AWWA CO50841

This paper describes a new mathematical technique that allows the user to design or adjust the performance of an injection well to achieve the maximum volume of injected water, per well, over a predetermined period of time. The injection process is the result of two distinct hydraulic actions: hydraulic head on the drop pipe and orifice to produce a flow to the casing area, and water level rise in the well casing producing a hydraulic head on the aquifer to inject the same volume of water into the aquifer. The drop pipe hydraulic restriction is the summation of the openings in the drop pipe (pump bowl, slotted pipe, or orifice). The aquifer hydraulic restriction is the summation of the aquifer pore spaces that contribute to controlling the flow. The empirical relationships provide a path for the user to calculate the drop pipe and aquifer hydraulic restriction areas, determine the maximum capable injection rate, design a new drop pipe orifice at a desired rate and pressure, determine the flow rate during meter failures, and estimate the well performance for any given day of the total injection season. Includes figures.