CCP 01-13-1992 - Laserfiche WebLink

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I ~ If ponding is required in the wetland preservation area, the top of the I baffled weir can be raised to an elevation of 972.0. This elevation will still keep the high water level of the pond at elevation 972.8 because 22 I cfs will go over the top of the weir in 100 year 24 hour storm. The water in I the pond will raise to an elevation of 971.3 before being treated by the weir which will pond water approximately 1.8 feet deep. I The 24" RCP pipe will convey the stormwater runoff through approximately 450 I feet of pipe from the wetland preservation area to the low area north of Arden View Drive. The 24" RCP pipe will be centered within permanent and temporary I construction easements. The City of Arden Hills is currently in the process of I acquiring the permanent and temporary construction easements around pond A-7a and to install the storm sewer from the wetland preservation are to pond A-7a. - Refer to page 5 at the end of this report, for a description and a drawing of the proposed permanent and temporary easements. This low area has been I designated by the North Central Drainage Report as the ponding area for the I entire 16.67 acre drainage area, labeled A-7. I Under current conditions the water level of pond A-7a is at elevation 945.3 with an overflow to the west at elevation 945.3 and a peak discharge from the North I Central Drainage Report of 4.8 cfs. The pond east of pond A-7a flows to a low I area that does not have an overflow to pond A-7a. Therefore, the flow that reaches pond A-7a is the area around pond A-7a and the flow being conveyed by I the 24" RC pipe. This amount of runoff, with a discharge out of pond A-7a through the existing channel of 4.8 cfs, requires a storage volume of 1.35 acre feet for the 100 year 24 hour storm. The pond will rise to elevation 946.50, which is approximately 1 foot higher than the present pond level. A maximum I