Avoiding Grading Problems in the Landscape

Figure 2.3 Stern Grove Concert Meadow Amphitheater, San Francisco, CA. Grading on sloping topography has provided visually attractive and informal seating for an outdoor amphitheater.

lAWrenCe hAlprin, lAndsCApe ArChiteCt Figure 2.4 Private residence, Malinalco, Mexico

MArio sChjetnAn, Grupo de diseño urbAno

Just as an architect must carefully design and detail a roof to avoid leaks, a grading designer must carefully analyze a site and develop a grading plan that will not result in slope failure, drainage into a building, or longterm maintenance problems such as the examples shown in Figures 2.5-A through 2.5-G. Figure 2.5-H demonstrates a properly designed and functioning parking lot grading solution where surface water is directed to an area catch basin. The photographic scenes in Figures 2.5-A thru G represent the equivalent of a leaky roof for the landscape. Such problems are the result of poor basic grading decisions involving the creation of slopes that are too steep relative to the soil condition, inappropriate user traffic, higher user traffic than anticipated, or allowing unwanted water to collect or flow into areas where it is not desired. The second failure conditions shown in Figures 2.5-C thru E were the result of inadequate subsoil preparation such as lack of proper compaction during construction or inappropriate installation of subbase material, or a combination of the two. Site-grading design and the selection and application of materials fall under the scope of work done in site grading. Instructions