Grant: Alliance Grants

Lakes in urban areas often experience nutrient enrichment, chloride pollution and suspended solids from stormwater runoff. These water quality issues are detrimental to aquatic life and recreational uses. Floating treatment wetlands are a promising emerging technology for water quality improvement but to date, there have been few studies demonstrating their efficacy on natural water bodies (as opposed to wastewater lagoons) and in cold climates. Floating wetlands are composed of buoyant rafts, planted with wetland plants with roots extending vertically down into the water column. The plant roots and biofilm take up and transform nutrients and other contaminants, while also slowing water velocities and encouraging sedimentation. Working with the Halifax Regional Municipality, we propose to install a pilot floating wetland system in an urban lake which is subject to nutrient enrichment, high chloride and suspended solids. We will monitor lake water quality and benthic invertebrate communities before and after floating wetland installation and measure nutrient uptake in wetland plant tissues over one summer. If the floating wetlands are found to improve water quality, the HRM will explore additional floating wetland installations. Furthermore, our findings will inform use of the technology in other Canadian cities and in other applications (e.g., rivers, stormwater lagoons). One master's student will be trained during the project who will work with both Dalhousie researchers and HRM staff.