Giménez et al. (2026) Subsurface conditions and hydrologic accumulation drive stream connectivity and flow intermittency in urban river networks

Identification

• Journal: Communications Earth & Environment
• Year: 2026
• Date: 2026-04-10
• Authors: Joaquina Noriega Giménez, Edwin Saavedra Cifuentes, Anna E. S. Vincent, Aaron I. Packman
• DOI: 10.1038/s43247-026-03477-0

Research Groups

• Civil and Environmental Engineering, Northwestern University, Evanston, IL, USA
• Northwestern University’s Center For Water, Northwestern University, Evanston, IL, USA

Short Summary

This study investigated the controls on stream network connectivity and flow intermittency in the Little Calumet River Watershed, USA, revealing that subsurface conditions and hydrologic accumulation are primary drivers, challenging the prevailing view that impervious cover dictates these dynamics.

Objective

• To determine how urban land cover, subsurface characteristics, and weather collectively control stream network connectivity and flow intermittency in the Little Calumet River Watershed, USA.

Study Configuration

• Spatial Scale: Little Calumet River Watershed, USA, focusing on urban river networks and headwater tributaries.
• Temporal Scale: Analysis of hydrological responses, including correlation with antecedent effective precipitation over a 6-day period.

Methodology and Data

• Models used: HYSEP (A Computer Program for Streamflow Hydrograph Separation and Analysis).
• Data sources:
  • Cook County LiDAR data (2022)
  • U.S. Geological Survey (USGS) National Land Cover Database (NLCD) (2025)
  • Chicago Metropolitan Agency for Planning (CMAP) 2020 Land Use Inventory
  • Illinois State Geological Survey surficial geology maps (2020-2025)
  • Web Soil Survey data from the Natural Resources Conservation Service, USDA
  • U.S. Geological Survey National Water Information System (USGS 05536310 Calumet Union Drainage Canal, 2024)
  • National Oceanic and Atmospheric Administration (NOAA) Multi-Radar/Multi-Sensor (MRMS) data (retrieved April 30, 2025)
  • Data and workflows available via GitHub repository (https://github.com/JoaquinaNG/COMMSENV-26-0252-T)

Main Results

• Contrary to prevailing expectations, headwater tributaries with greater impervious cover exhibited more persistent flow.
• Tributaries with a higher prevalence of permeable soils and paleo-sand deposits were found to be more intermittent.
• Subsurface conditions are a critical driver of urban stream connectivity.
• Active network drainage length showed the strongest correlation with antecedent effective precipitation accumulated over 6 days.
• Urban headwater systems primarily expand through hydrologic accumulation rather than immediate surface runoff.

Contributions

• Challenges existing assumptions regarding the fundamental drivers of urban stream connectivity, particularly the role of impervious cover.
• Emphasizes the significant, often overlooked, influence of subsurface conditions on urban stream network dynamics.
• Provides a new understanding of how hydrometeorological, land surface, and subsurface conditions interact to control network dynamics, offering a foundation for urban watershed resilience strategies.

Funding

• National Science Foundation (Grant No. 2331932 - SmartWater)
• National Science Foundation Graduate Research Fellowship Program (DGE-2234667)

Citation

@article{Giménez2026Subsurface,
  author = {Giménez, Joaquina Noriega and Cifuentes, Edwin Saavedra and Vincent, Anna E. S. and Packman, Aaron I.},
  title = {Subsurface conditions and hydrologic accumulation drive stream connectivity and flow intermittency in urban river networks},
  journal = {Communications Earth & Environment},
  year = {2026},
  doi = {10.1038/s43247-026-03477-0},
  url = {https://doi.org/10.1038/s43247-026-03477-0}
}