| Title: | The impact of damming on riverine fluxes to the ocean: A case study from Eastern Iceland |
| Author(s): | Eiriksdottir ES; Oelkers EH; Hardardottir J; Gislason SR; |
| Address: | "Institute of Earth Sciences, Sturlugata 7, 101 Reykjavik, Iceland; Marine and Freshwater Research Institute, Skulagata 4, 101 Reykjavik, Iceland. Electronic address: eydis.salome.eiriksdottir@hafogvatn.is. Institute of Earth Sciences, Sturlugata 7, 101 Reykjavik, Iceland; GET, CNRS/URM 5563-Universite Paul Sabatier, 14 rue Edouard Belin, 31400, Toulouse, France; Earth Science, University College London, Gower Street, WC1E 6BT, United Kingdom. Icelandic Meteorological Office, Bustadavegur 7-9, 108 Reykjavik, Iceland. Institute of Earth Sciences, Sturlugata 7, 101 Reykjavik, Iceland" |
| DOI: | 10.1016/j.watres.2016.12.029 |
| ISSN/ISBN: | 1879-2448 (Electronic) 0043-1354 (Linking) |
| Abstract: | "Anthropogenic water management has extensively altered the world's river systems through impoundments and channel diversions to meet the human's need for water, energy and transportation. To illuminate the effect of such activities on the environment, this study describes the impact of the installation of the Karahnjukar Dam in Eastern Iceland on the transport of riverine dissolved- and particulate material to the ocean by the Jokulsa a Dal and the Lagarfljot rivers. This dam, completed in 2007, collects water into the 2.2 km(3) Halslon reservoir and diverts water from the glacial Jokulsa a Dal river into the partially glaciated Lagarfljot lagoon via a headrace tunnel. The impact of the damming was evaluated by sampling water from both the Jokulsa a Dal and the Lagarfljot rivers over a 15 year period spanning from 1998 to 2013. The annual flux of most dissolved elements increased substantially due to the damming. The fluxes of dissolved Zn, Al, Co, Ti and Fe increased most by damming; these fluxes increased by 46-391%. These differences can be attributed to changed saturation states of common secondary minerals in the Jokulsa a Dal due to reduced discharge, increased residence time and dissolution of suspended material, and, to a lesser degree, reduced photosynthesis due to less transparency in the Lagarfljot lagoon. The removal of particulate material and thus decreasing adsorption potential in the Jokulsa a Dal is the likely reason for the Fe flux increase. In contrast, approximately 85% of the original riverine transported mass of particulate material is trapped by the dam; that which passes tends to be relatively fine grained, increasing the average specific surface area of that which continues to flow towards the ocean. Consequently, the particulate geometric surface area flux is decreased by only 50% due to the damming. The blooming of silica diatoms during the spring consumes dissolved silica from the coastal waters until it becomes depleted; making the riverine spring dissolved silica flux an important source of this nutrient. Despite extensive riverine flux changes due to the Karahnjukar dam construction, the total spring dissolved silica flux increased, and thus so too the potential for a silica diatom spring bloom in the coastal waters. This is likely because the spring flux is dominated by snow melting downstream of the dam" |
| Keywords: | "*Environmental Monitoring Humans Iceland Oceans and Seas *Rivers Seasons Water Pollutants, Chemical Anthropogenic effects Basaltic river catchments Dissolved element fluxes Glacial river damming Halslon reservoir Karahnjukavirkjun Suspended material fluxe;" |
| Notes: | "MedlineEiriksdottir, Eydis Salome Oelkers, Eric H Hardardottir, Jorunn Gislason, Sigurdur Reynir eng Research Support, Non-U.S. Gov't England 2017/02/17 Water Res. 2017 Apr 15; 113:124-138. doi: 10.1016/j.watres.2016.12.029. Epub 2016 Dec 19" |
