The non-equilibrium equation can be used to determine the storage coefficient and transmissivity of confined aquifers. These aquifer constants are useful in the design of tubewells and for studying groundwater movement. Several approximate solutions have been developed for the purpose. Some of them are outlined in the following paragraphs: 1. Theis Method: This is a graphical method of superposition that [...]
Storage coefficient of an aquifer is the volume of water discharged from a unit prism, i.e., a vertical column of aquifer standing on a unit area (1 m2) as water level (piezometric level in confined aquifer—artesian conditions) falls by a unit depth (1 m). For unconfined aquifers (water table conditions) the storage coefficient is the same as specific yield, Fig. [...]
Two properties of an aquifer material related to its storage function are its porosity and specific yield. Porosity is the ratio of the volume of voids or pores in a soil mass to its total volume. Shape, size and packing of the grains affect the porosity of granular material. The grain size distribution of the formation or aquifer material can [...]