Evaluating Regime Shifts and Shifting Environmental Policy in the Arkansas River near Larned, KS

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Characterizing the drivers of flow in non-perennial streams is increasingly important for understanding the impacts of variable flow regimes on local communities and ecosystems. Regime-shift theory has been used to explain changes in other hydrologic systems, but non-perennial streams have yet to be fully explored. Here, the Arkansas River Basin near Larned, KS serves as a place-based case study to determine if changes between flow and no-flow conditions can be described using a regime-shift framework. This thesis combines hydrological, meteorological, and ecological time-series data to test for the presence of statistical early-warning signs commonly associated with regime shifting systems and used a sequential t-test analysis of regime shifts (STARS) algorithm to test for regime shifts in the time series of weekly and monthly no-flow days. While flow data exhibit hints like critical slowing down and asymmetry in flow rates, evidence for increases in both variance and autocorrelation signatures in surface water data level was weak. STARS identified at least five shifts between dry, intermediate, and wet regimes between 1998 and 2021, which are characterized by predominantly no-flow conditions, alternating flowing and no-flow conditions, and predominantly flowing conditions in the river, respectively. The intermediate regime appears to be a transitory phase between the stable wet and dry regimes observed at Larned. Regime shifts at the site are likely driven by a complex interaction between climate, pumping, local vegetation, and stream-aquifer interactions. Recent proposals to federal water policy, including the redefinition of “waters of the United States,” do not alter future protections for the Arkansas River as a navigable waterway. However, evidence of negative feedback loops that enforce no-flow conditions at the Larned site indicates that policy should refrain from excluding non-perennial stream systems from federal protection, especially those of low and ephemeral flow patterns.


Type of resource text
Date created May 30, 2022
Date modified December 5, 2022
Publication date June 2, 2022; May 30, 2022


Author Popescu, Ilinca
Thesis advisor Jones, James H.
Thesis advisor Konings, Alexandra
Thesis advisor Zipper, Sam
Department School of Earth Energy & Environmental Sciences


Subject Federal Water Pollution Control Act (United States)
Subject Kansas Geological Survey
Subject Hydrogeology
Subject Regime Shift Theory
Genre Text
Genre Thesis

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Popescu, I. (2022). Evaluating Regime Shifts and Shifting Environmental Policy in the Arkansas River near Larned, KS. Stanford Digital Repository. Available at https://purl.stanford.edu/vr862zx5273


Undergraduate Honors Theses, Doerr School of Sustainability

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