Human and Hydrologic Influences on Nebraska's Endangered Rainwater Basin Wetlands

Authors

Sarah Thompson, University of Nebraska-LincolnFollow

First Advisor

Erin Haacker

Second Advisor

Jesse Korus

Date of this Version

12-2022

Citation

Thompson, Sarah, "Human and Hydrologic Influences on Nebraska's Endangered Rainwater Basin Wetlands" (2022.). Dissertations & Theses in Earth and Atmospheric Sciences.

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment Requirements For the Degree of Master of Science, Major: Earth and Atmospheric Sciences, Under the Supervision of Professors Erin Haacker and Jesse Korus. Lincoln, Nebraska: December, 2022

Copyright © 2022 Sarah Thompson

Abstract

Over half of wetlands in North America have been lost or degraded. Rainwater Basin (RWB) wetlands, located in south-central Nebraska, are a primary example of such loss; an estimated 90% have been destroyed by land conversion for agriculture. Remaining RWB wetlands are often embedded in row-crop fields, where they are threatened by altered surface water runoff flow, drainage features, and excess sediment inputs. Efforts at the state and federal level have been made to preserve this wetland complex due to the critical stopover habitat these wetlands provide for migratory birds. Land managers work to maintain sufficient water levels during migratory seasons and control invasive plant species through various methods such as grazing, excavation, and pumping of water.

Hydrologic research on RWB wetlands is limited. Studies on RWB wetland hydrology and the impact of restoration efforts are needed to aid management efforts of these endangered wetlands. This study attempts to evaluate which variables positively or negatively impact water quantity in wetlands, and to what degree. The variables analyzed include ones pertaining to climate, land characteristics, and restoration efforts. Results indicate certain precipitation variables and land-use types in the watershed are the most important; however, most variables were of modest and marginally differing importance. Exploratory analyses of water level data were also performed to extrapolate the influence of precipitation, current water levels, ET, and infiltration on water level changes. RF models predicted daily water level declines of 5 – 6 mm per day, with 1 – 2 mm of differences between sites. The model predicted modest differences in water level response to precipitation between sites when other predictor variables were held the same.

Advisors: Erin Haacker, Jesse Korus