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Surface system Forsmark. Site descriptive modelling SDM-Site Forsmark

Abstract

SKB has undertaken site characterization of two different areas, Forsmark and Laxemar-Simpevarp, in order to find a suitable location for a geological repository for spent nuclear fuel. This report focuses on the site descriptive modelling of the surface system at Forsmark. The characterization of the surface system at the site was primarily made by identifying and describing important properties in different parts of the surface system, properties concerning e.g. hydrology and climate, Quaternary deposits and soils, hydrochemistry, vegetation, ecosystem functions, but also current and historical land use. The report presents available input data, methodology for data evaluation and modelling, and resulting models for each of the different disciplines. Results from the modelling of the surface system are also integrated with results from modelling of the deep bedrock system. The Forsmark site is located within the municipality of Oesthammar, about 120 km north of Stockholm. The investigated area is located along the shoreline of Oeregrundsgrepen, a funnel-shaped bay of the Baltic Sea. The area is characterized by small-scale topographic variations and is almost entirely located at altitudes lower than 20 metres above sea level. The Quaternary deposits in the area are dominated by till, characterized by a rich content of calcite  More>>
Authors:
Lindborg, Tobias [1] 
  1. ed.
Publication Date:
Dec 15, 2008
Product Type:
Technical Report
Report Number:
SKB-R-08-11
Resource Relation:
Other Information: 180 refs., 108 figs., 32 tabs.
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; RADIOACTIVE WASTE DISPOSAL; UNDERGROUND DISPOSAL; SITE CHARACTERIZATION; CLIMATES; HYDROLOGY; SOILS; ECOSYSTEMS; PLANTS; SURFACE WATERS; SAFETY ANALYSIS; RADIONUCLIDE MIGRATION
OSTI ID:
951469
Research Organizations:
Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
Other: ISSN 1402-3091; TRN: SE0908136
Availability:
Also available from: http://www.skb.se/upload/publications/pdf/R-08-11webb.pdf; OSTI as DE00951469
Submitting Site:
SWDN
Size:
203 pages
Announcement Date:
Apr 24, 2009

Citation Formats

Lindborg, Tobias. Surface system Forsmark. Site descriptive modelling SDM-Site Forsmark. Sweden: N. p., 2008. Web.
Lindborg, Tobias. Surface system Forsmark. Site descriptive modelling SDM-Site Forsmark. Sweden.
Lindborg, Tobias. 2008. "Surface system Forsmark. Site descriptive modelling SDM-Site Forsmark." Sweden.
@misc{etde_951469,
title = {Surface system Forsmark. Site descriptive modelling SDM-Site Forsmark}
author = {Lindborg, Tobias}
abstractNote = {SKB has undertaken site characterization of two different areas, Forsmark and Laxemar-Simpevarp, in order to find a suitable location for a geological repository for spent nuclear fuel. This report focuses on the site descriptive modelling of the surface system at Forsmark. The characterization of the surface system at the site was primarily made by identifying and describing important properties in different parts of the surface system, properties concerning e.g. hydrology and climate, Quaternary deposits and soils, hydrochemistry, vegetation, ecosystem functions, but also current and historical land use. The report presents available input data, methodology for data evaluation and modelling, and resulting models for each of the different disciplines. Results from the modelling of the surface system are also integrated with results from modelling of the deep bedrock system. The Forsmark site is located within the municipality of Oesthammar, about 120 km north of Stockholm. The investigated area is located along the shoreline of Oeregrundsgrepen, a funnel-shaped bay of the Baltic Sea. The area is characterized by small-scale topographic variations and is almost entirely located at altitudes lower than 20 metres above sea level. The Quaternary deposits in the area are dominated by till, characterized by a rich content of calcite which was transported by the glacier ice to the area from the sedimentary bedrock of Gaevlebukten about 100 km north of Forsmark. As a result, the surface waters and shallow groundwater at Forsmark are characterized by high pH values and high concentrations of certain major constituents, especially calcium and bicarbonate. The annual precipitation and runoff are 560 and 150 mm, respectively. The lakes are small and shallow, with mean and maximum depths ranging from approximately 0.1 to 1 m and 0.4 to 2 m. Sea water flows into the most low-lying lakes during events giving rise to very high sea levels. Wetlands are frequent and cover 25 to 35% of some of the delineated sub-catchments. No major water courses flow through the central part of the site investigation area. Many brooks in the area have been deepened for considerable distances for drainage purposes. The horizontal hydraulic conductivity and specific yield of the till, the values of which are based on measurements, are typical or slightly higher than in the surrounding region. Groundwater levels in Quaternary deposits are very shallow, on average less than 0.7 m below ground during 50% of the time. Post-glacial land uplift, in combination with the flat topography, implies fast shoreline displacement. This has resulted in a young terrestrial system that contains a number of newborn lakes and wetlands. The recently isolated and shallow oligotrophic hardwater lakes that are typical for the area are unique in Sweden.The marine ecosystem at Forsmark is situated in a relatively productive coastal area in a region of otherwise fairly low primary production. The seabed is dominated by erosion and transport bottoms with heterogeneous and mobile sediments, consisting mainly of sand and gravel with varying fractions of glacial clay. Based on an overall conceptual model, it was possible to identify pools and fluxes of elements in the landscape that are of potential relevance for a safety assessment. The quantification of these elements, using both field- and model-based estimates, makes it possible to determine the relative importance of the different ecosystems with regard to elemental transport and accumulation. A special emphasis has been put on the description of transport and accumulation of organic matter, since detailed knowledge on the carbon dynamics provides a way of analysing how different ecosystem components are linked to each other through fluxes of energy, i.e. carbon. This provides a baseline for making predictions of dispersal and accumulation of matter, including radionuclides, within and between ecosystems. By this approach, the safety assessment is provided with a tool to predict how and where radionuclides are transported and accumulated in the landscape, making it possible to calculate potential doses to humans and other biota for the specific site. In the terrestrial landscape at Forsmark, many of the vegetation types are sinks for organic matter. The largest sink is the vegetation itself, but also the soil accumulates organic material, although in smaller quantities. The exception is the wetlands that are of significant importance for accumulation of organic matter and other elements, such as phosphorus, in the soil organic pool. In particular, the reed-dominated wetlands surrounding many of the lakes accumulate large amounts of organic matter and associated elements. The most important inflow of elements to lakes is via water from the terrestrial areas.}
place = {Sweden}
year = {2008}
month = {Dec}
}