What are groins breakwaters and seawalls?

Hello, I'm an expert in coastal engineering with a focus on the design and function of various coastal structures. Let's dive into the topic of groins and seawalls. Groins are coastal structures that extend perpendicular to the beach to reduce the rate of longshore drift. They are built to stabilize the beach by trapping sediment and reducing erosion. Groins can be made from a variety of materials, including rocks, concrete, or wood, and are typically designed to be permeable to allow water to flow through while still retaining sediment. Seawalls, on the other hand, are structures built parallel to the shoreline to protect the land from the direct impact of waves. They are often used in urban areas where there is a lot of infrastructure or property that needs to be protected. Seawalls can be made from a variety of materials, including concrete, stone, or steel, and they can take on many different forms, such as vertical walls, sloping walls, or a combination of both. Both groins and seawalls have their advantages and disadvantages. Groins can be effective at stabilizing a beach but may cause erosion downcoast as they trap sediment that would otherwise be transported along the shore. Seawalls can provide a strong defense against wave action but can also reflect energy back onto the beach, potentially causing increased erosion. It's important to consider the specific context and goals of a coastal protection project when choosing between these structures. A thorough understanding of the local coastal processes and an integrated approach to coastal management are key to making the right choice.

Seawalls, groins, jetties and other shoreline stabilization structures have had tremendous impacts on our nation's beaches. Shoreline structures are built to alter the effects of ocean waves, currents and sand movement. They are usually built to "protect" buildings that were built on a beach that is losing sand.