1. a School of Civil and Environmental Engineering , Nanyang Technological University , 50 Nanyang Avenue, Singapore , 639798 , Singapore E-mail:
2. b School of Civil and Environmental Engineering and State Key Laboratory of Water Environment Simulation , Nanyang Technological University , 50 Nanyang Avenue, Singapore , 639798 , Singapore E-mail:
3. c Department of Civil and Environmental Engineering , Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge , MA , 02139 , USA
4. d State Key Laboratory of Water Environment Simulation and School of Environment , Beijing Normal University , Beijing , 100875 , China E-mail:
5. e School of Civil and Environmental Engineering , Nanyang Technological University , 50 Nanyang Avenue, Singapore , 639798 , Singapore E-mail: