The goal of this work is to illustrate a methodology aimed atplanning a monitoring network in urban areas affected by hydrogeologicalinstability phenomena. The monitoring network will providea continuous collection of data and their transmission through aGlobal Position System (GPS) to a central collecting and processingoffice.The monitoring of an area prone to high landslide risk, as couldbe any urban area (the town of Poggioreale in our study case),should take into consideration the collection of data relevant bothfor the knowledge of the landslide features as well as for the planningof reclamation action. At the same time it would also seem opportuneto collect data relating to deep movements, to neutral pressuresand to atmospheric parameters. All these data will be detected,collected and transmitted using a GPS technology in order to createa database to be consulted in real time, easily added to in time anduseful for defining the pre-alert and/or alert thresholds. Of course, acareful evaluation of the geological and geomorphological elementsis needed to optimize the amount and the distribution of the monitoringpoints in the planning of such a monitoring network. The characterizationof the geological, hydrological and morphologicalaspects is necessary to identify the parameters to be used for monitoringpurposes.In the Poggioreale area, the lithological and hydrological featuresand the amount of rainfall constitute the main factors responsiblefor gravitational processes (MONTELEONE et alii, 2000). Themorphology of the area as a whole is in particular or especially characterizedby complex landslides which indicate the precarious stateof the slopes. The monitoring of the Poggioreale area, should thereforeprovide for: deep displacement, surface displacement, neutralpressures and rainfall conditions (BAMBINA et alii, 2003). Those sitesselected as monitoring points of the network, lie in the downtownurban area and in its immediate neighbourhood. The choice of suchpoints has been made according to two basic criteria: the presenceof areas particularly subject to reactivation slope processes andthe presence of public infrastructure, dwellings and technologicalsystems representing areas of greatest economic value.The different types of landslide impose also a random planningof sections relating to surface and deep movements, whose positionscorrespond to those significant areas, aimed at controlling the evolutionof the slope instability.The piezometric control network has been planned taking intoconsideration the variability of the water table which is a function ofthe different degree of permeability showed by different elements ofthe Sandy-Marly Formation of the Belice Valley.
|Rivista||RENDICONTI DELLA SOCIETÀ GEOLOGICA ITALIANA|
|Stato di pubblicazione||Published - 2007|
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