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1c. Harrison Hill Trail Drainage Imp Project: Award Contract CITY OF CHANHASSEN 7700 Market Boulevard PO Box 147 Chanhassen, MN 55317 Administration Phone: 952.227,1100 Fax: 952.227.1110 Building Inspections Phone: 952.227,1180 Fax: 952.227.1190 Engineering Phone: 952.227.1160 Fax: 952,227.1170 Finance Phone: 952.227.1140 Fax: 952,227.1110 Park & Recreation Phone: 952.227.1120 Fax: 952,227.1110 Recreation Center 2310 Coulter Boulevard Phone: 952.227.1400 Fax: 952.227.1404 Planning & Natural Resources Phone: 952.227.1130 Fax: 952.227.1110 Public Works 1591 Park Road Phone: 952,227,1300 Fax: 952.227.1310 Senior Center Phone: 952:227,1125 Fax: 952.227.1110 Web Site www.ci.chanhassen.mn.us MEMORANDUM TO: ie- i- Todd Gerhardt, City Manager FROM: Terrance Jeffery, Water Resources Coordina~ DATE: April 12, 2010 SUBJ: o~. Harrison Hill Trail Drainage Improvement Project PW116C2: Award of Contract PROPOSED MOTION "The City Council approves a construction contract in the amount of $29,976.01 to Minnesota Dirt Works for work to be performed on the Harrison Hill Drainage Improvement project." City Council approval requires a simple majority vote of the City Council present. BACKGROUND The stormwater conveyance system in Longacres ih Addition has failed on at least two separate occasions. In October of2005 and again in August of2009, the storm sewer between 7136 and 7150 Harrison Hill Trial surcharged and the resulting overland flow resulted in flooding of7150Harrison Hill Trail. A number of factors contributed to the flooding. The house was constructed lower than the design elevation. Landscaping and other land alteration occurred within the emergency overflow between the two residences. The adjoining property owner lowered the elevation of the berm to accommodate the placement of a swing set. The storm sewer had insufficient capacity to handle flows during larger rain events. All of these contributed to the basement flooding at 7159 Harrison Hill Trail. Staff modeled the rain event of August 2009 and determined that there was not adequate capacity in the pipe between the two residences to convey the water. Staff had WSB & Associates, Inc. (WSB) look at the model and the corroborated staffs' conclusion. Staff worked with WSB to develop a plan to redirect a significant portion of the stormwater to the wetland located south of the stormwater pond. This area still discharges to the same larger wetland complex to the south. This will alleviate the burden on the existing system without creating any downstream issues. Chanhassen is a Community for Life - Providing for Today and Planning for Tomorrow Todd Gerhardt Harrison Hills Trail Drainage Improvement Project April 12, 2010 Page 2 Staff has had numerous discussions with the effected property owners along Harrison Hill Trail as well as with the President and Vice President of the Longacres Homeowners Association. QUOTES Requests for quotes were submitted to three grading contractors on March 16, 2010. The bids received are as follows: Minnesota Dirt Works $29,973.29 Min er Construction $39,998.20 Parrott Contracting, Inc. $42,392.00 The engineer's opinion of total project cost was $40,008.00. Minnesota Dirt Works performed the West-Central Lotus Lake Drainage Improvement Project in the summer of2008. The quality of their work was acceptable. Staff is recommending that they be awarded the contract for this project. There is no firm start date as we are waiting for drier conditions before mobilizing equipment into the area. Staff is anticipating a June 14, 2010 start. However, if antecedent moisture conditions allow, an earlier start date could be used. Assuming a June 14,2010 start date, the following schedule would be most likely: April 12, 2010 May 6,2010 June 7, 2010 June 14,2010 July 9, 2010 A ward contract Neighborhood meeting Preconstruction meeting Begin construction Substantial completion Staff is proposing to fund this project from the Fees for Services account of the Surface Water Management Fund (SWMP) 720-0000-4300. There is currently $175,000 still remaining in this fund. Attachments: 1. Project Area Map 2. WSB, Figure 3, Improvement Option 1 - selected option c: Dan Ames, Minnesota Dirt Works, Inc. Todd Hubmer, WSB & Associates, Inc. g:\eng\public\pwl16c2 -longacres-harrison hills trail\award construction_041210.doc Legend D Study Area . C1lYOY lHllll1m -t, o 800 I Feet 1,600 City of Chanhassen Harrison Hill Stormwater Improvements Feasibility Report Figure 1 Study Location Map ... WSB - ,( A..,,,......... f,~... '" 1,l1f,f IW'!\<!\ w+, s o 50 .Feet 100 City of Chanhassen Harrison Hill Stormwater Improvements Feasibility Report Figure 3 Improvement Option 1 . WSB "'h_',,'n,I~.