Which of the following is NOT a method of coastal protection?

The correct answer is identified as piers because they do not serve the primary purpose of coastal protection. Piers are structures built out into the water, typically used for recreational purposes, fishing, or docking boats. While they may alter local hydrodynamics to some extent, their main function is not to prevent erosion or protect the coast.

In contrast, seawalls act as barriers to wave action, thereby preventing erosion of the shoreline. Groynes are structures built perpendicular to the shore designed to interrupt the flow of sediment and reduce sediment drift, which helps to build up beaches and protect against erosion. Beach nourishment involves adding sand to a beach to replenish it and combat erosion, thereby enhancing the natural protection of the coastal area. All these methods are directly aimed at mitigating the impacts of coastal erosion and protecting the coastline.