A Comprehensive Study of Best Management Practices for Flood Mitigation Strategies in River Basin Watersheds

Abstract

Flooding remains one of the most recurrent and economically damaging natural hazards affecting river basin communities worldwide, and the problem is intensified in monsoon-fed catchments where intense seasonal rainfall combines with regulated reservoir releases to generate peak discharges that exceed the natural conveyance capacity of river channels. This paper presents a comprehensive review and synthesis of Best Management Practices (BMPs) for flood mitigation, framed around a representative case context drawn from the Koyna River Basin in Maharashtra, India, where flood hazard index (FHI) zonation has identified the downstream village of Tambave as a site of concentrated vulnerability. BMPs are classified into three broad categories: structural measures (check dams, detention and retention ponds, channel improvement, levees and flood embankments), non-structural measures (floodplain zoning, rainwater harvesting and urban drainage enhancement, early warning systems and reservoir operation coordination), and vegetative or bio-engineering measures (afforestation and reforestation, grass waterways and vegetative buffer strips). Each category is examined with respect to its hydrological mechanism, reported effectiveness in the peer-reviewed literature, and contextual suitability for steep-gradient, monsoon-dominated basins of the Western Ghats. The review draws on more than thirty published studies spanning hydrological modelling (SWAT, MIKE 11/MIKE SHE, PCSWMM, SWMM), field-monitored check-dam and detention-pond performance, floodplain zoning policy evaluation, and flood early-warning system design. The synthesis indicates that no single BMP is sufficient in isolation; rather, a tiered combination of upstream attenuation (check dams, afforestation), mid-basin storage (detention/retention ponds, channel improvement), and downstream protection (levees, zoning, early warning) constructed around the basin's FHI zonation offers the most cost-effective and ecologically sound pathway to reducing flood inundation extent and protecting vulnerable downstream settlements such as Tambave village.