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Water Quality
Rice Creek Watershed
Rice Creek Watershed
Dissolved Oxygen
 What

measure of dissolved oxygen in the water
 Why

is it?
does it matter?
Clean, healthy water has plenty of DO. When
water quality decreases, DO levels drop and it
becomes impossible for many animals to
survive. Time of year also matters.
 How
do DO levels in the water drop?
Biochemical Oxygen Demand
 What

measures the amount of oxygen consumed
by microorganisms in the process of
decomposing organic matter in water
 Why

is it?
does it matter?
A high BOD means less oxygen is available
for other aquatic life, they become stressed,
suffocate, and die.
 How
do BOD levels rise?
Coliform Bacteria
 What

Fecal coliform bacteria are naturally present
in the human digestive tract but are rare or
abesent in unpolluted water.
 Why

is it?
does it matter?
High levels of fecal coliform bacteria are a
warning sign that water can make you sick.
 How
does fecal coliform get in the water?
pH
 What

pH is a measurement of the acidity or basic
quality of water
 Why

is it?
does it matter?
At extremely high or low pH levels (above 9.6
or below 4.5), the water becomes unsuitable
for most organisms.
 How
low?
do levels of pH become too high or
Temperature

What is it?


Temperature is a measure of how much heat is
present in the water
Why does it matter?

Temperature affects
• Dissolved oxygen levels in water – cold holds more O2
• Photosynthesis – high temps increases plant growth and
decomposition, leading to decreased O2 levels
• Animal Survival – ideal temperature ranges for organisms
• Sensitivity to toxic wastes and disease – waste generally
increases water temps leading to lower O2 levels.

How does water get warmer?
Nitrate

What is it?


Extra nitrogen in water leads to rapid plant growth
Why does it matter?

Can lead to eutrophication:
1.
2.
3.
4.
Nitrogen enters the water
Plants take up the nitrogen and grow and grow and grow
Plants (algae) die and sink to the bottom
Bacteria at the bottom decompose the dead plants, using
up oxygen in the process
5. Oxygen levels drop, killing fish or aquatic insects
6. Nitrogen continues to enter the water
7. The cycle continues

How does too much nitrogen get in the water?
Phosphate

What is it?


Phosphorus is a nutrient found in all living things.
Why does it matter?

when too much phosphorus enters a river or lake, plants grow
more…leads to eutrophication!








Phosphorus enters the water
Plants take up the phosphorus and grow too much
Plants (algae) die and sink to the bottom
Bacteria at the bottom decompose the dead plants, using up oxygen
in the process
Oxygen levels drop, killing fish or aquatic insects
Phosphorus continues to enter the water
The cycle continues
How does too much phosphorus get into the water?
Turbidity
 What

measures of how cloudy a water body is
 Why

is it?
does it matter?
When the water is turbid
• floating particles absorb heat from the sun and
cause the water temperature to rise
• blocks sunlight
• floating particles may clog fish gills
 How
do turbidity levels rise?
Conductivity

What is it?


Why does it matter?


Determines the total concentration of ions in a water
sample.
Gives general indication of the level of total dissolved
solids in a lake or stream. These conductive ions
come from dissolved salts and inorganic materials
such as alkalis, chlorides, sulfides and carbonate
compounds.
How do inorganic pollutants get into water?
In your groups answer the
following…
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How do DO levels in the water drop?
How do BOD levels rise?
How does fecal coliform get in the water?
How do levels of pH become too high or low?
How does water get warmer?
How does too much nitrogen get in the water?
How does too much phosphorus get into the
water?
 How do turbidity levels rise?
 How do inorganic pollutants get into water?