Assessment of Vadose-Zone Wells for Enhancing Groundwater Recharge in the Mississippi Delta

摘要

Current pumping rates in the Mississippi River Valley Alluvial Aquifer in the Mississippi Delta are unsustainable as they are depleting the water level in the aquifer. The following thesis is a feasibility analysis on groundwater recharge to the Mississippi River Valley Alluvial Aquifer using vadose zone wells. Two days were spent in the field at Sky Lake near Belzoni, Mississippi, collecting core soil samples, bag soil samples, and constant head hydraulic conductivity values. Numerous days were spent in the lab conducting sieve analyses, Atterberg limits, and falling head hydraulic conductivity tests. The Atterberg limit test and sieve analyses were used to create a soil profile of the investigation area, and the hydraulic conductivities were used to find the flow rate of water from the vadose zone well into the soil. Using the data, it was found that an excessive number of wells would be required to offset the historical decline for the entire Delta. A smaller target area (37.5 square miles) was examined and it was determined that a remediation process of 283 wells at 8 wells per square mile would be a reasonable scenario in offsetting the decline in this analysis. In conclusion, vadose zone wells are not a feasible option for remediation of water-level decline over the entire Delta, but can be useful on a smaller scale.