Effect of material particle size on the permeability characteristics and sediment retention performance of cascade permeable dam

•Sediment clogging obviously causes the decrease of the permeability coefficient and the rise of the water level.•The sediment retention performance of D = 1–2 mm is significantly better than that of D = 3–5 mm.•The sediment mass retained by the unit mass of coarse sand caused by the unit volume of water decreases with the increasing flow rate.•The predicted values of the water level before the first dam obtained from the prediction formula are in good agreement with the observed values.