Gregor Petkovšek

Rainfall and runoff erosivity in the alpine climate of north Slovenia: a comparison of different estimation methods

Abstract Rainfall and runoff erosivity is often assessed by using the R factor. For its computation different methods may be used. The aim of this study was to compare some estimation methods for the alpine climate in the Slovenian Alps. Monthly and annual R factor values were calculated according to the RUSLE, using daily precipitation data for the period 1990–2002 in Solčava, which is typical of the alpine region in Slovenia. In this alpine area with rather low rainfall intensities, the expression for computing the rainfall kinetic energy proposed by van Dijk et al. yielded on average 17.9% higher rainfall erosivities than the RUSLE approach. The newly proposed A index yielded on average 40% lower rainfall erosivities than the RUSLE approach. These lower values of rainfall erosivity were caused by the structure of rainfall during erosive events in the alpine region. The analysis in the alpine climate in Slovenia does not support the use of the proposed A index as a replacement for the usually used R factor when assessing rainfall erosivity.

Remediation of Mercury Polluted Sites Due to Mining Activities

During the 500 years of mercury mining in Idrija, large quantities of Hg were released into the environment. Due to chemical transformation (reduction, methylation, oxidation, demethylation) and the transport of mercury enriched particles into the river system and the Gulf of Trieste, the mercury problem is of local, regional, and global concern. The results of some studies indicate that Hg is actively accumulated in terrestrial and aquatic food webs, which leads to an increased exposure of inhabitants frequently consuming food, particularly, fish produced in a contaminated area. In order to understand the impact of mercury mining on the environment and human health, it is necessary to integrate the experience of various disciplines (e.g., chemists, biologists, geologists, hydrologists, epidemiologists, economists, etc.). Political support at the local and regional level in Slovenia and Italy is as well an ultimate requirement for the successful implementation of remediation, based on scientifically based criteria.

Estimating the R factor from daily rainfall data in the sub-Mediterranean climate of southwest Slovenia / Estimation du facteur R à partir de données journalières de pluie dans le climat sub-méditerranéen du Sud-Ouest de la Slovénie

Abstract Abstract Rainfall and runoff play an important role in the process of soil erosion, which is usually expressed with the R factor. To calculate the R factor, long-term precipitation data are needed with high temporal resolution, typically available for only few locations. The aim of this study was to obtain an approximate relationship between the more commonly available daily precipitation data and the R factor. A set of equations is presented for calculating monthly and annual R factor values based on daily precipitation data for a sub-Mediterranean region in southwest Slovenia, and their applicability is discussed. The sum of squares of daily precipitation was found to be the best descriptor of the monthly R factor. The ratio between the R factor and the sum of squares of daily precipitation varies throughout the year and generally follows the mean monthly temperature, with the efficiency coefficient, e, of 0.869 between predicted and observed data on the annual basis.