Document Type

Dissertation

Degree

Doctor of Philosophy (PhD)

Major/Program

Earth Systems Science

First Advisor's Name

Assefa M. Melesse

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Rene Price

Second Advisor's Committee Title

committee member

Third Advisor's Name

Wossenu Abitew

Third Advisor's Committee Title

committee member

Fourth Advisor's Name

Dean Whitman

Fourth Advisor's Committee Title

committee member

Keywords

Groundwater Model, Drought, Teleconnection, Inverse modeling, Biscayne Aquifer, Everglades, Hydrology

Date of Defense

4-24-2020

Abstract

Developing a self-sufficient water supply system in Southeast Florida is one input to the success of the ongoing restoration effort in the Everglades. Maintaining a high groundwater level in the urban side of the Biscayne Aquifer (BA) is important to sustain the urban water supply. However, the long-term groundwater table condition in the Biscayne Aquifer (BA) is threatened by a combination of drought, groundwater pumping, and sea-level rise. Further, the long-term drought pattern, drought drivers, and the aquifer’s response to drought and other stress conditions are not well known. As a result, options that would help to maintain a high groundwater table condition in the urban section of the aquifer without being dependent on recharge from the Everglades water are not outlined. In this study, long-term drought and the causes of drought variability in the area, the effect of drought on the groundwater table condition, and the contribution of potential groundwater management options are assessed. The study results indicated that the drought in Southeast Florida was driven by a combination of ENSO fluctuation (short-term drought variability) and AMO fluctuation (long-term drought variabilities). Since the early 1990s, the area has been receiving rainfall higher than the long-term average (by 16%). The combination of higher rainfall in August and lower rainfall in May and October results in uni-modality in the previously bi-modal rainfall regime in Southeast Florida. By modeling the groundwater table dynamics in the BA, we found that drought, causing groundwater recharge limitation and a decline of surface water stag in canals, has a regional influence on the position of the groundwater table. Sea-level rise and groundwater pumping have a more substantial impact over the groundwater table in the coastal region and close to the well-field areas, respectively. Given that drought has a regional influence over the groundwater table, its effect on long-term freshwater availability is sizeable. Application of a hypothetical artificial recharge zone in the western margin of the model domain indicated a promising potential to mitigate the groundwater table decline attributed to drought and pumping pressure. However, the feasibility of the recharge zone must be studied further.

Identifier

FIDC008890

ORCID

https://orcid.org/0000-0003-2842-5054

Previously Published In

Abiy, A.Z., Melesse, A.M., Abtew, W. and Whitman, D., 2019. Rainfall trend and variability in Southeast Florida: Implications for freshwater availability in the Everglades. PloS one, 14(2).

Abiy, A.Z., Melesse, A.M. and Abtew, W., 2019. Teleconnection of Regional Drought to ENSO, PDO, and AMO: Southern Florida and the Everglades. Atmosphere, 10(6), p.295.

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This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Available for download on Saturday, April 09, 2022

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