Theses and Dissertations

Date of Award

5-1-2026

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Ocean, Coastal, and Earth Sciences

First Advisor

Tian Dong

Second Advisor

Juan L. Gonzalez

Third Advisor

Jude A. Benavides

Abstract

The Isabel Delta is a recently formed flood-tidal delta within the restored Bahia Grande system on the Rio Grande Delta Plain, Texas, USA, where renewed tidal connectivity has created conditions for rapid sediment buildup and landform evolution. This study quantified morphological changes from 2008 to 2025 using satellite imagery. It assessed sediment retention by comparing the effective sediment discharge required to reproduce observed delta growth with field-based estimates of sediment supply derived from channel hydrodynamics, cross-sectional area, and suspended sediment concentration. The delta expanded steadily throughout the study period, with increases in bar, channel, and total surface area, and an evolving shoreline characterized by a larger mean radius and greater complexity. This growth accelerated following the enlargement of the Pilot Channel, suggesting that enhanced tidal connectivity encouraged faster geomorphic development. Sediment-budget analysis identifies the delta as a partially retentive tidal depositional system; central retention is estimated at 23–25% (range: 12–46%), with the remaining sediment likely redistributed and stored within the Bahia Grande or exported through ebb-dominant pathways. Spectral analysis further suggests that short-term morphological changes are influenced more by morphodynamic feedback than by direct synchronization with hydrologic forcing.

Comments

Copyright© 2026 Aleen Pertuz Paz. All Rights Reserved. https://proquest.com/docview/3371136078

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