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Turbidity Power point.notebook 1 September 17, 2012 Sep 171:19 PM Turbidity What is turbidity and how does it affect the quality of water?
Transcript of Sep 171:19 PM
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Turbidity What is turbidity and how does it affect the
quality of water?
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What Is Turbidity?• The appearance of suspended particles in water is
called TURBIDITY.
• Turbidity is an important factor in assessing water quality because:
• Measuring turbidity shows the volume of matter present in a body of water.
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Factors That Influence Turbidity
• Human activities can influence turbidity. For instance, straight pipe sewage dumping poses major contamination risks.
• Human-caused erosion stems mainly from activities like road building, construction, agriculture, logging, and other endeavors that remove or disturb vegetation.
• Natural erosion and the resulting turbidity is a common occurrence in some watersheds
Human Activities
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Environmental Impacts • Erosion increases the amount of sediment in water.
• SEDIMENT is the #1 source of nonpoint pollution.
• Nonpoint source pollution means one cannot detect the origin of a stressor.
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How are River Organisms Effected by Turbidity?
• Many fish need clear water to spot their prey
• Macroinvertebrates, fish eggs, and larvae require oxygen-rich water circulating through clean gravel beds to survive. High turbidity levels will lower the Bio Index
• Sediments can smother fish eggs and aquatic insects and suffocate clams and oysters.
• Cloudy water absorbs more of the sun‛s energy than clear water. This leads to higher water temperatures
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• The instrument used to measure turbidity is called a secchi disk (top left). It has a string with measurements attached to the ring.
• The caption (bottom left) shows the lowering of the secchi disk to measure the turbidity of algae.
Secchi Disk
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Turbidity Reading
This caption shows a low turbidity reading. The secchi disk is easy to read and the light refracted shows the water is clear and safe for macros.
This caption shows a high turbidity reading. As you can see the light refracted shows cloudy , murky water which becomes a stressor for macros.
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Turbidity & Sediment Effects People
• At water treatment plants, sediment is the first thing filtered out of source water.
• It is one of few water quality contaminants that must be monitored daily.
• Suspended solids can harbor harmful bacteria and can also decrease the effectiveness of chlorination used to help remove those harmful bacteria.
• The time and costs required to treat the water increases due to the increase of sediments.
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Is High Turbidity A Good Thing?
• Many rivers carry high sediment loads due to the nature of the rock and soil layers that they pass through.
• Limestone and Sandstone are examples of types of rock material that have a high erosion capacity.
• Some organisms actually adapt to the muddy water and thrive.
• Channel catfish have barbells on their snouts that serve as probes for food in dark , murky water.
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So What Is The Solution?
If erosion and runoff are the largest contributors to sediments in our waterways then slowing runoff and minimizing erosion is crucial to improving water.
Sometimes human-caused erosion can be managed to reduce the turbidity of waterways.
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BEST MANAGEMENT PRACTICE STRATEGIES
RUNOFF BASINS (above)
Using straw bales to control sediment.
SILT FENCES at Construction Sites
CONTOUR PLOWING – Plant cover crops between seasons and establish buffer zones between agriculture areas and water.
