Seasonality of mean flows as a potential tool for the assessment of ecological processes: Mountain rivers, Polish Carpathians

Artur Radecki-Pawlik; Andrzej Wałęga; Dariusz Młyński; Wojciech Młocek; Rafał Kokoszka; Tamara Tokarczyk; Wiwiana Szalińska

doi:10.1016/j.scitotenv.2020.136988

Seasonality of mean flows as a potential tool for the assessment of ecological processes: Mountain rivers, Polish Carpathians

Sci Total Environ. 2020 May 10:716:136988. doi: 10.1016/j.scitotenv.2020.136988. Epub 2020 Jan 30.

Authors

Artur Radecki-Pawlik¹, Andrzej Wałęga², Dariusz Młyński³, Wojciech Młocek⁴, Rafał Kokoszka⁵, Tamara Tokarczyk⁶, Wiwiana Szalińska⁶

Affiliations

¹ Cracow University of Technology, Faculty of Civil Engineering, Division of Structural Mechanics and Material Mechanics, Poland.
² University of Agriculture in Krakow, Department of Sanitary Engineering and Water Management, Poland. Electronic address: andrzej.walega@urk.edu.pl.
³ University of Agriculture in Krakow, Department of Sanitary Engineering and Water Management, Poland.
⁴ University of Agriculture in Krakow, Department of Applied Mathematics, Poland.
⁵ MGGP S.A., Krakow Branch, Poland.
⁶ Institute of Meteorology and Water Management, National Research Institute, Poland.

PMID: 32059323
DOI: 10.1016/j.scitotenv.2020.136988

Abstract

The classification of river catchments according to their hydrological regime is crucial elements of regionalisation. In absence of hydrological data, the regionalisation of catchment method may be used to asses many flows characteristics like regime or design flow and thus provide help in the analysis of hydrological and ecological processes and also in the management of water resources. Correct clarification of catchments requires knowledge about the main factors that influence on river regime, like meteorologic conditions, land cover/land use, geology, soil properties terrain features, human activities. The aim of the study was to analyse the relationship between selected catchment attributes along with precipitation climatology and seasonality of mean flows (MQ) in the mountainous rivers in the Upper Vistula basin (the biggest and the most important river in Poland) and regionalisation catchments based on seasonality index. To achieve the objective of the study, we concentrated on the mountain stream and river catchments that are regionalised to the Upper Vistula basin (all of which are Vistula tributaries) and we employed the Colwell's seasonality index in an attempt to clear up the said ecohydrological measures. The study confirmed that in mountainous catchments, where response time to rainfall is shorter due to larger slopes, higher seasonality of mean monthly discharges, as expressed by the seasonality index M, is observed. In this case, variability of seasonal rainfall affected seasonality of MQ. In case of smaller slopes and large forest cover and catchment areas, seasonality of flows was lower. The innovative aspect of the presented study is the attempt to correlate the Colwell's seasonality index with the physiographic and meteorological characteristics of the catchment. Until now, the characteristics of the catchments have been used as factors differentiating the hydrological regime of the catchments, thus allowing for agglomeration of similar catchments. Our results foster better understanding of the natural processes in the river basin, which definitely would help in better management of the environment and its relationship with huge number of people living there and depend on it. These results show that the regression tree methods based on CART algorithm can be used as effective tool for classification of catchments.

Keywords: Mountain catchments; Regionalisation; Regression trees; Seasonality of flows; Substrate permeability.