Adam Bartnik

Changes in water quality of a small urban river triggered by deep drainage of a construction site

Abstract The paper presents the results of the monitoring of the selected physicochemical properties of the Jasień River waters (in Łódź, the third biggest city of Poland) and their changes under the influence of drainage of a railway station Łódź Fabryczna construction site. Even 25 years ago the Jasień River was a receiver for the sewage from the Łódź textile factories. The drainage of the excavations and disposal of the water into the Jasień River was started on January 2014 and changed stable hydrological, physical and chemical regime of the river once again. In a consequence, average monthly flows exceeded the Jasień River flow in its upper section by six times, and at the beginning by even ten times. Chloride concentration was systematically growing over the study period. This growth and higher water pH were probably associated with increasing level of contaminants in the discharged water and its gradually decreasing uptake. Average annual water temperature increased and a decrease in its amplitude was observed. The annual conductivity and pH patterns became more uniform and the changes in pH followed a clear trend of monthly changes. Water turbidity increased by two times and during summer floods this parameter was often even a few times higher than before the drainage commenced. Chlorides improved water conductance and sodium and potassium increased basicity.

DIURNAL VARIATIONS OF THE BASIC PHYSICO-CHEMICAL CHARACTERISTICS OF A SMALL URBAN RIVER – THE SOKOŁÓWKA IN ŁÓDŹ – A CASE STUDY

The main purpose of the paper was to identify day-and-night variations of the selected physico-chemical water characteristics (discharge, electrical conductivity, temperature, pH and dissolved oxygen) of a small urban river that had been heavily transformed by human activity (Sokołówka river catchment with the area of 7.71 km2). The data came from measurements conducted in the period between 4 October 2011 and 3 October 2012, using the YSI 6920 V2 (multi-parameter probe) and ISCO 2050 (automatic current meter), in 15and 10-minute intervals, respectively. The research has proven the existence of rhythms of diurnal and seasonal variability to the selected water characteristics. The variability of the hourly values of the tested characteristics in particular days depends to a large extent on the value of the analysed feature itself. The variability coefficients of discharge and conductivity increase with the increase in the values thereof. For dissolved oxygen, pH, and water temperature, the variability coefficients decrease with the increase in the values thereof. In the case of water pH, its conductivity, and temperature, the correlations between the given feature and its variability observed at different times of day are not linear, but they run along loops of varying curvature. The average day-and-night variability of the Sokołówka river’s SEC and pH was significantly changed as a result of human impact. The maximum readings of the conductivity and the pH shifted to the morning hours, with no change to the minimum readings.

Seasonality Of The Basic Physical And Chemical Characteristics Of Water Flowing Through The Cascades Of Small Reservoirs In Urban And Suburban Areas

Abstract The paper showed the changes of characteristics of river water flowing through the cascades of reservoirs. One of the cascades is located in a highly urbanized area of Lodz. The second is in a suburban area on the northern outskirts of Lodz agglomeration. However, it still remains under the influence of storm water discharged from the highway. Every 2 weeks, in 4 monitoring points (on the input and on the output of each cascade), the measurements of basic physical and chemical water parameters were made (using data registered in cross-sections obtained between 2006 and 2012). The analysed characteristics can be divided into three groups: 1. No changes in the seasonal fluctuations of analysed characteristics before and after the cascade of reservoirs and no differences between urban and suburban areas in the influence of the cascades on river water; 2. Significant changes in the seasonal fluctuations of analysed characteristics before and after the cascade of reservoirs and no differences between urban and suburban areas in the influence of the cascades on river water; 3. Significant changes in the seasonal fluctuations of analysed characteristics before and after the cascade of reservoirs and also significant differences between urban and suburban areas in the influence of the cascades on river water. The first group includes the temperature and pH of the water, the second group water conductivity and the third group water turbidity and dissolved oxygen in water.