Sediment delivery processes and the spatial distribution of caesium-137 in a small Sicilian basin

Abstract

Abstract:The sediment delivery processes occurring in a small Sicilian basin are modelled using the spatially distributed SEDD model recently proposed by Ferro and Minacapilli. The model is applied by using soil data (grain-size distribution, organic matter content, etc.) of 129 samples uniformly distributed over the study area and compiling the available information (topographic map, soil data, etc.) into a Geographical Information System. Finally, the predictive capability of the distributed sediment delivery approach is tested experimentally using the caesium-137 measurement technique. The comparison between calculated sediment yield and the corresponding measured caesium-137 loss is used to validate the SEDD model at the scale of both the single morphological unit and the entire basin. #

Assessing soil erosion in a small Sicilian basin by caesium-137 measurements and a simplified mass balance model

“…For estimating the baseline input of iy7 Cs to the basin, Cs re f (equal to 94.4 mBq cm' 2 ), a hilltop location having minimum slope and undisturbed by cultivation was selected. Details on the estimation of reference inventory are reported in Ferro et al (1998a). To avoid biased soil redistribution processes resulting from a small number of samples drawn for estimating Cs n ,f and having a high coefficient of variation of 137 Cs activity, a robust estimate of Cs re f was obtained by employing the bootstrap technique to generate sequences of reference values having known mean value (equal to 94.4 mBq cm'") and large sample size (Di Stefano et al, 2000).…”

“…Initially, the basin was divided into morphological units and each polygon of the basin discretization map was digitized. Following the sequential approach suggested by Ferro & Minacapilli (1995) and Ferro et al (1998aFerro et al ( , 1998b, the within-basin variability of the sediment delivery processes was modelled by calculating the sediment delivery ratio SDRi of each morphological unit using the following equation:…”

“…in which t p j is the travel time of each morphological unit, l p>i and s p j are the length and the slope of the hydraulic path, (3 is a coefficient which is assumed constant for a given basin and is equal to 0.0001952 for the Sparacia basin (Ferro et al, 1998a), N p is the number of morphological units localized along the hydraulic path, and Ày and S[j are the length and the slope of each morphological unit i localized along the hydraulic pathj.…”

Estimation of the quantity of soil loss in the thalwegs of the streams formed by heavy rainfalls in the breakup furrows at arable slopes: application of satellite imagery, GIS and radiocesium method

“…95, 302026, Орёл, Россия, e-mail: trofimetc_l_n@mail.ru 2 Санкт-Петербургский государственный университет, институт наук о Земле, кафедра картографии и геоинформатики, 10 линия ВО, д. 33, 199178, Санкт-Петербург, Россия; e-mail: panidi@ya.ru, e.panidi@spbu.ru3 Орловский государственный университет имени И.С. Тургенева, институт естественных наук и биотехнологии, кафедра географии, ул.…”

Ecological Goals and Wetland Preservation Choice

“…These factors are captured within the Universal Soil Loss Equation (USLE), which has been used within a GIS framework to estimate the erosion risk of watershed areas in several previous studies (Yitayew et al 1999;Lee 2004;Lu et al 2004). These studies do not consider sediment delivery, but others have combined the USLE technique with a sediment delivery model (SEDD), incorporating the sediment delivery ratio, in order to estimate the amount sediment that actually reaches watercourses (Ferro et al 1998;Fernandez et al 2003;Fu et al 2006). Since quality GIS-based wetland information is scarce and the analysis of wetlands is difficult using prefabricated models, many erosion risk studies are forced to ignore wetland areas.…”