Agenda - Public Works Committee - 03/20/2012

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elevation in the ponds. This includes an 18" HDPE outlet and precast concrete outlet structure with a removable grate for access to the planks. It is proposed to leave the overflow at the same elevation as existing, which will have minimal impacts on the elevation of the standing water and the high water levels of the ponds. The estimated cost to install this new outlet is $29,853. Area 2 Based on the high water levels in the ponds near the clubhouse, it appears flooding of the cart paths near Hole 41 may be an issue during large stone events. The existing culverts consist of a 12" CMP and 15" HDPE. To reduce the frequency of the flooding, we recommend installing 24" diameter culverts under the two existing cart paths. The paths would continue to be inundated during storm events greater than 3.5 ", but would not be inundated during storm events less than 3.5 ". The estimated cost to replace the culverts is $6,642. If the golf course does not feel that the cart path flooding is a concern, replacing the culverts is not a necessity. Area 3 The soil in the fairway of Hole #15 has become saturated. There is an existing rock dam southeast of this fairway and it appears that water being contained by the rock dam may be infiltrating into the soil and saturating the fairway. We recommend lining the creek upstream of the rock dam with an impermeable liner and replacing andlor installing new drain tile in the fairway of Hole #15. Lining the creek will eliminate the infiltration into the soil and the drain tile will keep the soil from becoming saturated. The estimated cost for these improvements is $13,530. Area 4 Holes #3 and #17 have had flooding issues. The ponds and swales near the two holes are drained through three 15" CMP culverts. Different sized culverts at different elevations were analyzed. These different sized culverts did not have a significant impact on the high water levels in the area. Without lowering the entire swale and creating more storage, it does not appear that replacing the culverts would have a significant impact. It is our recommendation that the three culverts not be replaced. 163 Lane There is an existing, landlocked low area south of 163 Lane and east of Wolfram Street. During a majority of the year, stormwater runoff infiltrates into the soil. However, during early spring when the ground is frozen and during periods of heavy rainfall, water levels have risen to levels that cause flooding of adjacent properties. Different sized outlet pipes were analyzed to drain the low area. Installing an outlet will have a significant impact on the high water levels in the area and, most importantly, the length of inundation will be greatly reduced. We recommend directionally drilling an