As a new alternative countermeasure to protect the coastal zone and to increase the surfing possibilities in the Leirosa area of Portugal, multifunctional artificial reefs were investigated numerically in this paper. The primary surfing parameters used in the design (i.e., breaker type, peel angle, wave height at breaking, and currents around the artificial reef) were analyzed. The reef functionality was also analyzed for coastal protection. Two reef geometries with different reef angles of 45 and 66° were tested, considering two design wave conditions (storm and common) and two tide levels (medium and low). Simulations show that both reef geometries are adequate for surfing, although the reef angle of 66° is more suitable for standard surfers, and the 45° angle is more adequate for advanced/professional surfers. A morphodynamic study should be carried out to analyze the efficiency of the artificial surf reef for coastal protection.

The paper presents a risk assessment methodology for operational limit states of submarine outfall projects that considers: the environmental legislative framework, the climate agents acting on the coastline and prediction of the plume long-term behaviour near the coastline. The probability of operational failure or stoppage is assessed enabling decision on project design alternatives.