Assessment of nutrient loading in lake Ringsjön from the catchment of Hörbyån Creek in Southern Sweden.
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Lake Ringsjön, located in south of Sweden, has been subject of eutrophication since 1950s and received several restoration efforts. Latest restoration effort, “Project Ringsjön”, was proposed in 2003 to improve lake condition against eutrophication by reducing nutrient concentration.
This study was done to assess the nutrient loading into the lake from the catchment of Hörbyån Creek, which is discharging into the lake from southeast. Study addresses the nutrient loading conditions from Hörbyån Creek before and after the implementation of “Project Ringsjön” in 1998 and 2010 respectively. Thus a water quality analysis was performed to observe the changes in total nitrogen and total phosphorus concentration in Hörbyån Creek between these years. Effort was also made to investigate nutrients contribution of different watersheds in the catchment.
This study also addresses the effect of seasonal variability and land use on nutrient loading. In order to achieve objectives, annual and monthly water quality modelling was performed on the river. HEC-RAS software was used to simulate water quality variables loading from catchment into the lake, such as nitrates, nitrite, ammonium, organic nitrogen, inorganic phosphorus and orthophosphate. Results indicated increase in average annual total nitrogen concentration from 4.18 mg/l to 4.56 mg/l and reduction in average annual total phosphorus concentration from 0.165 mg/l to 0.083 mg/l in the water discharging into the lake from catchment. The watershed occupying mostly agriculture area was observed to have maximum nutrients contribution, which might be due to high fertilizer leakage. It was also observed that maximum nutrient loading was taking place in November and March; probably due to high runoff generated from precipitation and snow melting that carried additional nutrients to the water bodies. Results also indicated that the studied catchment area was contributing high nutrient concentration for eutrophication in both years; however, there was small decrease in total phosphorus concentration in 2010 compare to 1998.
Place, publisher, year, edition, pages
, TRITA-LWR Degree Project, ISSN 1651-064X ; 2013:40
Eutrophication, Nutrient loading, HEC-RAS and Water Quality
IdentifiersURN: urn:nbn:se:kth:diva-171855OAI: oai:DiVA.org:kth-171855DiVA: diva2:844716
Degree of Master - Environmental Engineering and Sustainable Infrastructure
Wörman, Anders, professor