A procedure to reduce the speed at which water is removed from the land. Water is directed to follow the gentler slopes of the terrace rather than the steeper natural slopes. Terracing is usually recommended only for intensively used, eroding cropland in areas of high-intensity rainfall. Terraces are costly to construct and require annual maintenance, but are feasible where arable land is in short supply or where valuable crops can be grown. In order to become self-sufficient in food production, ancient civilizations in Peru often constructed terraces in very steep, mountainous areas. Today, in Nepal, people living in the foothills of the Himalayas use terraces in order to have enough land available for food production.