Baffle blocks are concrete structures with different shapes, for example trapezoidal, [1] used in flowing water to reduce its force.[ citation needed ] They are arranged in several rows in stilling basins. [1] They are used in spillways and dams,[ citation needed ] in irrigation systems, [2] to protect fishes in rivers with hydrotechnical installations, [3] to improve sediment deposition, as a solution to scouring in hydraulic projects [4] and in flood control.