Water Quality Improvement Project
Spokane River and Lake Spokane Area:
The Washington State Department of Ecology (Ecology) has worked in partnership with state, local and federal
government, tribes, industry and the community to improve dissolved
oxygen in the Spokane River and Lake Spokane since 1998.
Dissolved oxygen is important for fish,
invertebrates and other aquatic life because they need oxygen to live. Excess
nutrients like nitrogen and phosphorus in the Spokane River and Lake Spokane
deplete dissolved oxygen and can also cause toxic algae blooms that are harmful
to human and animal health.
Portions of the river and lake have excessive algae blooms during low flow in
the summer months due to low dissolved oxygen and high phosphorus levels, which
violate the Washington State
Washington State is required by the Clean Water Act to develop water a quality improvement
plan because several segments of the river and lake were included on the
state’s 1996, 1998 and 2004 303(d) lists of impaired water bodies.
Improving the river and lake
Reducing nutrients is key to improving dissolved oxygen levels and reducing
algae blooms. Nutrients like phosphorus and nitrogen come from a variety
of sources including wastewater treatment plants that discharge water into the
river through a pipe. Discharges from pipes are called point sources. Ecology is working with point-source facilities along the river through the
National Pollutant Discharge Elimination System (NPDES) permit process to
upgrade treatment technology that will help meet water quality goals. The
permits limit the amount of nutrients and outline other water quality
requirements that point sources discharge into a body of water.
NPDES-permitted facilities along the Spokane River in Washington include:
The Spokane River flows from its source at Lake Coeur d’Alene in Idaho
through the city of Spokane, Washington. It then flows northwesterly through
Lake Spokane and the Spokane Tribe of Indian’s reservation on is path to Lake
Roosevelt. The river drains an area of about 6,640 square miles in two states.
Approximately 2,295 square miles are within Washington with the remainder of the
watershed in Idaho.
There are three facilities in Idaho that discharge treated wastewater to the
sources are also a significant source of nutrients to the river and lake.
These sources come from our activities on the landscape which enter
surface water through runoff or groundwater. Nonpoint sources in the
Spokane watershed include runoff containing fertilizer and pesticides from lawns
and croplands, organic debris from forest land, soil erosion, faulty septic
tanks, and stormwater. People can reduce nutrients from these sources by
applying best management practices. Examples include vegetated buffers
along waterways; keeping lawn clippings, manure, and livestock out of surface
water; and allowing water from your property to soak into the ground rather than
flowing onto streets or over the ground into ditches.
2010 Spokane River Dissolved Oxygen Total Maximum Daily Load report (TMDL) requires the following improvements
over a ten year time period:
- Remove more than 90 percent of total phosphorus from point sources in
- Reduce up to half of nutrients from nonpoint sources in Hangman and
Coulee creeks, the Little Spokane River, and surrounding Lake Spokane.
- Improve dissolved oxygen conditions in Lake Spokane by Avista Utilities.
Status of actions to improve water quality
Ecology is working with wastewater dischargers, Avista, local conservation
districts, environmental groups, and many others to implement the water quality
improvement plan. Following is a description of some of the activities taking place
to reduce nutrients in the river and lake. Another place to get
information about what is happening with the TMDL project and work to reduce nutrients
is the Spokane River Forum. The
Forum’s purpose is to serve as a clearinghouse and information exchange for all
Spokane River and Lake Spokane issues.
Water Quality Monitoring on Lake Spokane at Suncrest
NPDES Permit Schedule
Avista Water Quality Attainment Plan
Monitoring data can be found in our
Lake Spokane Nutrient Monitoring, 2010-2011: Data Summary Report. Wastewater dischargers and Avista are also required to monitor and report water
quality information for the river.
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