Richter et al. (2025) Overconsumption gravely threatens water security in the binational Rio Grande-Bravo basin

Identification

• Journal: Discover Water
• Year: 2025
• Date: 2025-11-20
• Authors: Brian D. Richter, Karem Abdelmohsen, Sameer Dhakal, J. S. Famiglietti, Keirnan Fowler, Henry Green, Landon Marston, Mesfin M. Mekonnen, Enrique Prunes, Melissa M. Rohde, Benjamin L. Ruddell, Richard Rushforth, Natalie Shahbol, Eric Sjöstedt, Samuel Sandoval-Solís
• DOI: 10.1007/s43832-025-00301-2

Research Groups

• Sustainable Waters, Abiquiu, USA
• World Wildlife Fund US, Washington D.C., USA
• Global Futures Laboratory, School of Sustainability, Arizona State University, Tempe, USA
• Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, USA
• School of Informatics, Computing and Cyber Systems, Northern Arizona University, Flagstaff, USA
• College of Engineering, University of Alabama, Tuscaloosa, USA
• Rohde Environmental Consulting, Seattle, USA
• College of Environmental Science and Forestry, State University of New York, Syracuse, USA
• School of Complex Adaptive Systems, Arizona State University, Tempe, USA
• Department of Land, Air, and Water Resources, University of California at Davis, Davis, USA

Short Summary

This study provides the first comprehensive accounting of consumptive water uses and losses in the binational Rio Grande-Bravo basin, revealing that 52% of direct water consumption is unsustainable, primarily driven by irrigated agriculture, leading to severe depletion of reservoirs, aquifers, and river flows.

Objective

• To assemble detailed water consumption estimates from a broad array of sources to describe how surface and ground water were consumed for both direct uses (agricultural, municipal, commercial, thermoelectric power generation) and indirect uses (reservoir evaporation and riparian evapotranspiration) in each of 14 sub-basins during recent decades.
• To quantify the degree to which annual water consumption has exceeded annual replenishment in recent decades by estimating changes in reservoir storage, groundwater volumes, and annual river volumes.

Study Configuration

• Spatial Scale: Binational Rio Grande-Bravo (RGB) basin, divided into 14 sub-basins; Hydrologic Unit Code 12-digit (HUC12) and HUC-8 scales; 2.5 arc-minute grid cells; 30-arcminute spatial resolution; 30 meter resolution; 500 meter resolution; 4.6 kilometer resolution.
• Temporal Scale: Recent decades, specifically 2000–2019 for water consumption estimates, and 2002–2024 for water resource trend analysis (reservoir, aquifer, river outflow depletion). Monthly and annual estimates.

Methodology and Data

• Models used:
  • Seasonal Autoregressive Integrated Moving Average (SARIMA) time series model (for backcasting thermoelectric power plant water use).
  • WaterGAP global hydrologic model (for Mexican municipal/commercial water use).
  • Environmental Policy Integrated Climate (EPIC) model (for Mexican annual crop actual evapotranspiration).
  • CropGBWater model (for Mexican perennial crop green/blue water consumption).
  • Penman–Monteith-Leuning Evapotranspiration V2 (PML-V2) product (for Mexican riparian evapotranspiration).
  • Seasonal-Trend decomposition using LOESS (STL) (for isolating long-term trends in water compartments).
  • Machine learning model (for US public supply reanalysis).
• Data sources:
  • United States Geological Survey (USGS) public supply reanalysis dataset (2000–2020) and Watershed Boundary Dataset (WBD).
  • WaterGAP global hydrologic modeling team (University of Kassel, Germany) for Mexican water use.
  • USGS thermoelectric power plant water use reanalysis dataset (2008–2020).
  • Estadísticas del Agua en México annual reports and Compendio Básico Del Agua en México reports (Sistema Nacional de Información del Agua) for Mexican thermoelectric water consumption.
  • Global Energy Monitor Wiki for Mexican power plant characteristics.
  • Modeled Irrigated Agriculture of the United States (MirAG-US) for US crop water requirements.
  • HarvestGRID for US crop-specific irrigated acreage.
  • Irrigation and Water Management Surveys (2003, 2008, 2013, 2018) for US irrigation depth.
  • National Land Cover Database (NLCD) and Landsat-based National Irrigation Dataset (LANID) for US irrigated pasturelands.
  • Cropland Data Layer (CDL) for US irrigated other hay.
  • Municipal-level agricultural statistics from Mexico (DGSIAP) and Comision Nacional del Agua’s Agricultural Statistics database.
  • Global Lake Evaporation Volume dataset and HydroLAKES database for reservoir evaporation.
  • Google Earth Engine Python API, USGS National Hydrography Dataset Plus version 2, Mexico’s RED Digital Hydrographic database, Global Shuttle Radar Topography Mission Landforms dataset, Global 30 meter Land Cover Change Dataset for riparian mapping.
  • OpenET (for US riparian evapotranspiration) and gridMET (for precipitation).
  • Interbasin Transfer Database Standard Version 1.0 (IBTDS 1.0) for inter-basin transfers.
  • USGS “Water Data for the Nation” and International Boundary & Water Commission for river outflow volumes.
  • US Bureau of Reclamation’s “Reclamation Information Sharing Environment (RISE),” Natural Resources Conservation Service’s “Air & Water Database Report Generator,” Texas Water Development Board’s “Water Data for Texas,” and International Boundary & Water Commission’s “Water Data Portal” for reservoir volumes.
  • NASA GRACE and GRACE Follow-On (GRACE/FO) satellite observations (JPL-RL06.1 M, CSR-RL06.02 M, GSFC-RL06v2.0 M) for total water storage changes.
  • North American Land Data Assimilation System (NLDAS) (NOAH, VIC, MOSAIC models) for soil moisture storage.

Main Results

• Only 48% of water directly consumed for anthropogenic purposes in the Rio Grande-Bravo basin is supported by renewable replenishment; the remaining 52% is unsustainable, causing depletion of reservoirs, aquifers, and river flows.
• Irrigated agriculture is the dominant direct water consumer, accounting for 87% of direct consumption in the basin (2000–2019 average). Cattle-feed crops (alfalfa, grass hay, pasture) comprise 56% of irrigation water consumed.
• Indirect water uses (riparian evapotranspiration and reservoir evaporation) account for 56% of overall water consumption, with riparian ET being the single largest category at 44% and reservoir evaporation at 12%.
• Total direct water consumption increased at an average rate of 12.1 million cubic meters per year (MCM/yr) basin-wide since 2000, despite decreases on the US side (43.1 MCM/yr) due to farmland reduction, which were offset by increases on the Mexican side (55.2 MCM/yr).
• From 2002–2024, the basin experienced an average annual water depletion totaling 2,900 MCM/yr, comprising:
  • Reservoir storage loss: 177.6 MCM/yr (12% of total storage since 2002).
  • Groundwater depletion: 2,700 MCM/yr (approximately 15 times greater than reservoir depletion), with severe overdrafts in Pecos River (950 MCM/yr), Rio Grande New Mexico (630 MCM/yr), and Rio Conchos (490 MCM/yr).
  • River outflow declines: 22.4 MCM/yr at the basin outlet, indicating further depletion of an already heavily depleted river (85% loss prior to 2002).
• Farmland contraction occurred in the US portion: 18% of farmland in Colorado, 36% along the Rio Grande in New Mexico, and 49% in the Pecos River tributary.
• Urban water conservation efforts have reduced municipal water use in some cities (e.g., Albuquerque population grew 40% while water use declined 17%), but municipal and commercial consumption only accounts for 7% of direct use.

Contributions

• Provides the first comprehensive, basin-wide accounting of consumptive water uses and losses (direct and indirect) for the binational Rio Grande-Bravo basin, disaggregated into 14 sub-basins.
• Quantifies the degree of unsustainable water consumption (overconsumption) by integrating estimates of reservoir, aquifer, and river outflow depletion with consumptive use data.
• Highlights the disproportionate role of irrigated agriculture (87% of direct consumption) and indirect uses (56% of total consumption) in the basin's severe water crisis.
• Offers a detailed, multi-source methodology for estimating various water consumption components across a complex binational river system, addressing data gaps and inconsistencies.
• Underscores the urgency of the water crisis in the RGB basin, arguing it is arguably more severe than the Colorado River Basin, and identifies critical areas for intervention and policy reform.

Funding

• National Science Foundation's Sustainable Regional Systems Program, the Transformation Network (NSF Grant #2115169)
• National Science Foundation Grant RISE-2108196
• Thornburg Foundation

Citation

@article{Richter2025Overconsumption,
  author = {Richter, Brian D. and Abdelmohsen, Karem and Dhakal, Sameer and Famiglietti, J. S. and Fowler, Keirnan and Green, Henry and Marston, Landon and Mekonnen, Mesfin M. and Prunes, Enrique and Rohde, Melissa M. and Ruddell, Benjamin L. and Rushforth, Richard and Shahbol, Natalie and Sjöstedt, Eric and Sandoval-Solís, Samuel},
  title = {Overconsumption gravely threatens water security in the binational Rio Grande-Bravo basin},
  journal = {Discover Water},
  year = {2025},
  doi = {10.1007/s43832-025-00301-2},
  url = {https://doi.org/10.1007/s43832-025-00301-2}
}