Date of Award

2024-12-01

Degree Name

Master of Science

Department

Geological Sciences

Advisor(s)

Richard P. Langford

Abstract

This study focused on five arroyos flowing into the Rio Grande, in the stretch between Caballo Dam and Las Cruces, New Mexico. Drone imagery was acquired from study areas in each arroyo. Photogrammetry was used to create high-resolution digital elevation models (DEMs), point clouds, drone imagery and potential discharges were acquired for each arroyo. Investigation of seven different methods resulted in the selection of the Terrain Ruggedness Map (TRM) as a predictor of surface roughness, along with high-resolution DEMâ??s to illustrate small and low-relief channel features. The five arroyos with varying sediment sizes and characteristics were studied to understand how arroyo morphology is reflected in grain size variation within the channel. The TRM in conjunction with grain size measurements observed in both the field and those detected from photographs using BASEGRAIN software and discharges computed using the Flood Potential Portal (FPP), were used to calculate and interpret these correlations.Measurement of gravel clasts using BASEGRAIN software confirms a correlation between clast diameter and TRM. Riffle zones with coarse materials exhibit the highest TRM values (>0.05), while pools and smoother sections, characterized by finer sediments, display lower TRM values (<0.02). Sandbars show intermediate conditions influenced by flow energy and depositional dynamics, with upstream bars retaining coarser grains and downstream bars accumulating finer materials. Vegetated and eroded bars and surfaces like banks, amplify ruggedness through steep margins and dissected bars, expose coarser substrates and create secondary flow paths. The basin areas and discharge estimates increase in the order Hersey < McCleod < Rincon, while mean TRM and grain size followed an opposite trend: Rincon < McCleod < Hersey, implying an inversely proportional relationship between TRM and flood potential discharge.

Language

en

Provenance

Recieved from ProQuest

File Size

84 p.

File Format

application/pdf

Rights Holder

Shandell Thomas

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