Some of the larger spate irrigation rank among the largest farmer managed irrigation systems in the world. The structures are sometimes spectacular: earthen bunds, spanning the width of a river, or extensive spurs made of brushwood and stones. Spate systems are made in such a way that ideally the largest floods are kept away from the command area. Very large floods would create considerable damage to the command area. They would destroy flood diversion channels and cause rivers to shift. This is where the ingenuity of many of the traditional systems comes in. Spurs and bunds are generally made in such a way that the main diversion structures in the river break when floods are too big. Breaking of diversion structures also serves to maintain the flood water entitlements of downstream land owners.