Modelling of Water Exchange in Flommen Lagoon System in Skanör-Falsterbo, Sweden
(2020) In TVVR 20/5003 VVRM01 20192Division of Water Resources Engineering
- Abstract
- The Flommen Lagoon system is located in Skanör-Falsterbo, Sweden. It hosts a diverse and sensitive ecosystem. There have been concerns about the water quality in this lagoon due to impaired water exchange.
The objectives of this thesis is to determine the current state of the water exchange in the lagoon and investigate possible measures to improve it. These possible measures revolve around the construction of a new inlet, and the potential closing of the inlet Slusan. Flow velocities, especially those in the inlet Slusan, will also be briefly elaborated upon in an effort to gain a better understanding of the sedimentation issues. At present, the sedimentation at the inlet is alleviated by regular dredging.
To accomplish these... (More) - The Flommen Lagoon system is located in Skanör-Falsterbo, Sweden. It hosts a diverse and sensitive ecosystem. There have been concerns about the water quality in this lagoon due to impaired water exchange.
The objectives of this thesis is to determine the current state of the water exchange in the lagoon and investigate possible measures to improve it. These possible measures revolve around the construction of a new inlet, and the potential closing of the inlet Slusan. Flow velocities, especially those in the inlet Slusan, will also be briefly elaborated upon in an effort to gain a better understanding of the sedimentation issues. At present, the sedimentation at the inlet is alleviated by regular dredging.
To accomplish these objectives, a hydrodynamic model of the Flommen Lagoon system was created. The modelling software IPH-ECO was used to create the model. This model was used to calculate the flushing time in the lagoon as a measure of the water exchange. Spatially distributed residence time was also calculated and used as a measure to investigate the water quality in different parts of the lagoon.
Simulation results indicate a flushing time of 33 days in the current state of the lagoon with Slusan open. Should a new inlet be built to compliment Slusan, then a flushing time of 22 days is expected. But this likely comes at a cost of increased sedimentation issues due to lower flow velocities at Slusan. If instead this new inlet is built and Slusan closed, then a flushing time beyond 60 days can be anticipated. This measure would reduce the costs associated with dredging, but cause a decline in the water quality in the lagoon. (Less) - Popular Abstract
- Coastal lagoons can be found in the transitional zone between sea and land, constituting water bodies that are connected to the sea by one or several inlets. These inlets allow for water exchange between the lagoon and the sea. The ecosystems found in lagoons are often unique and delicate, functioning as a habitat for many animal species. The health and vitality of these ecosystems very much depend on the water quality of the lagoon.
There have been concerns about the water quality in the Flommen Lagoon system due to insufficient water exchange between the lagoon and sea. The current sole existing inlet, Slusan, is crucial for the water quality in the lagoon. Should it be blocked by sediment, then water exchange between the sea and the... (More) - Coastal lagoons can be found in the transitional zone between sea and land, constituting water bodies that are connected to the sea by one or several inlets. These inlets allow for water exchange between the lagoon and the sea. The ecosystems found in lagoons are often unique and delicate, functioning as a habitat for many animal species. The health and vitality of these ecosystems very much depend on the water quality of the lagoon.
There have been concerns about the water quality in the Flommen Lagoon system due to insufficient water exchange between the lagoon and sea. The current sole existing inlet, Slusan, is crucial for the water quality in the lagoon. Should it be blocked by sediment, then water exchange between the sea and the lagoon will cease, adversely impacting the water quality.
The objectives of this thesis was to determine the current water exchange in the Flommen Lagoon system and to investigate different measures that could enhance water exchange with the sea and thus improve water quality in the lagoon.
Several conclusions regarding the water quality in the lagoon were accomplished by a mix of computer software and field measurements. These were used to create a working computer model of the lagoon and its behaviour. A combination of calculations and field measurements were then used to verify the reliability of the model.
One of the key findings is that the construction of a new inlet to supplement Slusan would aid in improving the water quality of the lagoon. However, this solution would come with one drawback. Increased maintenance costs can be expected to keep both inlets open. Another possible solution investigated would be to close Slusan and rely solely on the new inlet to provide water exchange for the lagoon. The results seem to indicate that this leads to a significant reduction of lagoon water quality over time.
Vast differences between water quality in different parts of the lagoon can be seen. Water quality seems to be correlated with proximity to the inlet. The part of the lagoon closest to the inlet enjoyed significantly better water quality than the parts deeper inside the lagoon. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9007316
- author
- Lay, Kenny LU and Ångbäck, Kristian
- supervisor
- organization
- course
- VVRM01 20192
- year
- 2020
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- water exchange, sedimentation, flommen lagoon system, iph-eco, modelling
- publication/series
- TVVR 20/5003
- report number
- 20/5003
- ISSN
- 1101-9824
- language
- English
- additional info
- Examiner: Hans Hanson
- id
- 9007316
- date added to LUP
- 2020-03-31 15:42:15
- date last changed
- 2020-04-02 09:14:40
@misc{9007316,
abstract = {{The Flommen Lagoon system is located in Skanör-Falsterbo, Sweden. It hosts a diverse and sensitive ecosystem. There have been concerns about the water quality in this lagoon due to impaired water exchange.
The objectives of this thesis is to determine the current state of the water exchange in the lagoon and investigate possible measures to improve it. These possible measures revolve around the construction of a new inlet, and the potential closing of the inlet Slusan. Flow velocities, especially those in the inlet Slusan, will also be briefly elaborated upon in an effort to gain a better understanding of the sedimentation issues. At present, the sedimentation at the inlet is alleviated by regular dredging.
To accomplish these objectives, a hydrodynamic model of the Flommen Lagoon system was created. The modelling software IPH-ECO was used to create the model. This model was used to calculate the flushing time in the lagoon as a measure of the water exchange. Spatially distributed residence time was also calculated and used as a measure to investigate the water quality in different parts of the lagoon.
Simulation results indicate a flushing time of 33 days in the current state of the lagoon with Slusan open. Should a new inlet be built to compliment Slusan, then a flushing time of 22 days is expected. But this likely comes at a cost of increased sedimentation issues due to lower flow velocities at Slusan. If instead this new inlet is built and Slusan closed, then a flushing time beyond 60 days can be anticipated. This measure would reduce the costs associated with dredging, but cause a decline in the water quality in the lagoon.}},
author = {{Lay, Kenny and Ångbäck, Kristian}},
issn = {{1101-9824}},
language = {{eng}},
note = {{Student Paper}},
series = {{TVVR 20/5003}},
title = {{Modelling of Water Exchange in Flommen Lagoon System in Skanör-Falsterbo, Sweden}},
year = {{2020}},
}