Semester of Graduation

Fall 2018

Degree

Master of Science in Civil Engineering (MSCE)

Department

Civil and Environmental Engineering

Document Type

Thesis

Abstract

The Mississippi River Alluvial Aquifer (MRAA) locates in northeastern Louisiana, extending from the north border of Louisiana and Arkansas to south central Louisiana and underlies the Mississippi River Valley. The MRAA is the second most used groundwater source with about 390 million gallons per day in 2010, which accounts for 25% of all groundwater withdrawals in Louisiana. The groundwater uses are mainly for irrigation, public supply and industries. The excessive groundwater pumping and the economic importance of the MRAA have drawn attention to build a groundwater model to study future water resources management and sustainability plans. The model is the first comprehensive and detailed groundwater model for the MRAA. For developing an MRAA groundwater model, firstly, a hydrostratigraphic architecture of the MRAA was constructed with 7,259 well logs using a natural neighbor interpolation method for developing a three-dimensional computational grid. Secondly, the sinks and sources in the model included surficial recharge estimated from a hydrologic model, rivers and bayous (including Mississippi River) that had interconnections with the alluvial aquifer, and pumping wells that consisted of irrigation, public supply and industrial wells. Lastly, the groundwater model was calibrated using the groundwater level data from the USGS to estimate model parameters. A small root-mean-square error of 1.14 m was achieved between simulated and historically observed groundwater levels. The simulation results show strong interactions between the major streams, the Mississippi River and the alluvial aquifer. The streams are the main inflow sources to the MRAA. The water budget analysis shows that groundwater levels in the MRAA have declined in recent years as groundwater demands for agriculture is increasing in the region. In conclusion, a sound groundwater management plan is needed in the near future to recover groundwater storage in the MRAA to sustain the valuable water source. The developed MRAA groundwater model would be a valuable tool to assist future groundwater management plan development.

Date

10-24-2018

Committee Chair

Tsai, Frank T.-C.

Share

COinS