Prediction of groundwater recharge rates with sediment-laden water

A 30° small model aquifer with fine sand was used to simulate the process of groundwater recharge through wells under gravity flow. The sediment-laden water was characterized by suspended solids which were a mixture of 50 percent bentonite and 50 percent kaolinite, tested in low, medium and high concentration. Suspended solids in the recharge water were filtered out in the model aquifer. Time and spatial distribution of suspended solids in the aquifer were measured. The experimental data showed exponential decrease of suspended solids in the aquifer medium during recharge. The proportionality factors of these exponential processes also logarithmically decrease with time. The accumulation of suspended solids near the well occurred more rapidly than in the far zone. Measurement of hydraulic pressure distribution in the aquifer indicated that a greater variation in hydraulic gradient was experienced near the well as compared to the far zona. In fact, hydraulic gradients near the well increased with time, because of huge accumulation of suspended solids there. ..