1. Physical Variables of Water Health
1. Temperature
determines the kinds of organisms that can survive there.
Cold water = more oxygen
Warm water = less oxygen
Warmer water dissolves more solid substances but dissolves less of important gases (DO, and CO2)
What are some ways that the temp of a river can increase? Power plants, using lakes and rivers as a cooling agent. Lake Julian

2. Nuclear Power Plants use cooling lakes, which increases the temperature of the water

3. Physical Variables of Water Health
2. Turbidity - is a measure of how clear water is.
The more suspended solids are in the water, the higher the turbidity
The higher the turbidity, the poorer the water quality

5. Chemical Variables of Water Health
1. pH – is a measure of how acidic or basic something is
7 is neutral < 7 is acidic > 7 is basic

6. Chemical Variables of Water Health
2. Dissolved Oxygen (DO) - Oxygen that is dissolved in water
The O2 molecules are mixed with the H2O molecules

7. Chemical Variables of Water Health
Dissolved Oxygen (DO)
All organisms use DO
Mayfly, caddisfly, stonefly

8. Chemical Variables of Water Health
How DO gets in the Water
naturally through diffusion with the oxygen in the air

9. Chemical Variables of Water Health
How DO gets in the Water
byproduct of photosynthesis

10. Cold water = more DO Warm water = less DO
Trout, salmon. Bass, catfish

11. Chemical Variables of Water Health
Levels of DO
Levels of DO can predict health of the water
Pollutants (sewage, fertilizer, runoff, animal waste) can decrease DO levels
Since all organisms use DO, it is a good indicator of the “health” of the stream or lake.

12. Chemical Variables of Water Health
3. Nitrates and Phosphates are natural occurring compounds
Small amounts of these compounds in water are natural
However, elevated levels can be harmful to organisms and humans
Higher levels = more plants and more algae bloom

13. Chemical Variables of Water Health
Sources of Nitrates and Phosphates
Runoff contaminated with fertilizers
Septic tank leakage
Sewage
Enter waterways from human and animal waste
laundry
Cleaning supplies
Phosphates and nitrates = algae which blocks out oxygen and sunlight

15. Biologic Variables of Water Health
The presence, condition, and numbers of the types of fish, insects, algae plants and other aquatic life provide accurate information about the health of water.