Modelling of water and material transport in River Storån to Lake Bolmen
(2021) In TVVR21/5006 VVRM01 20211Division of Water Resources Engineering
- Abstract
- The change of color of water from yellow to brown termed as brownification process is mainly due to leaching of humus and iron concentrations. In recent years, this problem is increasing in lake Bolmen, a major source of drinking water in Skåne county, Sweden. This process has been a threat to aquatic life and increasing the water treatment cost too. Storån river being the main tributary of the lake has a significant contribution to this browning process.
This study deals with the hydraulic model and water quality model in the river system, modelled in HEC-RAS software to visualize the variation of brownification in Storån, for which color concentration was taken as a parameter to measure. Daily varying discharge and watercolor... (More) - The change of color of water from yellow to brown termed as brownification process is mainly due to leaching of humus and iron concentrations. In recent years, this problem is increasing in lake Bolmen, a major source of drinking water in Skåne county, Sweden. This process has been a threat to aquatic life and increasing the water treatment cost too. Storån river being the main tributary of the lake has a significant contribution to this browning process.
This study deals with the hydraulic model and water quality model in the river system, modelled in HEC-RAS software to visualize the variation of brownification in Storån, for which color concentration was taken as a parameter to measure. Daily varying discharge and watercolor concentration were taken as input for the HEC-RAS model for the simulation. The 67 km reach of Storån river starting from downstream of Flatten Lake to Bolmen lake was modelled and multiple sources of color concentration from major tributaries were simulated with time-varying discharge data series.
For model setup, a Digital Elevation Model was created from bathymetric data from 18 measured cross-section and LiDAR data were taken and then merged and developed in Arc GIS and RAS mapper tools. For hydraulic analysis, daily discharge data from 2004-2019 were taken from SMHI. In the water quality model, color data from 2012-2016 were taken from SLU and analyzed. The actual transport of materials was mimicked by tracer analysis with multiple sources. The transport mechanism was solved through Advection Diffusion Equation. The hydraulic model was calibrated through velocity and elevation comparison of computed and observed values during the field survey. On the other hand, the water quality model was calibrated by steady analysis with some color data taken from SLU.
Result shows that there is an increasing trend of the brownification in river Storån. From year 1985 to 2019, the color concentration has been increased by more than 1.5 times (from 159 mg Pt./l in 1985 to 265 mg Pt./l in 2019). The reason behind this could be the change in the land use pattern, climate change and seasonal variation in the catchment. From the model simulation, it was found that the watercolor concentration in the river is higher in a wet climate, like in autumn and winter, rather than in the drier season like in spring and summer. The possible reason for this is that high runoff draws more materials from catchments for the brownification process. Among all tributaries, it was found that catchment for the Lillån- Havridaån (R7) has significant effect in the color variation. The study would have been better if there were more measurement stations as well as a high frequency of measurements in all tributaries.
Keywords: Brownification, Water Color, Dissolved Organic Matter, Discharge, hydraulic analysis, Tracer Analysis, Dispersion coefficient, Advection and Diffusion, Bolmen Lake, Storån River (Less) - Popular Abstract
- Surface water exhibits large variation while transporting chemicals and other materials to downstream. The concentration of such material varies as per time as per the water discharge in the river and its tributaries. In lake Bolmen, some organic compounds and metal ions are causing the change in color of water to yellow or brown known, as brownification. For this, river Storån being the main tributary for the lake plays a significant role in the transport of these materials. The color concentration of water in river Storån has been increased about double in recent 35 years, and it has been a bad effect on the living organisms underwater, tourism and for drinking water purposes from the lake.
This study focuses on the transport of... (More) - Surface water exhibits large variation while transporting chemicals and other materials to downstream. The concentration of such material varies as per time as per the water discharge in the river and its tributaries. In lake Bolmen, some organic compounds and metal ions are causing the change in color of water to yellow or brown known, as brownification. For this, river Storån being the main tributary for the lake plays a significant role in the transport of these materials. The color concentration of water in river Storån has been increased about double in recent 35 years, and it has been a bad effect on the living organisms underwater, tourism and for drinking water purposes from the lake.
This study focuses on the transport of materials causing the brownification in the term of color concentration. Such watercolor variation due to the mixing of water in the river and tributaries has been analysed using mathematical modelling software. Storån river with seven major tributaries was set to study about the mixing mechanism and transport of materials from the south of lake Flatten to lake Bolmen. From the study, it was found that there is an increasing trend in the change in water color. Further, the change in water is seemed to be more in winter where there is high water flow in comparison to the low discharge in the river in spring and summer. The increase in the brownification might be due to the land use change, seasonal variation, and climate change. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9054536
- author
- Sukupayo, Imjal LU
- supervisor
- organization
- alternative title
- Hydraulic and water quality analysis in Storån river.
- course
- VVRM01 20211
- year
- 2021
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Brownification, Water Color, Dissolved Organic Matter, Discharge, hydraulic analysis, Tracer Analysis, Dispersion coefficient, Advection and Diffusion, Bolmen Lake, Storån River
- publication/series
- TVVR21/5006
- report number
- 21/5006
- ISSN
- 1101-9824
- language
- English
- additional info
- Examiner: Rolf Larsson
- id
- 9054536
- alternative location
- https://drive.google.com/file/d/11yXpUomkBiJFFJ_Rd2uWXzrC_6qWg5un/view
- date added to LUP
- 2021-06-15 11:00:00
- date last changed
- 2021-06-17 15:11:05
@misc{9054536,
abstract = {{The change of color of water from yellow to brown termed as brownification process is mainly due to leaching of humus and iron concentrations. In recent years, this problem is increasing in lake Bolmen, a major source of drinking water in Skåne county, Sweden. This process has been a threat to aquatic life and increasing the water treatment cost too. Storån river being the main tributary of the lake has a significant contribution to this browning process.
This study deals with the hydraulic model and water quality model in the river system, modelled in HEC-RAS software to visualize the variation of brownification in Storån, for which color concentration was taken as a parameter to measure. Daily varying discharge and watercolor concentration were taken as input for the HEC-RAS model for the simulation. The 67 km reach of Storån river starting from downstream of Flatten Lake to Bolmen lake was modelled and multiple sources of color concentration from major tributaries were simulated with time-varying discharge data series.
For model setup, a Digital Elevation Model was created from bathymetric data from 18 measured cross-section and LiDAR data were taken and then merged and developed in Arc GIS and RAS mapper tools. For hydraulic analysis, daily discharge data from 2004-2019 were taken from SMHI. In the water quality model, color data from 2012-2016 were taken from SLU and analyzed. The actual transport of materials was mimicked by tracer analysis with multiple sources. The transport mechanism was solved through Advection Diffusion Equation. The hydraulic model was calibrated through velocity and elevation comparison of computed and observed values during the field survey. On the other hand, the water quality model was calibrated by steady analysis with some color data taken from SLU.
Result shows that there is an increasing trend of the brownification in river Storån. From year 1985 to 2019, the color concentration has been increased by more than 1.5 times (from 159 mg Pt./l in 1985 to 265 mg Pt./l in 2019). The reason behind this could be the change in the land use pattern, climate change and seasonal variation in the catchment. From the model simulation, it was found that the watercolor concentration in the river is higher in a wet climate, like in autumn and winter, rather than in the drier season like in spring and summer. The possible reason for this is that high runoff draws more materials from catchments for the brownification process. Among all tributaries, it was found that catchment for the Lillån- Havridaån (R7) has significant effect in the color variation. The study would have been better if there were more measurement stations as well as a high frequency of measurements in all tributaries.
Keywords: Brownification, Water Color, Dissolved Organic Matter, Discharge, hydraulic analysis, Tracer Analysis, Dispersion coefficient, Advection and Diffusion, Bolmen Lake, Storån River}},
author = {{Sukupayo, Imjal}},
issn = {{1101-9824}},
language = {{eng}},
note = {{Student Paper}},
series = {{TVVR21/5006}},
title = {{Modelling of water and material transport in River Storån to Lake Bolmen}},
year = {{2021}},
}