Consideration regarding the aquatic ecosystems developed in the open pit lakes from Oltenia mining region

Abstract

Formation of so-called open-pit lakes has become an increasingly common practice in Romania (more precisely in the Oltenia Mining Basin, where the lignite deposit contained in Dacian and Romanian formations was and is extracted through open-pits). The flooding process of the remaining gaps is in general a natural one, as water comes from underground sources (phreatic and pressurized aquifers) and from precipitations (including runoff waters from the surrounding terrains). This practice is considered to be a type of ecological reconstruction of former exploitation areas and has been applied worldwide for quite a time (in Germany, Poland, Czech Republic, Spain, USA, Australia, etc.). The present paper aims to present some ecological aspects regarding these lakes, and, as case study, we chose the lake formed in the remaining gap of Urdari open-pit (within the Rovinari Mining Basin). However, the authors consider that given the multitude of similar conditions (bioclimate, geology, topography, etc.) in which they form, the preliminary conclusions of this study can be extrapolated for other lakes in the area (existing, such South Peșteana and Moi, or planned, such as Roșia and North Peșteana). This study presents data on the existing biotope and biocenoses (restricted to species identification), without going into specific details about populations, ecosystem production, energy and matter flows within it, as these investigations demand a longer period of time and more resources and are foreseen for a future development stage of this study.