Rainwater Harvesting Design and Optimization in Semi-Arid Mediterranean Climates: A Technical Review with Focus on Türkiye

Abstract

A comprehensive technical review of current literature regarding rainwater harvesting (RWH) systems in terms of design, feasibility and optimization in Türkiye and similar Mediterranean climates is presented here in. Research has been conducted through a peer-reviewed study process (2010-2026). It was created to provide hydraulic engineers with design specifications and sizing methodologies for use in urban settings. The results indicated that for optimal residential tank size in Türkiye would be dependent upon several factors including roof area (30-270 m²), rainfall (292-1180 mm/year), and demand profile, but generally ranged from 2-21 m³. Particle Swarm Optimization and Linear Programming were identified as the most effective sizing methods to achieve 90-98 % volumetric reliability while minimizing the total lifecycle cost. Potential water savings resulting from implementation of an RWH system range from 20-70 % of domestic water usage, which could result in discounted payback times ranging from 12-36 years based on the configuration of the RWH system and local water pricing structures. The review also emphasized the importance of hydrologic models, filtration requirements and optimization techniques for designing RWH systems in semi-arid Mediterranean climates.