Erosion Stability of Dgr Potential Sites
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00 Final report 25/2015/ENG EROSION STABILITY OF DGR POTENTIAL SITES Authors: Tomáš Hroch, Tomáš Pačes et al. Czech Geological Survey Prague, November 2015 |1| EROSION STABILITY OF DGR POTENTIAL SITES Team of authors: Tomáš Hroch Tomáš Pačes Jan Hošek Daniel Nývlt Jiří Šebesta Petra Hejtmánková Report number: Erosion Stability of DGR Potential Sites SÚRAO TZ 25/2015/ENG Content 1 Introduction .................................................................................................................... 8 2 Expert Report of T. Hroch ..............................................................................................10 2.1 Introduction ............................................................................................................10 2.2 Erosion and denudation processes and their control factors ...................................10 2.3 Determination of rates of erosion and denudation ..................................................13 2.4 The rate of erosion in the Bohemian Massif ...........................................................13 2.5 Geomorphological analysis ....................................................................................14 2.6 Geomorphological characteristics of potential DGR sites .......................................17 2.6.1 Březový potok .................................................................................................17 2.7 Čertovka .................................................................................................................17 2.7.1 Čihadlo ............................................................................................................22 2.7.2 Horka ..............................................................................................................22 2.7.3 Hrádek ............................................................................................................26 2.7.4 Magdalena ......................................................................................................26 2.7.5 Kraví hora .......................................................................................................29 2.8 Prognosis of morphological development of individual potential DGR sites ............29 2.8.1 Březový potok .................................................................................................29 2.8.2 Čertovka ..........................................................................................................29 2.8.3 Čihadlo ............................................................................................................30 2.8.4 Horka ..............................................................................................................30 2.8.5 Magdalena ......................................................................................................31 2.8.6 Kraví Hora .......................................................................................................31 2.9 Summary ................................................................................................................31 3 Expert Report of T. Pačes .............................................................................................34 3.1 Introduction ............................................................................................................34 3.2 Denudation rates in different geomorphological and climatic conditions .................36 3.3 The rate of erosion in the Bohemian Massif ...........................................................43 3.4 Effect of glaciation on the rate of erosion in the Bohemian Massif ..........................49 3.5 Influence of terrain slopes on erosion in the surveyed localities .............................50 3.6 Conclusions............................................................................................................53 4 References ....................................................................................................................55 4 Report number: Erosion Stability of DGR Potential Sites SÚRAO TZ 25/2015/ENG List of illustrations: Fig. 1 The ideal profile of a balanced watercourse gradient curve. (http://thebritishgeographer.weebly.com). .............................................................................11 Fig. 2 Gradient curve change and distribution of prevailing fluvial processes in the river system due to the vertical movements of the Earth's crust (Leeder 1999) ............................12 Obr. 3 Reaction of the river system to erosion base fall (http://www.gly.uga.edu). ................12 Fig. 4 Geomorphological scheme of the Březový potok area ................................................19 Fig. 5 Geomorphological scheme of the Čertovka area ........................................................20 Fig. 6 Geomorphological scheme of the Čihadlo area ..........................................................21 Fig. 7 Geomorphological scheme of the Horka area .............................................................24 Fig. 8 Geomorphological scheme of the Hradek area ...........................................................25 Fig. 9 Geomorphological scheme of the Magdalena area .....................................................27 Fig. 10 Geomorphological scheme of the Kraví Hora area ...................................................28 Tab. 4 Denudation rate in New Mexico calculated from data of Waren and Cook (1973) ......37 Fig. 11 Distribution of denudation values; the red column shows the geometric mean, the green column shows the median, and the yellow column shows the arithmetic mean. .........39 Fig. 12 Rate of erosion in the catchment area of the world's rivers and smaller watercourses (Burbank, 2002) ....................................................................................................................40 Fig. 13 Rate of erosion derived from accumulation of the cosmogenic isotope 10Be in various types of landscape and depending on terrain slope (Portenga and Bierman 2011). .............41 Fig. 14 Rate of erosion derived from accumulation of the cosmogenic isotope 10Be depending on rock type, climate zone, and tectonic activity (according to Portenga and Bierman 2011) ......................................................................................................................42 Fig. 15 Rate of erosion in glaciated areas, and rates of erosion caused by fluvial systems ..42 (Burbank, 2002). ...................................................................................................................42 Fig. 17 Small catchment area (usually 0.5 - 3 km2) used to measure the mass balance of the chemical element“i"; Measured inputs: P – Precipitation, A - Anthropogenic inputs (fertilising, liming, and other artificial inputs) Source: W - Wethering (release of the element by weathering of rocks); outputs: B - Biological fixation of the element in harvested organic matter (tree felling, harvesting crops), R - Runoff of the element in the solution, M - Mechanical erosion (removal of the element in suspended solids). ......................................45 Tab. 8 Rates of erosion and denudation in small catchment areas of the Bohemian-Moravian Highlands and the Ore Mountains (Pačes, 1985) .................................................................48 List of tables: Tab. 1 Legend with the main allocated geomorphological forms at DGR sites: .....................15 Tab. 2 Average erosion rates according to various authors. Literary sources in Kukal (1983). ……………………………………………………………………………………………………36 Tab. 3 Denudation extent in the UK, calculated from data from Kirkby (1967) ......................37 Tab. 5 Erosion rates calculated from data on accumulation and decay of cosmogenic isotopes 10Be and 26Al and by the use of complementary methods .......................................38 5 Report number: Erosion Stability of DGR Potential Sites SÚRAO TZ 25/2015/ENG Tab. 7 The average advance of denudation in the Elbe related to the profile in Litoměřice assuming the density of the weathered rock of 2,650 kg.m-1 (Pačes, 1985) ........................47 Tab. 9 The rate of weathering, erosion, and denudation in two small catchments in the Ore Mountains and in the Behemian-Moravian Highland in the periods from 1978 to 1995 and from 1990 to 1995 (Melega, 1998)........................................................................................48 Tab. 10 Estimated thickness of permafrost in the Upper Vistula Pleniglacial in the Czech Republic according to Balojev, Čápicina, and Czudek (Czudek, 2005) .................................49 Tab. 11 Gradient distribution in the surveyed sites ...............................................................51 List of abbreviations: A.S.L. Above See Level BP Before Present ČHMI Czech Hydrometeorological Institute DEM Digital Elevation Model DGR Deep Geological Repository EUVN European Vertical GPS Reference Network RAWRA Radioactive Waste Repository Authority 6 Report number: Erosion Stability of DGR Potential Sites SÚRAO TZ 25/2015/ENG Abstract Evaluation of erosion stability for areas selected for sites of deep geological repository for the next 100 thousand years is based on literature review and interpretation of available published data, as well as unpublished data by two independent experts leading to evaluation of erosion stability. The evaluation focused on the definition of the main factors controlling erosional processes, the evaluation of geomorphological setting of selected areas based