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• Scott Harlicker February 19, 1999 Page Two • The small cul-de-sac in the southeast corner of the plat has several house pads that will have very steep driveways. We would recommend that these be reviewed and either the street raised or the house pads lower to lessen the grade of the Driveways. • There are a significant number of areas in this grading plan where drainage: from one lot to another will not follow the lot lines and it will, therefore, not be within the normal drainage and utility easements. This is often the case where trees are tc be saved and existing topography is not to be disturbed. We would recommend, however, wherever there is proposed grading, attempts be made to keep rear and side yard drainage within the described easements. Where this is not possible, additional drainage and utility easements will be necessary to provide for drainage not along lot lines. • Along the south plat line, there are a couple of low areas and additional drainage issues that need to have more information provided to determine the effects on Deerfield Third Addition located immediately to the south. • A number of the intersecting streets and cul-de-sacs along 193fd Avenue. which is the southerly east-west street, have relatively steep approach grades with little or no landing area provided. Ultimately, 193` Avenue will carry a significant amount of traffic. All intersecting streets should be provided with some type of landing for vehicles coming to a stop condition. • B. DRAINAGE ISSUES • The drainage calculations that were submitted seem to be somewhat in adequate. The drainage area that flows to the northeast pond in Outlot C needs to be modeled as if there is no outlet. There is a 12-inch pipe shown as an outlet to the north but that leads to another land locked pond. it is unclear whether or not there is an opportunity for water to flow from the north to the south. This drainage area and pond need to be modeled based on 100-year 24-hour storm verses a 10-day snow melt. The pond in the southeast corner of the plat is shown to be constructed within the City right-of-way. The first question here is this allowable? The reason the • developer has shown it this way is it is a temporary pond and the only ether option would be to dedicate two or three lots for a temporary pond and make them buildible when the pond can be eliminated. This, however, would require the clearing of all trees on those lots. The thought being that building the pond in the right-of-way does no damage to trees that could be saved because the right-of-way will need to be cleared anyhow. This pond also needs to modeled as a no outlet pond. There is a 10-inch outlet shown heading to the east. it is unclear where this flow would go to and how frequently this pond would discharge. We believe the pond should be modeled with no outlet. The drainage in the southwest corner of the plat flows to an existing wetlanc, partially on this property, but the majority falls within the Deerfield Third Additim. The • Deerfield Third Addition constructed over 10 years ago discharges directly to this wetland, however, wetland laws have changed since that time. Hillside Estates 9th Howard R. Green Company 0./PROJ./410-0218.FEB CONSULTING ENGINEERS 17©/73'd 672E 1779 TS9 'OD N93�i9 SIH 8 :TT 666T-6T-Sed