6.7. - 6.9. SR 09-16-1996 - Laserfiche WebLink

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SEP-i~-i~6 1~:06 Po0~0~ Mr. Steve Ach September 13, 1996 Page Two B. PRELIMINARY GRADING AND DRAINAGE PLAN The drainage concept shown consists of picking up the flow from the north side of 193rd and piping it through the development to the west edge where it will be allowed to discharge in the park. There is a pond located in the development along the western edge. The remainder of the site is storm sewerefl and the flow is brought to the southeast comer where the connection is made to the existing system in Jackson Avenue. The drainage concept as shown is adequate. We have not received detailed storm drainage calculations nor are any of the pipe sizes shown on this plan. This detailed storm drainage calculation will be required prior to final approval. At that time, we will review it to ensure that the condition that no additional drainage after development is conveyed to the park is met. We will also review it to ensure that the ponds and the quality control issues are adequately addressed. The Grading Plan appears to adequately address drainage issues throughout the development. We would comment that the six single-fmnily lots appear to have their first floor elevations set too low relative to 193rd Avenue NW. We assume that they are set this way so that the walkout level will match the grade at the rear of the homes. We would suggest that the first floor elevations be raised slightly, either by additional depth in the basement, or raising the whole house. The drainage from the rear of the single-family lots is overland westerly toward the west plat boundary. It will be necessary to ensure that there is adequate easement provided in the plat to accommodate this drainage as it tums from west to south. It should be noted that the Grading Plan appears to save trees in the center of the development, approximately 325 feet long by approximately 150 feet wide, and along the extreme southwestern corner, approximately 200 feet long by 50 feet wide. In order to accomplish the saving of these u'ees, it will be necessary to install a retaining wall along the north edge. This retaining wall will be up to seven to nine feet tall at its tallest point. C. PRELIMINARY PLAT As discussed previously with the Developer, the Preliminary Plat shows an individual lot surrounding each of the i5 cottages. The single-family homes at the north end of the plat also have individual lots. D. PRELIMINARY UTILITY PLAN 1. The utility layout has no sizing provided on any of the pipes. As we have discussed before with the Developer, they should be required to bring 16-inch 230~261 - 1303.sep