RAINWATER HARVESTING PRACTICES IN THE DRY ZONE OF SRI LANKA

Abstract

Rainwater harvesting enables producers to achieve sustainable water management by reducing their reliance on external sources and enhancing resilience. Water scarcity remains a persistent challenge in Sri Lanka’s Dry Zone due to highly seasonal rainfall, prolonged dry periods, and increasing pressure on conventional surface and groundwater resources. Rainwater harvesting (RWH) has been practiced in the region for centuries through traditional systems, while modern techniques have been increasingly promoted in recent decades. However, comprehensive evaluations comparing the effectiveness of different RWH practices across multiple scales remain limited. This study examines the major rainwater harvesting practices used in Sri Lanka’s Dry Zone and evaluates their effectiveness in addressing domestic, agricultural, and institutional water needs. The study adopts a structured secondary data–based review and qualitative synthesis approach, drawing on peer-reviewed journal articles, government reports, institutional publications, and documented case studies published between 1995 and 2023. A thematic and comparative analytical framework was applied to assess four main categories of RWH practices: traditional tank cascade systems, rooftop rainwater harvesting, surface runoff harvesting, and institutional-scale systems. The findings indicate that traditional tank cascade systems continue to play a critical role in landscape-level water regulation and agricultural support. However, their effectiveness is increasingly constrained by sedimentation, land-use changes, and inadequate maintenance. Rooftop rainwater harvesting emerges as the most effective option for improving household-level water security, particularly during dry periods. Surface runoff harvesting primarily enhances agricultural resilience through supplementary irrigation, while institutional RWH systems provide reliable non-potable water for sanitation and operational needs but face limitations related to cost and scalability. The study concludes that no single RWH method can independently address water scarcity in Sri Lanka’s Dry Zone, highlighting the need for an integrated approach that combines traditional knowledge with modern rainwater harvesting practices to enhance long-term water security and climate resilience.