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Larenciro Cannon Minc -Groundwater Technical Report <br />• <br />Estimated hydraulic conductivity is from the regional data provided by Howard. Examining the <br />values of hydraulic conductivity, this value is estimated as 0.0408 ft/day. This value can be <br />translated to transmissivity (T) by the equation T = Kb, where T is transmissivity, K is hydraulic <br />conductivity, and b is the aquifer thickness. Therefore: <br />T=Kb <br />T = (0.0408 ft/day)(1000 ft) <br />T = 40.8 ftZ/day or 305 g/d/ft (estimated for entire thickness) <br />The potential pumping rate from a fully penetrating well can be estimated from the equation <br />Q=Ts/2000. (derived from Fetter, ]980). [n this calculation Q is the flow rate, T is the <br />transmissivity (determined from the hydraulic conductivity T=Kb), s the available drawdown, and <br />2000 is a constant (accounts for conversion of T in g/d/ft). Therefore: <br />Q = 305 g/d/ft [1000 ft (formation thickness)]/2000 <br />Q = 152 gpm (for regional data) <br />Generally, [he rate of evacuation for the wells during the sampling events is estimated as 1.0 gpm. <br />This value and the potential pumping rate for the well (determined above utilizing regional data) <br />compare favorably; therefore the range of the transmissivity in this zone is probably 305 g/d/ft. <br />• Groundwater seepage velocity (v,) can be determined from the gradient (dh/dl, or I), effective <br />porosity (rte, and hydraulic conductivity (IC). Seepage velocity represents the rate at which water <br />actually moves through the pore spaces. The relationship v,=Ki/r><, is utilized to determine this <br />value (Fetter, 1980). From the above analyses: <br />K = 0.98 ft/day (for regional values) <br />I = 0.008 ft/ft <br />ne=10% <br />Therefore: <br />yr = Ki/r1< <br />v, _ (0.0408 ft/day) (0.008 ft/ft)/10 %a <br />v~ = 3.3 x 10-' ft/day or 1.19 ft/yr (from regional data) <br />Comparison of the transmissivity estimated from a fully penetrating well indicates this formation <br />is potentially a good to fair formation for domestic use; however, the thickness precludes <br />installation of economically viable household wells. <br /> <br />Groundwaier.475\December 9, 1996 45 <br />