Berms are also used to control erosion and sedimentation by reducing the rate of surface runoff. The berms either reduce the velocity of the water, or direct water to areas that are not susceptible to erosion, thereby reducing the adverse effects of running water on exposed topsoil. Following the 2010 "Deepwater Horizon" oil spill in the Gulf of Mexico, the construction of berms designed to prevent oil from reaching the fragile Louisiana wetlands (which would result in massive erosion) was proposed early on, and was officially approved by the federal government in mid-June, 2010, after numerous failures to stop and contain the oil leak with more advanced technologies.