Sediment transport by overland flow over an area of net deposition

Flume studies were conducted in order to evaluate the influence of:slope, s ediment size, discharge and inflow sediment concentration on sediment depos ition by overland flow. Additionally, experiments were carried out to measu re transport capacity of overland flow at low slopes, using a wide range of discharges. The experimental data show that the hydraulic conditions where net deposition occurs can be divided into two domains. The first domain is characterized by hydraulic conditions where transport capacity is not sign ificant. In the second domain net deposition still occurs but transport cap acity is significant. The size of the latter domain is dependent on the sed iment size distribution, on the hydraulic roughness and on the inflow sedim ent concentration. The experiments clearly indicate the necessity of incorp orating a threshold value in any deposition equation, These experiments dem onstrate that shear stress is a valuable threshold for deposition modelling . Copyright (C) 1999 John Wiley & Sons, Ltd.