Hydrograph separation in the subarctic catchment of Kaalasjärivi in northern Sweden using alkalinity as a tracer

• Main Author: Öhlander, Emelie
• Format: Bachelor Thesis
• Language: English
• Published: Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK) 2013
• Subjects: h ydrograph separation; alkalinity; subsurface flows; Kaalasjärvi; Sweden; Abisko; Northern Sweden; Subarctic
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-92987

In northern latitudes, research about subsurface hydrology is expanding. Knowledge about the origin of water and distribution of subsurface flow paths is of wide interest for scientists in order to detect any changes of the hydrology due to, for example, climate change. In order to detect changes, knowledge about the amount of water that actually flows in the subsurface under recent times must improve. This study uses alkalinity as a geochemical tracer to separate the total stream flow from Kaalasjärvi catchment into water that originates from deep groundwater flow versus shallow flow through the sub-surface. The aim was to find out the portioning of flow through the domains and to see if there were any similarities with the nearby catchment in Abisko. Two periods were investigated, one long-term period 1995–2012 and the shorter period 2007–2012 that had a complete winter record of alkalinity. For the period 1995–2012 the deep ground-water flow contribution to the stream ranged between 61%–69%, depending on the ap-proach stating the deep flow concentration. For the period 2007-2012, on the other hand, the deep flow was higher with a range between 67%–73%. All of these separa-tions were higher than the result from Abisko and therefore the conclusion is that these catchments differ in their subsurface flow distribution.