Silting in dams raise the erosionbase. This can prevent guilybed from cutting down, and banks from expanding;
坝地淤积,抬高了侵蚀基准面,可以防止沟道下切和沟岩扩张;
2
The OECD report attributes the rise to 'weakening social integration and erosion of the traditional family support base for the elderly, ' as well as a fast-changing economy over much of the period.