Firmly seat culverts with soil compacted at least halfway up the side of the pipe. Never use less than one foot of cover. The distance between pipes in a multiple culvert installation should be a minimum of half the pipe diameter. When it's necessary to protect approaches and roadbed fills near bridges, provide adequate erosion protection using head walls, wing walls, rip rap, or other methods. Use temporary bridges to minimize stream bank disturbances and provide a means of temporary access to critical areas when permanent structures are not warranted or needed.
Fords Use rock fords if no practical alternative exists.
Approaches, stream banks, and stream bottoms must be hard enough or sufficiently stabilized to minimize stream bottom and bank disturbance.