Where roads and water intersect, trouble follows. Roads cut off streams and bleed sediment; meanwhile, floods often erode roadbeds into muddy gullies. In Kenya and in nearly 20 countries around the world, "green roads" are repositioning roads as environmental assets instead of liabilities: they use embankments, channels, and dikes to control floods, harvest excess water for use in irrigation, and slash maintenance costs. In the Ethiopian state of Tigray, for instance, green road techniques raised the water table and improved the productivity of adjacent farms by 35 percent.