groundwater recharge from mains leakage CE 394K.3 GIS in Water Resources groundwater recharge from mains leakage Beatriz Garcia-Fresca November 2002
datasets: GEOLOGY
geology + city footprint
datasets: WATER MAINS source: City of Austin GIS datasets
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
relative permeabilities
relative permeabilities
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 413514.96 1994 39,806 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 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
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
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
datasets: WASTEWATER MAINS Work in progress source: City of Austin GIS datasets
a fun digression
conclusions the urban induced recharge in Austin is significant utility lines can be analyzed using ArcHydro tools ArcGIS presents more operational problems than ArcView
future work add recharge from wastewater mains refine calculations: what are the qualitative implications? refine calculations: include infiltration coeffs. of soils?