DBPapers

MEASUREMENT AND ANALYSIS OF A FLOOD WAVE PROPAGATION ON THE KACZA RIVER IN GDYNIA IN NORTHERN POLAND

T. Widerski, W. Szpakowski, M. Szydlowski
Monday 11 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7408-04-1 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 31, 453-460 pp, DOI: 10.5593/sgem2017/31/S12.057

ABSTRACT

Kacza river is located in northern Poland in the neighborhood of the Gulf of Gdansk and the Baltic Sea. A Kacza having length of 15 km and catchment area of 53 km2 collects the water into the Gulf mostly from inhabited and forested areas within the administrative boundaries of the city of Gdynia. On the 14th and 15th of July 2016 in northern Poland on the large area of Tri-City agglomeration (Gdynia, Gdansk and Sopot) total daily sum of precipitation over 150 mm was recorded. Rapid rainfall in the area of Tri-City occurred together with a very strong wind from the north-east and east direction. Precipitation lasted continuously from afternoon hours on the 14th of July to the early morning hours on July 15. This hydrometeorological situation caused significant increasing of water levels in rivers and streams flows through the Tri-City agglomeration. As a result, local inundations occurred in the whole region. Kacza river is a good example of extremely high water flow which negatively affected the urbanized neigbourhood of the city of Gdynia.
The article describes the hydraulic effects of the Kacza stream flood wave transition by the urbanized areas of Gdynia. The estimated maximal flow of Kacza stream during the flood episode was determined. After the crest of a flood in Kacza river, on the basis of geodetic measuring of elevation marks left on the obstacles (flood marks) a profile of a maximal range of the flood wave were specified. Geodetic measurements were made using the method of GNSS and leveling technology. Above measurements were compared with water level for probabilities of occurrence 1%, which had been previously defined in order to implement flood hazard maps in the area of Gdynia and the Kacza river.

Keywords: Land surveying, measurement, flood wave, inundations, GIS