WMesh Coastal erosion control barriers

Introduction

THE "WMesh" SYSTEM WAS DESIGNED TO IMPROVE TRADITIONAL STONE BREAKWATERS FOR COASTAL PROTECTION.
Traditional stone breakwaters have detrimental collateral effects for the coastal area, the seabed, and the surrounding environment.

The main problems related to stone breakwaters are the following:

• poor water recirculation and therefore stagnant, turbid, and malodorous water
• muddy seabed
• excessive algal accumulations
• sudden level drop after the breakwater
• more depth close to breakwater interruptions
• irregular seabed with dangers for swimmers
• irregular foreshore with promontories and creeks
• visual obstacle on the horizon interfering with rescue operations.

Although the use of breakwaters is widespread for coastal protection, in some cases breakwaters worsened erosion phenomena.
the reason is that such structures relevantly change the direction of marine currents, and the consequences can only be assessed after installation.
If, on the one hand, breakwaters reduce wave impact, on the other hand they cause a level difference between beach and seabed after the breakwaters themselves, which causes crosswise currents carrying sand offshore and create dangerous dips for swimmers.

The WMesh anti-erosion barrier was designed to reach the following objectives:

• dissipate wave energy
• counter-act marine current
• foster sand input and create shallows
• contrasting sediment removal from coasts and lengthen beach nourishment lifetime.

Without radically altering the environment where it is installed.

Other advantages:

• the deflectors composing the modules deviate incoming currents upwards, thus oxygenating water
• the whole barrier becomes a marine habitat regeneration area
• it prevents trawling close to the coast.

"Seafloor" barrier means the barrier lies under the water surface, thus with a low environmental impact, it does not interrupt the horizon and does not interfere with rescue operations.

Features and operating principle

The "WMesh" structure is composed of precast reinforced concrete modules manufactured by Edil Impianti2 with CE-certified materials.
Designed to be transported with traditional lorries to reduce shipping and installation times, the weight was calculated so to arrange the modules on the seabed with small dredges.
The whole structure is placed onto the seabed by installing the modules next to each other in a raw, by using specific hooks to lay and remove the modules.
Since the structure is permeable, the barrier can be continuous and parallel to the coastline, with no dangerous interruptions for water recirculation, as the sea water can flow through the whole structure.
If necessary, the WMesh barrier can follow irregular coastlines or it can be adequately oriented to counteract currents.
In front of ports or channels, the barrier can be interrupted or lower modules can be used in order to enable ship and boat transit.
The module shape makes the barrier resistant against heavy sea in all directions. The module deflector elements can deviate currents upwards, thus reducing wave energy and crosswise currents, which are the main cause of coastal erosion in many cases.