How do Seasonal Changes in Ecoroof Plants Impact Stormwater Runoff and Weed Establishment?
Abstract
Ecoroofs remove abundant stormwater runoff from the combined sewer system in Portland, Oregon. A limited number of studies focused on comparing stormwater retention by ecoroof plants. This research aims to study the seasonal impact on water retention of two functionally different species, Buffalograss (Bouteloua dactyloides) and White stonecrop (Sedum album) while evaluating weed growth as a factor in water absorption. Seven tray structures are built: three planted with Buffalograss, three with White stonecrop, and one containing bare substrate. The trays are monitored for one year starting in June 2023, measuring plant coverage, biomass, leaf area index, and weed count. Plant coverage was nearly identical for both species, although the weed count was higher in Buffalograss trays. Plant results are to be compared to stormwater runoff data measured by tipping buckets by the environmental engineering department at Portland State University. This research aims to provide in-depth data on different plant types and their impact on stormwater runoff. Part of the Central City 2035 plan requires ecoroofs on newly built commercial buildings of 20,000 ft. Our results aim to understand plant absorption and use it to our benefit in reducing excessive stormwater runoff from impervious surfaces.
How do Seasonal Changes in Ecoroof Plants Impact Stormwater Runoff and Weed Establishment?
Ecoroofs remove abundant stormwater runoff from the combined sewer system in Portland, Oregon. A limited number of studies focused on comparing stormwater retention by ecoroof plants. This research aims to study the seasonal impact on water retention of two functionally different species, Buffalograss (Bouteloua dactyloides) and White stonecrop (Sedum album) while evaluating weed growth as a factor in water absorption. Seven tray structures are built: three planted with Buffalograss, three with White stonecrop, and one containing bare substrate. The trays are monitored for one year starting in June 2023, measuring plant coverage, biomass, leaf area index, and weed count. Plant coverage was nearly identical for both species, although the weed count was higher in Buffalograss trays. Plant results are to be compared to stormwater runoff data measured by tipping buckets by the environmental engineering department at Portland State University. This research aims to provide in-depth data on different plant types and their impact on stormwater runoff. Part of the Central City 2035 plan requires ecoroofs on newly built commercial buildings of 20,000 ft. Our results aim to understand plant absorption and use it to our benefit in reducing excessive stormwater runoff from impervious surfaces.