Safeguarding Venice

The Nortek Aquadopp has been chosen for the monitoring of flow patterns in the lagoon of Venice, Italy.

Over the last century, the Venice lagoon has experienced a drop in the relative land level by more than 23 cm with respect to sea level due to the combined action of a rise in sea level (eustasy) and a drop in land level (subsidence). This loss of land height means that tidal levels, which in the last century would not have flooded built-up areas, now represent “high water” events.

To protect cities and towns in the lagoon, a solution safeguarding them not just from “exceptional” tides, but also from the most frequent flooding has to be found.

Numerous measures are being taken to reduce the effect of these changes, with local schemes in historic and built-up areas of the lagoon for protection against high tides, and mobile barriers at the lagoon inlets, for tides too large for the local protection. The local protection system consists of three breakwaters to the south of the lagoon inlet, raising part of the lagoon bed to –14 meters, and making a section of the inlet itself narrower. This increases the bottom friction, thus reducing the intensity of the tidal currents at the lagoon inlets, which in turn attenuates the tidal elevation.

The mobile barriers are activated when the local protection systems are not sufficient, and they will temporarily isolate the lagoon from the sea.

The measures taken to prevent the high tide water from reaching Venice and its surroundings will lead to changes in the flow pattern, the distribution of salinity and temperature, and it will have an effect on the particle concentration in the Venice lagoon. In order to monitor these parameters, both prior to and after implementation of the preventive measures, 9 fixed stations equipped with Nortek Aquadopp current meters, interfaced to Seabird CTD probes and OBS-3 turbidity sensors will be established.

The Aquadopp was chosen because of its reliability and robust design, the easy interface to high quality CTD and turbidity sensors, and because it never needs recalibration. The deployment of the Nortek Aquadopp meters will be carried out by Thetis SpA (http://www.thetis.it) of Venice, Italy – a company operating as system integrator within environmental and civil engineering.

More about the Aquadopp can be found here.