The importance of sustainable stormwater management in urban areas - A case study on current and future development in Lerum, Sweden
Typ
Examensarbete för masterexamen
Program
Infrastructure and environmental engineering (MPIEE), MSc
Publicerad
2021
Författare
Norlén, Karl
Oscarsson, Linda
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The risks of pluvial flooding in urban areas are expected to increase due to climate
change leading to heavier rainfall events in the future. In addition, urbanisation
contributes to impermeable surfaces which further increases the risk of flooding.
Sustainable stormwater management that mimics nature based solutions is considered a favourable way to treat urban flooding. The use of sustainable stormwater
management also enables incorporation of ecological and social services whilst reducing the impacts of urban flooding. Infiltration and surface roughness are two key
parameters in assessing how efficient these sustainable stormwater solutions are. Infiltration has been established to have a large impact on flooding, while more recent
studies have shown that surface roughness impacts runoff to a large extent. This
project aims to further investigate the impact of infiltration and surface roughness on
sustainable stormwater management. To achieve the aim, a case study is performed
in the municipality of Lerum, Sweden. The softwares SCALGO Live and MIKE 21
are used to identify current and future infrastructure at risk for flooding in Lerum.
Stormwater solutions to manage floods in the area are then implemented in suitable
locations into the software SCALGO Live. The model is then imported into MIKE
21 where the solutions’ properties are altered to correspond to permeable or impermeable surfaces to study the effect of infiltration and surface roughness. Thereafter
simulations are performed to obtain results on flow speeds and water depths to assess risk levels stemming from the flooding, as well as investigating the impact of
the alterations in infiltration and surface roughness. The results are compared and
show that stormwater solutions with high surface roughness lowers flow speed and
solutions with high infiltration capacity lowers water depths. Both parameters con tribute to lower risk levels, which leads to the conclusion that both parameters are
important to manage the runoff by affecting separate aspects of a flooding event.
Beskrivning
Ämne/nyckelord
flood risk levels , infiltration , multifunctionality , pluvial flooding , surface roughness , sustainable stormwater management