What do you mean by strengthening dikes and dredging rivers?

It is used for waterway regulation, including deepening, widening and cleaning existing waterways, dredging rivers and dredging, and removing underwater obstacles. Its purposes are: first, dredging the river, increasing the longitudinal slope and sediment discharge capacity of the river, reducing the siltation rate of the river and ensuring flood control safety; The second is to dig sand into the river, reduce the river bed elevation, maintain a certain depth, and facilitate navigation.