Which slope stabilizing technique involves excavating trenches along a level contour across the slope of the land, with bunds formed on the downstream side using the excavated material to reduce the velocity of runoff? 

Contouring is a method used to stabilize slopes and control erosion by forming contours—essentially level lines—across a slope. This technique involves: Excavating Trenches: Trenches are dug along contour lines, which are horizontal with respect to the slope of the land. Creating Bunds: The material excavated from these trenches is used to create bunds or embankments on the downstream side of the trench. Velocity and Runoff Control: These contour bunds help in slowing down the flow of water across the slope, reducing soil erosion and promoting the infiltration of water into the soil.