Theis Equation Drawdown vs Time | Drawdown vs Distance
Drawdown vs Time
Distance from pumping well: (feet)
Drawdown after 24 hours is feet
Drawdown vs Distance
Elapsed time since pumping started: (hours)
Radius of influence is * feet
Pumping rate: (gpm)
Transmissivity: (feet 2/day)
*Radius of influence assumes the farthest distance from the pumping well where drawdown is 0.1 feet. The maximum distance is one mile (5280 feet).
Hydraulics of Groundwater
The Texas Water Development Board developed the following interactive tools to assist interested parties in understanding the effects of pumping at select locations where aquifer properties are either known or can be estimated with a some degree of certainty. This implementation is based on the text "Hydraulics of Groundwater" by Jacob Bear (2007) and makes the following assumptions:
- the aquifer is infinite, confined, homogeneous, and isotropic;
- the aquifer is horizontal and groundwater flow is horizontal; and
- the well diameter is negligible.
The following formulae are used: