The primary stage of the water cycle is the precipitation stage, this is when the accumulated water droplets know as rainfall, precipitate from the sky in condensed concentrations of water, know as clouds. With the water hitting the ground some of the droplets will instantly absorbed by the earth. The soil would act like a large sponge collecting the water until it is fully saturated. Before humans inhabited the earth had a balanced Eco-system that would naturally balance out the inflow and outflow of water. The excess water would become runoff, then would flow down hills into valleys or lakes creating rivers and lakes. When the rainfall exceeded the rivers capacity (load) there would be a flood. It would be a naturally controlled flood, and the overflow of water would run into the natural flood plain. Unfortunately with human interference in the fluvial process, the rivers have had to change the natural flow patterns, and floodplains have be drastically altered. Humans like to live near bodies of water, and therefore have built unnatural levees and dams to try to control the rate of flow and where the direction of the river. With the changes that have been made the rivers and lakes now erode different landforms, and can cause catastrophic damage to human and wildlife habitats. After the water has made its way to the ocean from the rivers and other such run off. It begins to evaporate, and cause clouds to form again. Thus replenishing the water cycle.