LANDFORM GRADING AND SLOPE EVOLUTION

Transportation corridors and residential developments in steep terrain both require that some grading be carried out to accommodate roadways and building sites. The manner in which this grading is planned and e xecuted and the nature of the resulting topography or landforms that a re created affect not only the visual or aesthetic impact of the devel opment but also the long-term stability of the slopes and effectivenes s of landscaping and revegetation efforts. Conventionally graded slope s can be characterized by essentially planar slope surfaces with const ant gradients. Most slopes in nature, however, consist of complex land forms covered by vegetation that grows in patterns that are adjusted t o hillside hydrogeology. Analysis of slope-evolution models reveals th at a planar slope in many cases is not an equilibrium configuration. L andform-graded slopes on the other hand mimic stable natural slopes an d are characterized by a variety of shapes, including convex and conca ve forms. Downslope drains either follow natural drop lines in the slo pe or are hidden from view in swale-and-berm combinations. Landscaping plants are placed in patterns that occur in nature as opposed to rand om or artificial configurations. The relatively small increase in the costs of engineering and design for landform grading are more than off set by improved visual and aesthetic impact, quicker regulatory approv al, decreased hillside maintenance and sediment removal costs, and inc reased marketability and public acceptance.