Hydrology and Earth System Sciences www.hydrol-earth-syst-sci.net 1027-5606 1607-7938 7 1 2003 10.5194/hess-7-23-2003 http://www.hydrol-earth-syst-sci.net/7/23/2003/ http://www.hydrol-earth-syst-sci.net/7/23/2003/hess-7-23-2003.html http://www.hydrol-earth-syst-sci.net/7/23/2003/hess-7-23-2003.pdf 23 32 0000-00-00 An easily installable groundwater lysimeter to determine waterbalance components and hydraulic properties of peat soils K. Schwaerzel H. P. Bohl Institute of Ecology, Department of Soil Sciences and Soil protection, Technical University of Berlin, Salzufer 11-12, 10587 Berlin, Germany CSIRO Land and Water, Davies Laboratory Townsville, PMB PO AitkenvaleQLD 4814, Australia Email for corresponding author: Kai.Schwaerzel@TU-Berlin.de A simple method for the installation of groundwater lysimeters in peat soils was developed which reduces both time and financial effort significantly. The method was applied on several sites in the Rhinluch, a fen peat land 60 km northwest of Berlin, Germany. Over a two-year period, upward capillary flow and evapotranspiration rates under grassland with different groundwater levels were measured. The installation of tensiometers and TDR probes additionally allowed the in situ determination of the soil hydraulic properties (water retention and unsaturated hydraulic conductivity). The results of the measurements of the unsaturated hydraulic conductivity demonstrate that more than one single method has to be applied if the whole range of the conductivity function from saturation to highly unsaturated is to be covered. Measuring the unsaturated conductivity can be done only in the lab for an adequately wide range of soil moisture conditions. Keywords: peat soils, soil hydraulic properties, evapotranspiration, capillary flow, root distribution, unsaturated zone