DBPapers
DOI: 10.5593/SGEM2016/B31/S12.057

HYDROLOGICAL CONSEQUENCES OF MINING SUBSIDENCE IN THE SZOTKOWKA RIVER VALLEY (SILESIAN UPLAND, SOUTHERN POLAND)

R.Machowski
Wednesday 7 September 2016 by Libadmin2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-61-2 / ISSN 1314-2704, June 28 - July 6, 2016, Book3 Vol. 1, 437-444 pp

ABSTRACT
The land subsidence caused by underground mining results in the transformation of water relations in the Silesian Upland, which is located in southern Poland. The valley reach downstream of Szotkówka River sources, of nearly 12 km in length, has been studied in detail. The purpose of the study was to determine the hydrological consequences of underground mining, which has taken place in the area examined since the 1960s. As part of the study, the geological structure of the area was examined and a detailed hydrological mapping was conducted. Cartometric measurements were carried out based on the cartographic material collected. Laboratory tests using the 850 Professional IC ion chromatograph from Metrohm included chemical analyses of the water samples retained in the water bodies formed in subsidence basins. The underground extraction of coal in the study area has resulted in far-reaching changes in water relations. The character of the surface watercourse network has changed. The length of the river increased from 10.68 km in 1961 to 11.52 km in 2012 and water bodies formed in subsidence basins in the mining subsidence area within the river valley. By 2012, there were seven such water bodies. The smallest of the water bodies studied had an area of 0.40 ha and the largest one was 14.95 ha in area. Their total area was 51.02 ha. The water bodies are flow-through ones and are primarily fed by the Szotkówka River. As a result of the development of mining in the study area, surface waters were heavily contaminated, especially with compounds that result in their high salinity. The presence of chlorides at levels ranging from 288.52 mg Cl-/dm3 to 304.34 mg Cl-/dm3 and of sulphates at levels ranging from 382.59 mg SO42-/dm3 to 448.16 mg SO42-/dm3 was detected in limnic waters. The water bodies examined are also burdened by nitrates (7.46-9.55 mg NO3-/dm3), which are primarily responsible for their eutrophication.

Keywords: lakes, water body, subsidence basins, Silesian Upland