groundwater recharge from mains leakage

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groundwater recharge from mains leakage
CE 394K.3 GIS in Water Resources

• Beatriz Garcia-Fresca
• November 2002

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datasetsGEOLOGY
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geology city footprint
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datasetsWATERMAINS
sourceCity of Austin GIS datasets
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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

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relative permeabilities
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relative permeabilities
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calculations
  Pumpage pumpage real loss daily average
Year (millions of gallons) millions m3 millions m3 m3/d
1993 39,824 151 10.57 413514.96
1994 39,806 151 10.56 413328.05
1995 39,542 150 10.49 410586.79
1996 45,835 174 12.16 475930.55
1997 42,812 162 11.36 444541.04
1998 46,438 176 12.32 482191.84
1999 46,422 176 12.32 482025.70
2000 52,193 198 13.85 541949.23
2001 50,140 190 13.30 520631.78
? ?
City of Austin - Water and Wastewater Utility City of Austin - Water and Wastewater Utility City of Austin - Water and Wastewater Utility City of Austin - Water and Wastewater Utility
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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

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summary and results
average pumpage CoA 520631.78 m3/d ? CoA Water
Wastewater Utility total V of
pipes 672465.55 m3 ? from GIS project
coeff. 0.774
area of Austin 271.8 sqmi ? City of Austin
Austin Facts 703.962 Km2 annual
precipitation 840 mm ? NOOA
total mains loss 12 ? Austin American
Statesman, 1998 real loss
(leakage) 7 ? Thornton, 2002 36434.2 m3/d ?
results from GIS project 13.3 million
m3/a 18.89 mm/a 4.80 in/a
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datasetsWASTEWATERMAINS
Work in progress
sourceCity of Austin GIS datasets
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a fun digression
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conclusions

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

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future work

• add recharge from wastewater mains
• what are the qualitative implications?
• refine calculations
• include infiltration coeffs. of soils?