Geographic Characteristics of the Area Exposed to Inundations in the Pšata River System (Central Slovenia)

Abstract

I. Introduction (by Darko Radinja) The purpose of the whole research theme »Geography of the Areas Exposed to Inundations in Slovenia« is explained. In the part I of the research theme about the Pšata river system the most suitable met hod of research should be elaborated.

II. Hydrogeographic Characteristics of the Area Exposed to Inundations (by Darko Radinja) The study shows the sphere and extent of the area exposed to inundations by the Pšata river. It distinguishes between the area of exceptionally high, and the area of regular inundations. It establishes the frequency, the seasonal distribution, and the duration of inundations. It tries to determine the height of inundating waters, their origin and dynamism. After this hydrogeographic analysis of the area exposed to inundations, the study discusses the relief concept of the area exposed to inundations, and the role of ammeliorations and regulations for the present transformation of the area. At the end it opens broader hydrogeographical problems connected with the further regulation of the whole region.

III. The Main Geomorphologic Characteristics of the Pšata River System (by Milan Šifrer) The Pšata river takes its source at the southwestern foot of the central part of the Kamnik Alps (the source is in the village of Pšata), and it enters the Kamniška Bistrica river near Beričevo. The whole river runs over a flat area; its course, however, is much winding and full of sharp curves, and its riverbed only slightly deepened. For this reason, the river frequently overflows its banks. Important for the frequency of inundations is also the fact that its hilly and mountainous hinterland, especially along its upper course above the Moste village, has such forms of relief and geological structure that it accelerates the rapid flow of waters down into the valleys. To this comes in the middle and lower course of the Pšata river also a rich influx of the groundwater from the plain of the Kamniška Bistrica river. Important for the extent of inundations is also the youngest accumulation which has been accelerated with man's interference in the nature. With the deposition of alluvion and with the raising of the floor of the valley along the Pšata river the extent of inundations has been locally considerably increased.

IV. Soil and vegetation in the Area exposed to Inundations by the Pšata River (by Franc Lovrenčak) The study gives in a short survey the main types of vegetation and soil in the area exposed to inundations by the Pšata river. It discusses briefly also the influence of inundations on the vegetation and on the property of soils, as well as the influence of vegetation upon inundations.

V. Regulations and Ammeliorations in the Pšata River System (by Marko Kolbezen) The unregulated efflux conditions of the Pšata river were the cause of extensive inundations. »The General Water Community Ljubljanica — Sava« tried to improve the flow of the river with extensive regulation works. The first phase, begun in 1949, ended in fact inundations in its lower course beteen the village of Mengeš and the mouth of the Pšata river where it enters into the Kamniška Bistrica river. The second phase, in the years 1960—1962, covered the area exposed to inundations northwest of the village of Mengeš. These regulations were combined with hydroammeliorations with which agricultural surfaces were obtained for the agricultural plant »Pšata«, which is oriented to the dairy cattle breeding, and »Jablje« whose fields yield yearly more than 45 q of wheat pro hectare.

VI. Sociogeographic Characteristics of the Area Exposed to Inundations in the Pšata River System (by Milan Natek) The study shows some of the most characteristic phenomena and processes in the area inundated by the rivers Pšata and Reka. Surveying the economic significance of running waters and their exploitation, the author discusses the manufacturing and other activities driven by water, the role of brooks for the irrigation of grassland and for the supply of settlements with drinking water. Man's interference in the nature with the regulation of the water net is seen in its rearrangement during the last 70 years, in the maintenance and upkeep of riverbeds and of the draining and irrigation canals. The effects and consequences of inundations for the landscape are shown in their relation to then forms of settlements and of peasant houses, in connection with the transport net, as well as with the changes in the exploitation of agricultural complexes in the period from 1896 to 1971.