1. groundwater recharge from mains leakage
CE 394K.3 GIS in Water Resources
groundwater recharge from mains leakage
Beatriz Garcia-Fresca
November 2002

2. datasets: GEOLOGY

3. geology + city footprint

4. datasets: WATER MAINS
source: City of Austin GIS datasets

5. data processing reprojecting  Texas Central State Plane (US ft)
spatial analysis  reclassification of geology according to relative permeability
calculations: CoA water usage  leakage
geoprocessing: isolating pipes by aquifer group

6. relative permeabilities

7. relative permeabilities

8. calculations Pumpage pumpage real loss daily average Year
Pumpage
pumpage
real loss
daily average
Year
(millions of gallons)
millions m3
m3/d
1993
39,824
151
10.57
1994
39,806
10.56
1995
39,542
150
10.49
1996
45,835
174
12.16
1997
42,812
162
11.36
1998
46,438
176
12.32
1999
46,422
2000
52,193
198
13.85
2001
50,140
190
13.30 ↑
City of Austin - Water and Wastewater Utility

9. calculations attributes: diameter & length calculations: V each pipe
total V pipes
daily V of water per pipe
daily leakage (~7%)
add leakage of all pipes

10. summary and results
average pumpage CoA m3/d  CoA Water & Wastewater Utility
total V of pipes m3  from GIS project
coeff
area of Austin sqmi  City of Austin – Austin Facts
Km2
annual precipitation 840 mm  NOOA
total mains loss 12 %  Austin American Statesman, 1998
real loss (leakage) 7 %  Thornton, 2002
m3/d  results from GIS project
13.3 million m3/a
18.89 mm/a
4.80 in/a

14. datasets: WASTEWATER MAINS
Work in progress
source: City of Austin GIS datasets

15. a fun
digression

18. conclusions the urban induced recharge in Austin is significant
utility lines can be analyzed using ArcHydro tools
ArcGIS presents more operational problems than ArcView

19. future work add recharge from wastewater mains refine calculations:
what are the qualitative implications?
refine calculations:
include infiltration coeffs. of soils?