The Paradela dam has a spillway that makes it possible to discharge a maximum flow of 400 m3/s, the water discharges being on the river Sela, about 2km upstream the river Cavado. After the first use of the spillway, some landslides have occurred on the right bank of the river Sela as a result of the erosion generated on its base about one hundred meters near some houses of a small village. This paper presents a study performed for the slope stability where finite element results are taken into account. A monitoring program was established that essentially consisted of measuring sub-horizontal displacements in points located in boreholes at different depths and also phreatic levels. Some monitoring results are presented.

Le barrage de Paradela a une decharge d'eau avec un debit maximal de 400 m3/s sur le fleuve Sela dans un endroit situe environ 2km sur l'amont du fleuve Cavado. Après la première utilisation de cette decharge, quelques glissements se sont verifies sur le versant droit du fleuve Sela resultant de l'erosion generee sur sa base dans une zone à 100 mètres de quelques maisons d'un petit village. Ce travail presente une etude realisee concernant la stabilite du versant avec la consideration des resultats des elements finis. Un programme d'auscultation a ete mis en place pour mesurer les deplacements sub-horizontales sur des points situes en forages à des differentes profondeurs. Quelques resultats de cette monitorization sont presentes.

Der Ueberlauf des Padela Dammes ermoeglicht das Ablassen einer max. Wassermenge on 400 m3/s in den Sela Fluss, ca. 2 km flussaufwaerts des Cavado Flusses. Nach Inbetriebnahme des Ueberlaufes traten in ca. hundert Meter Entfernung zur Wohnbebauung eine Dorfes Erdrutschungen am rechten Ufer des Sela Flusses auf, die auf Erosionen am Flussbett zurueckzufuehren waren. In der vorliegenden Studie wurde die Boeschungsstabilitaet unter Beruecksichtigung von Berechnungsergebnissen der Finiten Element Methode untersucht. Es wurde ein essprogramm ausgearbeiten, das im Wesentlichen auf Messungen der Untergrundverformungen in verschiedenen Bohrlochteufen sowie auf Grundwassermessungen beruht. Im Folgenden sind einige Messergebnisse dargestellt.


The hydroelectric development of river Cavado is located in the North of Portugal. The Paradela project is the fourth carried out with a rock-fill dam creating a reservoir with a 158 Mm3 capacity. The maximum height of the dam is 110m. The watertightness was achieved by an impervious reinforced concrete membrane placed on the upstream face over a layer of placed rock, which was used for a better distribution of the reaction of the dumped rock-fill on the membrane (Figures 1 and 2), (Fernandes et al., 1958). The water is diverted to a concrete lined pressure tunnel, with a total length of 9.5km and with an inside diameter of 2.8m to 2.25m. Near the reservoir, there is a caterpillar gate and a steel trash rack operated in an intake shaft.

The region of the river Sela is very close to the Paradela dam, which is located on the upper part of the river valley that has the exit of the spillway of the Paradela dam.

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