§671.APPENDIX B. Theis Equation Using Available Data

If pump test data is available for an unconfined/confined unconsolidated or non-fractured bedrock aquifer the lateral radius of influence can be calculated as follows:

 

r	=	the square root of	uTt
			2693S

 

            Where:

 

r	=	radius of influence (feet)
t	=	time well is pumped under normal operational conditions (minutes)
S	=	aquifer storativity or specific yield (dimensionless)
T	=	transmissivity (gallons per day per foot)
u	=	= is a dimensionless parameter related to the well function

 

 

W(u)	=	T(ho - h)
		114.6Q

 

Where:

 

W(u)	=	well function, the well function is calculated and u is obtained from Table A.
ho - h	=	drawdown in the piezometer or observation well (feet)
Q	=	production well discharge rate under normal operational conditions (gallons per minute)