The Gin–Nilwala Diversion Project is a significant water management initiative in Sri Lanka aimed at addressing water scarcity and supporting agricultural development in the Southeastern Dry Zone. The project is designed to divert excess water from the Gin and Nilwala river basins, particularly during periods of high flow, to areas facing chronic water shortages, thereby ensuring a stable water supply for irrigation, drinking, and industrial use.

Key Objectives and Components

• Water Diversion: The project will divert excess water from the Gin and Nilwala rivers to the Southeastern Dry Zone, addressing the region’s critical water shortages. The diversion is expected to supply 145 million cubic meters (MCM) of water annually for drinking and industrial purposes, and an additional 120 MCM for irrigation.
• Infrastructure Development:
  • Madugate Reservoir: This reservoir will have a capacity of 12 MCM, inundating 50 hectares and affecting 15 families.
  • Ampanagala Reservoir: With a capacity of 11 MCM, this reservoir will inundate 67 hectares and affect 75 families.
  • Kotapola Weir: A smaller structure with a capacity of 0.16 MCM, inundating 4.3 hectares and affecting 15 families.
  • Tunnels and Canals: The project includes the construction of several tunnels and canals to facilitate water transfer. Key structures include an 18-kilometer tunnel from the Madugate Reservoir, a 5.5-kilometer tunnel from the Kotapola Weir, and a 13.5-kilometer tunnel from the Ampanagala Reservoir. Additionally, a 30.8-kilometer canal will be constructed to further distribute water.
• Reservoir Enhancements: The Muruthawela Reservoir will be raised by 1.5 meters, increasing its capacity from 48 MCM to 55 MCM. This enhancement will support expanded irrigation and improve water availability in the region.