings and Recommendations page>
|
