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
Ecology teamed up with the United States Geological Survey (USGS) to evaluate
nutrient contribution to Lake Spokane through groundwater from on-site septic
systems. This study builds on a broader
study conducted by Spokane County, which recommends further investigation of
densely populated areas that rely on on-site septic systems for wastewater
treatment. Data gathered will be used to evaluate if there is a nutrient
contribution to the lake from areas with higher residential development compared
to an area without homes.
More information about water
quality monitoring on Lake Spokane at Suncrest
NPDES Permit Schedule
Ecology issued Washington municipal and industrial wastewater NPDES permits in
November 2011, which began a ten-year compliance schedule for the Washington
wastewater dischargers. Dischargers must meet certain milestones outlined
by their compliance schedules and are working toward installing advanced
treatment to reduce nutrients. By 2021, the wastewater dischargers will need to
be in compliance with the nutrient limits established by the water quality
The Environmental Protection Agency issued permits for the Idaho wastewater
dischargers in October 2014, which requires similar milestones and compliance.
Local conservation districts and other organizations are continuing to work
with landowners on reducing nonpoint sources by installing best management
practices. Many incentive and cost-share programs are available to help
off-set the cost for landowners to make needed improvements. These improvements
are described in the
Nonpoint Source Phosphorus Reduction Plan developed by Spokane County. The
plan identifies types of best management practices and where they should be
Local municipalities are also expected to help reach water quality goals
through stormwater management. Municipal stormwater permits require the cities
of Spokane and Spokane Valley along with Spokane County to reduce stormwater
flows or eliminate stormwater outfalls to the river. The city of Spokane is also
using their newly adopted
Water Plan to manage stormwater.
Avista Water Quality Attainment Plan
Avista identified actions in their Lake Spokane DO Water Quality Attainment
Plan, to increase dissolved oxygen and reduce excess nutrients, which is
available at their
water quality website.
Hangman Creek and the
River have water quality improvement plans to reduce bacteria, temperature
and turbidity. Actions and best management practices in these watersheds
will also reduce the amount of nutrients entering the streams, river, and lake.
Water quality improvement plan studies for dissolved oxygen and pH are in
various stages of development for Hangman Creek and the Little Spokane River.
Monitoring is underway on Coulee Creek and its tributary, Deep Creek, to gather
information about nutrient sources.
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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