Coastline Management to Prevent Erosion - Essay Example

It is a relatively open beach and is located on a sandy substratum supporting itself on the rocky basement found between two mountains which flank the beach. The average dimensions of the beach are 800 m in length, 110 m in width, and a surface area of 88,000 m2. The beach was facing gradual degeneration since last one century the chief reasons being (1) construction of a dam on a nearby Uruma river which had its mouth nearby and nourished the beach with sediments, (2) The construction of a coastal wall, on account of urban activities, in a direction parallel to the coast produced the occupation of the natural dunes on the beach, provoking a reduction in the volume of material and interference in the seasonal profile change mechanism, thus damaging the beach.

Consequently, there was a substantial depletion of sand on the beach and the slope of the floor growing in angle making it difficult for the surfers to conveniently use the beach. The water gradually moved inwards and engulfed a larger region with its movement towards the district. To overcome this situation, at the end of a detailed study, a strategic plan was designed which combined two systems, (a) sand replenishment for enriching the degenerated shore and (b) breakwater to provoke wave diffraction and prevent further damage.

At the elementary level of the design, it was intended that the interventions should have a minimum impact on the usability of the beach, aesthetics of the place, and minimum impact on the existing natural conditions. It was also considered that regeneration with sand should not provoke a very large increase in the slope of the beach floor. As a part of the design, a curved dike was constructed which extended into water to a length of 1100 m. The curve was designed using logarithmic calculations in order to sustain the impact loads imparted by the waves.

The size of the dike was vertically minimized to reduce its visual effect. This was coupled with the replenishment of the beach with uniform deposits of similar quality of sand along the length of the shore. Considering the data regarding the width of the beach and the loss/gain of sediments obtained during the monitoring that has been carried out, we can deduce that Gross Beach behaves, on occasion, irregularly and unpredictably due to the simultaneous participation of various factors: climate, current, dike, etc.

However, it has been observed that on account of the strategic placement of dike it has been possible to diffract the waves effectively. The replenishment with sand has helped to regenerate the beach which has ultimately restored its previous usability value. However, the dike being of a small size undergoes deformation and degeneration owing to occasional strong waves. This needs to be treated with periodic maintenance. The costing for the projected activity amounted to 7.829.683,60 for material, with the amount increasing to 11.075.087,47 with contracted work.

The project effectively combined an appropriate solution from a technical viewpoint with a work that has had little visual impact and preserved the natural beauty of this area. The fact that the project harmoniously integrated with the locale with minimal effect on the surrounding and restoring the pre-existing conditions clearly justifies the actions taken have been valuable not only from a technical viewpoint as far as the chosen alternatives were concerned, but also aesthetically and environmentally within San Sebastian's development strategies.