Techniques for estimating specific yield and specific retention from grain-size data and geophysical logs from clastic bedrock aquifers

Specific yield and specific retention are aquifer characteristics that are important in determining the volume of water in storage in an aquifer. These characteristics can be determined by laboratory analyses of undisturbed samples of aquifer material. However. quicker, less costly alternatives to these laboratory analyses are needed. This report presents techniques for estimating specific yield and specific retention based on grain-size analyses, and based on interpretation of borehole geophysical logs.