Water Quality Improvement Projects (TMDLs) > WRIA 55 > Little Spokane River Area Multi-parameter Project

Water Quality Improvement Projects
Little Spokane River Area

Introduction

The Little Spokane watershed drains approximately 700 square miles, including regions of north central Spokane County, southern Pend Oreille County, and southeastern Stevens County in northeast Washington, as well as a small section of Bonner County in Idaho. The majority of the watershed, approximately 417 square miles, is in Spokane County. Stevens and Pend Oreille Counties make up approximately 260 square miles of the watershed. Only 23 square miles is located in Bonner County, Idaho. The river is one of the two major tributaries to the Spokane River (Latah/Hangman Creek being the other). The river discharges into the Spokane River at River Mile (RM) 56.3, downstream of Nine Mile Dam.

The major tributaries to the Little Spokane River are Dragoon, Deadman, Little Deep and Deer Creeks as well as the west branch of the Little Spokane River. The largest lakes include Eloika, Diamond, Sacheen, and Horseshoe Lake which are all located in the northern half of the watershed.

Water quality issues

The Little Spokane River, Dragoon Creek, and Deadman Creek are currently on the 2008 303(d) list because they do not meet water quality standards for the following parameters:

*The PCB listing is being addressed through the Spokane River PCB TMDL.
**These listings are included in the 2008 Category 5 303(d) list.

When a water body does not meet state standards, it is placed on the federal Clean Water Act’s Section 303(d) list of impaired water bodies.

Why this matters

Ammonia (NH4+) is one measure of nitrogen, a nutrient that can increase the growth of plants and algae in water. When higher-than-normal levels of nutrients are present, plants and algae can get out of control and lead to changes in the water’s pH, dissolved oxygen and clarity. In addition, increased algae
and plants can be ugly, create odor problems when they die, decompose and interfere with recreational activities like boating and swimming.

Oxygen dissolved in healthy water is vital for fish and aquatic life “breathe” to survive. It is more difficult to transfer oxygen from water to blood than it is to transfer oxygen from air to blood. Therefore, it is critical that an adequate amount of oxygen is maintained in the water for this transfer to take place efficiently and sustain aquatic life. Oxygen is also necessary to help decompose organic matter in the water and bottom sediments as well as for other biological and chemical processes.

Fecal coliform is a type of “bacteria” common in human and animal waste. It can make people sick and cause the closure of shellfish harvesting beds. 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.

Pesticides and polychlorinated biphenyls (PCBs) can be toxic to fish and wildlife that use a contaminated water body.

In the past, PCBs were used as coolants and lubricants in electrical equipment such as transformers and capacitors. The United States banned the manufacture of PCBs in 1977 because they build up in the environment and can be harmful to humans and wildlife. PCB exposure can occur if you:

• Eat food, including fish, meat, and dairy products that is contaminated by PCBs.
• Drink PCB-contaminated water.
• Breathe air near hazardous waste sites that contain PCBs.

pH is a measure of how acidic or alkaline the water is. The pH is measured on a scale of 0-14, with the lower numbers indicating acidic conditions and higher numbers alkaline conditions. Optimal pH levels to support fish and wildlife should range from 6.5 to 9.0. A pH of 7 is neutral.

pH can affect the solubility of nutrients and metal compounds. By affecting the solubility of nutrients, it can change the amount of nutrients available for plant growth. If too many nutrients are available, aquatic plants can grow out of control. When these plants decompose, they can deplete the water of oxygen. The solubility of many metal compounds also changes greatly with pH. Generally, a reduction in pH (more acidic) increases the solubility of heavy metals. When more metals are dissolved in the water, aquatic animals may absorb them faster. Therefore, a lower pH (more acidic) may make these metals more toxic to aquatic life.

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. Threatened and endangered salmon 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 suspended fine sediments in a body of water. High turbidity in rivers and streams comes from both streambank erosion and sediments washed into drainages during storm events. Pollutants such as fecal coliform bacteria 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 runoff and by adding or maintaining vegetation on stream banks.

For more information on these impairments, please see our Environmental Importance of the Different Impairments 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 water quality improvement project called a Total Maximum Daily Load (TMDL). A TMDL is a common sense, science-based approach to cleaning up polluted water so that it meets water quality standards.

Ecology developed a TMDL to address low oxygen and high nutrients in the Spokane River and Lake Spokane (Long Lake). The Little Spokane’s contribution of nutrients and sediment to the Spokane River is important to this process and was taken into consideration during the development of a TMDL for the watershed.

Ecology, working with a local advisory group, developed a TMDL for the Little Spokane River Watershed. This TMDL focused on fecal coliform bacteria, temperature, and turbidity issues in the watershed. After a public comment period and responding to comments received, Ecology submitted the final TMDL to EPA for approval in February 2012. EPA approved the TMDL in April 2012.

Technical information

Related information

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