Research objectives: The thesis is focused on hydraulic calculation of small drainage works across of road such as: (step cascades, steep slope, velocity of soil scouring at culvert outlets and scour at culvert outlets). So that, Proposed solutions and selection methods to reinforced or choose the mitigating energy method relevant with downstream culverts on the roads; find solutions for small drainage works across the road with terrain characteristics matching the natural environment conditions and climate in Laos.
