Coastal planners need a better understanding of hydrological and ecological mechanisms to achieve design targets for stormwater volume and flow reduction. Today, minimal information exists about the hydrologic function and performance of vegetative systems (rain gardens, for instance) in landscapes with shallow water tables where surface and groundwater interactions are prevalent. Research is needed to examine the efficiency and effectiveness of these practices in reducing stormwater volume and improving water quality.
The research team plans to (1) define surface and groundwater contributions to hydrology as well as nutrient, polycyclic aromatic hydrocarbons (PAHs), and bacteria loading in bioretention (rain garden) systems, (2) quantify the unsaturated zone and saturated groundwater response to individual storm events in the subsoil of the practice, (3) compare and contrast the hydrologic interactions within and between surface and groundwater for these types of systems, (4) compare and contrast the nutrient, PAH, and bacteria removal efficiencies within the systems, (5) quantify nutrient and bacteria processing rates and rate limiting steps for these types of systems (as appropriate), (6) determine appropriate site conditions and subsequent requirements, design criteria, and specifications for bioretention systems, and (7) convey these results to practitioners and decision-makers via workshops, presentations at appropriate meetings, and an online mapping tool and hydrographical monitoring network.