Gravel road embankments in low-lying areas. Cellular confinement systems can be used to prevent the washboarding effect. The gravel used consists of varying amount of crushed stone, sand, and "fines". Fines are silt or clay particles smaller than , which can act as a binder. Crushed stone is used because gravel with fractured faces will stay in place better than rounded river pebbles. A good gravel for a gravel road will have a higher percentage of fines than gravel used as a subbase for a paved road. This often causes problems if a gravel road is paved without adding sand and gravel
Silt land in the past 50 years. With Dutch funding, the Bangladeshi government began to help develop older chars in the late 1970s, and the effort has since become a multi-agency operation building roads, culverts, embankments, cyclone shelters, toilets and ponds, as well as distributing land to settlers. By fall 2010, the program will have allotted some to 21,000 families. A main source of silt in urban rivers is disturbance of soil by construction activity. A main source in rural rivers is erosion from plowing of farm fields, clearcutting or slash and burn treatment of forests. The fertile black silt of