Cao et al. (2025) Hydroeconomic optimization for canal-well conjunctive irrigation and drainage management in an arid region with salinization

Identification

• Journal: Frontiers in Sustainable Food Systems
• Year: 2025
• Date: 2025-12-02
• Authors: Zhaodan Cao, Tingju Zhu, Baofu Li, Yuhan Yan, Yuanyuan Luo, Yanfeng Chen, Tao Pan
• DOI: 10.3389/fsufs.2025.1721178

Research Groups

• Sino-Belgian Joint Laboratory for Geoinformation, School of Geography and Tourism, Qufu Normal University, Rizhao, China
• ZJU-UIUC Institute, Zhejiang University, Haining, China
• Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States
• College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, China
• Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, China

Short Summary

This study developed an integrated hydroeconomic optimization framework to manage canal-well conjunctive irrigation and drainage in arid regions facing water scarcity and salinization. It identified that a 10% reduction in the surface-to-groundwater irrigation area ratio combined with an enhanced groundwater drainage capacity (α = 0.21 year⁻¹) is a sustainable strategy, simultaneously increasing agricultural net benefits, mitigating salinization, conserving water, ensuring food security, and maintaining groundwater sustainability over a 15-year horizon.

Objective

• To develop an integrated hydroeconomic optimization framework for canal-well conjunctive irrigation and drainage management in arid irrigated systems.
• To evaluate how varying canal-well conjunctive irrigation-drainage strategies impact farmers’ adaptive decisions on cropping patterns and water allocations, and their feedback effects on water-salt dynamics, agricultural productivity, profitability, and food security.
• To identify targeted sustainable canal-well conjunctive irrigation-drainage strategies that can simultaneously improve agricultural profitability, mitigate soil-groundwater salinization, ensure food security, and safeguard long-term groundwater sustainability.

Study Configuration

• Spatial Scale: Hetao Irrigation District (HID), China, specifically the Canal-Well Conjunctive Irrigation District (CWCID) comprising five sub-irrigation districts (Wulanbuhe, Jiefangzha, Yongji, Yichang, and Wulate). Each CWCID within a sub-irrigation district is treated as an independent water-salt balance unit (WSBU).
• Temporal Scale: 15-year planning horizon, with annual iterations for inter-annual water-salt dynamics.

Methodology and Data

• Models used:
  • Integrated Hydroeconomic Optimization Framework (HEM)
  • Agro-hydrological processes (inter-annual root-zone/groundwater water-salt dynamics, groundwater drainage simulation, salinity-driven crop yield assessment, canal-well conjunctive irrigation module)
  • Economic optimization framework
  • Positive Mathematical Programming (PMP) for model calibration and capturing farmers' adaptive decisions
  • Linear Reservoir Model (LRM) for groundwater drainage
  • Crop yield under salinity stress model (Allen et al., 1998)
  • General Algebraic Modeling Systems (GAMS) with CONOPT solver
• Data sources:
  • Previous studies (Wang, 2018; Ren et al., 2019; Xu et al., 2019; Dou et al., 2020; Zhu et al., 2020)
  • Reports from local governmental agencies (Bayannur Water Conservancy Bureau, 2019; Hetao Irrigation District Administration, 2019)
  • Base-year observed crop areas, yields, commodity prices, land and water costs, and available land and water resources.
  • Esri 2020 Land Cover for land use types.

Main Results

• Reducing the surface-to-groundwater irrigation area ratio (SGIAR) by 70% (under baseline drainage capacity α = 0.07 year⁻¹) expanded grain crop areas, enhancing food security, and reduced root-zone salinity by 9.2% (from 11,887 to 10,795 mg/L) and groundwater salinity by 8.0% (from 4,619 to 4,250 mg/L). This also led to a 9.7% (2.08 × 10⁸ m³) reduction in total conjunctive water consumption.
• Conversely, increasing SGIAR undermined food security by shifting land from grain crops to higher-value cash crops due to surface water scarcity.
• Enhancing groundwater drainage capacity to α = 0.21 year⁻¹ significantly mitigated soil and groundwater salinization, reducing root-zone soil salinity by 49% (from 11,887 to 6,086 mg/L) and groundwater salinity by 41% (from 4,619 to 2,734 mg/L) compared to baseline drainage (α = 0.07 year⁻¹), while concurrently improving agricultural productivity and net benefits.
• The "10% SGIAR reduction and α = 0.21 year⁻¹" scenario emerged as the most sustainable strategy, achieving the highest net benefits (4.12 × 10⁸ Yuan, a 60% increase over the optimal baseline drainage scenario), alleviating salinization, conserving water, sustaining food security, and ensuring groundwater sustainability (maintaining a stable groundwater depth of 2.66 m, above the 3.0 m ecological threshold for groundwater-dependent ecosystems) over the 15-year planning horizon.
• Under baseline drainage capacity (α = 0.07 year⁻¹), all strategies (whether increasing or decreasing SGIAR) progressively exacerbated soil salinization, reduced relative crop yields, and led to declines in agricultural net benefits over the 15-year period.

Contributions

• Developed a novel integrated hydroeconomic optimization framework that holistically integrates inter-annual root-zone and groundwater water-salt dynamics, salinity-stressed crop yield assessment, canal-well conjunctive irrigation, and farmers’ adaptive decision-making (calibrated with Positive Mathematical Programming) into an economic optimization framework.
• Quantified the systemic, inter-annual impacts of various canal-well conjunctive irrigation-drainage strategies on cropping patterns, water allocation decisions, water-salt dynamics, agricultural productivity and profitability, and food security.
• Identified a specific, economically optimal, and sustainable canal-well conjunctive irrigation-drainage strategy ("10% SGIAR reduction and α = 0.21 year⁻¹") that simultaneously achieves multiple sustainability objectives in arid irrigated systems.
• Provided a robust modeling and decision-making tool and policy insights for advancing sustainable irrigated agriculture in salinization-prone arid regions like the Hetao Irrigation District and analogous systems worldwide.

Funding

• Humanities and Social Sciences Youth Foundation of Ministry of Education of China (24YJCZH011)
• Shandong Provincial Natural Science Foundation (ZR2024QE348)
• National Natural Science Foundation of China (42171126)
• Taishan Scholars Project of Shandong Province (tsqn202306182)
• Rizhao City Natural Science Foundation (RZ2022ZR51)

Citation

@article{Cao2025Hydroeconomic,
  author = {Cao, Zhaodan and Zhu, Tingju and Li, Baofu and Yan, Yuhan and Luo, Yuanyuan and Chen, Yanfeng and Pan, Tao},
  title = {Hydroeconomic optimization for canal-well conjunctive irrigation and drainage management in an arid region with salinization},
  journal = {Frontiers in Sustainable Food Systems},
  year = {2025},
  doi = {10.3389/fsufs.2025.1721178},
  url = {https://doi.org/10.3389/fsufs.2025.1721178}
}