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

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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

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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