1. Key Laboratory of Soil and Water Conservation and Desertification Combating; Ministry of Education; College of Soil and Water Conservation; Beijing Forestry University; Qinghua East Road 35# Haidian District Beijing 100083 China
2. Sino-Canada Research Center of Energy and Environmental Studies; North China Electric Power University; Beijing 102206 China
3. Institute for Land and Water Management Research; The Federal Agency for Water Management; Pollnbergstraße 1 3252 Petzenkirchen Austria