Water Temperature
Water temperature is one of the most important factors
for survival of aquatic life. Most aquatic organisms
become the temperature of the water that surrounds
them. Their metabolic rates are controlled by water
temperature. This metabolic activity is most efficient
within a limited range of temperatures. If temperatures
are too high or low, productivity can decrease or metabolic
function cease. The organism can die. These extremes, or
lethal limits, vary for different species.
Temperature fact sheet
State Standards
| Class AA (Extraordinary) |
Not to exceed 16.0 degrees Celsius |
| Class A (Excellent) |
Not to exceed 18.0 degrees Celsius |
| Class D (Good) |
Not to exceed 21.0 degrees Celsius |
| Class C (Fair) |
Not to exceed 22.0 degrees Celsius |
(Source: WAC 173-201A-030)
- Reminder:
- To convert degrees Fahrenheit to degrees Celsius use the following formula: (F - 32) / 1.8 = C
To convert degrees Celsius to degrees Fahrenheit use the following formula: (C x 1.8) + 32 = F
FACTORS THAT INCREASE STREAM WATER TEMPERATURES
- Improper grazing practices, logging, mining and commercial industrial development that removes the shading and cooling effect of stream-side vegetation.
- Warm water releases from power plants, industrial facilities.
- Slowed water due to small hydropower projects, and diversion dams for irrigation.
Temperature: TLm (tolerance limit median)
12 Hour Tolerance Median for
Common Species
12 Hr-TLm is the temperature limit that half of a given species will perish at within 12 hours. This is a very important consideration of stream health.
Source: "The Stream Scene"
Temperature Testing
WATER
- Lower the thermometer a few inches below the water surface.
- Keep the thermometer in the water for the (3) minutes until a constant reading is obtained.
- Record the measurement in the temperature data record.
- Compare your temperature to federal and state standards in addition to the temperature ranges for aquatic life.
AIR
Use dry thermometer and hold it in the air until reading is steady. Sunny and shady sites may have different temperatures. Record your findings on data sheet.
