The study on the criteria used to distinguish floc sedimentation and gel-like network sedimentation of cohesive fine-grained sediment in a turbulent flow has rarely been carried out. In this preliminary study, we derive three criteria to distinguish these two different sedimentation phases by considering the comparison of the time that a characteristic floc takes to settle through mean distance between characteristic flocs and the time that it takes to move through the same distance under the influence of a turbulent flow. These criteria incorporate physical and chemical factors that have been verified to have some influences on the sediment flocculation in some published literatures, and a simple analysis result is found to be consistent with our qualitative understandings of flocculation phenomenon of cohesive fine-grained sediment.
 Feder, J. (1988). Fractals. New York: Plenum. http://dx.doi.org/10.1007/978-1-4899-2124-6
 Lu, S., Ding, Y., & Guo, J. (1998). Kinetics of Fine Particle Aggregation in Turbulence. Advances in Colloid and Interface Science, 78, 197-235. http://dx.doi.org/10.1016/S0001-8686(98)00062-1
 Zhu, Z., Yang, T., Zhao, M., & Liang, C. (2009). Preliminary Study on the Critical Criterion for Distinguishing Floc Sedimentation and Gel-Like Network Sedimentation. Journal of Sediment Research, 1, 20-25. (In Chinese)