Despite recent advancement in the field of sediment transport, the integration of cohesive sediment properties in large-scale transport models remain a challenging task. In order to model adequately the change in particle size that occurs in different environmental conditions, flocculation models based on the so-called Population Balance Equations (PBE) are often used. These models have to be efficient enough to be implemented in numerical transport models, and as full PBE's are time-expensive to run and depend on a huge amount of a-priori unknown parameters, simplifications have to be made. These simplifications comes unavoidably at the cost of properly accounting for the complex particle-particle and particle-fluid interactions. In order to stay as close as possible to the physical processes, we propose a different approach based on a logistic growth model that mimics the Particle Size Distribution (PSD) measured over time for all size classes. The parameters of the model can easily be found from laboratory measurements. In contrast to most models, the particle classes we propose are not defined by particle size, but in terms of mineral sediment composition. One class is composed of (unflocculated) mineral sediment particles, another of flocculated sediment particles and a third one of organic particles. The mass balance between classes and the way to obtain their corresponding average settling velocity are given. Mass balance and settling velocities are the required input parameters for all sediment transport models. The simplicity of the derived expressions, and their link with measurable variables, makes them good candidates for future implementation in such models.

尽管最近在沉积物运输领域取得了进步，但将粘性沉积物属性整合到大规模运输模型中仍然是一项艰巨的任务。为了适当地模拟在不同环境条件下发生的粒径变化，经常使用基于所谓的种群平衡方程（PBE）的絮凝模型。这些模型必须足够有效才能在数值传输模型中实现，并且由于完整的PBE运行非常耗时，并且依赖大量先验未知参数，因此必须进行简化。这些简化不可避免地要以适当考虑复杂的粒子-粒子和粒子-流体相互作用为代价。为了尽可能接近物理过程，我们提出了一种基于逻辑增长模型的不同方法，该模型模拟了所有尺寸级别随时间测量的粒度分布（PSD）。可以从实验室测量中轻松找到模型的参数。与大多数模型相反，我们提出的颗粒类别不是由颗粒大小定义的，而是根据矿物沉积物的成分定义的。一类由（未絮凝的）矿物沉积物颗粒组成，另一类由絮凝的沉积物颗粒组成，第三类由有机颗粒组成。给出了类之间的质量平衡以及获得其相应平均沉降速度的方法。质量平衡和沉降速度是所有沉积物输送模型的必需输入参数。派生表达式的简单性及其与可测量变量的联系，