2010年-世界发展银行全球_Sustainable_Groundwater_Irrigation___Approaches_to_Reconciling_Demand_with_Resources_40页_6mb

Summary of Sustainable Groundwater Management

Core Content

This document provides a strategic overview of sustainable groundwater management practices, particularly in the context of agricultural irrigation. It outlines the global trends in groundwater use, the challenges of overexploitation, and the lessons learned from GW•MATE's experiences in various regions.

Main Points

Global Boom in Groundwater Irrigation

• Over the past 20-40 years, groundwater irrigation has expanded significantly, especially in arid and semi-arid regions.
• In India, the area under groundwater irrigation has increased by 500% since 1960.
• Groundwater is preferred by farmers due to its accessibility, reliability, and compatibility with modern irrigation systems.
• Most irrigation waterwells are privately owned, though government support through subsidies and low-cost loans has played a significant role.
• Groundwater irrigation is often more expensive than surface water due to lack of cost recovery mechanisms.

Concerns About Depletion and Sustainability

• Overexploitation of groundwater leads to resource depletion and various negative impacts, including salinization, water-table decline, and ecological degradation.
• These impacts can occur even before the abstraction rate exceeds the natural replenishment rate.
• In arid regions, groundwater is often non-renewable or poorly recharged, making it critical to manage sustainably.
• Traditional irrigation practices such as spate irrigation are declining, and modern pressurized systems are increasing, which can exacerbate salinization and water-table decline.

Key Recommendations

• A pragmatic framework is essential to develop a balanced approach to groundwater management.
• This framework must consider technical, economic, institutional, and social measures tailored to the hydrogeological and socioeconomic context.
• The goal is to promote sustainable use while balancing the needs of agricultural production and environmental protection.

Key Information

Global Statistics

• Total global area under irrigation is approximately 301 million hectares.
• 38% of this area is equipped for groundwater irrigation.
• Groundwater accounts for 43% of total irrigation water use, with 545 km³ used annually.
• The largest groundwater-irrigated areas are in India (39 M ha) and China (19 M ha).

Regional Case Studies

The following boxes highlight GW•MATE's experiences in various aquifer systems:

• Box A: Carrizal Aquifer of Mendoza, Argentina

  • Success in integrating groundwater into irrigation systems, but issues with salinization affecting high-value crops.
  • Measures include waterwell drilling restrictions and legal reforms to prevent salinity mobilization.

• Box B: Apodi Aquifer System of Northeast Brazil

  • Focus on sustainable use through community participation and regulation.
  • Highlight the need for balancing irrigation with environmental and social concerns.

• Box C: Guantao County on the North China Plain

  • Emphasis on the importance of groundwater storage in arid regions.
  • Need for careful management to prevent irreversible degradation.

• Box D: Souss-Chtouka Basin of Morocco

  • Case of groundwater overexploitation leading to salinization and ecological issues.
  • Highlight the importance of monitoring and regulation.

• Box E: Weathered Hard-Rock Aquifers of Peninsular India

  • Challenges in managing hard-rock aquifers with limited recharge.
  • Stress the need for community-based management and self-regulation.

• Box F: Gangetic Plain in Uttar Pradesh, India

  • Focus on the interaction between groundwater and surface water systems.
  • Emphasis on conjunctive use and the role of macro-policies in shaping sustainable practices.

• Box G: Indus Penepplain in Central Punjab, India

  • Experience with groundwater conjunctive use and the impact of irrigation technology on water use efficiency.

• Box H: Silao-Romita Basin of Mexico

  • Highlight the importance of institutional capacity and stakeholder involvement in groundwater management.

• Box J: Ica Area Aquifers of Peru

  • Case study on the need for adaptive management and stakeholder engagement.

Management Instruments

• Groundwater Use Regulation and Charging: Essential for controlling abstraction and ensuring cost recovery.
• Community Participation and Self-Regulation: Encourages local involvement and sustainable practices.
• Finance of Local Demand and Supply-Side Measures: Requires investment in efficient irrigation technologies and alternative water sources.
• Alignment of Food and Energy Macro-Policies: Important for creating incentives that support sustainable use.
• Groundwater Conjunctive Use: Advocated for improving land and water productivity by integrating surface and groundwater resources.

Forward Look

• The need for a balanced and adaptive approach to groundwater management is emphasized.
• Continuous monitoring and modeling are key to improving scientific understanding and refining management strategies.
• The document stresses the importance of stakeholder engagement, transparency, and the development of 'exit solutions' for transitioning to less water-dependent economies.
• It calls for a more integrated approach that considers both the environmental and socioeconomic impacts of groundwater use.

Conclusion

GW•MATE advocates for a pragmatic and context-specific framework to guide sustainable groundwater management. The document highlights the importance of integrating various management instruments and fostering community participation to achieve long-term sustainability in agricultural irrigation.