engleski

Measurements Of Soil Erosion Production on the InvestigationPlots "Abrami" On Flysch In Central Istria /Croatia/

Abstract: The region of central Istria has all the physiogenetic predispositions necessary for the development of water erosion, which is excessive in many places. The water erosion is manifested there in various forms of pluvial erosion (surface wash), particularly in denuded areas so-called badlands, by torrential outflow regime and accordingly by discharge and delivery ratio of the sediment which is mostly deposited in watercourses. Soil erosion investigation in the area of central Istria in Croatia began in the fifties of the last century with a goal of testing the then modern protection methods of hilly surfaces from erosion, i.e. of acquiring necessary experiences on applicability of those methods on Istrian flysch and collecting data on construction costs as well as economic effect of such works. From series of locations under consideration, Abrami near town of Buzet was chosen, lying between 45024' and 45021' degrees of geographic latitude and 13031' and 13025' degrees of geographic longitude, in the upper reach of the Mirna River. It covers an area of 23.46 hectares, on east-north-east exposition. In terms of specific phenomena of soil erosion and torrent occurrences in Istria, that part is very illustrative, and according to expert opinions, in given circumstances also sufficiently representative enough central (flysch) Istria. In 1969 an investigation of quantitative indicators for erosion intensity on this location was organized. Six observation plots were set up to that purpose in order to measure erosion sediment production. Those plots encompass various erosion factors on surfaces with different vegetation cover. Selection of erosion factors investigated was directed towards planted woods and meliorative regulation methods of surfaces affected by erosion, used on a larger scale in wider area of central Istria for restoration of torrential areas. According to adopted program, the emphasis was put on hydrological-biological aspects of soil erosion, in order to acquire insights into effects of various antierosion undertakings on soil wash-outs. During the research, run-off and soil wash-out (sediment production) quantity were measured in dependence on changes of meteorological parameters, and also vegetation cover development was monitored to record more significant changes. Investigation of quantitative indicators for erosion intensity, i.e. quantity measurement of erosion sediment in Abrami was conducted from 1970 to 1977. On an initiative from Faculty for Civil Engineering Studies from Zagreb, measuring equipment on observation plots was resumed during 1999 and 2000, so the measurements continued and they are still going on. The paper briefly describes methodology, purpose and results of sediment production measurements on investigation plots Abrami in central part of Istria, and point out the possibilities of application this results. Precisely, sediment production measurement results in central Istria create a bank of measured data, on whose basis the evaluation of particular parameters within parametric methods for estimation the soil erosion effects may be conducted, and thereby an additional reliability of such methods can be achieved.

Soil erosion; erosion sediment; flysch; resumption of investigation; measurement; erosion parameters; parametric methods; evaluation of parameters.

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