WATER QUALITY MONITORING SUBCOMMITTEE

PILOT PROJECT – MARCH 1996

 Purpose & Objectives

The Water Quality Monitoring Subcommittee held it’s first meeting Feb.24, 1996. This pilot project arises from that meeting and from an earlier meeting of the Directors of SRES which established objectives. Four objectives of the Water Quality Monitoring Subcommittee are:

• to be better informed
• to respond to a problem
• to provide information/get assistance from government agencies
• provide public exposure of findings

More broadly we expect the program will provide training and practical experience for participants, removing barriers of scientific terminology and providing data which will add to the extensive background data available on the Salmon River, (in particular by Westwater Research of U.B.C.). The data obtained will help to monitor changes in environmental quality due to pollution or pollution control measures, will help to identify problems, will provide indicators to the public on ecosystem health and provide data to influence decision making. In addition to the scheduled "on site" water quality monitoring, the subcommittee will have the ability to collect samples for lab analysis.

On-site Testing Included:

• temperature
• dissolved oxygen
• pH
• nitrates
• phosphates
• turbidity
• total dissolved solids/specific conductance

 Temperature

Temperature is very important to aquatic life. Most aquatic organisms are cold-blooded, so their body temperatures are the same as the water temperature. Water temperature increases when the sun shines directly on a stream. Shading from trees, water surface area and volume, turbidity, stream bed colour, and orientation to the sun all affect the amount of sunlight absorbed by water.

Warm water contains less oxygen than cold water. When the water temperature increases, the concentration of dissolved oxygen decreases. As the temperature rises, animals use oxygen at a faster rate – the metabolic rate doubles with each 10° C increase. Plants grow faster and produce more oxygen, however, their decomposition consumes more oxygen. As the water temperature increases, animals become stressed and are more likely to succumb to contaminants, parasites, and disease. Organisms die when they cannot adapt to the new conditions.

Shading helps keep summer water temperatures low. Shaded streams are cooler than unshaded streams. In late summer, the water temperature increases between early morning and late afternoon. In unshaded streams, the daily increase can be as great as 10° C. Water loses heat very slowly even when it flows into shaded areas. Removal of streamside vegetation is a major cause of temperature problems in British Columbia streams. Logging, agriculture, dyking, and urban development often remove streamside vegetation. This adds sediment to the stream from erosion. Besides causing other water quality problems, sediment absorbs heat from the sunlight thereby raising water temperature. Planting streamside vegetation helps correct the problem.

Water withdrawal for irrigation purposes often reduces stream flow during the summer, when flows are already at minimum levels. Low water flows contribute to problems with daily temperature fluctuation because there is less water to buffer the impact of high temperatures.