The study looked at how different mixtures of soil and rock on spoil-banks affect runoff and sediment yield under simulated rainfall. Spoil-banks with more rocks had runoff starting earlier. Higher rainfall intensity led to more runoff and erosion. Spoil-banks with less soil had lower runoff and erosion rates. Runoff rates varied during rainfall, while erosion rates showed stability and fluctuation. Spoil-banks with more rocks had higher mean runoff and erosion rates. Overall, total sediment increased with total runoff.