Water Quality Improvement Projects (TMDLs) > WRIA 13 > Deschutes River Watershed Area Multi-parameter Project

Water Quality Improvement Project
Deschutes River Watershed Area:
Multi-parameter

Introduction

Living in the Deschutes watershed offers an abundance of beauty and water-related activities. Unfortunately, the quality of water in some areas of the Deschutes River, Capitol Lake and Budd Inlet are below state standards. In order to return the river to a healthy condition, a coordinated process has begun, called a “TMDL” or total maximum daily load.

Water quality issues

The Deschutes River is under pressure from growth, resulting in many small, uncontrolled sources of pollution entering the river. Local city, county, and state government agencies work hard to monitor and protect the quality of our water. Recently, water quality monitoring revealed that measurements of pH, dissolved oxygen, temperature, fine sediment, and fecal coliform were not normal, therefore triggering the “TMDL” process.

Why this matters

Water supplies must be of high quality for drinking water use and to support fish and wildlife. At the same time, water quality may depend on maintaining a sufficient amount of clean water to reduce the adverse effects of pollutants and increased surface water temperatures.  Water quality is closely tied to water quantity.  Also, removing streamside vegetation tends to raise water temperature to a level that may be harmful to fish and other aquatic animals, insects and plants.

Dissolved oxygen - 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 sedimentsas 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.

Phosphorus fuels the growth of algae. When algae die, they remove oxygen from the water. Fish and aquatic life need oxygen to survive.

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.

Status of the project

Advisory Committee information

Technical information

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