Morphogenesis of a Floodplain as a Criterion for Assessing the Susceptibility to Water Pollution in an Agriculturally Rich Valley of a Lowland River

Abstract

This study presents the results of the influence of the specific geological landforms occurring in a lowland river floodplain on the recharge and drainage conditions in an agricultural area. Particular attention has been paid to the presence of the buried erosional channels of flood waters, which may constitute the preferential paths for migration of agricultural contaminants. Moreover, the changes of effective infiltration which affect the hydrogeological regime of the tested area were analyzed. Priority was also given to the use of laboratory techniques in order to determine the parameters influencing the contaminant migration in the soil-water environment for the purpose of hydrogeological modeling. Laboratory tests, based on a column experiment, were performed in a Trautwein apparatus with reference to the constant head procedure, using conservative and reactive markers. The parameters of advection, dispersion, and sorption, obtained in the laboratory experiment were then used as the input data for the hydrodynamic model of groundwater flow and contaminant migration in the research area. Based on the created digital model of groundwater flow, the multi-variant analysis of the effect of specific geological features on the conditions of contaminant transport in a valley was performed. The presented tools and methods contributed to a significant increase in the accuracy of recognizing zones susceptible to water pollution and should be adopted in other valley areas exposed to contamination.

Modelling groundwater flow and nitrate transport: a case study of an area used for precision agriculture in the middle part of the Vistula River valley, Poland

“…These forms recognised in the study area concerned crevasses and zone of transformed floodplain (Bujakowski & Falkowski, 2017). It was also reported in our previous research (Sieczka et al, 2018) that in a situation of low and medium precipitation, these landforms, clearly visible in the numerical terrain model (ALS data), have no impact on conditions prevailing at the first aquifer level. However, the zones mentioned are activated during high precipitation, creating a local drainage base.…”

“…The results show a considerable decrease of nitrate concentration in groundwater, which is an effect of several processes that take place in the saturated zone. It was stated in our previous study (Sieczka et al, 2018) that nitrate transport was subjected to advection, hydrodynamic dispersion, sorption and biodegradation. The combination of these processes is a key factor in changes of nitrate concentration in the soil-water system.…”

“…In the case of conservative tracers, the correctness of the model design is limited to verification of the groundwater level in wells and piezometers, while filtration parameters are defined through measurement of hydraulic conductivity in field or laboratory tests. When taking into account other compounds, impacted by sorption or biodegradation in the soil-water environment, it is necessary to specify a number of additional parameters that correspond to the kinetics of these processes (Sieczka & Koda, 2016a, 2016bSieczka et al, 2018).…”

“…The model body and its boundaries(Sieczka et al, 2018). deep boreholes collected by the Central Geological Archive of the Polish Geological Institute-National Research Institute. The assumed homogeneity and isotropy of the separate layers of the model was also taken into account.…”

Hydrogeological Analysis Supported by Remote Sensing Methods as A Tool for Assessing the Safety of Embankments (Case Study from Vistula River Valley, Poland)

“…The dynamic development of remote sensing techniques based on airborne and satellite imagery in spectres reaching beyond the visible bandwidth, as well as measurement techniques based on laser scanning (ALS), enable the acquisition of high resolution data involving, for example, the morphology and dynamics of processes shaping the images of floodplains (e.g., [22][23][24]). Combined with the capabilities of the GIS software [25] and tools for mathematical modelling of groundwater filtration processes, these techniques enable the performance of advanced analyses of the spatial distribution of specific parameters characterising the hydrogeological environment and the very dynamics of the water filtration process in alluvial aquiferous strata [26].…”