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Impact of extreme sea levels and waves in the bay of Lundåkra - present situation and future scenarios

Ottosson, Sandra LU and Vendt, Karin LU (2013) In TVVR13/5011 VVR820 20131
Division of Water Resources Engineering
Abstract (Swedish)
This report is a study of the impacts of extreme sea levels and waves on the coastal area of the bay of Lundåkra. The bay is characterized by shallow sea bottoms and a flat topography, particularly in the north. Analyses have been based on historical data. To expand the analyses to apply for a future scenario a change in mean sea level has been considered. Based on general recommendations from the Swedish Meteorological and Hydrological Institute (SMHI) and recent research from the Arctic Monitoring and Assessment Program (AMAP) two future scenarios have been chosen, a sea level rise of 1 m and 1.6 m respectively, for the year of 2100.

The bay of Lundåkra is a Natura 2000 area and also contains smaller areas of nature reserves. The bay... (More)
This report is a study of the impacts of extreme sea levels and waves on the coastal area of the bay of Lundåkra. The bay is characterized by shallow sea bottoms and a flat topography, particularly in the north. Analyses have been based on historical data. To expand the analyses to apply for a future scenario a change in mean sea level has been considered. Based on general recommendations from the Swedish Meteorological and Hydrological Institute (SMHI) and recent research from the Arctic Monitoring and Assessment Program (AMAP) two future scenarios have been chosen, a sea level rise of 1 m and 1.6 m respectively, for the year of 2100.

The bay of Lundåkra is a Natura 2000 area and also contains smaller areas of nature reserves. The bay area holds many conservation values. Some of the most important ones are found in an area of coastal meadows in the northernmost part close to the Saxån estuary. This site is important to many red listed birds. This area is particularly threatened since the highway E6 runs very close to the coast here. The bay area is also of great importance for fish and other animals.

Bathymetry and topography data collected by a laser scan method have been obtained from the municipality of Landskrona and Kävlinge and combined with the New National Height Model (NNH) from Lantmäteriet. Modeled wave data (1994-2011) have been extracted for the bay from the company Denmark’s Hydrological Institute, DHI. Sea levels (1992-2012) have been obtained from SMHI and combined with a longer series extracted from a previous study by Karlsson Green and Martinsson (2010).

Return periods have been estimated for sea levels and waves by fitting the data to Weibull and Gringorten distribution functions. For the extreme event of the November storm in 2011-11-27 the waves reached 2.2 m, which has the estimated return period of 32.5 years. The sea level reached at the same time 1.47m, with the estimated return period of 27.5 years.

Applying the Bruun rule to the future scenarios a risk has been estimated of a coastline retreat of several hundreds of meters along the entire bay area. The northernmost part with the important coastal meadows will likely be flooded already at a sea level rise of 0.75 m. An analysis for calculating the wave runup levels indicate that the highway may be exposed to wave runup at extreme events in the future scenario of a 1 m sea level rise. The wave runup analysis further shows some indications that some sections of the coastline will be more exposed to wave erosion than others. (Less)
Please use this url to cite or link to this publication:
author
Ottosson, Sandra LU and Vendt, Karin LU
supervisor
organization
course
VVR820 20131
year
type
H2 - Master's Degree (Two Years)
subject
keywords
bottom profiles, climate change, sea levels, flooding, erosion, wave runup, Bay of Lundåkra, Natura 2000
publication/series
TVVR13/5011
report number
13/5011
ISSN
1101-9824
language
English
additional info
Examiner: Magnus Larson
id
3994490
date added to LUP
2013-09-11 11:07:01
date last changed
2019-03-29 11:34:15
@misc{3994490,
  abstract     = {{This report is a study of the impacts of extreme sea levels and waves on the coastal area of the bay of Lundåkra. The bay is characterized by shallow sea bottoms and a flat topography, particularly in the north. Analyses have been based on historical data. To expand the analyses to apply for a future scenario a change in mean sea level has been considered. Based on general recommendations from the Swedish Meteorological and Hydrological Institute (SMHI) and recent research from the Arctic Monitoring and Assessment Program (AMAP) two future scenarios have been chosen, a sea level rise of 1 m and 1.6 m respectively, for the year of 2100.

The bay of Lundåkra is a Natura 2000 area and also contains smaller areas of nature reserves. The bay area holds many conservation values. Some of the most important ones are found in an area of coastal meadows in the northernmost part close to the Saxån estuary. This site is important to many red listed birds. This area is particularly threatened since the highway E6 runs very close to the coast here. The bay area is also of great importance for fish and other animals. 

Bathymetry and topography data collected by a laser scan method have been obtained from the municipality of Landskrona and Kävlinge and combined with the New National Height Model (NNH) from Lantmäteriet. Modeled wave data (1994-2011) have been extracted for the bay from the company Denmark’s Hydrological Institute, DHI. Sea levels (1992-2012) have been obtained from SMHI and combined with a longer series extracted from a previous study by Karlsson Green and Martinsson (2010). 

Return periods have been estimated for sea levels and waves by fitting the data to Weibull and Gringorten distribution functions. For the extreme event of the November storm in 2011-11-27 the waves reached 2.2 m, which has the estimated return period of 32.5 years. The sea level reached at the same time 1.47m, with the estimated return period of 27.5 years.

Applying the Bruun rule to the future scenarios a risk has been estimated of a coastline retreat of several hundreds of meters along the entire bay area. The northernmost part with the important coastal meadows will likely be flooded already at a sea level rise of 0.75 m. An analysis for calculating the wave runup levels indicate that the highway may be exposed to wave runup at extreme events in the future scenario of a 1 m sea level rise. The wave runup analysis further shows some indications that some sections of the coastline will be more exposed to wave erosion than others.}},
  author       = {{Ottosson, Sandra and Vendt, Karin}},
  issn         = {{1101-9824}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{TVVR13/5011}},
  title        = {{Impact of extreme sea levels and waves in the bay of Lundåkra - present situation and future scenarios}},
  year         = {{2013}},
}