07
Mar
Specific Yield Of Aquifer. The rock sediment that is responsible of holding the ground water is the aquifers. Water-storage changes in the aquifer and in the overlying unsaturated soil profile cause local. Firstly some of the pores may not connect with other pores or they may e so tenuously connected that water cannot move readily from one to nother. A confining layeris a geologic unit having little or not intrinsic permeability less than about 10-2.
The specific capacity Qs w of a well is the discharge per unit drawdown in the well and is usually expressed in lpmm. Bear 1979 relates specific yield to total porosity as follows. The values of specific yield or drainable porosity depend on the grain size shape and distribution of pores compaction of the subsurface formation and duration of drainage. Specific yield is defined as the ratio of 1 the volume of water that a srturated rock or soil will yield by gravity to 2 the total volume of the rock or soil. Which shows that the specific capacity of a well is not constant but decreases with the increase in pumping rate Q and prolonged pumping t Fig. It has been suggested that such values are the result of inadequate representation of drainage processes in the unsaturated zone.
A confining layeris a geologic unit having little or not intrinsic permeability less than about 10-2.
For aquifer management purposes a correct quantification of the distinct specific yields of the two layers is important as a potentially highly capacitive layer represented by the saprolite may sustain the exploited water resources in the fractured layer. A confining layeris a geologic unit having little or not intrinsic permeability less than about 10-2. For aquifer management purposes a correct quantification of the distinct specific yields of the two layers is important as a potentially highly capacitive layer represented by the saprolite may sustain the exploited water resources in the fractured layer. 14 Specific yield and specific retention Porosity is a measure of how much water a rock can hold but it is not necessarily a measure of how much water an aquifer can yield or produce. Specific yield depends upon grain size shape and distribution of pores and compaction of the formation. It should be noted that fine-grained materials yield little water whereas coarse-grained materials permit a.