Das Projekt "Exploitation of geothermal energy by doublet for bathing and heating purposes in Straubing - Phase 1 -" wird vom Umweltbundesamt gefördert und von Stadtwerke Straubing GmbH durchgeführt. Objective: To produce geothermal energy to heat a resort centre, baths, sanatoria, schools and buildings in the town of Straubing in Niederbayern. The well has been drilled at 824 m into Malm limestone will be exploited at 180 m3/h flow rate and 35,6 deg. C. 10 per cent of the production for direct supply to brine pools at the existing health resort. The remaining hot water via heat pump will be used for heating purposes and sanitary hot water production. The drilling of an injection well 2 km apart (162 m3/h at 5 deg. C.) is necessary to maintain a sufficient pressure in the reservoir. One of the first geothermal doublet to exploit the Malm reservoir in south Bavaria. General Information: See results. Achievements: The Malm aquifer was found at 708 m and bored until the final depth of 824,8 m. Water bearing (confined water) karstic cavities have been found between 730 and 746 m. The drilling had to be carried out under permanent overflow (126 m3/h at 35 deg. C.). After the end of drilling one output and one long- time pumping test have been carried out. The output pumping test (13.08. - 20.08.90) showed a specific productivity index of 1,8 m3/h/m. The accompanying hydrochemical and isotope-chemical investigation programme showed that the water is a fluoridic sodium chloride-hydrogen carbonate thermal with a total mineralization of 1325 mg/l. The sampling temperature was between 35 and 36 deg. C. A dependance between water output and water quality could not be determined. The long-time pumping test (28.08. - 02.10.90) has been run at a constant pumping planned output during operation. At the end of the pumping test the depression was stabilized at 78 m. With regard to the water quality no changes could be determined compared with earlier analyses.