Semester

Summer

Date of Graduation

2022

Document Type

Thesis

Degree Type

MS

College

Eberly College of Arts and Sciences

Department

Geology and Geography

Committee Chair

Christopher Russoniello

Committee Co-Chair

Charles Shobe

Committee Member

Charles Shobe

Committee Member

Deon Knights

Abstract

Increased warming is driving unprecedented hydrologic changes within arctic deltas with implications for water storage, solute processing, and terrestrial and marine ecology. Thermokarst lakes within Arctic deltas store flood waters and filter solutes and sediments, thus moderating the impact of flood water discharge to arctic seas. However, this moderating influence is diminishing as lakes shrink on annual and seasonal time scales, especially close to active channels where lakes are shrinking most rapidly. This study investigates surface water-groundwater connectivity in arctic delta plains with coupled flow and heat transport models to provide a mechanistic understanding of how lake-channel proximity will impact aquifer connectivity and associated groundwater discharge to downgradient channels. Results show near-channel lakes have increased lake-to-channel advective heat transport and perennial connectivity and discharge to downgradient channel. However, connectivity and discharge from far-channel lakes is seasonal, where near-zero discharge occurs when lake and channel taliks are isolated. Near-channel lakes are perennially draining through taliks contributing to observed increases in Arctic channel baseflow. Lake drainage highlights the importance that lakes – especially near-channel lakes most vulnerable to loss – will have changing roles in moderating flood waters and nutrient processing before discharging to the arctic seas.

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