Understanding Water Quality in the Upper Salt River Watershed

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Understanding Water Quality in the Upper Salt
River Watershed
Water Quality Field Day April 24, 2004
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Understanding Karst

• By Pennie DuBarry

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Karst Is
A terrain underlain by soluble rock in which the
topography is chiefly formed by dissolving of
rock and may be characterized by sinkholes,
sinking streams, closed depressions, subterranean
drainage, and caves --- Field, 1999 (USEPA
Karst Lexicon)
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Karst in Kentucky
About 55 percent of KY has potential for karst
Study area
Areas in red have high potential for karst Areas
in bright green have moderate potential for karst
Other areas have limited or no potential for
karst
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Karst in the Region
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Sinkholes
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Sinking Streams
Sinking Creek, Rockcastle Co., Kentucky
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Artesian (Rise Pit) Springs
Orangeville Rise, southern Indiana
Roubidoux Spring, Missouri
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Karst -- Potential Contaminant Sources
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Water Quality in the Upper Salt River Watershed

• By Mark Ayers

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What is a watershed?
The area of land from which runoff (rain or
snowmelt) drains to a point on along a stream.
Its boundaries are identified by locating the
highest points of land around the water body.
Karst terrane often defies surface-water divides!
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Inner Bluegrass karst example
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Runoff and water quality
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Water-quality measurements

• Water pH
• Water temperature
• Dissolved oxygen (DO)
• Conductance
• Total dissolved solids
• Suspended sediment
• Nutrients
• Nitrogen
• Phosphorus
• Bacteria
• Pesticides

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Nitrogen

• Essential nutrient for all plants and animals
• Common forms nitrate, organic, and ammonia
• Elevated amounts can contribute to excessive
  algal growth, lowering dissolved oxygen, and
  stressing fish and other organisms
• Concentrations of nitrate above 10 mg/L in
  drinking water can be toxic to infants

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Water-quality sampling at Glensboro stream gage
since 1989
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Total Nitrogen
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Phosphorus

• Essential nutrient for plants and animals
• Common forms orthophosphate and organic
  phosphorus
• Typically bound to soil particles, but is
  released in runoff and accumulates in reservoirs
  and lakes
• some Kentucky soils are naturally high in
  phosphorus
• Concentrations above 0.1 mg/L in streams and
  0.05 mg/L in lakes can contribute to excessive
  algal growth, lowering dissolved oxygen, and
  stressing fish and other organisms

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Total Phosphorus Statistically significant
decline since 1989
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Estimates of nitrogen yield (pounds/acre/year)
for subwatersheds in the upper Salt using a
national NPS model were very comparable with data
collected at Glensboro site.
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USDA NRI
The was used to determine changes in land use
in the 6-county region from 1982 to 1997
Land in agriculture decreased 7 Pasture down
3 Cultivated down 4 Developed and undeveloped
land together increased 7
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Landsat satellite imagery
also was used to determine changes in land
use from 1992 to 2000. Comparisons were made for
the 6-county region and for the study area.
NLCD
KLCD
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Land-Use Changes in the Region From 1992 to 2000
Land in agriculture increased by 1 Pasture up
9 Cultivated down 8 Undeveloped land decreased
by 5 Developed land increased by 4
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Land-Use Changes in the Study Area from 1992 to
2000
Undeveloped land decreased by 4 Pasture land
increased by 5 Cultivated land decreased by
5 Urban land increased by 4
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Changes in Cultivated Land from 1992 to 2000
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Changes in Pasture Landfrom 1992 to 2000
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Changes in Undeveloped Land from 1992 to 2000
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Land-Use Changes in the Study Area from 1990 to
2000
Cultivated land decreased by 5 to 9 Urban land
increased by about 4 Pasture land probably
increased some Undeveloped land not sure
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Changes in River Quality from 1998 to 2003
2003 Sampling indicates that the reach now
fully supports swimming use
Upstream BMPs??? Declines in farms???
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1992 to 1997 changes in numbers of cow and hog
populations and farms from above impaired river
reach
Cow operations down 12.5Hog operations down 47
to 68
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Water-Quality Summary
Declining bacteria and phosphorus levels indicate
that the combination of best-management practices
(BMPs) and land-use changes in the watershed
likely are having a positive effect on water
quality. Lack specific information about BMPs.
Hard to separate.
Pasture and undeveloped land typically have less
impact on water quality than cultivated or urban
land uses. In fact, forests are
beneficial.Probably not enough urban growth in
the upper watershed yet to see an effect at
Glensboro???
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Other Potential or FutureWater-Quality Issues
Urban runoff Forest fragmentation Pesticides???
(BMPs, however, are similar to nutrient and
sediment controls)
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Annual Yields of Atrazine in the US, 1997-2000

• Karst areas of Kentucky have some of the highest
  annual yields of atrazine in the United States.

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Modified Sinkholes Are Used for Storm-Water
Drainage in Urban Areas
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Land-Use Practices That Benefit Water Quality
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Links
USGS - Kentucky Districthttp//ky.water.usgs.gov/
Kentucky Division of Waterhttp//www.water.ky.g
ov/ Kentucky Division of Conservationhttp//www
.conservation.ky.gov/