Hydrochemical transformations of river waters during the flow in the reception basin on the basis of Olechówka River in Łódź

Abstract

Abstract. This work presents the results of the research experiment of conducting hydrochemical observation of the Olechówka River in Łódź and its flow from the river source until its estuary. The main aim of the research was to set tendencies of changes in waters flowing down from municipal reception basin with developed rain drain system and in waters flowing into bathing areas at the same time. Along with the flow of the river, 12 measuring-research points were established. In each of those points, measurements of the discharge rate and mean flow velocity of water in the channel were performed, which enabled to set average time of the flow of water between individual measuring-research points. The time of storing water in reservoirs was taken into consideration. The total time of the flow of water in the Olechówka River amounted to 856 h and 15 min. The analyses included in situ measurements (T, pH, SEC), analytical determinations Cl -, NH 4 + , NO 3 -, TN, PO 4 3-, TP and Oxidability. The interchangeability of values of tested indicators and discharge point out to their decrease along with the increase of water flowing in the riverbed. There were self-cleaning processes identified in the Olechówka River: dilution and denitrification, along with the accumulation of total phosphorus in the river flow.

Response of diatom assemblages to the disruption of the running water continuum in urban areas, and its consequences on bioassessment

“…Its physical and chemical parameters, i.e., dissolved oxygen, pH, DOC 5 , total nitrogen, ammonium, nitrate, total phosphorus and phosphate content, confirms that from its origin, the stream is heavily polluted ( Table S1 ). The poor water condition of the stream has also been confirmed by other hydrobiological and physical and chemical analyses ( Bagrowicz et al, 2017 ; Fortuniak et al, 2018 ; Ziułkiewicz et al, 2019 ). Previous research using diatom indices also found both the spring section and the downstream range to be in poor ecological condition ( Szczepocka, Nowicka-Krawczyk & Kruk, 2018 ).…”

“…Due to its location, at the outskirts of the city, the stream was characterized by a high diversity of fish species and macroinvertebrates compared to other streams in Łódź. In addition, the hydrochemical conditions of the stream were also investigated in 2015 –2018 to determine the state of the stream using chemical markers ( Bagrowicz et al, 2017 ; Fortuniak et al, 2018 ; Ziułkiewicz et al, 2019 ).…”

Lifting of biogenic compounds by a riverbed from a municipal drainage basin on a day scale

“…1). PD represents the estuary section of the river, while ZM represents is the most naturally preserved part of the Olechówka River and the only one in which in 2016 the process of autopurification has been documented [2]. The characteristics of subcatchment closed with both mcp are presented in Table 1.…”

“…The image of pollution of the Olechówka River during flash flood was captured during the first research season in 2015 [1]. Hydrochemical changes of river water during flow from its "sources" to the estuary were documented in the second research season in 2016 [2]. The third season was devoted to 24-hour physicochemical observation conducted on the Olechówka River at two measurement-control points.…”

“…Work implemented in 2016 showed that during the water flow from the "sources" to the estuary, nitrate and phosphate concentrations decrease with the elongation of the water runoff time, and nitrates additionally with the increase of the discharge rate [2].…”