Exjobbsförslag våren 2021: Assessment of groundwater distribution to Swedens twelfth largest lake

Background

Lake Bolmen, located in southern Sweden is the twelfth largest lake of the country and holds a high ecological, recreational and resource value for the region and for the county of Skåne. Drinking water for almost 600.000 inhabitants in western Skåne originates from the lake. During the recent decades the lake water has increased in brown color, mainly related to and increase in dissolved organic matter, presumably leaching form the top soil layer in the catchment (Graneli, 2012).

The increased color has significant effects on the water quality and the ecological value leading to higher fish mortality and increased efforts for drinking water production. Main drivers and origin of the colored water are not yet fully researched and more knowledge is needed to allow the application of mitigating measures to secure the value of the lake. Origin and movement patterns of brown colored water inside the lake will be analyzed using a hydrodynamic model (box type or finite element type). Accuracy of such a model strongly depends on the input parameters and with increasing detailedness of them also the detailedness of the model will increase.

Besides the main tributaries to a lake another important distributor to the water of a lake is usually groundwater. In the case of Bolmen little is known about the groundwater distribution and more information is needed to allow the set up of a representative model of the lake.

Research Questions

1. What are the main geological features inside the Bolmen catchment and how is the groundwater catchment of the lake related to the hydrological catchment.
2. How large is the contribution of groundwater to Lake Bolmen or vice versa?

Procedure

A wide range of data is available regarding the geology (geological maps and model of the Swedish geological survey) of the lake Bolmen catchment, which will be used to analyze the main geological features. Groundwater measurements, conducted during the project, coupled with groundwater modeling will be used to assess the contribution of groundwater to Lake Bolmen. Exact scope and direction of the project can be adjusted to the students interests and based on the fact if the work is conducted by a group of two or a single student.

Contact

• Engineering Geology: Gerhard Barmen (gerhard.barmen@tg.lth.se)
• Water Resources Engineering: Clemens Klante (Clemens.Klante@tvrl.lth.se)

References

Graneli, W. (2012). Brownification of Lakes. In L. Bengtsson, R. W. Herschy, & R. W. Fairbridge (Eds.), Encyclopedia of Lakes and Reservoirs (pp. 117–119). Springer Netherlands. https://doi.org/10.1007/978-1-40204410-6_256