Giuliano Rodolfi

A typical “calanchi” landscape on the Eastern Apennine margin (Atri, Central Italy): geomorphological features and evolution

Abstract The surroundings of the town of Atri (Abruzzo Region, Central Italy), situated about 10 km from the Adriatic shoreline, can be considered as representative of most part of the Italian seaward peninsular landscape. The subject of this research, the calanchi landscape, often generally considered as “badlands” by non-Italian authors, is, in fact, made up of many singular landforms, each of which ( calanco ) corresponds to a more or less extended hydrographic unit. The dynamics are mainly the result of the action of the particularly aggressive climatic factors (such as the Mediterranean rainfall regime) on weak substrata (clay, silt and sand of the Plio–Pleistocene marine cycles). The morphogenetic activity is not only limited to channel erosion, but it is also due to repeated superficial slides, so that it should in fact be better to consider the calanco as the result of a “combined erosion” process ( sensu [Zachar, D., 1982. Soil Erosion. Elsevier, Amsterdam]). Since the mechanism regulating this process remains unclear, this work wants to offer a contribution to this research field. Multitemporal geomorphological analysis has helped us to distinguish the different areas in which the calanchi evolution has been more or less important in the past. In such a way, it has been possible to characterize the landscape evolution as a function of the parameters that influence soil loss, especially in areas, such as that of Atri, where calanchi -like landforms are highly developed. Moreover, this analysis, coupled with the processing of 40 years rainfall data, also taking into account the concurrent land use changes, has clearly shown that the areas affected by calanchi erosion on the Eastern Apennine margin, still tectonically active, are progressively diminishing.

Gully erosion modelling and landscape response in the Mbuluzi River catchment of Swaziland

Abstract In southern African countries soil erosion and the related problems, such as water quality issues or decreasing soil productivity, are the main topics affecting the inhabitants of both rural and urban areas. Therefore, the attention has been recently placed on those problems related to soil erosion. This can also be documented by an increasing number of studies carried out on erosion and by the development and application of erosion models. Nevertheless, gully erosion phenomena have been widely neglected in erosion modelling. This is because the development of erosion models was focused on those regions with an intense agriculture typical of developed countries on the one hand, and because of the spatial and temporal heterogeneity of gully erosion processes on the other hand. This study regards the identification of gully erosion forms and processes in the Mbuluzi River catchment (Kingdom of Swaziland) by using the Erosion Response Units (ERU) concept. The following modelling of gully erosion was done through the stable gully model [Catena 37 (1999) 401]. The input data were obtained through the application of remote sensing techniques (API method) and GIS-analyses. The example from Swaziland shows that the applied methods are able to identify areas affected by gully erosion. Furthermore, it is possible to estimate the amount of soil loss due to gully erosion, which, for example, is not taken into consideration by the USLE-type models.

Carta geomorfológica de la sección central y occidental de la Región Metropolitana de Santiago

The geomorphologic chart of the western part of the Santiago Metropolitan Region was made considering a lito-morphologic units definition purpose, especially for the interpretation and classification of homogenous slope systems. The chart goal was the identification of homogenous slopes systems, in which the base of the morpho dynamic interpretation is sustained in the geologic nature of the materials. Structurally, the monoclinals reliefs are emphasized. Also, the lithological nature of the layers and not it position in the monoclinal is considered into the analysis of the medium and low mountain environment because, from a geodynamic point of view, they generally operate in a similar way. In the intrusive reliefs, remnants of erosional surfaces are distinguished. The notion of tenaces is also considered in the alluvial forms according to age, distinguishing between pleistocenic, holocenic, and indeterminated tenaces. As results, polygons of units of equal morphogenesis, lithologic and present geodynamics are generated.

Impacto en la geodinámica actual del valle de Nantoco, cuenca del río Copiapó, asociado a la reconversión productiva

The change in productive land use in the Copiapo valley began in the mid seventies, with an increase in the area planted with bush vines in the order of 236%. This has meant the introduction of significant morphological changes, exceeding in many places the morphodynamic thresholds, and generating impacts on the morphology dynamic. These impacts are significant in terms of increased vulnerability to mass removal occurring in episodes of heavy rains associated with the Nino years, with hazard for the resident population and agricultural workers, and in generating significant loss of infrastructure. We present the case of Nantoco basin, a sub-basin of the river Copiapo, which has experienced a notorious human intervention over the past three decades and which was analyzed in reference to its current morphodinamic behavior and the magnitude of its intervention.

Evaluación de la amenaza natural en ambiente semiárido, sustentada en la geomorfología y el modelamiento de índices topográficos. Salamanca, Región de Coquimbo, Chile

In the framework of territorial transformations in the Choapa river valley, we analyze the dynamics of geomorphic processes on basin scale. Special attention is given to changes due to human activities. In semiarid environments, both natural and anthropic landscapes have an immediate dynamic response to varying intensity and impact of rainfall events such as the phenomenon of El Nino. Intensive farming on hillsides, cones and glacis, is an emerging industry, inducing transformations of topography, vegetation and soil. We analyze the current geomorphology characterized by inherited forms, features and their process dynamics. Geomorphological and topographical models are applied to assess the relevant morphodynamics. The models yield information on the natural hazard of mass movements and fl uvially triggred erosion processes for the two study areas Salamanca and Panguesillo.

Assessment of Natural Hazards and Vulnerability in the Rio Copiapó Catchment: A case study in the ungauged Quebrada Cinchado Catchment

Intensive precipitations in desert areas are a very scarce phenomenon. Nevertheless, from time totime these events take place, as in 1997 in Southern Atacama Desert in Chile. The study area withinthe Copiapo catchment is intensively exploited by mining activities. However, in recent years thelandscape has been more and more used for agricultural purposes. Vineyards for grape production areirrigated with water from the Copiapo River and from groundwater aquifers. The agricultural activityis mainly focusing on the flat valley bottoms, as well as drainage lines that become active in casesof precipitation events. Thus, this study seeks to investigate the geo-hazards related to precipitationevents in order to quantify the risk for population and agricultural areas. Therefore, this study appliesa hydrological model calibrated in the ungauged basin of Quebrada Cinchado. The results demonstratethat events like the one on the 12.06.1997 generate intensive floods and related sediment dischargesthat endanger population and agricultural areas. The applied methodology allows quantification offlooding and mudflow risks, as well as to assess the spatial distribution of geo-hazards.

Aspectos geodinámicos de un paleoestuario del desierto marginal de Chile: Río Copiapó

In this investigation we analyze the evolution of forms that constitute the Copiapo River estuarine system during the past 30 years. Through photo interpreta...

Remote Sensing And GIS As Tools For The Hydro-geomorphological Modeling Of Soil Erosion In Semi-arid Mediterranean Regions

2 3 Abstract This contribution highlights the advantages of using a multidisciplinary modelling approach to the characterisation of the environmental dynamics of a typical semi-arid Mediterranean region, the Flumendosa river basin located in central Sardinia (Italy). Here, the widespread presence of geomorphological active processes interacts with the consequences of intense human activities on crop cultivation and forest management to produce a fragile environment the equilibrium of which must be carefully surveyed and maintained. To this end, an hydro-geomorphological soil erosion hazard model was devised and applied using remote sensing and G.I.S. techniques as support tools. Radiometric enhancement and supervised classification processing of multitemporal Landsat TM images were used to derive land cover mformation, allowing to understand the seasonal evolution of the area and to monitor the presence and movement of organic materials. These data were then combined with those derived from ground truth and ground survey campaigns concerning geology and geomorphology. At the same time, rainfall simulations were carried out in order to evaluate the principal parameters involved in the soil erosion processes. On these data a hydro-geomorphological model based on the spatial prevalence of the different erosion processes, was applied. Six main parameters (i.e. soil erosivity, land use, hillslope gradient and curvature, contributing area and soil infiltration capacity) were used and combined with a matrix linear combination. Results show that the model could represent, if routinely applied at a local administrative level, a valuable tool for forecasting the relative risk of soil erosion in the framework of a correct environmental management.

Condiciones geodinámicas derivadas del terremoto y tsunami de 2010 en la costa de Chile central: El caso de Pichilemu

The earthquake and tsunami of 2010, triggered changes in the geomorphological and sedimentary dynamics along the coast of Pichilemu, in central Chile. These changes were evidenced through the retreat and erosion of sandy beaches and coastal sand dunes. Modifi cation patterns were identifi ed through analysis of satellite images prior to and after the earthquake/tsunami, and compared with records from geomorphological fi eldwork carried out in 2004 that measured essential features of representative beach profi les in the headland bay beaches. The variability of beaches dominated by waves was analyzed. The results indicate that there is coastal erosion and a change in the sedimentary balance associated with the subsidence of the coast, and that four years after the earthquake/tsunami, after the erosive phase, a change in tendency towards progradation of sandy coastlines in the headland bay beaches can be observed

Relación entre el cambio de uso del suelo en la cuenca del Aconcagua y su litoral arenoso correlativo: Chile central

Resumen es: En la cuenca del Aconcagua los procesos de modernizacion e intensificacion del uso de suelo se han traducido tanto en una reconversion agricola como en e...