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Where a current needs to be diverted away from a river bank to prevent erosion, one or more groynes (a protective structure of stone or concrete, also spelled groin) may provide a viable option.

Positioning a groyne in a river forces the water to travel further, which slows the water, reducing the eroding effect. As with all river structures, groynes need to be substantial enough to withstand the pressure of the highest floods that occur.

This picture shows a series of groynes placed on a stretch of the Minnow river.

Care needs to be taken to ensure that constructing a groyne to resolve a current flow problem at one point in a river does not simply cause another one further downstream.

Some trial and error over a number of years may be needed before the desired result is achieved.