Oral Presentation Society for Freshwater Science 2025 Annual Meeting

Decadal headwater stream network contraction and expansion analysis across the CONUS using the CREST hydrological model (117022)

Mengye Chen 1 , Alex Webster 2 , Shannon Speir 3 , Joanna Blaszczak 4 , Arial Shogren 5 , Adam Wymore 6 , Shang Gao 7 , Yang Hong 1
  1. University of Oklahoma, Norman, OK, United States
  2. University of New Mexico, Albuquerque, NM, USA
  3. University of Arkansas, Fayetteville, Arkansas, USA
  4. University of Nevada Reno, Reno, Nevada, USA
  5. University of Alabama, Tuscaloosa, Alabama, USA
  6. University of New Hampshire, Durham, New Hampshire, USA
  7. University of Arizona, Tucson, Arizona, USA

Headwater networks pose special challenges for hydrological modeling, due to their sensitivity to terrains, different water sources/sinks, and non-perennial nature. Yet, the tight linkage between terrestrial and aquatic systems at the headwaters makes them the hydro-biogeochemical reactors for surface water chemistry. The comprehensive hydrological modeling for headwater basins is needed to bridge the hydrological system with the biogeochemical field. Here, we present the modeled network contraction and expansion patterns for five selected headwater basins across the CONUS from 2015 to 2024, using the hydrological simulation results from the CREST model. The five selected basins, in New Hampshire, Alabama, Arkansas, New Mexico, and Nevada, represent a gradient of climatic conditions and terrestrial features. The results indicate that the headwater basin in New Hampshire does not exhibit significant non-perennial behavior over the 10-year simulation period. However, the headwater basins located in the arid regions showed very volatile patterns of network contraction and expansion. This volatility gradually increases from the east to the west of CONUS, likely driven by increasing aridity. The results generally synchronize the climate changes that we have experienced in the past decade, where the western part of the USA is getting dryer and the eastern part of the USA is getting wetter. In this presentation, we have also identified a few general assumptions that the hydrological models have, which do not apply to headwater modeling.