1. Department of Earth Science, Rice University, Houston, TX 77251, USA.
2. Ven Te Chow Hydrosystems Laboratory, Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Champaign, IL 61801, USA.
3. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, P. R. China.
4. Yellow River Institute of Hydraulic Research, Zhengzhou, Henan 450000, P. R. China.
5. Department of Geology, University of Illinois at Urbana-Champaign, Champaign, IL 61801, USA.