What are spurs designed to do?

Spurs are structures typically built into riverbanks or adjacent to waterways with the primary purpose of redirecting water flow away from specific areas, such as the banks or structures. By altering the flow of water, spurs can help prevent erosion of the bank where structures are located, thereby ensuring the stability and integrity of those structures. They achieve this by changing the direction and speed of the water, which can mitigate the impact of strong currents on vulnerable areas.

While there are other objectives associated with waterways, such as reducing sedimentation, increasing river depth, and supporting fish habitats, these functions are not the main purpose of spurs. Their design specifically targets water flow management, making the first answer the most accurate in describing the function of spurs in the context of river engineering and bridge safety inspections.