Zeinab Karimi *1, Ali Talebi2
1- Shiraz University
2- Yazd University
2- Yazd University
Abstract: (10 Views)
Extended Abstract
Introduction and Objective: The Zayandeh-Rud watershed is among the most politically, economically, and environmentally sensitive basins in Iran. In recent decades, excessive water extraction, industrial expansion, and weak governance have severely threatened the environmental water rights (EWRs) of rivers, especially the Pelasjan River. The main objective of this study is to assess and improve the EWR status of the Pelasjan River by using the DPSIR (Driving force–Pressure–State–Impact–Response) framework and hydrological methods, namely the Montana method and Flow Duration Curve (FDC).
Material and Methods: Hydrometric data from Eskandari Station over a 20-year period (2001–2021) were analyzed. The average annual river flow was calculated at 14.6 m³/s, corresponding to an annual volume of 52.3 million cubic meters. The Montana method was employed to estimate monthly environmental flow requirements, using 40% and 60% of monthly flows during wet and dry seasons respectively. The Q90 value from the FDC method was also used to determine the minimum ecological flow. Stakeholder workshops (30 participants, including local council members, environmental and water experts, and academic researchers) were conducted to draw problem and objective trees focused on EWR issues. DPSIR elements were identified, and expert opinions were analyzed and prioritized using the Friedman test.
Results: Hydrological analysis revealed that March to May are wet months with flows above the annual average, while June to October are dry with significantly lower flows. The highest recorded flow occurred in April (88.7 m³/s), and the lowest in August and September (~0.08 m³/s), indicating strong hydrological instability and ecological stress. According to the Montana method, the average EWR for wet and dry months was calculated as 3.78 m³/s and 0.92 m³/s respectively. Management scenarios showed that under "poor" and "very poor" categories, flows were often significantly below these thresholds. The FDC method provided a critical Q90 value of 1.38 m³/s, considered the minimal acceptable ecological flow. Within the DPSIR framework, two main driving forces—climate change and agricultural expansion—were identified. Institutional pressures such as outdated policies, lack of water use restrictions, and top-down governance were also crucial. This has resulted in negative environmental states including reduced vegetation cover, increased erosion, and imbalance between supply and demand. Impacts include conflicts among stakeholders, increased flood damage, and violations of downstream water rights.
Conclusion: This study highlights that the Polasjan River faces a multifaceted crisis involving ecological degradation and institutional failure. The DPSIR analysis demonstrates that environmental flow scarcity is not just an ecological problem but also a governance and socio-political issue. Responses such as promoting bottom-up governance, revising outdated policies, optimizing water allocations, and restoring hydrological structures are essential. Ultimately, setting a minimum EWR of 1.38 m³/s as a baseline for the Pelasjan River can help protect its ecological functions, reduce stakeholder conflicts, and enhance the long-term sustainability of the Zayandeh-Rud watershed.
Keywords: Eskandari Watershed, Regulation of water rights, Agricultural development, Tree of problems and objectives, Stakeholders.
Introduction and Objective: The Zayandeh-Rud watershed is among the most politically, economically, and environmentally sensitive basins in Iran. In recent decades, excessive water extraction, industrial expansion, and weak governance have severely threatened the environmental water rights (EWRs) of rivers, especially the Pelasjan River. The main objective of this study is to assess and improve the EWR status of the Pelasjan River by using the DPSIR (Driving force–Pressure–State–Impact–Response) framework and hydrological methods, namely the Montana method and Flow Duration Curve (FDC).
Material and Methods: Hydrometric data from Eskandari Station over a 20-year period (2001–2021) were analyzed. The average annual river flow was calculated at 14.6 m³/s, corresponding to an annual volume of 52.3 million cubic meters. The Montana method was employed to estimate monthly environmental flow requirements, using 40% and 60% of monthly flows during wet and dry seasons respectively. The Q90 value from the FDC method was also used to determine the minimum ecological flow. Stakeholder workshops (30 participants, including local council members, environmental and water experts, and academic researchers) were conducted to draw problem and objective trees focused on EWR issues. DPSIR elements were identified, and expert opinions were analyzed and prioritized using the Friedman test.
Results: Hydrological analysis revealed that March to May are wet months with flows above the annual average, while June to October are dry with significantly lower flows. The highest recorded flow occurred in April (88.7 m³/s), and the lowest in August and September (~0.08 m³/s), indicating strong hydrological instability and ecological stress. According to the Montana method, the average EWR for wet and dry months was calculated as 3.78 m³/s and 0.92 m³/s respectively. Management scenarios showed that under "poor" and "very poor" categories, flows were often significantly below these thresholds. The FDC method provided a critical Q90 value of 1.38 m³/s, considered the minimal acceptable ecological flow. Within the DPSIR framework, two main driving forces—climate change and agricultural expansion—were identified. Institutional pressures such as outdated policies, lack of water use restrictions, and top-down governance were also crucial. This has resulted in negative environmental states including reduced vegetation cover, increased erosion, and imbalance between supply and demand. Impacts include conflicts among stakeholders, increased flood damage, and violations of downstream water rights.
Conclusion: This study highlights that the Polasjan River faces a multifaceted crisis involving ecological degradation and institutional failure. The DPSIR analysis demonstrates that environmental flow scarcity is not just an ecological problem but also a governance and socio-political issue. Responses such as promoting bottom-up governance, revising outdated policies, optimizing water allocations, and restoring hydrological structures are essential. Ultimately, setting a minimum EWR of 1.38 m³/s as a baseline for the Pelasjan River can help protect its ecological functions, reduce stakeholder conflicts, and enhance the long-term sustainability of the Zayandeh-Rud watershed.
Keywords: Eskandari Watershed, Regulation of water rights, Agricultural development, Tree of problems and objectives, Stakeholders.
Keywords: Eskandari Watershed, Regulation of water rights, Agricultural development, Tree of problems and objectives, Stakeholders.
Type of Study: Research |
Subject:
ساير موضوعات وابسته به مديريت حوزه آبخيز
Received: 2024/06/15 | Accepted: 2025/08/9
Received: 2024/06/15 | Accepted: 2025/08/9
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