世界银行-重视绿色基础设施：以塔吉克斯坦瓦赫什河流域为例（英）-2023.9-129页_4mb

Summary of "Valuing Green Infrastructure: A Case Study of the Vakhsh River Basin, Tajikistan"

Introduction
This report assesses the economic and environmental potential of landscape restoration interventions in the Vakhsh River Basin, Tajikistan. The basin faces significant challenges from soil erosion and sedimentation, threatening hydropower, agriculture, and water security. Green infrastructure interventions, such as orchards, woodlots, and rotational grazing, offer solutions to mitigate these issues while generating economic benefits.

Main Findings

Environmental Benefits

• Sediment Reduction: Mosaic landscape restoration (combining orchards, woodlots, and rotational grazing) reduces erosion by 4.4 m³/ha/year, decreasing sediment inflow to reservoirs. This extends reservoir lifespan and improves hydropower efficiency.
• Hydrological Improvements: Restoration increases water retention, reduces runoff, and enhances groundwater recharge, contributing to improved irrigation and water availability.
• Carbon Sequestration: Orchards and woodlots offset 3–6 tCO₂-eq/ha/year, generating value through carbon credits.

Economic Benefits

• Per Hectare Benefits:
  • Orchards generate US$4.2 in value for every dollar invested, with an NPV of US$61,240/ha.
  • Woodlots yield US$3.3 in benefits per dollar, with an NPV of US$31,690/ha.
  • Rotational grazing provides modest returns (US$2.1–3.3 benefits per dollar) but scales across large areas.
• Total Catchment Impact: Scaling restoration across 966,616 ha delivers:
  • US$8.3 billion NPV to Tajikistan society.
  • US$4.8 billion avoided climate damages globally.
  • US$765 million in carbon credit revenue.

Methodology

• Integrated Modeling: SWAT and custom sediment models assess hydrological and erosion impacts.
• Cost-Benefit Analysis: Conservative assumptions (6% discount rate, 30-year horizon) show robust financial viability for interventions.
• Stakeholder Engagement: Consultations with farmers, NGOs, and government agencies ensured context-specific interventions.

Policy Recommendations

1. Develop a national landscape restoration strategy integrating watershed approaches into hydropower and agriculture policies.
2. Mainstream sustainable grazing and forest management into legislation.
3. Establish councils for cross-jurisdictional coordination.
4. Scale up payments for ecosystem services (PES) and explore public-private partnerships (PPPs).
5. Repurpose subsidies to incentivize green infrastructure investments.

Conclusion

Landscape restoration in the Vakhsh Basin delivers significant environmental and economic co-benefits. By addressing sedimentation and climate resilience, it enhances hydropower, agriculture, and water security. Minimal upfront investment costs make these interventions accessible for poverty alleviation and sustainable development.