Not only will they blend in with the natural surroundings, but properly constructed, they will last. To describe the construction of the rolling grade dip we like to use an analogy conceived by a friend. Think of a spoon oriented with the handle on the downhill side of the trail tread. The entire downhill side of the dip is opened up for drainage. This promotes high volume drainage with very low water velocity.
Water moving slowly is less apt to cause erosion cuts or channeling in the surface of the tread.
Take the excavated soil and pile on the trail at the lower end of the dip a slight hump no more than six to eight inches tall. Think of the part of a spoon where the handle joins the main part of the spoon. The hump and the handle should be built in layers. Pack each layer with a McLeod or some other large surface packing device before piling on more dirt. This will keep the center-line from dishing or forming a rut.