Revision of the safety plan of Nyirád drinking water supply
The Nyirád drinking water supply worked by Transdanubian Regional Waterworks Co. Ltd. (DRV Ltd.) is one of the two biggest karst water supplies in Hungary (the other biggest is Miskolc karst water supply).
The safety plan of the water supply was completed in 2005. Because of the special characteristics of the water supply, the safety plan must have been revised in 2016.
Surface and deep mining activity was begun in the 1950’s in the Nyirád region. Flowing karst water in the fractured dolomite and fault systems made deep mining impossible in the area. Mining activity could be carried out when karst water level was decreased under the level of the mined bauxite bodies with construction and operation of pumping wells. In this way entering of the karst water to the mine could be excluded. As a consequence of water exploitation drastic karst water level decrease occurred around the wells.
Through decades the exploitation of karst water exceeded the natural recharge of the karst system so the yield of the springs and pressure conditions of groundwater significantly decreased in the area of Transdanubian Range. At the end of 1980’s serious environmental consequences arose in the area of Transdanubian Range. Due to political, industrial, economic and social changes and increasing influence of environmental activists the bauxite mines in Nyirád were closed in 1990.
In the 1990’s regeneration of the karst system began. In these days natural conditions are restored.
At the recharge area of the water supply there are many subsurface pits – former mines – filled with karst water that are potential risk to drinking water quality.
There are abandoned opencast mines and collapsed subsurface pits at many places in the recharge area. These surface depressions are often used as illegal waste depository and can function as a sinkhole.
During the revision new protection zones were determined due to regenerated karst water level and potential risks were identified and evaluated.