Browsing by Subject "vertical hydraulic gradient"

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Access status: Open Access ,
Assessment of the geogenic salinity conditions in the hyporheic zone of the Moszczenica River in the Rogóźno salt dome zone (Zgierz district) based on radium isotopes
(Wydawnictwa AGH, 2025) Ziułkiewicz, Maciej; Grabowski, Paweł; Długosz-Lisiecka, Magdalena
On the border of the Kujavian Anticlinorium and the Łódź Synclinorium, the Rogóźno salt dome was formed and broke through the overburden of Mesozoic formations. The groundwater circulating around them leaches the salt body and, being saline, is subject to drainage in the Moszczenica valley. Previous measurements of vertical hydraulic gradients and physicochemical analyses showed conditions favorable for the penetration of aqueous solutions of Zechstein salt into the riverbed, which is particularly intensified at low surface water levels. The main objective of this publication is to determine the origin of groundwater flowing into the hyporheic zone (HZ) of Moszczenica using radium isotopes. Hydrochemical studies were carried out on deep groundwater in the supply area, flow and drainage zones of the Groundwater Body, within the boundaries of which the salt dome is located. The preliminary assessment of the hydrochemical specificity of HZ waters, carried out using the EMMA method, showed that these are waters which, as a mixture, cannot be related to any of the end member elements selected from the set of local groundwaters. Based on previous hydrochemical studies, the share of deep groundwaters in the HZ was determined to be 22–33%. On this basis, the reconstruction of the sought mixing end element was performed with the isotopic signature of the river water and the mixture of HZ waters. Using several computational scenarios, it was indicated that these may be waters from deep parts adjacent to the salt diapir of Cretaceous aquifers from the southwest.
Access status: Open Access ,
Hydrochemical aspects of water exchange through the bottom of headwater stream in suburban zone on the example of the Malina watercourse in Zgierz (Central Poland)
(Wydawnictwa AGH, 2024) Ziułkiewicz, Maciej; Grulke Rafał
Among the many factors determining the quality of river waters, the influence of the hyporheic zone (HZ) is gaining in importance. Watercourses that exist in the higher parts of catchments are relatively steep and shallow, and the topography of their valleys activate hyporheic flow. The main goal of this work is to assess the impact of the HZ on the hydrochemical state of the head watercourse of the Malina in the suburbs of the city of Zgierz with the focus on biogenic compounds. The riverbed of this stream was researched across two distinct stretches: erosive and accumulative, which differ in the conditions for the hyporheic zone’s interaction with the riverbed. The nutrients are delivered to the stream mainly in the erosive stretch and are related to the inflow of nutrient-rich groundwater from the urbanised catchment. The pollutants transported down by the stream are then delivered to the HZ in the accumulative stretch, where nitrates are denitrified and phosphates are deposited with the suspension. Ammonium nitrogen, in turn, is introduced into the stream from the HZ as a result of either the process of ammonification of organic matter deposited in sediments or inflow with polluted groundwater. The results indicate that the winter season is the most important period in shaping the interaction of river waters with the underlying hyporheic zone, in which the causal side of the relationship should be associated with the subchannel environment, and the effects are recorded in the river waters.