The storage coefficient in an unconfined aquifer is equal to which of the following?

The storage coefficient in an unconfined aquifer is accurately identified as specific yield. In hydrogeology, the storage coefficient refers to the volume of water that an aquifer will yield per unit surface area of the aquifer for a unit decline in hydraulic head. For unconfined aquifers, this value is equivalent to specific yield, which represents the portion of water that can be released from the aquifer due to gravity drainage.

Specific yield is defined as the ratio of the volume of water that drains from the aquifer due to gravity to the volume of the aquifer material. This property is crucial in understanding how much water can be extracted from an unconfined aquifer, making it essential for water resource management and aquifer studies.

In contrast, transmissivity refers to the ability of an aquifer to transmit water through its saturated thickness, and hydraulic conductivity is a measure of how easily water can flow through the aquifer material itself. Storativity, while related to storage, applies to confined aquifers and encompasses both the elastic storage (due to compression of water) and the specific yield, but it does not apply in the same way to unconfined conditions. Therefore, the relationship between the storage coefficient and specific yield is the reason