Course of ice phenomena in small water reservoir in Katowice (Poland) in the winter season 2011/2012

Investigations on the ice phenomena were carried out on a small water reservoir located in the northern part of Katowice, at A4 motorway, in terrains of the Shopping-Service Centre “3 Ponds” (“Trzy Stawy”). Observations on the course of ice phenomena were performed in the winter season 2011/2012. Measurements were started in the moment occurrence of the first forms of the ice phenomena and were finished after their complete disappearance. The investigations had a character of systematic, daily observations and consisted in the mapping of ice phenomena. Among basic research aims should be numbered as follows: evaluation of the ice phenomena course, the identification of the ice phenomena forms, determination of changes in the range of ice cover and its characteristics in terms of recreational use as well. The first effects of low air temperatures occurred on the 19th November of 2011. At the beginning the ice phenomena in a form of so-called shore naledi and shore ice appeared. The formation of a compact ice cover happened not before than after nearly two months. Permanent ice cover formed on 16th January 2012. At the end of ice cover occurrence its crashing followed, reflecting in a form of numerous fissures in the ice. The complete disappearance of processes and forms ice phenomena happened on the 21st March 2012. Ice phenomena in the winter season 2011/2012 occurred for 124 days from the 18th November 2011 till the 21st March 2012, including uninterruptedly for 65 days. Ice cover in the initial stage had an ephemeral character. Safe recreational use of ice cover at the reservoir (e.g. walking, fishing, ice skating) was possible only for about 20 days, when its thickness exceeded 15 cm and ice composition had a homogenous (crystalline) structure. The course of ice phenomena indicates their quasinatural character, resulting from the natural conditions.