Publication Date

2024

Document Type

Dissertation/Thesis

First Advisor

Lenczewski, Melissa E.

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Earth, Atmosphere, and Environment (EAE)

Abstract

Characterizing and predicting groundwater flow in complex karst aquifers poses significant challenges. This study explores the potential application of Acoustic Doppler Current Profiler (ADCP) technology for in-situ groundwater flow measurement within sinkholes (cenotes) in the Yucatan Peninsula, Mexico. Two specific questions are addressed: 1) Can ADCP determine flow within Yucatan Peninsula sinkholes? 2) Are groundwater flow vectors related to water clarity in open cenotes? The geological setting of the Yucatan Platform is characterized by horizontal sedimentary strata with highly permeable limestones and extensive karst features. The research focuses on the Holbox fracture zone, where groundwater flow dynamics remain elusive. The methodology targeted three selected cenotes: VL, PV, and LP. ADCP equipment measured groundwater flow speed and direction in a structured arrangement, producing detailed single-point vectors at depths of 2, 4, 6, 8, and 10 meters, across various locations in open cenotes, with 120-second measurement intervals. Water clarity assessments employed the Secchi disk and turbidity measurements using Hydrolab HL4. Rose diagrams effectively illustrated speed and direction variations, revealing diverse flow patterns. VL exhibited southwest flow, PV displayed multiple directions, and LP lacked a clear predominant direction. Water visibility ranged from 2 to 10.64 m, and turbidity varied from 0.0 to 1.7 NTU. VL demonstrated higher visibility and a predominant flow direction, contrasting with PV and LP. Interestingly, groundwater flow speed within cenotes did not correlate with water visibility or turbidity, but a predominant flow direction appeared correlated with water visibility. This study demonstrates ADCP's feasibility for in-situ karst groundwater flow measurement, providing comprehensive insights into the Yucatan Peninsula aquifer. Moreover, this method proves to be efficient, non-invasive, and involves straightforward data processing.

Extent

89 pages

Language

en

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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