Two-string water well and its duty design

Abstract

Uninterrupted supply of inhabited localities and various industries with drinking water is provided by water supply systems including water wells. It is found that incrustation of filters shortens the life of water wells and increases specific energy input of water lift. The design of the operating water wells should be such that to ensure fine accessing to producing aquifers as well as the early and high yield at the preserved careful isolation of the wells from each other, on the one hand, and, on the other hand, the wells should possess high operating characteristics: long service life, low energy spent to water lifting, minimized rate of decrease in productivity, high maintainability. The duty design procedure for a two-string two-filter water well includes the analytical and semigraphical methods. The well flow rates are determined in case of one and two operating pumps. The analytical and semigraphical methods provide the identical capacities of pumps in their concurrent and isolated operation. Installation of two pumps of different capacities enables well operation at different flow rates to conform with a water consumption diagram. During peak time, two pumps operate, in case of low water consumption, the pumps can operate in turn. This approach allows avoiding essential lowering of water level in wells at any water consumption rate in case when one powerful pump is installed in a single-string well. As a consequence, incrustation of the well filter, which arises under great drawdown because of water column aeration and oxygen ingress in the filter zone of the well, is reduced.