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Project No. 9929.G Geotechnical Investigation/Vineyard Avenue, Pleasanton 8 August 2003 <br />gradient away from the exterior foundation for a distance of 3 feet. Should the recommended <br />surface gradient not be constructed by the developer as designed by the project Civil Engineer, or <br />should the homeowner alter the surface drainage provided by the developer, then a subdrain <br />system may be required around the perimeter of the structures. Specific recommendations for <br />subdrain construction will be provided upon request. Surface drainage requirements constructed <br />by the developer should be maintained during landscaping. In particular, the creation of planter <br />areas confined on all sides by concrete walkways or decks and the residence foundation is not <br />desirable as any surface water due to rain or irrigation becomes trapped in the planter with no <br />outlet. If such a landscape feature is necessary, surface area drains in the planter area or a <br />subdrain along the foundation perimeter must be installed. <br />32. Continuous roof gutters are recommended. Downspouts from the gutters should be <br />provided with closed pipe conduits to carry storm water away from the structures and graded <br />areas and, thus, reduce the possibility of soil saturation adjacent to the foundations and <br />engineered fills. <br />33. Flower beds or planters are not recommended adjacent to the building foundations <br />because of the possibility of imgation water affecting the foundations or slabs. Should planters <br />be constructed, foliage requiring little irrigation should be planted. It is preferred that irrigation <br />adjacent to the building foundations consist of a drip system. Sprinkler systems may be used; <br />however, it is preferred that sprinkler heads do not water closer than 3 feet from the building <br />foundations. If sprinklers are used within 3 feet, then excessive watering should not be allowed; <br />and good surface drainage in the planter area must be provided. In any case, it is recommended <br />that area surface drains be incorporated into the landscaping to discharge any excessive irrigation <br />or rainwater that may accumulate in the planter area. These surface drains must be constructed in <br />a manner that easy flow of surface water runoff is allowed into the pipe inlets. Ground cover <br />must be maintained to provide uninterrupted flow of surface water to the area drains. <br />TERRASEARCH, inc. Page 20 of 53 <br />