Biodrainage: A Sustainable Bio-engineering Approach for Water Management in Salt-affected and Waterlogged Soils

Abstract

Biodrainage is a nature-based bio-engineering approach that uses deep-rooted, high-transpiring vegetation to regulate shallow groundwater tables and reduce waterlogging in salt-affected agricultural landscapes. This review examines the concept, scientific basis, mechanisms, species selection, system configurations, functions, constraints, integration with conventional drainage, and future research needs of biodrainage. The approach relies primarily on plant water uptake and transpiration, with effectiveness governed by root architecture, water-table depth, soil hydraulic properties, groundwater salinity, climate, plantation geometry, and seasonal evapotranspiration. Species including Eucalyptus camaldulensis, Casuarina equisetifolia, Tamarix articulata, Populus deltoides, Acacia nilotica, Prosopis juliflora, and Leucaena leucocephala are discussed in relation to their suitability for saline and waterlogged environments. The review further considers monoculture, agroforestry, mixed-species, strip and border, constructed-wetland, floating, and integrated biodrainage configurations. Biodrainage can contribute to water-table regulation, salinity management, soil improvement, biomass production, carbon sequestration, and agroforestry-based land use, while reducing dependence on energy-intensive drainage infrastructure. However, its performance is site-specific and may be constrained by soil texture, groundwater quality, species tolerance, land competition, establishment costs, ecological risks, and limited long-term monitoring. Integration with conventional drainage can improve overall system performance where biological drainage alone is insufficient. Future research should prioritise species optimisation, long-term water-balance assessment, climate resilience, ecological trade-offs, monitoring technologies, and decision-support frameworks for appropriate site-specific implementation.