Water Quality Short Course

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Water Quality Short Course April 11, 2007 Lake
and Reservoir Dynamics Dan Obrecht
UMC obrechtd_at_missouri.edu
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Talk Topics

• Nonpoint source pollution
• Most common pollutants and how they impact water
  quality
• Most common sources
• Variability
• Regional Trends?
• Spatial and Temporal variation
• Thermal Patterns (briefly)

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Most common pollutants
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Most common pollutants
- Nutrients - Metals
- Suspended Sediment
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Most common pollutants
- Nutrients - Metals
- Suspended Sediment
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Proposed 2004/2006 303(d) Impaired Waters
List Lead 1 lake (Mercury?)
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Most common pollutants
- Nutrients - Metals
- Suspended Sediment
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PHOSPHORUS NITROGEN
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Missouri Lakes Phosphorus vs Algal
Biomass
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Missouri Lakes Nitrogen vs Algal Biomass
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Algae are the base of the aquatic food web and
supply dissolved oxygen to the water.
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Excessive algae can

• Decrease recreational value - Cause extreme
  dissolved oxygen fluctuations
  - Increase treatment cost - Reduce
  water clarity

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Most common pollutants
- Nutrients - Metals
- Suspended Sediment
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Suspended sediment can
- Fill in lake bottom - Impact
substrate habitat - Increase cost to treat
- Reduce water clarity
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Secchi Disk
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Secchi Disk
MO values Average 39 Minimum 3 Maximum
gt360 (30 FEET!)
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Leading sources
Agriculture Municipal point sources Urban runoff
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Agriculture
Source of both nutrients and sediment
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Municipal Point Source
Source of nutrients
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Most lakes in Missouri do not have Sewage
Treatment Point Sources in their watershed.
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Urban Runoff
Source of both nutrients and sediment
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Regional Patterns?
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Glacial Plains
Ozark Border
Osage Plains
Mississippi Lowlands
Ozark Highlands
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Average Values (for physiographic regions)

• Region Sediment Phosphorus
• 
  (mg/L) (ug/L)
• Glacial Plains 6.8
  44 Osage Plains 16.5
  73 Ozark Border
  4.5 40
  Ozark Highlands 2.1 17

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Long-term average phosphorus for six Glacial
Plains lakes
Reservoir TP (µg/L) Maysville (n10)
182 Grindstone (n5) 147 Unionville
(n10) 98 Long Branch (n20)
48 Viking (n16) 26 Forest (n19)
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Missouri LakesForest vs. Phosphorus
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Missouri Lakes Row Crop vs
Phosphorus
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Long-term average phosphorus for six Glacial
Plains lakes
Reservoir TP (µg/L) Crop Maysville
(n10) 182 25 Grindstone (n5)
147 55 Unionville (n10) 98 21 Long
Branch (n20) 48 34 Viking (n16)
26 15 Forest (n19) 23 3
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Reservoir TP (µg/L) Crop Res.
Time (months) Maysville (n10) 182
25 2.9 Grindstone (n5) 147 55
6.3 Unionville (n10) 98 21
6.3 Long Branch (n20) 48 34
10.5 Viking (n16) 26 15
70.6 Forest (n19) 23 3
32.4
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Temporal Variability
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Longview Lake Seasonal patterns
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Lake Jacomo - Chlorophyll Values
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Spatial Variability(Individual Lake)
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Lake of the Ozarks Average phosphorus values
(mg/L)
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Table Rock Lake Average phosphorus values (mg/L)
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Longview Lake Average phosphorus values (ug/L)
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930 acres Approximately 1 mile between the two
sites.
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Vertical Variability
Site 1
Site 2
Lake Surface
Phosphorus 10 µg/L 21
µg/L Nitrogen 260 µg/L
330 µg/L Phosphorus 63 µg/L
94 µg/L Nitrogen 420 µg/L
570 µg/L
Lake Bottom
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Stratification and Turnover
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Winter Stratification
Summer Stratification
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Thanks