Fresh and thermal waters of the Łódź Basin – potential threats to exploitation in the Łódź agglomeration

Abstract

. The Łódź agglomeration, due to its location in the watershed zone, has very limited possibilities of using surface water resources. Its establishment and dynamic development was determined by the abundant aquifer structures of the Łódź Basin and its Ceno zoic overburden. The area of the Mogilno-Łódź Basin shows a considerable geothermal potential. It partly results from the saturation of the deep bedrock of salt structures showing increased heat conductivity. The Lower Cretaceous and Lower Jurassic geothermal reservoirs are considered most promising. Waters occurring there, apart from high temperature, are characterized by high mineralization and high reservoir pressures. The Lower Cretaceous aquifer seems to be most threatened. Geothermal installations generate a potential increase of the risk of ascension of its highly mineralized waters from Triassic and Jurassic sediments. The threat does not exist outside the boundary separating fresh and mineral waters because in this area the aquifer loses its importance as a useful fresh water aquifer.