Wednesday, November 15, 2006 - 8:45 AM
291-2
The Effect of Vegetation Type on the Hydrology and Macronutrient Cycling of Newly Established Rain Gardens.
Bioretention of urban stormwater using residential rain gardens has grown in popularity over the past 15 years intensifying the need to understand these systems. In this study, our objective was to quantitatively evaluate the mechanistic performance of newly established rain gardens relative to differences in vegetation. Through mass balance budgeting of the hydrologic and macronutrient cycles, we tested hypotheses ranging from the movement and storage of water to the movement and storage of nitrogen. For example, we hypothesized that: 1.) the volume of effluent water would rank by treatment in the following order due to differences in evapotranspiration rates: Control (no vegetation) > Sod > Shrub > Prairie; and 2.) evapotranspiration rates would rank by treatment in the following order due to differences in net primary production among treatments: Prairie > Shrub > Sod > Control. To test these hypotheses, we constructed 12 experimental rain gardens (7.8 m3 each) during the summer of 2005 with three replicates of each of the four treatments including non-vegetated controls. Runoff from a corrugated metal roof was equally distributed among the 12 gardens and all transfers and accumulations of water, biomass, nitrogen, phosphorus, and potassium were quantified. Flows of metal contaminates present in the roof water were also examined. In this presentation we demonstrate the variability in these mass flows relative to vegetation type in newly established rain gardens.
Recorded presentation