specific yield
1. The ratio of the water drained from a rock under the influence of gravity, or removed by pumping, to the total volume of the rock voids or pore space in the drained rock. The difference is caused by the retention of water in the rock, owing to molecular attraction and capillarity. See specific retention.

2. The volume of water released by a falling water-table from a given volume of fully saturated rock.

specific yield
1. The ratio of the water drained from a rock under the influence of gravity, or removed by pumping, to the total volume of the rock voids or pore space in the drained rock. The difference is caused by the retention of water in the rock, due to molecular attraction and capillarity. See SPECIFIC RETENTION.

2. The volume of water released by a falling water-table from a given volume of fully saturated rock.