University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Master / Diploma Thesis:
Sabrina Nadine Kapus
(2018):
The influence of substrate and vegetation on stormwater retention of extensive green roof systems.
Master / Diploma Thesis - Institut für Meteorologie (BOKU-Met),
BOKU-Universität für Bodenkultur,
pp 76.
UB BOKU
obvsg
- Abstract:
- Green roofs contribute to several ecosystem services important for mankind. One of them is the ability to retain stormwater, and thereby reducing pressure on urban sewage systems. The present study will focus on the effect a layer of vegetation has on the water retention capability of an extensive green roof. In order to further the understanding of the impact living plants have on retention performance, three stacking containers were modified to serve as a miniature green roof. Three cutouts with a substrate depth of 7,5 cm were taken from a seven year old green roof located in Vienna and placed into two of the containers. From one of these cutouts all plants were removed, leaving only the substrate. The third container was filled with gravel obtained from the same green roof. Data was collected using a rain gauge sensor for discharge and a volumetric water content (VWC) sensor for both soil temperature and VWC. For the mass balance approach, the gravel module's discharge was used as the point of reference for the amount of water entering the vegetation and substrate-only modules. Rainfall data from the close-by weather station wasn't used because its sensors were not exposed to exactly same conditions as the modules. The data was gathered between July 13th and October 31st. The collected data of the entire study period displays a mean percent retention (%R) of the vegetation and substrate-only module of 79,8 % and 82,7 % and a cumulative %R of 58,7 % and 64,2 % respectively. Results prove that VWC has a medium negative effect on %R, meaning the greater the VWC, the greater the discharge. Furthermore, if the difference in VWC was greater than 4 vol%, the module with the lower VWC level was able to retain more rainfall. During the dry weather period (DWP) after a rainfall, the vegetation module dried out more slowly in the first few days compared to the substrate-only module. But over the entire course of the DWP both modules showed a similar decrease in VWC.
- Beurteilende(r): Mursch-Radlgruber Erich
- 1.Mitwirkender: Lapin Katharina