Subsurface Gravel Wetland Design Specification

Developed by the University of New Hampshire Stormwater Center (UNHSC) (2009), this design specification provides guidance on designing subsurface gravel wetlands that treat stormwater through subsurface flow, sedimentation, and microbial processes within a gravel and wetland plant matrix. It helps designers size wetland cells, configure inlet and outlet structures, and integrate subsurface flow paths to enhance pollutant removal while maintaining a low surface footprint and supporting cold-climate performance.