HR: 0800h
AN: H11D-0321    [Abstracts]
TI: Measurement Techniques for Determination of Groundwater Velocity in the German Scientific Borehole LUD-1
AU: * Kessels, W
EM: w.kessels@gga-hannover.de
AF: Leibniz Institute for Applied Geosciences (GGA), Dr. Winfried Kessels Institut f�r Geowissenschaftliche Gemeinschaftsaufgaben Stilleweg 2 30655 Hannover Germany, Hannover, 30655 Germany
AU: Panteleit, B
EM: b.panteleit@nlfb.de
AF: Geological Survey of Bremen, Dr. Bj�rn Panteleit Nieders�chsisches Landesamt f�r Bodenforschung - Geologischer Dienst f�r Bremen - Friedrich-Mi�ler-Stra�e 46/50 28211 Bremen Germany, Bremen, D-28211 Germany AU: Binot, F
EM: f.binot@gga-hannover.de
AF: Leibniz Institute for Applied Geosciences (GGA), Dr. Winfried Kessels Institut f�r Geowissenschaftliche Gemeinschaftsaufgaben Stilleweg 2 30655 Hannover Germany, Hannover, 30655 Germany
AB: The scientific boreholes Lud 1/1A and additional observation wells in the surrounding are used to determine the groundwater velocity in the marsh area with three different methods.The boreholes are located in the marsch area south of the German town Cuxhaven 6 km far from the coast line. The here discussed scientific work is part of the Coastal Aquifer Test field (CAT-Field) activities. This Test field has the size of about 60 km to north-south and 30 km to east-west. A sandy hilly geest area with a high recharge is located in the middle of the CAT field. The fresh- saltwater transition zone is determined in a depth of 60m in the fully screeened boreholes LUD1/1A by logging (Panteleit et.al.,2003). Discussed are here the following investigations to determine the groundwater velocity. The push-pull-test during drilling the borehole Lud1a was a uranine mud tracer test. From this test first values for the dispersion coefficient and the groundwater velocity value were derived by Panteleit et. al. (2003). High resolution water level monitoring is done to determine the dynamics of the groundwater regime in the vicinity of the scientific borehole LUD1. They are performed in 12 observation wells in the vicinity of LUD1. The time dependent variations of the hydraulic gradients are derived from triangle interpretations. A density correction was necessary due to the influence of the deeper salt water body. The high resolution water level measurements reflect, the strong influence of the surface water flow in the drainage system. Colloid observations are carried out with the Phrealog technique in 10 depth horizons. The measurements show a very strong time dependent fluctuation in a time range of hours, but from long time averages useful data for the determination of ground water velocities are expected. With Multi electrode measurements on the borehole wall a tracer with a selected electric conductivity is injected near the electrodes and observed by geoelectric measurements. The application of the multi electrode technique is designed by borehole sleeves installed behind the casing (Kessels et. al., 2002) and the movable double wall packer system (Kessels, W.& Zoth, G., 1998). As the goundwaterflow is measured directly in the aquifer, and not in the borehole itself, the results of the double wall packer experiment are stable in direction and value. {References:} KESSELS, W., ZOTH, G.(1998): Doppelmantel - Packers mit geoelektrischer Me�technik zur Bestimmung der Abstandsgeschwindigkeit des Grundwassers, Patent Az:19855048.0,GGA-Hannover. PANTELEIT, B., KESSELS, W., BINOT, F.(2003): Mud Tracer Test while Drilling Soft Rock, submitted W.R.R., thesis, University Bremen KESSELS, W., RIFAI, H., THORENZ, C., ZOTH, G.(2002): Multi Electrode Geoelectric on the Borehole Wall -Determination of groundwater velocity and dispersion parameters-, AGU spring meeting, Washington
DE: 1899 General or miscellaneous
DE: 3094 Instruments and techniques
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting