Del. Code tit. 17, § 901

The Department shall drain or cause to be drained by suitable and sufficient ditches, or other conduits, waters which have backed upon lands along the right-of-way of any road or highway caused by the construction, alteration or changing of the natural contour lines and levels along and over the area confined within such right-of-way, whereby the natural flow and drainage from such lands along and over such right-of-ways is retarded, hindered or stopped.