Many of already existing roads cross wetland river valleys. Also the roads nowadays planned are cutting through valuable wetlands. It is necessary to evaluate the range of their impact on the natural environment. This paper focuses only on the analysis of the road crossing impact on the groundwater level. Two options of crossing the wetlands were analyzed, building the road on embankments and in the bridge. It was assumed that the valley is filled with organic material under laid by permeable sands. Calculation results showed that building a road in the valley affects groundwater level only to the slight extend. Water conditions in the valley may be affected only during the construction of the road. Calculation results were confirmed by field observations.
It should be stressed that the object of this paper is the evaluation of water conditions. Environment might be influenced by other factors.
Soil-plant conditions in selected valleys typical for Bellsund Region are varying from hardly favourable (Skilvika), to favourable (Calypsostranda) and medium (Lyellstranda). Plant growth and development of a soil cover are favoured by grain size composition (loamy sands and light loams), quick warming-up of a soil, relative stability of a ground, location and shape of valleys, etc. Unfavourable soil-plant conditions result from too light or too heavy grain size composition, considerable dynamics of ground mechanical features and high compactness of a soil. Varying contents of carbonates and alkaline reaction (except for almost neutral reaction in organic horizons) were typical for the studied soils. Thickness of humus horizons as well as contents of organic C vary at the three studied sites. Significant is high concentration of easily available Ca and Mg, sometimes also of Na.
The abundance of water has certainly been a very important resource for the development of the Po Valley and has necessitated, more than once, interventions of regulation and drainage that have contributed strongly to imprint a particular conformation on the land. Already in Roman times there were numerous projects of canalisation and intense and diligent commitment to the maintenance of the canals, used for navigation, for irrigation and for the working of the mills. The need to control the excessive amount of water present was the beginning of the exploitation of this great font of richness that was constantly maintained in subsequent eras. In the early Middle Ages, despite the conditions of political instability and great economic and social difficulty, the function of the canals continued to be of great importance, also because the paths of river communication often substituted land roads, then left abandoned. After the 11th century A.D. the resumption of agricultural activity was conducive to the intense task of land reclamation of the Lombardian countryside and of commitment by the cities to amplify their waterways with the construction of new canals and the improvement of those already existing. The example given by Milan, a city lacking a natural river, that equipped itself with a dense network of canal, used in various ambits of the city life (defence, hygiene, agriculture, transport, milling systems) and for connections with the surrounding territory, can be considered as emblematic. In the surrounding countryside, the activity of the Cistercian monks of Chiaravalle represents one of the situations more indicative of how land reclamation and waterways contributed fundamentally to the organisation of the territory over the span of the ages.
According to the current state of research five sand-gravel accumulation levels of Quaternary age are visible in the morphology of the western part of the Holy Cross Mountains, within the Wierna Rzeka, Hutka and Bobrza river valley systems and the lower stretches of the Biała Nida and Czarna Nida river valleys. Two upper levels (V and IV) correspond to valleys formed during the Odranian Glaciation-Saalian, MIS6 and its reccesional phases under the influence of proglacial and extraglacial waters beyond the extent (to the east) of the maximal ice-sheet limit of this glaciation, reaching to the present-day Leśnica-Gnieździska-Łopuszno line. Two lower levels (III and II) are terraces that were typically formed during the climatic conditions thatprevailed during Vistulian stadials. Sands and gravels of the three upper levels (V−III) contain numerous debris flow deposits and cryoturbation structures documenting periglacial conditions during their accumulation. The lowermost level (I) is a typical Holocene floodplain.