Seite - 621 - in Book of Full Papers - Symposium Hydro Engineering

Summarising, following devices have been installed and continuously monitored:  GPS installed on board (Fig. 14) of the pontoon to know in every moment real time position of the submersible pump (x,y,z coordinates);  Sediment concentration device installed on board of the pontoon (on the pumping pipeline) able to continuously record sediment concentration of the “slurry”. Fig. 14 Dredging pump positioning Positionnement de la pompe de dragage GPS coupled with topographic maps of the area to be dredged (Fig. 14) allowed to check every now and then if the dredging thickness required by the Client has been respected. According to Client’s requirement, sediment percentage in the slurry has been continuously checked in three different positions: on board of the pontoon, at the toe of the dam, and at the confluence between Ambiesta stream and Tagliamento river. To correctly understand the location of the dredging activity, the submersible pump productivity, and the new water depths after dredging, the bathymetric survey, done using a multi-beam de- vice (Fig. 15) just before dredging starting, has been compared to a second survey, developed just after dredging activity (Fig. 16). 621