Year of Award


Document Type


Degree Type

Master of Science (MS)

Degree Name


Other Degree Name/Area of Focus


Department or School/College


Committee Chair

W. Payton Gardner

Committee Co-chair

Hilary Martens

Commitee Members

W. Payton Gardner, Hilary Martens, Adrian Borsa


hydrogeodesy, hydrology, storage-discharge relationship, hydrogeology


University of Montana

Subject Categories

Hydrology | Water Resource Management


Uncertainties associated with climate change and increasing demands for water resources require better methods for estimating water availability at small to intermediate watershed scales (<1500 km2). Temporal changes in watershed storage and transport across various watersheds in the western U.S. were investigated using the hydrologic loading signal from GPS vertical displacements as a proxy for changes in watershed total terrestrial storage. GPS vertical displacement and streamflow discharge relationships were analyzed at daily to monthly temporal resolution. Stream connected storage changes were inferred using discharge using a first-order dynamical system model. Storage inferred from discharge, GPS vertical displacement and storage inferred from a regional scale western U.S. GPS network array were compared. Analyzing the average behavior over the period of record (10+ years), we find that GPS vertical displacement is well correlated to discharge during periods of hydrograph recession resulting in R2 values ranging from (0.78 to 0.96) with 30-day smoothing. We show that local GPS measurements are in close agreement with regional GPS storage inferences. When GPS station array density is sparse, local GPS stations display better agreement with discharge inferred storage estimates and have the potential to provide higher spatial and temporal resolution relative to current published methods of inferring storage from regional GPS inversions. The GPS vertical displacement-discharge relationship provides an independent analysis of watershed function, insight into antecedent conditions, and strong correlations that may enhance predictive power when estimating water availability at local watershed scales most useful to hydrologist and water resources management.



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