Low Impact Development and Green Infrastructure as Source Water Protection: Mitigating Nonpoint-Source Contamination of Municipal Drinking Water Supplies

Abstract

Municipal drinking-water protection often begins after contaminants have entered a reservoir, river intake, or aquifer. This review examines low-impact development and green infrastructure as preventive source-water controls, synthesizing evidence on bioretention, permeable pavement, vegetated buffers, and treatment trains, with emphasis on sediment, nitrogen, phosphorus, fecal indicators, and contaminant mobilisation. A source–pathway–receptor framework connects runoff-generating land, distributed controls, groundwater recharge zones, surface-water intakes, and treatment processes. Evidence supports consistent reductions in suspended solids and many particle-associated pollutants, while performance for dissolved nutrients, chloride, and pathogens depends more strongly on media characteristics, hydraulic residence time, temperature, antecedent moisture, bypass, and maintenance. Infiltration also creates an obligation to protect groundwater from mobile contaminants. The framework therefore incorporates intake sensitivity, aquifer vulnerability, treatment consequences, lifecycle maintenance, and mass-load monitoring into routine stormwater design. Green infrastructure can serve as an upstream barrier within a multiple-barrier drinking-water system when each practice is appropriately matched to a contaminant source, transport pathway, and municipal receptor. Performance-based siting, treatment trains, conservative pathogen controls, and shared governance can strengthen public-health protection before conventional treatment.