The Department of Ecology has made substantial changes to the total maximum daily load, TMDL to restore dissolved oxygen in the Spokane River and Lake Spokane, warranting a new public review period, which continues through October 15.
This TMDL has been revised from previous drafts issued in 2007 and 2008 by containing a dissolved oxygen responsibility for a hydroelectric dam, accounting for stormwater pollution, and cumulatively assessing the dissolved oxygen impacts from all point sources in Washington and Idaho.
Lake Spokane, also known as Long Lake, has a long history of water quality problems. Eutrophication of the lake has been one of the major water quality concerns for the area over the past 40 years.
From its source at Lake Coeur d'Alene, the Spokane River flows west across the Idaho - Washington state line to the City of Spokane. From Spokane, the river flows northwesterly through Lake Spokane and the Spokane Tribe of Indians' reservation to its confluence with the Franklin D. Roosevelt Lake impoundment of the Columbia River.
The Spokane River (Photo courtesy Hydropower Reform Coalition)
Formed by Long Lake Dam, which is operated by Avista Utilities, the 24-mile long reservoir on the Spokane River, called Lake Spokane or Long Lake, is downstream of the City of Spokane. The study area for this TMDL stretches from Long Lake Dam to the outlet of Lake Coeur d'Alene.
The TMDL, also known as the Spokane River/Lake Spokane Dissolved Oxygen Water Quality Improvement Plan, will guide work toward a healthier Spokane River in compliance with state and federal water quality standards for dissolved oxygen.
Unique to this improvement plan, the industrial and municipal point-source dischargers from a pipe are required to help reduce phosphorus from other diffuse, non-point sources as well. Non-point sources include farms, septic systems, stormwater runoff, animal waste, and fertilizers used at home.
In addition, the plan gives Avista Corporation, operator of Long Lake Dam, part of the responsibility to improve dissolved oxygen levels in Lake Spokane.
A public meeting is planned for 6 to 9 pm, Thursday, September 24 at the Spokane Community College's Sasquatch Room in the Lair Building #6, 1810 N Greene St., Spokane to discuss the revised TMDL.
"This document has been controversial and the subject of many years of community discussion," said Water Quality Program Manager Kelly Susewind. "We heard the community's concerns during the previous public comment period and we have worked hard on this draft plan to address those concerns. Now it's time to take one more look."
The water quality improvement plan outlines how the community will reduce phosphorus and other substances in the Spokane River and Lake Spokane to prevent algae blooms, increased growth of aquatic plants and the related declines in Lake Spokane's dissolved oxygen.
Phosphorus is the primary nutrient causing excess algae and plant growth in the Spokane River and Lake Spokane. It behaves like a fertilizer, causing algae and other aquatic plants to grow and thrive. When the plants decompose, they use up dissolved oxygen that fish need to breathe. More algae means less oxygen.
In addition, unsightly algae blooms can become toxic and cause nuisance smells or human skin irritations. They can make Lake Spokane unhealthy for swimming, and compromise its ecological balance.
The Spokane River/Lake Spokane Dissolved Oxygen Water Quality Improvement Plan will lead to reducing phosphorus pollution from industrial and municipal pipes by more than 90 percent. Its phosphorous limits for industrial and municipal discharges are among the most stringent in the country.
This TMDL establishes a management plan to reduce nutrients in the Spokane River and Lake Spokane to prevent low dissolved oxygen, excessive algae blooms and degradation of downstream water quality. The dissolved oxygen levels in this system are affected by nutrients; therefore, this TMDL establishes limits for ammonia, total phosphorus and carbonaceous biochemical oxygen demand.
The U.S. Environmental Protection Agency, working with Ecology, the Idaho Department of Environmental Quality and the Spokane Tribe of Indians hired experts at Portland State University to conduct new computer modeling after the EPA changed its procedures in 2008.
Instead of measuring background levels of phosphorus and other nutrients at the Idaho/Washington border, EPA reversed course and said background levels used should be from Lake Coeur d'Alene, miles upriver.
This change in course changed the numbers used to calculate how much phosphorus each industry and municipality along the river is allowed to discharge on both sides of the state line. Changes were made in the water quality improvement plan based on the new course, new computer modeling and two prior public comment opportunities in the past two years.
Click here to view the "Spokane River and Lake Spokane Dissolved Oxygen Total Maximum Daily Load Draft Water Quality Improvement Report."
Copyright Environment News Service, ENS, 2009. All rights reserved.