GDR December Lolland and Fehmarn, land connection areas Ground Water Conditions

Transcription

1 GDR December 2011 Lolland and Fehmarn, land connection areas Ground Water Conditions

2 Lolland and Fehmarn, land connection areas. Ground water conditions December 2011 GDR Femern A/S Vester Søgade København V Tel.: Fax.: CVR no Prepared by Rambøll Danmark/Arup JV co Rambøll Hannemanns alle 53 DK-2300 København S Danmark Phone Rambøll Arup JV Danish reg. no: CVR-NR Member of FRI Prepared Checked Approved JRF LMM KCH JAN JPE LMM KCH JRF

3 Table of contents Table of contents Introduction General Background material Description of the series of layers Geology of the fixed link area The area on southern Lolland Maps CPTs and Production Site borings Borings from the 2009 and 2010 on- and offshore campaign Borings from the 1995/96 investigation for the fixed link Borings from the DSBs (now Banedanmarks) geotechnical archive and from Geotechnical Inst. (now GEOs) archive Investigations for and observations in bentonite pit The Rødby 1 and Rødby 2 oil prospection borings The municipality s geological model of Lolland Summary of soil conditions at southern Lolland The Fehmarn area Maps Observations in the Heiligenhafen coastal cliff and in borings for the Fehmarnsund Bridge Borings from the 2009 and 2010 boring campaigns for the fixed link Borings from the 1995/96 investigation for the fixed link Borings for the harbour constructions and for the road and railway connection from before Borings from 2008-investigation for a road across Fehmarn Summary of expected soil conditions at Fehmarn Groundwater conditions The area on southern Lolland Introduction Groundwater reservoirs Abstraction The Fehmarn area General Ground water reservoirs Abstraction References

4 1 Introduction 1.1 General Femern A/S has commissioned Rambøll Arup JV under contract signed 28 th of April 2008 to undertake geotechnical services for the Fehmarnbelt Fixed Link project. The commission is a framework agreement which extends over 4 years to 2012 with a possible 2 year extension to The proposed project is an approximately 19 km coast to coast link between Rødby in Denmark and Puttgarden in Germany. The proposed crossing will be a four-lane motorway and twin-track railway. It is not yet determined whether it will be a bridge, with approach viaducts and a cable stayed or suspension bridge over the shipping channels, or an immersed tunnel. The purpose for the actual report is to present a brief description of the geology and based on the description a detailed description and evaluation of the ground water conditions in the parts of Lolland and Fehmarn where the land connections from the fixed link are supposed to be located and for a possible Production Site on Lolland. The evaluation has been based on existing information and general knowledge on the two areas in combination with the results of the and geophysical/ geological/geotechnical/geohydrological investigations. The evaluations have a general character and are not related to any specific bridge- or tunnel construction. 4

5 2 Background material The descriptions and evaluations in chapter 3 and 4 have been based on: General knowledge on the geology of Fehmarn and southern Lolland, including observations of the series of layers in the Heiligenhafen Coastal Cliff on the land side of Fehmarnsund west of the bridge. Furthermore, information on the boring profiles for the Fehmarnsund Bridge from 1959/60 and Older geotechnical reports on the soil and ground water conditions in the Puttgarden and Rødbyhavn supplemented by later photos of the excavated piers in Rødby (dry inside temporary embankments) when these were constructed in the early 1960-ties. Geological maps and topographic maps of Fehmarn and Lolland: Topographic map of Fehmarn (1951) Hydrogeological map of Fehmarn Geologic map of Fehmarn showing the petrography of the uppermost soils layer Map of Fehmarn combining morphological landscape type and upper soil layer Map showing depth to basis of Pleistocene in Schleswig-Holstein Topographic maps of Lolland (dated 1964 and 1989) Map of kind of deposits in upper metre on Lolland ("karteringskort") Geologic Basisdata-map of Lolland Maps from geologic reports from the municipality Geological model of Lolland Results of seismic investigations performed both offshore and onshore in the 2008 and the 2010 surveys Results of 4 deep borings (09.A ) performed on land in the land connection area on Lolland side Results of 7 deep borings (09.A ) performed on land in the land connection area on Fehmarn side and further 2 borings (10.A.607 and 10.A.610) performed on land on Fehmarn in 2010 Results of offshore borings performed rather close to the coast on both sides of the Belt with special emphasis on borings 10.A.071 and 10.A.072 which were conducted with special focus on mapping possible water bearing sand layers. Collected boring profiles for a rather big number of older geotechnical borings performed in the area pointed out as a possible Production Site area east of the ferry harbour in Rødbyhavn 5

6 Results of 10 onshore borings (11.A ) and 10 offshore borings (11.A ) performed with focus on water bearing sand layers in the possible Production Site area at Lolland Results of 57 shorter CPTs (11.B ) performed in the possible Production Site area at Lolland. In the actual connection those are only really relevant when evaluating the distribution of the uppermost, Postglacial sand layers Boring logs for c. 90 short borings performed in 2008 for the planned road from south of the Fehmarnsund and across Fehmarn in an almost N-S direction The 1995/96 borings performed as part of the initial investigation for the Fehmarnbelt fixed link. Of course the two borings on land and are the most important in the present connection A big number of mostly short borings performed in the two relevant areas and collected from different authorities and companies in the first phase of the 1995/96 investigations Boring logs for a number of deeper and shorter geotechnical borings performed for DSB for different constructions in the harbour area and on the railway station area (collected from Banedanmark s archives) Two very deep borings performed for oil prospecting at Rødby on Lolland Borings and other investigations for and observations in a c m deep test pit north of Rødbyhavn for excavation of very high plasticity clay supposed to be used for bentonite Other boring profiles in GEUS Jupiter-database Oral information on the results of the geotechnical investigations for the Rødsand 1 and 2 wind farms 6

7 3 Description of the series of layers Below is given a very short briefing on the geology of the total fixed link area. This is followed by a review of the information collected from the above references at Lolland and Fehmarn respectively. Finally, a conclusive summary for each of the two coastal areas is given. 3.1 Geology of the fixed link area Figure 1 Geological section across Fehmarnbelt Down to the depth investigated by borings for the project, the series of layers consists of the following units (listed with decreasing age upwards): Postglacial marine sand and gyttja Postglacial/Lateglacial basin deposits Glacial deposits (Upper and Lower till and interlayered meltwater deposits) Palaeogene high and very high plasticity clay Cretaceous chalk The distribution of the layers across Fehmarnbelt appears from Figure 1. The upper part of the Palaeogene clay and possibly also the glacial deposits are heavily affected by glacial-tectonic disturbances (faulted and folded). The strange shape of the chalk surface is due to halokinism (=uplifting caused by a rising salt body). Groundwater catchment and potential groundwater problems in the land connection areas are always related to meltwater sand deposits in the tills and the uppermost postglacial marine sand. 7

8 3.2 The area on southern Lolland Generally, Lolland - and especially Southern Lolland - is among geologists known as a flat, gently undulating glacial landscape (/1/); normally build up by clay till from the surface to considerable depth, and with only few and small inclusions of meltwater sand in the till. By this reason gravel pits are very rare in the area. The geology of the Danish land connection area for the fixed link is described shortly in the following on basis of the available maps and borehole information. The borehole information from the different investigations and sources listed in section 2 has been described in subsections for each investigation. Furthermore, the conclusions from the geological model, which has been developed by the former county "Storstrøms Amt" /7/, and additional geophysical mapping of the area, have been summarized. The location of the borings in the area is shown in Figure 2. Geological cross sections located at the lines shown in the figure have been shown in Figure 8 and Figure 9. Figure 2 Location of borings at the coastal area of Lolland 8

9 3.2.1 Maps The topographic map of the Rødbyhavn area (1411 II SV) illustrates the very flat glacial landscape with a big number of small, water filled marl pits and a few small depressions which are supposed to contain peat and/or gyttja. No gravel pits at all are shown on the map. The same picture appears from the older map - M4622 from 1964 which is also available in Rambøll s archives. Most of Denmark is covered by maps showing the results of the ongoing geological mapping of the uppermost metre of intact soil. Unfortunately, most of Lolland has yet not been mapped in detail, and only the less detailed map in 1: covering all Denmark has been published for the area. Figure 3 is a part of this map. Figure 3 Geological map of surface deposits (0-1 m s depth) in the Rødby area (/2/). 9

10 The map on this figure gives information about the soil type in the uppermost metre below the surface. The map shows that meltwater deposits are rather rare in the area. Another interesting observation is that postglacial marine deposits are common in the onshore area along the southern coast. This observation is somehow surprising as the area is situated in a part of Denmark that has been constantly sinking compared to the sea level since Lateglacial time (/3/). This means that there is no heaved sea bottom in the area, and the blue areas must therefore either both be situated below elevation zero and reclaimed or have been temporarily covered by sea in a flood situation as the famous one in Borings performed in the area show that the marine deposits normally are often only thin (up to 3-4 m thick) and dominated by sand, but often with a gyttja layer at the bottom CPTs and Production Site borings CPTs to depths between 3 and 11 m, but typically 4-5 m have been performed in the land part of the proposed Production Site area along the coast east of the ferry harbour in Rødbyhavn. Based on the results of those in combination with collected borehole logs from older borings a map of the base levels for the postglacial, sand dominated deposits has been prepared /14/. Furthermore 10 high quality geotechnical borings (figure 2) have been performed onshore and another 10 offshore within the Production Site area, all to a depth of c. 30 m. Two of the borings have reached Palaeogene clay (11.A.712 and 11.A714) while the eighteen are stopped in the Quaternary deposits. Referring to the description of the overall geology of the fixed link area (section 3.1), the new borings have provided a more detailed, but certainly also a more complicated picture of the Quaternary deposits and especially the Upper till unit than what was hitherto available. Based on the information on water contents and plasticity indexes on the boring logs it has been concluded that all of the offshore borings and 5 of the 10 onshore borings only have met the Upper till unit but this till unit has shown to include bigger and smaller remnants of more than one meltwater deposit.- Only locally and always in deep levels have Lower till been detected (boring 11.A.705 below elevation -26.5, 11.A.712 below elevation and 11.A.714 below elevation -26.4), and in borings 11.A.709 (below elevation -28) and in 11.A.713 (below elevation -22.5) has an easily recognizable, almost white, very calcareous till ( chalk till ), which is interpreted as a separate till within the Lower till unit (/15/), been detected (figure 8 and 9). As already mentioned, 15 of the 20 new boring were still in the Upper till unit when they were stopped in a depth of 30 m, but this unit has shown to include remnants of at least two and possibly three different meltwater deposits. The most easily recognizable of those is an often rather thick, fine grained deposit, including silt- and clay layers. It is present in elevations about -20 in borings 11.A.073, 11.A.074, 11.A.075, 11.A.080, 11.A.081, 11.A.082, 11.A.712 as well as in the older borings 09.A.014 and 09.A.018. The sand layer in the same elevation in borings 11.A.075, 11.A.076, 11.A.077, 11.A.078 and in 11.A.708 probably belongs to the same unit. It is often totally dominated by clay and silt layers but in other borings the sand part is considerable. It has in /15/ been suggested, that the Upper till unit in reality consists of two tills, divided by this rather special meltwater deposit. 10

11 It is more uncertain if the meltwater sand deposits situated rather close below the surface/sea in borings 11.A.710 (-7,6 - -8,7), 11.A.078 (-11, ,5) and 11.A.71 (-15, ,0) are erosion remnants of one and the same deposit or they instead are parts of one or more deposits which have been disturbed by glacial tectonics. A number of quite thin sand layers in different level in several of the borings are interpreted as local, isolated bodies, probably also created by glacial tectonics. Finally, a deep lying sand/gravel layer has been found in levels below elevation -26 in borings 11.A.073, 11.A.076, 11.A.080, 11.A.081, 11.A.705 and in the older borings and 09.A Borings from the 2009 and 2010 on- and offshore campaign Most of the land borings in the 2009 boring campaign have shown the expected series of layers, locally with a thin, upper postglacial marine sand layer above a clay till but more often going directly into till that continues down to the surface of the Pre-Quaternary (Palaeogene) deposits. An exception from this pattern is, however, boring 09.A.701 which has passed an almost 2.5m thick meltwater sand deposit between the depths of 15 and 17.5 metres. - No borings on land on Lolland have been performed as part of the 2010 boring campaign. In boring 09.A.702 two very thin meltwater sand layers have been detected in the depths of 10.75m and between 26 and 27m. Of the offshore borings, 09.A.018 and 09.A.014 are located closest to the Lolland coast, however still in a distance of more than 1 km. Boring 09.A.018 is situated closest to the coast, and it has between elevation and -33 met a thick deposit that seems to be dominated by meltwater sand. Unfortunately it is very uncertain how much meltwater sand is actually present in the unit, as there has been no recovery in quite a big part of it. Boring 09.A.014 has passed a 0.7 m thick, medium to coarse grained meltwater sand layer shortly below the sea bottom in elevation to Below that, between elevations -23 and the same, irregular deposit with changing meltwater sand and clay till and a lot of no recoveries has been passed. As mentioned in section 3.2.8, it seems to be a rather thick meltwater unit present in a wide area south and east of the harbour (figure 8) which in the area seems to separate two different tills, both belonging to the Upper till unit and both dominated by hard or very hard clay till of normal grain size distribution. Also in the older boring situated in a little bigger distance from land than the two above mentioned borings, the special, meltwater sand dominated unit is present. Boring 10.A.071, which is located in a very relevant position in this connection, has passed a 2 m thick layer of clayey meltwater silt below elevation -20. At the bottom of this layer a 10 cm thick sand layer has been observed. It is likely that this meltwater deposit belongs to the same unit. Figure 8 presents a section through the series of layers perpendicular to the coast, east of Rødbyhavn. 11

12 3.2.4 Borings from the 1995/96 investigation for the fixed link Of the 1995/96 borings (/4/) only boring is really of interest for an evaluation of the ground water conditions in the land connection area in Lolland. This boring has passed an upper fill layer that is a little more than 3m thick above a thin layer of marine sand and some Late Glacial clay and silt deposits. In elevation -2 it has reached the surface of very hard clay till, and it continues almost un-interrupted in this deposit until the surface of high plasticity Palaeogene clay of the Røsnæs Clay formation was reached in elevation -32. The Palaeogene clays continue to the bottom of the boring in elevation -62. It is, however, interesting for the present evaluation that a thin layer of melt water sand in the clay till was passed in the level from -24 to -26. The borehole log for boring has been included in Figure Borings from the DSBs (now Banedanmarks) geotechnical archive and from Geotechnical Inst. (now GEOs) archive As a part of the preliminary work for the 1995/96 investigations boring log/location for a rather big number of borings performed in the late 1950-ties for the construction of the Rødby ferry harbour and for a number of later constructions in the ferry harbour area and in the station area were collected. Also a number of borings from the Geotechnical Institutes (now GEOs) archive was included. Recently a few more boring logs from Banedanmarks archive have been added. Logs for all the deeper of the borings have been included in the Fehmarnbelt Geo Information System /4/. A number of the geotechnical borings especially for the ferry harbour are pretty deep (more than 20m). The general picture of the soil conditions is that a 1-3 m thick layer of fill covers the area nearest to the harbour. Below that, a 0.5-4m thick postglacial marine deposit is present in the areas near to the coast. It is dominated by sorted sand, but it includes up to 2 m thick layers of gyttja, and in a few borings even peat layers have been described. Below that follows a thick, homogenous clay till unit with very high strength and a low water content. Most of the borings have been stopped in this, but in some of the deepest borings thin layers of melt water sand have been passed in the glacial deposits below elevation 15. A number of photos in Banedanmark s archives show the excavated harbour constructions. Those were excavated in a reclaimed area inside a dike, and all excavations were performed in clay till. No melt water sand units at all are to be seen on the pictures Investigations for and observations in bentonite pit About 1990 the idea came up that the Palaeogene clay in the Rødby-Rødbyhavn area might be interesting for production of bentonite. A geophysical investigation was performed to map the areas where the surface of the Palaeogene deposits was situated closest to the terrain surface. 3 different areas were pointed out for further investigations, and a total of 4 borings were performed in The location of the boreholes and the mapped series of layers are illustrated on Figure 4. 12

13 Figure 4 Fence diagram illustrating the geology of the area with the 4 bentonite borings. The Palaeogene clay is shown with a green colour, two interpreted different till units are shown with the two brownish colours and meltwater sand layers are yellow. (From /5/). 3 of the borings were stopped rather short down in the Palaeogene deposits, but B1 starting from elevation was drilled to a depth of 91m, where the top of the Cretaceous chalk just was reached. As the top of the Palaeogene deposits were met in a depth of 13.5m, the Palaeogene deposits were a little more than 77m thick. The uppermost c. 40m was correlated to the Holmehus Formation, while the deposits below that level were interpreted as belonging to the Æbelø Formation. Of special interest in the actual connection is that the Quaternary deposits in B1-B3 only consisted of clay till, while in B4 a c. 6m thick layer of meltwater sand was passed between elevation and The Rødby 1 and Rødby 2 oil prospection borings Two deep borings for oil prospecting were performed at the Rødby salt dome respectively right east of and a few hundred metres west of the little town Rødby, ca. 4 km north of Rødbyhavn (/6/). The Rødby 1 boring was taken to 1537m s depth. In the present connection only the uppermost part is interesting. According to GEUS boring log the uppermost 29m was glacial clay till, and directly below that the boring met Cretaceous chalk, and that continued down to elevation

14 Rødby 2 was taken all down to 2941m, down through the Permian salt layers which were passed between elevation and For the uppermost part of the boring, information is very sparse. It is on the boring log only written that between the surface and elevation 143 m was passed varying, small layers. Below that, Cretaceous chalk was reached between 143 and The municipality s geological model of Lolland As a part of the national ground water investigation programme in Denmark a geological model for Lolland has been developed (/7/). All old data was included (geological information from borings, seismic etc) in the research. Figure 5 is a contour map of the top of the Cretaceous chalk in the area around Rødby and Rødbyhavn. The colours indicate the level of the surface of Cretaceous chalk. An estimate of the corresponding base level of the Palaeogene clay is given in Figure 6. It appears from the figures that the top of the Cretaceous chalk is found only 20 metre below ground surface north of the harbour. The figures clearly illustrate the impact from the salt dome far below the chalk in the Rødby area. The surface of the Pre-Quaternary deposits is rather irregular in the area around Rødbyhavn and Rødby as can be seen on Figure 6. Parts of the structures are related to the salt pillow below Rødby. Figure 5 Map of the surface of the Cretaceous chalk /7/. 14

15 The difference between the surface level for the Cretaceous chalk (Figure 5) and the Palaeogene clay (Figure 6) gives an estimate of the thickness of the Palaeogene clay in the area around Rødbyhavn and Rødby (Figure 7). The Palaeogene clay is rather thick around the harbour area and the station area. The surface of the Palaeogene clay is located only metre below the terrain surface. Moving against north to the area around Rødby the Palaeogene clay almost disappears. Figure 6 Map of the surface of Pre-Quaternary deposits /7/. The Ministry of Environment in Denmark still investigates the geology of Lolland. A SkyTEM mapping of the NE-part of Lolland was performed in 2007/2008, and a supplementary seismic investigation was performed in 2010 (/12/). As the southern boundary of the area treated in this investigation is situated a little north of Rødby Town, the investigation results are evaluated to be of limited interest in the actual connection Summary of soil conditions at southern Lolland Based on all the above information, the expectations to the overall geological series of layers in the Southern Lolland area appears as: Especially in the harbour area, the station area and on the dike (figure 9) an upper fill layer is often present In the coastal area a Postglacial marine deposit dominated by sorted sand but with significant gyttja layers in the basal part is present as a surface deposit. The layer can have a total thickness of up to 4.5m in the areas close to the coast 15

16 Below the marine deposits in the coastal area and directly below the topsoil in the rest of the area, homogenous, very hard clay till, the Upper till is present. The upper ½-1½ m has often been re-deposited by soil flow processes during the Lateglacial period Especially east of the harbour where the borings for the production site has been performed, a number of often thin sand layers have been detected within the Upper till unit (figure 8) but both the number and the thickness of those seem to be currently reduced in the direction against the harbour (figure 9). Figure 7 Map of the estimated thickness of Palaeogene clay (/8/). Red and orange colours indicate m of Palaeogene clay. Green colour indicates m of Palaeogene clay. The black lines show the location of older seismic profile lines. A thick and outspread, meltwater unit dominated by sand but interrupted by both meltwater silt- and clay layers and even thin layers of clay till is present in elevations typically between -22 and -35 in the parts of the area (see section 3.2.2). The layer seems to divide the Upper till unit in two separate tills (Figure 8). The layer seems to be missing in the coastal zone of the alignment. The surface of the Pre-Quaternary Palaeogene clay is very irregular and situated in levels between elevation -12 and -50 in the Rødbyhavn area. 16

17 Figure 8 Section through the series of layers in the coastal zone, perpendicular to the coast east of the harbour in Rødby 17

18 Figure 9 Longitudinal geological section through the Production site area, onshore and parallel to the coast 3.3 The Fehmarn area The morphology of Fehmarn is a little different from that of Southern Lolland. While the latter can be characterized as almost flat, Fehmarn is dominated by gently sloping, very elongated hills, typically with a direction between East-West and East/Southeast- West/Northwest. The shape of the hills can possibly indicate that they have been created as small push moraines by glaciers that came to the island from a northern or northeastern direction Maps Rambøll/Arup has received a number of geological maps ordered from Landesamt für Landwirtschaft, Umwelt und ländliche Räume Schleswig-Holstein. Relevant information for the actual purpose has especially been found on: 18

19 The topographic map that clearly shows the elongated hills described above A petrographic map, showing the soil type in the uppermost layer. A section of the map is included as Figure 10 in this report A combined geomorphological and petrographic map, interpreting some of the terrain elements on Fehmarn Figure 10 Part of petrographic map, showing that clay till (lilac-brown colour) totally dominates the upper soil layers in the actual area. Meltwater sand is shown with a yellow colour on the map. A hydrogeological map. The content of this is explained in chapter 4, see Figure 17, and a section of it has been used as background for Figure 19. A map showing the depth to the Pre Quaternary surface in Schleswig-Holstein, indicating that this should be situated in between 25 and 50 ms depth under almost all of Fehmarn Observations in the Heiligenhafen coastal cliff and in borings for the Fehmarnsund Bridge The only location in the whole area where an open profile is present is the Heiligenhafen coastal cliff (/10/) on the landside west of the Fehmarnsund bridge (Figur 11). This profile is interesting in several ways as there are indications on that both the series of layers and the tectonic situation is the same as below the Fehmarnsund Bridge and maybe at least to a certain degree also below the northernmost part of Fehmarn where the land connection for the fixed link will be located. 19

20 Figure 11 Location of Heiligenhafen coastal cliff and a geologic profile of the cliff. (From /9/) The profile is dominated by three different clay till units. As Figure 11 shows, the upper of those lies horizontally above a glacially disturbed series of layers which contains the two lower clay till units, minor melt water sand/gravel deposit and three different units of Palaeogene/Neogene origin. The lower units are folded and faulted by a glacier that reached the area from a North-Eastern to Eastern direction, creating the elongated hill that reaches the coast in the up to 16m high exposure. As figures 11 and 12 show, permeable sand/gravel layers are present, however only as rather thin units. Not less interesting is it that two of the three Palaeogene/Neogene units exposed in the coastal cliff have yet not been found in borings at Fehmarnbelt, even though the series of layers is supposed to be pretty much the same on the two locations. Well known from the borings in Fehmarnbelt is a dark green to olive green, very high plasticity clay. From old times it has got the local name Tarras, but there seems to be no doubt that it is a Palaeogene deposit. As the literature describes both green tarras and red tarras, it seems to be a qualified guess that they can be directly correlated to the Lillebælt clay formation and the Røsnæs clay formation in the Danish area. It is also interesting that a layered, somehow indurated, high porosity silica-stone ( Heiligenhafen Kiselgestein ) is present as a 2-4 m thick unit above the green tarras in the cliff (Figure 11). This unit has not been found in the Fehmarnbelt borings and, furthermore, they have as far as known never been found in Danish Palaeogene deposits. However, some "bands" with silica-concretions have been detected in the Røsnæs clay and locally also in the Ølst Clay in the Fehmarnbelt-borings, and they might be "variants" of the Heiligenhaven Kiselgestein. 20

21 Figure 12 Folded sand layers in the Heiligenhafen coastal cliff (/9/) Not less interesting is it that a floe of black, Miocene mica clay is (or has been?) exposed in the cliff profile. It is supposed that Miocene deposits originally has covered all the southern Danish area, even though they later have been totally eroded away in the southeastern part of the country, and the presence of a floe of the deposit in the Heiligenhafen area supports that theory and indicates that such deposits maybe also can be present in floes in the glacial deposits in Fehmarnbelt. Deutsche Bahn has kindly delivered a big amount of drawings, reports etc., mostly from the late 1950-ties and the early 1960-ties when the Fehmarnsund bridge was built. The 9 binders include situation plans and boring profiles for a big number of geotechnical borings performed for the Fehmernsund Bridge. The boring profiles indicate that both the land abutments and the bridge foundations are placed on series of layers which to a remarkable degree are disturbed by glacial tectonics. The disturbed series of layers includes clay till, meltwater sand/gravel and very high plasticity Palaeogene clays Borings from the 2009 and 2010 boring campaigns for the fixed link 7 borings have been performed on land on Fehmarn as part of the 2009 boring campaign, and further 2 have been added in Most of those have passed thinner or thicker floes of Palaeogene clay within the dominating clay till deposits, but layers of meltwater sand/gravel only seems to be included in the glacial tectonic disturbed series of layers in smaller parts of the area. This evaluation is based on the fact that the deep 09.A.603 has met no meltwater sand at all, 09.A.604 has only passed a very thin sand layer in a depth of 42m below thick floes of Palaeogene clay and 09.A.605, which has been taken down to a depth of 50.5m without reaching the surface of the Palaeogene clay, only has met a 0.6m thick sand layer almost from the surface. On the western side of the railroad, 09.A.606 has detected a rather thick unit dominated by meltwater sand but including clay till layers in a depth between 8 and 12.5m. 21

22 Quite different is the situation in the area where 09.A.601, 09.A.602 and 09.A.607 are located. In this area the disturbed series of layers below an upper clay till layer contains major floes of both meltwater sand/gravel and Palaeogene clay. The extreme variation in the geological series of layers even within short distances is illustrated from the fact that 09.A.607 was given up in 2009 because of severe problems with boring in water bearing sand and gravel layers. A new boring - 10.A was performed in 2010 located only c. 5 m from the first position. The new boring did not meet the problematic sand/gravel layers at all. In the off shore borings located closest to the Fehmarn coast the only sand detected is postglacial marine sand in the surface layers in 09.A.001, 09.A.002, 09.A.003 and possibly as a very thin layer in 09.A.005. In the older part of the series of layers no sand seems to be present at all in the offshore, coastal area. As part of the 2010 campaign, boring 10.A.072 has been added, located close to the coast, east of the harbour. The boring has below 2.2m Postglacial, marine sand passed directly into Palaeogene clay. The very uppermost part of this might to some degree have been disturbed by the glaciers during the Quaternary. No sand layers are present below the postglacial layer, see Figure Borings from the 1995/96 investigation for the fixed link The only boring from this investigation that is really of interest in the actual connection is boring This boring has from the basis of the topsoil and down to elevation -16 only met clay till. Below that level clay till is still the dominating soil type, but significant floes of high plasticity clay of Palaeogene origin has been dislocated into the till. Down to the bottom in elevation the boring has passed no sand layer at all Borings for the harbour constructions and for the road and railway connection from before 1963 As a part of the 1995/96 investigations Rambøll collected a rather big amount of boring logs from borings performed in the harbour area in Puttgarten and on the railway area up to c. 2 km south of the harbour. Most of the boring logs were delivered by Geologisches Landesamt Schleswig-Holstein. Only a few of the deepest borings in the harbour area has been included in the Geo Information System. The others are only available as paper copies in Rambøll/Arups files. Most of the borings are between 10 and 20m deep. Clay till is by far the most common soil type in the profiles, but layers of meltwater sand of 1-3m s thickness seem to appear as isolated bodies in the till deposits. "Tarras" has been described from a few of the borings, but often it is present as floes, as the boring has reached clay till below the "tarras". A few borings have, however, been stopped in "tarras". 22

23 3.3.6 Borings from 2008-investigation for a road across Fehmarn FB has received a CD-rom with the main results of a phase 1 geotechnical investigation for the planned road across Fehmarn. The investigation covers the part of the alignment from a little west of Heiligenhafen to c. 2 km south of the waterfront in Puttgarten Harbour. The borings have typically been performed with an internal distance of 200m. They have been drilled to a depth of not less than 5m, and some of them have been drilled to significantly bigger depth. A few of them are 15m deep. The report contains information of the series of layers in the borings, illustrated on coloured longitudinal sections, of measured water levels and water contents, plasticity index and grain size analyses including the fine grained part. In the actual connection it is interesting to see, that while most of the borings in the southern part of Fehmarn have met layers of water bearing, sorted sand have those on the northern part either met no sand layers at all or only passed through rather thin, local sand layers. Only a single boring boring seems to have met very high plasticity clay of supposed Palaeogene origin Summary of expected soil conditions at Fehmarn Based on all the above information, the expectations to the overall geological series of layers in the northern Fehmarn area appears as: In the harbour area and near coast area outside the harbour an uppermost layer of Postglacial marine sand is locally present Directly below the Postglacial unit in the coastal offshore area and below the topsoil in the rest of the area follows a rather thin, homogenous clay till unit Below the upper till unit a glacially disturbed, folded and faulted unit follows. Several different deposits are included in the disturbed unit, and it seems like at least two lower till units, a meltwater sand unit and disturbed floes of very high plasticity clay of Palaeogene origin is included in it. It is supposed to be several tens of metres thick, but the sand layers are only rather thin at least in the northernmost part of Fehmern. The 2009 borings indicate that the sand/gravel floes are only very locally present in the disturbed series of layers. In the area where 09.A.601, 09.A.602 and 09.A.607 are located rather thick floes of meltwater sand/gravel seem to be present in depths bigger than 10 á 12 m Below the glacially disturbed unit, Palaeogene clay is present. The upper part of this clay is folded in giant folds by the glaciers, and according to the CPTs performed in 09.A.603, the surface of the undisturbed Palaeogene clay is only reached in a depth of c.84m below the surface. The described Quaternary layers are only present in the land part and maybe continuing a short distance outside the coast. Outside this area, folded Palaeogene, high plasticity clay is present directly below local and thin Postglacial marine deposits, Figure

24 Figure 13 Section through the series of layers in the coastal zone, perpendicular to the coast east of the harbour in Puttgarden 24

25 4 Groundwater conditions 4.1 The area on southern Lolland Introduction The Pre-Quaternary surface consist of Cretaceous chalk in the northern part of Lolland and Palaeogene clay in the southern part except at Rødby salt dome, where the surface consist of chalk, as the chalk and Palaeogene clay have been heaved by the salt dome activity and the Palaeogene clay has been removed by the eroding glaciers. The Quaternary deposits are dominated by clay till. A 3D geological model has by Storstrøms Amt been established for Lolland, /7/. The meltwater sand deposits in the Quaternary layers have in the interpretation in this model been classified into four units, 1 to 4, from the Pre Quaternary surface and upwards. The distribution of sand unit 3, having the largest distribution in the land connection area at Rødbyhavn can be seen in figure 13. The distribution below the sea area is uncertain. In the model it is based on a limited data basis estimated that larger occurrences of meltwater sand deposits are generally not present from 0 to 5 km from the southern shore except for in sand unit 3. The thickness of sand unit 3 is most often on a magnitude of c. 5 m, but varies from 1 to 30 m. Figure 14 Sand unit 3 in the Lolland area. Data basis and estimated extension and thickness. Catchment areas for water abstractions are shown with black, dotted lines /8/ 25

26 The chalk and the larger sand deposits in the Northern part of Lolland are used for abstraction of drinking water. The catchments areas can be seen on figure 14. The infiltration to the ground water reservoirs is, however, limited of a magnitude of c. 20 mm/year - because of the clay dominated Quaternary deposits and the low ground level (/10/). No substantial ground water abstraction takes place in the southern part of Lolland as the few sand layers of limited extension cannot sustain a larger abstraction of groundwater. The groundwater in the Cretaceous chalk at Rødby, boring no is salty. The Cretaceous chalk in the southern part of Lolland is not suitable for abstraction of drinking water as it is located very deep below the ground surface and as the recharge to the reservoir is very low according to the low ground level and the thick cover of low permeable layers of clay till and Palaeogene clay. The groundwater in the chalk is furthermore more or less salty in the large areas with surface level below sea level in the southern part of Lolland, see figure 1, and the ground water flow is probably upwards from the chalk in these low laying areas. The low lying areas are kept dry by channels that lead drained groundwater and surface water to pumping stations, where the water is pumped out in the sea. The different catchments areas of the pumping stations are marked in Figure 16. The pumping rate at the pumping station at Kramnitse that covers the former Rødby Fjord area see the upper left corner in Figure 16 is as an average c. 2 m 3 /s but reaches a maximum of approx. 20 m 3 /s. The pumping rates for the two smaller catchment areas West and East of Rødbyhavn is not known, but is probably in the magnitude of 0,1 m 3 /s considering the area of the catchment areas compared to the whole of the former Rødby Fjord area. The pumping rate has not been measured, but may be estimated more precisely based on the power consumption of the pumps Groundwater reservoirs Groundwater reservoirs are expected to be present in the geological formations described below: In the land connection area at Lolland a postglacial marine deposit dominated by sorted, water bearing sand but with significant gyttja layers is present in the coastal area. The layer can have a total thickness of 4.5 m in the areas close to the coastal line and a bottom elevation at c. -4. The sand is generally described as fine to medium with some layers of medium to coarse sand. The permeability may be in the magnitude of 1 x 10-4 m/s. 26

27 A thick and outspread unit of meltwater deposits is present in elevations typically between -19 and -26 in the area from the shore line to more than one kilometre from the shore in the area east of Rødbyhavn, see Figure 15. In a big part of the area the unit is dominated by clay and silt, and in those areas only few and thin sand layers are present. But in other parts of the area, sand is dominating. The sand layers are generally met at c. - 20, however in the eastern borings 11.A A.081 the sand layers are only reached at c In the onshore borings 11.A.707, 11.A.708, 11.A.711, 11.A.712 a thinner meltwater deposit is met c. at -20. The sand layers in this meltwater deposits might be connected to sand layers met in the offshore borings. The sand is generally described as fine to medium. Figure 15 Possible distribution of meltwater deposits/sand layers in the area southeast of Rødbyhavn In boring 11.A.074 meltwater sand has been found from c. -21 to -24. The permeability may be of the size 1 x 10-4 m/s. The transmissivity of the sand layer - the permeability multiplied by the thickness of the layer - varies, it is however estimated that the transmissivity generally is of the same size as in boring 11.A.074 or lower. A deep lying sand/gravel layer has been found below elevation c. -30 in borings 11.A.073, 11.A.076, 11.A.080 and 11.A.081, see Figure 15. This layer might be connected to the sand layer found onshore between c. elevation -25 and -27 in borings 11.A.705 and in the older borings and 09.A

28 In boring B4 of the bentonite borings a c. 6 m thick layer of meltwater sand was passed between elevation and It may be connected to the sand layer described above, but is can also be a local deposit. Apart from the postglacial marine deposit dominated by sorted, water bearing sand, the occurrence of sand layers above elevation c. -20 is sparse. A number of thin sand layers have been found in different level in several of the borings. They are interpreted as local, isolated bodies. The isolated meltwater sand deposits situated rather close below the surface/sea in borings 11.A.710 (-7,6 - -8,7), 11.A.078 (-11, ,5), 11.A.713 (-15, ,0) and the older boring 09.A.701(-14, ,8) and 09.A.702 might have a larger distribution, but are after all considered as small locale reservoirs, see Figure 15. In the old boring B103 in the harbour area of Rødbyhavn two layers of sand with a combined thickness of 0.8 m was met from elevation 14.5 to 17.5, and a simple pumping test was performed on those in connection with the evaluations of the need for groundwater handling in connection with the excavations for the harbour constructions in the early 1960-ties. The maximum yield from the boring was 10 l/hr and the permeability of the sand was estimated to be of the size 1 x 10-6 m/s, which is rather low Abstraction No water abstraction for public water supply takes place inside the area shown on Figure 16. Three licenses for abstraction of surface water have been given inside the area. Only one surface water abstraction is located so close to the land connection area that it is of interest here. The permitted abstraction for this abstraction located approx m east of Rødbyhavn is m 3 /year. The license for this abstraction is valid until December 23,

29 Figure 16 Locations of private ground water abstraction of limited size and surface water abstraction for irrigation. The registered private ground water abstractions are all located so far from the land connection area that they are of no interest in the present connection. 4.2 The Fehmarn area General The area of the Island Fehmarn is 185 km 2, and the highest point is the 27 m high Hinrichberg in the southern part of the island. In the northern part of the island the ground level generally is lower than +5 m except for a few points. At the land connection area at the harbour in the northern part a little hill reaches a level of 12 m. In the clay dominated Quaternary layers a few local ground water reservoirs in occurrences of diluvial (=melt water) sand can be found according to an older geological map, see Figure 17. The höffigkeit mentioned on the map is a German way of describing the water bearing capacity of a reservoir. It is supposed to be defined as the possibility of permanent extraction of certain water quantities in case of sufficient ground water replenishment. 29

30 The Quaternary layers are glacially disturbed, why the occurrence of larger, connected sand layers is unlikely. However, it seems that the amount of sand in the Quaternary layers increases against south on the island. Below the upper, clay dominated Quaternary layer a transitional zone on the magnitude of 50 m of glacially disturbed Palaeogene clay can be seen. Below that the intact Palaeogene clay is met with surface level around elevation -75 a -80. The surface of the water bearing Cretaceous chalk is situated more than 100 m below ground. The chalk is, as in the southern part of Lolland, not suitable for abstraction of drinking water as it is located very deep below the ground and the recharge of the reservoir is very low according to the low ground level and the thick covering, low permeable layers of clay till and Palaeogene clay. Most of the average annual precipitation of approx. 500 mm will evaporate or run off as surface runoff or near surface runoff. Probably just a few mm may reach the Cretaceous chalk. Figure 17 An older map of the groundwater reservoirs in the Quaternary deposits from Geologische Landesaufnahme von Schleswig-Holstein. 30

31 4.2.2 Ground water reservoirs As the chalk is not suitable for abstraction of water the only potential groundwater reservoirs are the Quaternary sand layers. There are as described above no larger groundwater reservoirs at Fehmarn, but small delimited aquifers are present within the quaternary layers on the island. In the land connection area water bearing Postglacial marine sand may locally be present in the upper 1 to 4 metres in the harbour area and near the coast area outside the harbour. In Figure 18 an estimate is given of the position of the upper level of the glacially disturbed Palaeogene clay deposits based on CVES/Mep lines. In the boring clay till was met from the bottom of the top soil down to elevation 16, which was expected based on the CVES/Mep lines. There is no indication of sand layers in the CVES/Mep lines except for in the northwestern part of the map area, where the surface of the glacially disturbed Palaeogene clay deposits is estimated to be at a deep elevation, see Figure 18. This sand layer has been verified by boring 09.A.606 in which a sand layer was met from c. elevation -8 to -12, see Figure 19. The CVES/Mep method and investigation results are described in /11/. In the area where the boring no. 09.A.601, 09.A.602 and 09.A.607 are located rather thick floes of meltwater sand/gravel seem to be present in depths bigger than 10 á 12 m, see Figure 19. The extension of this water bearing zones is not known, buts sand layers of several 100 metres extension may be met in the area. However, since the glacially layers are supposed to be disturbed, folded and faulted, it is not likely that sand layers of much larger extension may be met. 31

32 Figure 18 An estimate based on CVES/Mep lines of the upper level of the glacially disturbed Palaeogene clay deposits (/11/). 32

33 Figure 19 A section of the map in Figure 17. The location of the CVES/Mep lines from Figure 18 is shown together with a possible location of a sand layer (yellow) based on the CVES/Mep results Abstraction The public drinking water supply on Fehmarn comes from water works on the mainland. There are two private water works on the island. Both water works are for the water supply of a camping ground on the southern part of the island: WBG Wulfen e.v. and WV Campingplatz Wulfener Hals, /13/. The maximum discharge of the water works are between 15,000 and 65,000 m 3 /year. 33