Assessing the effect of Land Assessing the effect of Land use on the Edward’s aquifer use on the Edward’s aquifer
water qualitywater quality
Julien VillardJulien VillardUniversity of Texas CE 394kUniversity of Texas CE 394k
Facts about the Facts about the Edward’s Edward’s aquiferaquifer
22 to 55 million 22 to 55 million acre-feetacre-feet
Head drop > Head drop > 1 foot/day1 foot/day
Increased Increased environmental environmental concerns:concerns:Urban sprawlUrban sprawlOverdraftingOverdrafting
Municipal wells in San Antonio, 1895
Contamination sourcesContamination sources85%
15%
• Agricultural areas Fertilizers, farming, animal dejections
• Urban areasDomestic sewage, storm water runoff
• Industrial areasOrganic industrial wastes
Well location shapefileWell location shapefileSelection by location
Selection by attribute“Water_Qual”=“Y”
My new shapefile
Water quality dataWater quality data
Travis, Hays, Comal, Bexar, Medina, Uvalde, Kinney
Sulfate, Chloride, Fluoride, Nitrate, TDS
Sulfate 2003 Nitrate 2003
Chloride 2003Fluoride 2003
Land cover classification system
•Urban Low residential High residential
•Industrial Commercial Industrial
•Agricultural Pasture Row crops Small grains Fallow
USGS Land use dataUSGS Land use data
Density rastersDensity rasters
Urban density % Agricultural density%
ResultsResults Urban areasUrban areas
contaminants versus urban density
0
50
100
150
200
250
0 50 100 150
urban density%
conc
entr
atio
n(m
g/L)
sulfate
nitrate&fluoride versus urban density
02468
1012141618
0 20 40 60 80 100urban density %
nitratefluoride
ResultsResults
Agricultural areasAgricultural areas
0
2
4
6
8
10
12
14
16
18
0 20 40 60 80 100 120agricultural density %
nitratefluoride
sulfate vs agricultural density
0
50
100
150
200
250
0 20 40 60 80 100 120
agricultural density %
conc
entra
tion(
mg/
L)
sulfate
Crop density
ResultsResults Crop areasCrop areas
sulfate vs crop density
0
50
100
150
200
250
0 20 40 60 80 100
crop density %
conc
entr
atio
n(m
g/L)
sulfate
fluoride&nitrate vs crop density
y = 0.0335x + 7.2376
0
2
4
6
8
10
12
14
16
18
0 20 40 60 80 100
crop density %
conc
entr
atio
n(m
g/L)
f luoride
nitrate
Linear (nitrate)
ResultsResults
fluoride&nitrate vs crop density
y = 0.0335x + 7.2376
0
2
4
6
8
10
12
14
16
18
0 20 40 60 80 100
crop density %
conc
entr
atio
n(m
g/L)
f luoride
nitrate
Linear (nitrate)
Selection of points at less than +/- 5% off the straight line
ConclusionConclusion NoNo apparent apparent correlationcorrelation between between
land use and fluoride, sulfate.land use and fluoride, sulfate. Small trend between nitrate Small trend between nitrate
concentration and land use in the concentration and land use in the recharge area.recharge area.
Recharge area more sensitive to land Recharge area more sensitive to land use?use?
Any Questions?My brother
was having fun while I was preparing my slides