The following map of the groundwater temperature distribution is based upon 433 measurement points that were gathered between 1978 to 1998. In areas with earlier measurement periods 1997 – 1998 temperature dispersions were repeatedly included. For a time from January to October 1991 measurements were reported every two months. Generally the temperature profiles were gathered from the near surface water to the expansion depth. The measurement point distance normally was 1 m. For the measurement a resistance dependent on temperature was used. The accuracy of the measurements was within ± 0,1 °C.
