How Man Made Things on Instagram: "A dam changes how a river looks and flows. Water collects behind the dam to form a reservoir. The flat valley upstream turns into a lake. Downstream, less water and sediment reach the river, so the channel becomes narrow and erodes differently. Floodplains shrink and the slope of the river changes. Over time the river creates a new shape that is different from its natural form. . like this content ? follow us @howmanmadethings . #manmadewonder #humaninnovation