How should a groyne be designed?

Four key considerations for designing a groyne are shape, length, spacing, and direction. The groyne should be shaped like a triangle with a base along the shore and a “hockey stick” end, which is a downstream facing bend in the groyne. Groyne’s should be spaced so the flow can’t reach the banks, and they should be installed using a field fit technique, meaning they are adjusted and modified based on the river’s response in the field. Direction is also important, as a downstream groyne is the preferred design.