Erosion and sedimentation

In the rivlets and canals of the Venice lagoon, the mechanical erosion of banks and foundations is due to the wave motion, the horizontal flow of water caused by the tides and the movement of water, caused by the transit of more or less large boats.

The tides, those that come directly from the sea and in the same way those produced by the rechange water system in the lagoon, cause the water level in the lagoon to rise and fall cyclically and alternately make the water flow from the open sea towards the interior of the lagoon and vice versa.

The horizontal currents originating from the entry into the lagoon of sea water through the inlets have considerably higher speeds than those due to the entry of water through the lagoon's water exchange system and are therefore potentially more erosive .

In the lagoon and in particular in Venice, in the points where the transit speed of the water is minimal or nil, there is the phenomenon of sediment deposition, which can go as far as obstructing rivlets and partly canals, creating difficulties for navigation.

If well structured, the water exchange system prevents or at least limits the phenomenon of unwanted sedimentation.

Erosion and sedimentation seem to be two different and extraneous phenomena, in reality they are two sides of the same coin. At least in part, they both depend on the speed of water flows. The measures adopted for both phenomena are of the same type, they are simply applied in reverse.

Where debris settles, the replacement system increases the flow rate of the water, at least to some extent, and where the flow of water causes erosion, it moderates the flow rate at least in part.

A ship of considerable tonnage, which passes through a channel inside the lagoon, moves a considerable amount of water towards the shore laterally in the bow. When a point on the shore is reached by the body of water, the water level rises rapidly against the shore and then decreases just as rapidly as the ship passes the point. This phenomenon is particularly erosive towards the banks and foundations facing the transit area.

Using non-turbulent engines will significantly reduce erosion.

The patented system, for the collection, distribution and exchange of water in Venice, significantly reduces the erosion caused by navigation.