CONCLUSIONS
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CONCLUSIONS |
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| With the success achieved
in the protection and partial restoration of Praia Mansa
and the southern section of Praia Brava, we can conclude: 1. Gabions has proven themselves to be a powerful instrument, both in the protection and in the restauration of beaches. In protection, it has proven itself to be an excellent energy dissipator of waves up to 3.0 meters. In recuperation, the small permeable gabion groins dissipate energy and allows water passage which reduces velocity, thus helping in the deposit of sand. 2. After the conclusion of our project, gabion jobs done by third parties in the northern part of Praia Brava and at Matinhos Beach (just to the north of Praia Brava) were executed with flaws in planning as well as in execution. Shortly afterward, the gabions were destroyed by the sea, proving that this kind of work must be planned and executed by experienced professionals. 3. The three unsuccessful attempts made in the State of Parana of artificial beach nourishment failed, proving that this solution should not be tried again. 4. Emergency protection jobs done with large stones can give relative protection, but, as we have seen, in a few months the stones will be buried and lose their protection function. This can be more harmful in the erosion point-of-view, because it can speed up the process of erosion. 5. Pluvial water must be channalized, and the discharge must be done through pipes that carry it into the sea, or at controlled points with energy dissipation. This is one of the most important, but least followed rules of the trade. 6. Gabions jobs must be done under observation for a minimum of five years, with interventions depending upon the behavior of the sea. Repairs, eventually needed, must be done immediately after damage caused by the sea or, mainly, by vandalism. 7. The great advantage of this kind of job over traditional ones, such as artificial nourishment with a groin field, is that we do not need great knowledge about environmental variables nor studies about environmental impacts, because we interfere only in the micro environment (the backshore and foreshore), reproducing the conditions of dissipation of energy that existed before, indeed helping the sea itself to restore what it itself has removed. Thus, there is no significant alteration of the downstream beaches, other than that which would happen anyway if the previous beach were there. 8. In conclusion, I say over and over again: gabions are the most powerful and cost/beneficial instrument available for beach protection and restauration, that is, if they are properly projected, executed, adjusted and maintained. And, if prejudice about them, based on gabion experiences that did not work because they were poorly applied, is given up... |
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