Scholarlink

<p>Effective watershed management in semi-arid regions requires a precise understanding of how land use change (LUC) and climate change (CC) will jointly alter hydrological cycles. This study addresses a critical gap in assessing their relative impacts by evaluating the individual and combined effects of future LUC and CC on key hydrological variables in the Siminehrud River Basin, Iran, a region vulnerable to water scarcity. The Soil and Water Assessment Tool (SWAT) model was calibrated and validated for streamflow simulation. Future LUC for 2040 was projected using the Dyna-CLUE model under three distinct scenarios: sustainable development (MTSS), rapid expansion (MSSS), and business-as-usual (MBAU). Climate projections from five General Circulation Models under RCP4.5 were statistically downscaled using LARS-WG. Results indicated a marginal increase in annual precipitation (0.9%) by 2040, accompanied by a substantial temperature rise (+ 1.2&#xa0;°C&#xa0;min, + 1.4&#xa0;°C max). Hydrological simulations revealed divergent impacts: annual streamflow decreased by -1.0% (MTSS), -3.1 to -4.5% (MSSS, accounting for potential ET‑driven microclimate feedbacks), and -2.5% (MBAU), while evapotranspiration (ET) showed a contrasting response, decreasing by 5.2% under MTSS but increasing significantly by 14% and 11% under MSSS and MBAU, respectively. Crucially, scenario analysis demonstrated that LUC alone was the dominant driver of hydrological alteration, exerting a stronger influence than CC alone. These findings highlight a critical paradox: socio-economic development strategies reliant on land-use intensification may inadvertently exacerbate water scarcity by amplifying ET and reducing streamflow. Consequently, this study highlights that sustainable watershed planning must explicitly prioritize land-use management and rigorously address the trade-offs between development and water conservation to ensure future water security.</p> Graphical Abstract <p></p> <p>This graphical abstract provides a rapid, visually compelling summary of a comprehensive hydrological impact assessment study in the Siminehrud River Basin, Iran. It illustrates the principal methodological steps, beginning with the application of IPCC Representative Concentration Pathways (RCPs). Future climate projections from multiple Global Climate Models (under RCP4.5) and three distinct land-use scenarios for 2040, Sustainable Development (MTSS), Rapid Expansion (MSSS), and Business-as-Usual (MBAU), form the core inputs. These scenarios were developed using the Dyna-CLUE model, the results of which are visualized as classified land-use maps highlighting changes in Built-up areas, Irrigated cultivation, Rainfed agriculture, and Rangelands. The central flowchart depicts how these climate and land-use change projections are integrated into the SWAT (Soil and Water Assessment Tool) hydrological model for simulation. The right section presents a key comparative result, showing average monthly evapotranspiration (ET) and outflow (streamflow) variations for the combined scenarios against the baseline. The chart visually encapsulates the study's main finding: while future precipitation shows a slight increase, rising temperatures and land-use change drive a critical hydrological shift. The simulations project an overall decrease in annual streamflow alongside significant increases in ET under most scenarios. Crucially, the analysis revealed that land-use change was the dominant driver of hydrological alteration, surpassing the impact of climate change alone. This graphical abstract efficiently conveys the study's core warning: sustainable watershed management must explicitly address the trade-off between land-use development strategies and their unintended consequences on water scarcity, as visualized through the divergent pathways of streamflow and ET.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Land-Use Change Outpaces Climate Change as the Dominant Driver of Water Scarcity in Iran’s Siminehrud Basin: A Hydrological Trade-off Analysis

  • 期刊论文

  • 发表日期：

    2026年8月3日

查看全文
  • Soheila Youneszadeh Jalili,
  • Ali Salajegheh,
  • Tayebeh Mesbahzadeh,
  • Massoud Tajrishy,
  • Shahram Khalighi-Sigaroodi,
  • Bagher Shirmohammadi,
  • Martijn J. Booij

摘要

Effective watershed management in semi-arid regions requires a precise understanding of how land use change (LUC) and climate change (CC) will jointly alter hydrological cycles. This study addresses a critical gap in assessing their relative impacts by evaluating the individual and combined effects of future LUC and CC on key hydrological variables in the Siminehrud River Basin, Iran, a region vulnerable to water scarcity. The Soil and Water Assessment Tool (SWAT) model was calibrated and validated for streamflow simulation. Future LUC for 2040 was projected using the Dyna-CLUE model under three distinct scenarios: sustainable development (MTSS), rapid expansion (MSSS), and business-as-usual (MBAU). Climate projections from five General Circulation Models under RCP4.5 were statistically downscaled using LARS-WG. Results indicated a marginal increase in annual precipitation (0.9%) by 2040, accompanied by a substantial temperature rise (+ 1.2 °C min, + 1.4 °C max). Hydrological simulations revealed divergent impacts: annual streamflow decreased by -1.0% (MTSS), -3.1 to -4.5% (MSSS, accounting for potential ET‑driven microclimate feedbacks), and -2.5% (MBAU), while evapotranspiration (ET) showed a contrasting response, decreasing by 5.2% under MTSS but increasing significantly by 14% and 11% under MSSS and MBAU, respectively. Crucially, scenario analysis demonstrated that LUC alone was the dominant driver of hydrological alteration, exerting a stronger influence than CC alone. These findings highlight a critical paradox: socio-economic development strategies reliant on land-use intensification may inadvertently exacerbate water scarcity by amplifying ET and reducing streamflow. Consequently, this study highlights that sustainable watershed planning must explicitly prioritize land-use management and rigorously address the trade-offs between development and water conservation to ensure future water security.

Graphical Abstract

This graphical abstract provides a rapid, visually compelling summary of a comprehensive hydrological impact assessment study in the Siminehrud River Basin, Iran. It illustrates the principal methodological steps, beginning with the application of IPCC Representative Concentration Pathways (RCPs). Future climate projections from multiple Global Climate Models (under RCP4.5) and three distinct land-use scenarios for 2040, Sustainable Development (MTSS), Rapid Expansion (MSSS), and Business-as-Usual (MBAU), form the core inputs. These scenarios were developed using the Dyna-CLUE model, the results of which are visualized as classified land-use maps highlighting changes in Built-up areas, Irrigated cultivation, Rainfed agriculture, and Rangelands. The central flowchart depicts how these climate and land-use change projections are integrated into the SWAT (Soil and Water Assessment Tool) hydrological model for simulation. The right section presents a key comparative result, showing average monthly evapotranspiration (ET) and outflow (streamflow) variations for the combined scenarios against the baseline. The chart visually encapsulates the study's main finding: while future precipitation shows a slight increase, rising temperatures and land-use change drive a critical hydrological shift. The simulations project an overall decrease in annual streamflow alongside significant increases in ET under most scenarios. Crucially, the analysis revealed that land-use change was the dominant driver of hydrological alteration, surpassing the impact of climate change alone. This graphical abstract efficiently conveys the study's core warning: sustainable watershed management must explicitly address the trade-off between land-use development strategies and their unintended consequences on water scarcity, as visualized through the divergent pathways of streamflow and ET.