Tuesday, September 10, 2013

Ground water Yield

Ground water specific Yield:
Specific Yield  = (Volume of water obtained by gravity drainage/ Total volume of sub-soil) *100

Specific Retention =(Volume of water held against gravity drainage/ Total volume)*100

Porosity= Specific Yield + Specific Retention

Formula for ground water velocity:
(1)  Slichter's formula: 
   V= (k.SD^2)/U
V = velocity of ground water in m/day
k = constant (approx. 400)
S = Slope of hydraulic gradient line
D = Effective size of the particle in aquifer (in mm)
U = Dynamic Viscosity

(2) Hazen's Formula:
V = [K.SD^2(1.8T+42)]/60
K = constant approx. 1000,
T = Temperature in degrees Celcius.

No comments:

Post a Comment