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1998 Trail ProjectHoward R, Green Qompany CONSULTING ENGINEERS February 3, 1998 File: 801380j-0026 £.: rmerly MSA C,msu/tmg Engineer~ Mr. Todd Hoffman Park and Recreation Director City of Chanhassen 690 City Center Ddve Chanhassen, MN 55317 RE: 1998 CHANHASSEN TRAIL PROJECT ALIGNMENT OPTIONS AND ISSUES GALPIN BOULEVARD NORTH OF LAKE LUCY ROAD Dear Mr. Hoffman: As requested by the Park and Recreation Commission on Tuesday, January 27t~, we are providing additional information on the proposed trail segment along Galpin Boulevard mIrth of Lake Lucy Road. As you know, at the January 27th meeting, the commission recommended that the trail be extended to Mayflower Street, however, the commission requested more inforr, aation before deciding what side of Galpin Boulevard to construct the trail on. We hope to provice that requested information in this correspondence. Because the trail will be constructed along the curb line, easements will be minimized along either the west or east side of Gatpin Boulevard. Below is a summary of the num:~er of properties affected by the proposed trail segment W..est Side Properties along proposed trail alignment Estimated temporary easements required 18 15 2-5 4-6 The temporary easements would be needed to match proposed slopes into existing slopes off the edge of the trail. Temporary easements may also be needed to construct drainage swales and divert stormwater to appropriate locations. Construction of retaining walls downslope from the trail could allow for trail construction with ferrer temporary easements. EXIST. JNG UTIL_I.TIE8 Existing utilities along Galpin Boulevard north of Lake Lucy Road include water and sewe: along the west side of the road and power poles and overhead wires along the east side of the road. If the trail is constructed along the west side of the road, the trail will cross sanitaw sewer manhole covers and water valves. These would need to be raised to the grade of the trail or trail embankment. Mr. Todd Hoffman February 3, 1998 Page Two We contacted Mr. Jim Carlson, at NSP, about the possibility of constructing a trail along the east side of Galpin Boulevard. Mr. Cadson indicated that most if not all of the power poles would need to be relocated to construct an 8*foot wide bituminous trail. There are 17 poles along the east side of Galpin Boulevard between Lake Lucy Road and Mayflower. Mr. Carlson estimated that the cost for relbcation would be $3000-$4000 per power pole. He said that NSP would charge for moving the poles because of the narrow constraints of the project limits and th~,t the west side of Galpin is a viable alternative to the east side. Other utilities located along the east side of Galpin Boulevard include 5 telephone boxes. U,S. West was unavailable to comment..pn this issue. Several of the boxes would need ",o be relocated. ..TREES AND VEGETATION Vegetation disturbance is minimized with construction of the trail along the proposed curb line, however, vegetation removal cannot be completely avoided. Much of the vegetation !o :ated adjacent to Galpln Boulevard north of Crestview Circle is within the right-of-way. If the trail is constructed along the west side of the road, we estimate removal of vegetation along the following properties: 6410 Galpin Boulevard 2051 Melody Hill Road Some clearing and grubbing of natural brush may also be necessary along the wetland ~t the north end of the trail segment. Along the east side of the road, we estimate that vegetation would need to be removed along the following properties: 1960 Whitetail Ridge Court 6441 Galpin Boulevard 1941 Melody Hill Circle 1940 Melody Hill Road 1910 Moline Circle 1900 Moline Circle The properties listed are generally those properties with the brush "hedge* along Galpin Boulevard. It is possible that portions of tl3is hedge may be saved by installing a retainir=g wall along the back of the trail, however, this would also add additional expense to the r. roject. Some clearing and grubbing of natural trees and brush may also be necessary across from the wetland at the north end, adjacent to the steep bank, Howard R, Green Oompany CONSULTING ENGINEERS Mr. Todd Hoffman February 3, 1998 Page Three DRAINAGE AN[:) WETLAND ISSUE8 With construction of the trait along curb and gutter drainage characteristics of the road w II be changed. The existing drainage configuration along Galpin Boulevard consists of ditches and swales that carry runoff away from the road. Curb and gutter will trap water along the curb line, conveying runoff along the road alignment. At Iow points, catchbasins will need to be ins:ailed to drain the runoff from the curb into a storm sewer pipe and ultimately to a pond or wetland. If the trail is constructed on the west side of the road, there is additional cost of extending .storm sewer under Galpin Boulevard. At the north end of the project, a logical destination for the runoff would be the wetland on the east side of the road. If the trail is constructed on the east side, runoff could be diverted directly into the wetiand. Another potential Iow point Js near Crestview Drive. At a minimum, two storm sewer crossings would need to be installed under Galpin Boulevard. Costs for these crossings are shown below. If the trail is constructed on the east side of Galpin Boulevard, there is potential for a sign:ficant wetland impact at the north end of the project. The trail would be constructed with a 3:1 embankment slope that would extend out into the wetland. We estimate the impact in this area would be 0.25 acres of fill. SAFETY CQNCER _NS We understand from the January 27th meeting that several residents have a concern over the safety of pedestrians in this area. We understand these concerns and offer the foll.~wing comments. If the trail is constructed on the west side of the road, signs could be installed warning motorists of pedestrian crossings to the trail at Melody Hill Circle and Pheasant Ddve_ If the trail is constructed on the east side of the read, the trail would carry pedestrian,;., from these neighborhoods to the south, crossing at Lake Lucy Road to the west side of Galpin Boulevard. Regardless of where the trail is constructed, additional pedestrian crossings will be occurring. Signs should be installed at appropriate locations to warn motorists of these crossings. CONSTP,~CTION COST At the January 27th meeting we presented construction cost estimates of $86,375 for the ~:rail on the west side and $95,835 for the trail on the east side. The previous estimates included trail construction and site work. Below are more detailed estimates for constructing the ?.rail on either the west side or east side of Galpin Boulevard north of Lake Lucy Road, J.Lc.m .West Side East Side Trail Construction $81,375 $85,835 Site Work $5,000 $10,000 Utility Relocation $7,050 $50,006 Storm SewedDrainage Issues _$t.2.000 _. $6.00(; Total $10,5,425 $151,83~ Howard R, Green Company CONSULTING F_NQINEERS Mr. Todd Hoffman February 3, 1998 Page Four It is impossible at this time to estimate the required easements costs for each alternative. Some residents along the east side of Galpin Boulevard have indicated they would grant easements at no cost to the City. Based on our estimated impacts for the trail alternatives, more temporary easement square footage would be needed if an 8-foot trail was constructed on the east side of the road verses the west side of the road. We hope the above information is helpful to the Park and Recreation Commission for making this important decision. We will be in attendance at the February 4"' special meeting to discuss the above information and answer any questions the commission may have. Sincerely, Howard R. Green Company David E. Nyberg, P.E. Project Manager DEN/et O:~roj\801350t380-0306-feb owa © R. G een Qompany CONSULTING ENGINEERS