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Calculations for Aquifer Properties <br /> q P <br /> ITransmissivity - Jacob Method <br /> I 1 Graph Drawdown vs Time for each monitoring well on semi-logrithmic paper <br /> Drawdown in feet <br /> Time in minutes <br /> 2 Calculate change in drawdown (As) per log cycle for each graph <br /> 3 Determine Transmissivrty (T) <br /> T = 264 Q / As Q=-pumping rate in gallons per minute (gpm) <br /> T=transmissivity (gpolft) <br /> IStorativity <br /> 4 Extend line on Drawdown vs Time graph for each well <br /> Read time where this line crosses zero drawdown <br /> Convert time to days (to) <br /> 5 Determine radius from pumping well in feet (r) <br /> lieFor pumping well, use well diameter <br /> 6 Calculate storativity (S) <br /> 5 = 03 Tto/r2 <br /> Radius of Influence <br /> 7 On Drawdown vs Time graphs, read drawdown for eachP <br /> ra h at a specific time <br /> g p <br /> For each time used, plot drawdown x s distance for each well on semi-logrithnzic paper <br /> 1, 10 and 100 minutes were used <br /> I 8 Draw line through drawdown in pumping well and drawdown in one observation well, <br /> using the same time reference Read NN here line crosses "drawdown = 0" line <br /> Well Efficiency <br /> Q/SA - T/2000 <br /> E_ <br /> T/2oao <br /> S = 1 ft' * Porosis 7 48gallons/ft') Porosity assumed to be 35 % <br /> T,,,11 — E = Taquifer <br />