06-26-1989 Council Packet - Laserfiche WebLink

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Mr. A1 Greig Page 2 June 20, 1989 You indicated that the developer intends to install the ponding area to decrease the rate of runoff through the houses on Chevy Chase Drive. Again, this runoff does not pass through your lot but rather your neighbors. Because there will be little increase in peak flow due to the proposed new house, we feel the only justification for the ponding area as shown on the plans is to remedy an existing poor drainage condition. Apparently this existing problem drainage comes form the golf course itself and not from the area of the house. The pond, if functioning properly, would serve to decrease the rate of flow of water between the houses of your neighbors. However, again it will not affect your lot in terms of runoff. The ponding area as proposed would appear to have a normal water elevation higher than your basement level. While it is not clear whether such a pond would affect groundwater tables in the area, the distance to your house is less than 150 feet and the addition of a ponding area with long term standing water could potentially raise the water table or provide a seepage source for water to reach your basement. The proximity of the pond to your house increases the possibility of groundwater problems in your basement. The design of the pond in particular may cause a problem as the outlet for the pond is only a 4" pipe. Pipe outlets this sm^ 3re easily plugged sometimes by something as simple as a pop can. The nor. standard of design for ponds in the woods would not be to use sue'- a small outle. Based on the results of our review, we feel the ponding area as proposed, north of your property does absolutely no good in terms of improving the surface water conditions on your property and it may result in higher groundwater levels and water in your basement. We think it would better for you if they never built the pond but just left the land the way it is. If the golf course is creating a surface water problem, the club should build a pond further to the north on the golf course property itself rather than right on the property line adjacent to your lot. That location for a pond increases a possible water impact and also results in cutting down all the trees next to your lot. It would be better, in terms of your property, if they just built the new house and didn't fool around with the pond. The impact on your neighbors in terms of surface water discharge is another matter. Please contact me if you have any questions or require further information. Yours truly. SUNpE ENGINEERING, INC. Gerald M. Sunde, P.E. Consulting Engineer GMS/sg •i * ■*