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A proper study of high intensity precipitation allows a reduction of the uncertainty in the estimation of the return period of the extreme rainfall, useful for hydraulic works design and for the management of hydrological risk. Because of the intrinsic uncertainty of the rainfall phenomena, it is necessary to adopt a probabilistic approach based on the definition of a theoretical probability distribution that can adequately describes observed data. Nevertheless, a recurring problem, concerns the presence of missing values and the discontinuity of the rainfall recorded data. Therefore, it is important to evaluate when an empirical sample can be considered reliable for an objective estimation of the return period associated to an extreme event. In this paper we used observation of annual maxima rainfall to investigate the changes in the intensity- duration-frequency (IDF) curves when varying the considered registration period length. Short duration and high intensity rainfall data recorded by eight rain gauges in Lazio region (central Italy) for the period between 1928 to 2017 are available. [ABSTRACT FROM AUTHOR]

Erosion is an exogenous phenomenon, antagonistic to the constructive forces both of an endogenous nature (i.e. orogeny) and of a biological nature (i.e. coral reef), leading to the dismantling of the earth's surface and filling, with the clastic material produced, sedimentary basins and depressions in order to level differences in altitude [1]. It is estimated that, in Europe, 25 million hectares of soil are subject to "accelerated erosion processes" [2] and that, in several areas, the magnitude of soil loss is around a few tens of tons per year. Approximately 77% of Italy is at risk of accelerated erosion [3], also due to the lack of conservative measures for soil (hydraulic-agrarian measures, drainage, grassing, etc.). The phenomenon takes on particular importance in cultivated areas, where drastic changes have been imposed in soil use and sometimes, instead of natural and stable land cover, bare soil is subject to erosive agents. In this paper, the erosivity density approach introduced in Revised Universal Soil Loss Equation 2 (RUSLE2 [4]), will be used to develop monthly erosivity maps for the Lazio region (in central Italy). This was achieved through a full investigation carried out on the monthly (Pmd), daily (P24h) and sub-daily (15-minute time-scale, P15) precipitation amounts available from rain gauges deployed across the study area. [ABSTRACT FROM AUTHOR]