Site investigation SFR. Hydro Monitoring Program. Report for May 2008-August 2009

SKB conducts bedrock investigations for a future extension of the final repository for low- and medium-level radioactive waste (SFR) at Forsmark within the Oesthammar municipality. As a part of this investigation, hydrogeological monitoring is performed. The objectives of the groundwater monitoring are, in a short-term perspective, to measure pressure responses during drilling, pumping and interference tests and also, in a long-term perspective, to create time series in order to increase the knowledge of the hydraulic conditions. Data presented in this report are collected during the period of May 2008 until August 2009 and include groundwater levels in surface boreholes and groundwater pressure in boreholes situated in the tunnel. The data collecting system in HMS (Hydro Monitoring System) consists of a measurement station (computer) that communicates with and collects data from a number of data loggers. The computer is connected to the SKB Ethernet LAN. All data are collected by means of different transducers connected to different types of data loggers: Minitroll, LevelTroll and Datataker. In order to calibrate registrations from the data loggers, manual levelling of all surface borehole sections is made, normally once every month. The logger data are converted to water levels using calibration constants. All collected data are quality checked once every three or four months. During this work, obviously erroneous data are omitted and calibration constants are corrected so that the monitored data comply with the manual levelling. At these occasions the status of the equipment is also checked and service might be initiated. Diagrams of groundwater levels and groundwater pressure for the period of May 2008-August 2009 (one data point per section and twenty-four hours) are presented in Appendix 2. The original data are stored in the primary data base Sicada. The data in this data base may then be used for further analysis. There are no nonconformities with respect to the activity plan or the method description