The well operates at a constant 1,500 gpm. What was the average specific capacity for the year?Ī well has a specific capacity of 42 gpm per foot. See attached for proposed dewatering pit.
The given pump rate of 100 gpm can be adjusted so that the water table is below proposed dewatering pit however within the aquifer. Using the given pump rate calculate the drawdown using an excel spreadsheet. The pumping level averaged 55 ft bgs for half the year and 68 ft bgs the other half. Calculate well drawdown for each 121 wells placed in grid at 9.9 feet spacing. For half the year the static water level was 25 ft bgs and half the year 42 ft bgs. If the original drawdown was 42 ft what is the current specific capacity?Ī well pumped 538 AF over a one year period averaging 10 hours of operation per day. In addition, the drawdown has decreased by 15%. The efficiency of the well has dropped 35%. When a well was first constructed it was pumping 1,750 gpm. After 3 hours of operation, the well produced 279,000 gallons. What is the pumping level of the well?Ī well has an hour meter attached to a water meter totalizer. A drawdown has been calculated out to be 65 ft. If the drawdown on this well is 44 ft and the pumping level is 80 ft bgs, what is the static water elevation above sea level?Ī deep well has a static water level of 122 ft bgs.
#Well drawdown math license
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#Well drawdown math free
Additional Resources Take a FREE Class D Water License Practice Test. This is an example of our Five-Step Approach to solving math problems. What is the drawdown?Ī groundwater well has a base elevation of 1,125 ft above sea level. Sections of Pipe Required Texas Class D Water Math. Well diameter is infinitesimally small such that the volume of water removed from the well bore during pumping does not affect the total amount of water in the aquifer.\)Ī well has a static water level of 23 ft bgs and a pumping level of 58 ft bgs.The cone of depression is the potentiometric or gravity free pressure surface and extends radially outward from the well and is a function of storativity, transmissivity, the pumping rate of the well and time.įigure 4 shows the radial flow from r = 0 at the well to as the cone of depression radiates out from the well.įor the theoretical analysis of the hydraulic head drawdown in a proposed well, we will make the following assumptions: The drawdown is computed in terms of the radial distance from the cone of depression which surrounds the pumping well. = function of the thickness of the saturated aquifer and the specific storativityįigure 3: Cone of Depression in a Confined AquiferĮquation 4 provides solutions in terms of the drawdown based on the physics of the movement of the flow towards a well during pumping. = function of Hydraulic Conductivity and the thickness of the saturated aquifer Hence, we convert Equation 3 into radial coordinates (Appendix D) to describe the hydraulic head in terms of the drawdown around the well. It is assumed that the flow towards the well, where water is being removed, is radial. Incorportating the two basic assumptions of essentially horizontal flow obeying Darcy's Law which reduces the equation to a two dimensional form and that the flow is in an aquifer that is homogeneous, saturated and isotropic (i.e. In this form, the equation describes a flow through a saturated anistrophic porous medium. The solution gives the value of the hydraulic head at any point in a flow field at any time. A nonsteadystate flow is a flow in which the velocity changes direction or magnitude at some point in time. A confined aquifer is a primary source for well tapping and is defined to be an aquifer bounded by an upper and lower bed of material that allows only small amounts of groundwater to penetrate through. Groundwater resources in a confined aquifer with a nonsteady-state flow can be evaluated for the consideration of the construction of wells. Next: Theis Equation Up: No Title Previous: Darcy's Law in
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