WATER BALANCE -- MADERAS GOLF COURSE

V. M. PONCE

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  1. Total contributing drainage area: A = TC4 + SC2 + TC = 138 + 101 + 25 = 264 ac

  2. Maderas property area: Am = 160 ac

  3. Maderas turf area: At = 88 ac

  4. Maderas non-turf area: An = Am - At = 72 ac

  5. Non-Maderas contributing drainage area: Ac = A - Am = 264 - 160 = 104 ac

  6. Total contributing drainage area: A = At + An + Ac = 88 + 72 + 104 = 264 ac

  7. Mean annual precipitation: P = 13.5 in = 1.125 ft

  8. Estimated groundwater recharge: G = 0.2 P = 0.2 × 1.125 = 0.225 ft

  9. Mean annual runoff: Q = 0.09 P = 0.09 × 1.125 = 0.101 ft

  10. Deep percolation: D = 0.02 P = 0.02 × 1.125 = 0.0225 ft

  11. In turf area At, only deep percolation can be captured. Surface runoff remains on premises, and subsurface runoff is already appropriated.

  12. In non-turf area An, only deep percolation can be captured. Surface runoff remains on premises, and subsurface runoff is already appropriated.

  13. In non-Maderas contributing drainage area Ac, deep percolation may be captured. Surface runoff remains on premises, and subsurface runoff is already appropriated.

  14. Volume that can be captured in a sustainable way: Vc = D A = 0.0225 × 264 ac = 5.94 ac-ft

  15. Mean annual sustainable socioeconomic yield: Cs = 5.94 ac-ft

  16. Capture of all recharge (unsustainable): Cu = G A = 0.225 × 264 = 59.4 ac-ft

  17. Capture authorized by CUP in 1999: Ca = 150 ac-ft

  18. Average consumptive use by Maderas: Uc = 450 ac-ft

  19. Volume of runoff collected in the premises: R = Q A = 0.101 × 264 ac = 26.7 ac-ft

  20. Volume of imported water required (maximum): I = Uc - R = 450 - 26.7 = 423.3 ac-ft

  21. Evapotranspiration of turf (warm-season Bermuda grass): Ec = 54.2 in = 4.52 ft

  22. Volume consumed by turf: Ut = Ec At = 4.52 × 88 = 398 ac-ft

  23. Estimated volume consumed by non-turf: Un = Uc - Ut = 450 - 398 = 52 ac-ft

  24. Average use of groundwater by Maderas in 7-yr period 2001-08: Ua = 151 ac-ft.

  25. Maderas has been authorized by the City of Poway (2000) to pump up to Ca = 280 ac-ft.