A large part of flood control is about knowing the environmental norms for an area and planning to control seasonal variations in flood water. So a large part of this planning would be about the landscaping and drainage. These landscaping and drainage methods include planning the right vegetation for retaining water and maintaining hillsides; gradually terracing hillside slopes to slow water flow downhill; and man made physical drainage of floodways such as french drains, dykes, dams, drainage canals, and floodways leading to larger public utility maintained sewerage systems.