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Integrating catchment expansion-contraction dynamics into cross-continental hydrobiogeochemical predictions

Active Dates 9/1/2023-8/31/2025
Program Area EPSCoR-Experimental Program to Stimulate Competitive Research
Project Description
Integrating Catchment Expansion-Contraction Dynamics into Cross-Continental Hydro-biogeochemical Predictions

Alex Webster, University of New Mexico

River networks link terrestrial and aquatic ecosystems through the movement of water and materials (e.g., carbon, solutes, and sediment) from land to water and from upstream to downstream. Most water and materials enter aquatic ecosystems via small “headwater” streams, which comprise ~80% of all river miles on Earth. Headwater stream networks act as “reactors” due to their large reactive surface area compared to the volume of water and materials they transport, and this transport reflects multiple upstream material sources and ecological processes. Due to their ubiquity, close connection to the landscape, and reactivity, headwater stream networks provide sensitive indicators of freshwater resource vulnerability and ecosystem change.

Headwater stream networks often dynamically extend and contract in response to precipitation inputs and periods of drought. Climate change is leading to anomalous precipitation patterns that directly influence streamflow persistence and network extent. These climate-mediated changes in patterns of network expansion and contraction have the potential to interact with material processing within headwater networks and change material export to downstream waters. We currently lack a predictive understanding of this complex interaction and how it may alter surface water quality, habitat sustainability, and drinking water security across the United States.

This project will address hydrologic and biogeochemical change in headwater networks that dynamically expand and contract. Our approach integrates hydrologic modeling with complementary hydrologic and biogeochemical observations within five watersheds across the United States’ cross-continental aridity gradient. Specific aims include: 1) developing predictive models of the spatial patterns of changing headwater network structure, 2) determining how these spatial patterns influence material fluxes, and 3) exploring how dynamic expansion and contraction controls the scaling behavior of material export from headwaters.

Our project team primarily consists of early career researchers at institutions across six EPSCoR states that are invested in understanding watershed responses to a changing climate. This work will enhance collaboration and advance the competitive research capacities of five early career faculty directly and others indirectly; contribute to the training and development of postdoctoral researchers, project staff, undergraduates, and graduate students; and strengthen institutional relationships with researchers and programs at the Department of Energy’s Oak Ridge National Laboratory and across multiple EPSCoR states. Through these activities, we will improve mechanistic inference about headwater processes to improve our ability to predict and manage water quality, water quantity, and ecosystem responses to a changing climate.
Award Recipient(s)
  • University of New Mexico Albuquerque (PI: Webster, Alex)