Postdoctoral Fellowship: EAR-PF: Evaluating spatiotemporal dependence in groundwater-dependent ecosystem processes

Lurtz, Matthew R, Lake Winnebago MO

Investigators

Abstract

Dr. Matthew Lurtz has been awarded an NSF Earth Sciences Postdoctoral Fellowship to carry out research and professional development activities at Colorado State University under the mentorship of Dr. Michael Ronayne and at the University of Technology Sydney under the mentorship of Dr. Alfredo Huerte. Throughout the western United States and elsewhere, inland groundwater dependent ecosystems (GDEs) occur alongside many rivers and lakes where the water table is close to the land surface. These ecosystems host a variety of native and nonnative vegetation that provide benefits such as: reduce agricultural-borne pollutants, protect species habitat, and stabilize stream sediment transport. The vegetation communities utilize water (i.e., plant transpiration), representing an important water budget component for the integrated surface-groundwater system. Therefore, GDEs can be used to identify the groundwater supply connected to vulnerable river systems. In this study, water uptake by GDEs in different climatic regions will be quantified using a combination of site instrumentation, remote sensing methods, and numerical groundwater modeling. By increasing the scientific understanding on GDEs, it is possible to enhance the knowledge base surrounding groundwater supply which is key to human and environmental sustainability. The importance of this work will be realized by engaging with beneficiaries in the water conservancy districts of southeastern Colorado and Arizona, where the field research will be conducted. This project will benefit the next generation of scientists by using place-based education and synthesizing water conservation strategies employed by inhabitants of American and Australian territories. The project will rely on Colorado State University’s (CSU) educational outreach programs to communicate scientific findings and conservation methodologies, including traditional indigenous methods. Data acquired, and models and mapped products created during the fellowship will be shared on local-to-international scales. Groundwater dependent ecosystems play a dominant role in supporting flora and fauna, but little information is available to help quantify GDE health (i.e., evapotranspiration) with varying time, space and climatic scales. The main goal of the study is to uncover temporal and spatial dependence in GDEs using remotely-sensed and numerical modeling methodologies. This study will utilize hypothesis testing to investigate how small scale GDE processes translates to larger spatial scales which will bolster predictive models used to address national water challenges. On a temporal basis, the trend direction between GDE health and groundwater availability will be investigated by collecting environmetrics on plant functional groups found in GDEs under varying groundwater and climatic conditions with data in the western United States. A dimension reduction method will be applied to the environmetric data to infer the trajectory of groundwater dependent ecosystems with reductions in groundwater supply. From a spatial-scale perspective, this work will begin by deriving the function form to describe the relationship between GDE health and groundwater availability at the point scale using a Bayesian regression framework. To examine spatial structure in GDEs beyond the point scale, this work will use the derived function as a subroutine in a spatially distributed parameter modeling scheme to build a scale-enlightened numerical model. This project will result in a more accurate representation of GDEs in water resource models using a research framework that is hypothesis-driven, based on the current state of science, and informed by sustainable engineering concepts. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.