Civil Engineering May 2021 | Vol 29 No 4

HARBOUR , COASTAL AND MAR I NE ENG I NEER I NG The Big Bay area is well known for its sandy beaches and picture-postcard views of Table Mountain. Waves rolling in from the Atlantic Ocean provide ideal condi- tions for surfing and other water sports. But those waves also wreak havoc with the coastline, especially with artificial coastal defences put in place to protect man-made developments. This was the case with the 40-year-old Big Bay gabion wall. After years of storm activity, the underpinning structures of the wall finally failed, triggering an emer- gency coastal protection operation by the City of Cape Town. And just to prove that she is not to be messed with, Mother Nature brought some heavy winter storms as work got under way. BACKGROUND For over 30 years, the stretch of coastline south of Big Bay up to the northern end of Small Bay was defended by a gabion wall. Maria le Roux Pr Eng Head: Coastal Engineering & Optimisation City of Cape Town maria.leroux@capetown.gov.za Pierre Roux Senior Coastal Engineer City of Cape Town pierre.roux@capetown.gov.za Emergency operation keeps the waves at (Big) bay When the 40-year-old gabion wall at Big Bay, Cape Town failed, the implementation of an emergency coastal protection structure was required during the Covid-19 lockdown, while the fiercest storms in decades lashed the Peninsula. The complete structure (Credit: Bruce Sutherland, CCT) Civil Engineering May 2021 11