Water quality function of an extensive vegetated roof

Dimitar Todorov; Charles T Driscoll; Svetoslava Todorova; Mario Montesdeoca

doi:10.1016/j.scitotenv.2017.12.085

Water quality function of an extensive vegetated roof

Sci Total Environ. 2018 Jun 1:625:928-939. doi: 10.1016/j.scitotenv.2017.12.085. Epub 2018 Jan 4.

Authors

Dimitar Todorov¹, Charles T Driscoll², Svetoslava Todorova², Mario Montesdeoca²

Affiliations

¹ Department of Construction Management, School of Business and Justice Studies, Utica College, 1600 Burrstone Rd, Utica, NY 13502, United States; Department of Civil and Environmental Engineering, College of Engineering and Computer Science, 151 Link Hall, Syracuse University, Syracuse, NY 13244, United States. Electronic address: ditodorov@utica.edu.
² Department of Civil and Environmental Engineering, College of Engineering and Computer Science, 151 Link Hall, Syracuse University, Syracuse, NY 13244, United States.

PMID: 29306833
DOI: 10.1016/j.scitotenv.2017.12.085

Abstract

In this paper we present the results of a four-year study of water quality in runoff from an extensive, sedum covered, vegetated roof on an urban commercial building. Monitoring commenced seven months after the roof was constructed, with the first growing season. Stormwater drainage quality function of the vegetated roof was compared to a conventional (impermeable, high-albedo) membrane roof in addition to paired measurements of wet and bulk depositions at the study site. We present concentrations and fluxes of nutrients and major solutes. We discuss seasonal and year-to-year variation in water quality of drainage from the vegetated roof and how it compares with atmospheric deposition and drainage from the impermeable roof. Drainage waters from the vegetated roof exhibited a high concentration of nutrients compared to atmospheric deposition, particularly during the warm temperature growing season. However, nutrient losses were generally low because of the strong retention of water by the vegetated roof. There was marked variation in the retention of nutrients by season due to variations in concentrations in drainage from the vegetated roof. The vegetated roof was a sink of nitrogen, total phosphorus and chloride, and a source of phosphate and dissolved inorganic and organic carbon. Chloride exhibited elevated inputs and leaching during the winter. The drainage from the vegetated and impermeable roofs met the United States Environmental Protection Agency freshwater standards for all parameters, except for total phosphorus.

Keywords: Green infrastructure; Green roof; Nutrients; Stormwater management; Water quality.