Rapid river bed recovery after the in-channel mining : the case of Vistula River, Poland

Abstract

The effects of in-channel wet-pit mining is nowadays widely discussed in terms of negative influence of the created pits on the river ecosystem and fluvial processes. The pits induce an alteration of natural flow or sediment transport. This paper describes the post-mining channel recovery observed in a relatively short time in a gravelly sand bed lowland river. The study was based on repeated bathymetry of the channel and grain size analyses of bed material taken from the mining area and its surrounding upstream and downstream pit. We also use calculations of possible bedload sediment movement in the studied river reach. We noticed that the excavation pit exceeded the maximum depth of 8.8 m in 2014 and, immediately after the end of mining, the bedload started to infill the pit. The bathymetric measurements in 2019 indicated that the process of pit infill was completed after five years, though the former pit is refilled with material finer than the natural bedload observed in the discussed river reach, and consists mainly of sand. The studied process of pit infilling runs continuously, even during the annual average water stages.