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Investigation of landslide processes in the Vistula river valley were made as a part of geological work entitled "Identifying and cataloguing natural geological hazards (especially landslides and other geodynamic phenomena) over Poland's territory", commissioned by the Ministry of the Environment and financed by the National Fund for Environmental Protection and Water Management.
Steep escarpments of the Vistula River valley and ice-marginal valleys promote the development of surface mass movements. An additional factor catalyzing landslide processes is the river dynamics, particularly during violent flood rising. Analysing groups of landslides with similar origin and geological and geomorphological conditions and their concentration in the Vistula river valley, the following five zones of intense landslide processes were isolated: the western boundary of the Nadwislanska Lowland, loess escarpment near Sandomierz, the Warsaw City escarpment, the Wloclawek artificial lake zone, Kujawy and the Lower Vistula valley.
Landslides of the Nadwislanska Lowland occur at the edge of the Malopolska Upland. They develop in the cover of loesses due to the activity of the meandering Vistula river. A wide, recently partly stabilized landslide zone extends along the left side of the river, from Krakow to the village of Witow. Loess upland cut by numerous erosional valleys and ravines is a main factor forming the morphology of the earth surface in the Sandomierz region. The predominant type of mass movements developed in this area are rockfalls and relatively low active creeps. Easily soaking shales, which occur there, make favorable conditions for mass movements development within the Warsaw escarpment. Landslips of Quaternary sediments over the top surface of Pliocene measures are observed in zones where the top of Pliocene shales is located over the mean Vistula river level and is sloped towards the river. The area of the Wloclawek artificial lake, and particularly its right bank, is a part of the biggest landslide area in Polish Lowland outspread between towns of Plock and Wloclawek. The easily soaking shales occur at the lake level and their top is inclined towards the water level. Dangerous and intensely developing landslides arise under such conditions. The bank of the lake is destroyed by abrasion caused by intensive water undulating as well. In the zone of Kujawy and Lower Vistula, landslides develop in high slopes of ice-marginal valley of the Vistula river and inside ravines cutting its edges. They are generated by bank erosion of Vistula, effluent seepages of groundwater and bad drainage of rainwaters and meltwaters from the upland.
Detailed geodetic measurements, resistivity tomography and shallow geological drillings were made at selected landslides, which endangered the environment. The aim of those studies was to obtain input data for generating digital models of landslides and recognize them prior to routine monitoring of landslides development.
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