Minutes - Public Works Committee - 09/21/2004

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jj City Engineer Jankowski advised there may be a number of issues in the feasibility study. In particular it may be suggested that the City may participate with trunk funds to extend the water main looping past the properties that benefit. Motion by Counciltnember Elvig, seconded by Councilmember Cook, to recommend to City Council that a feasibility study for the petition improvements be directed upon verification ofthe petition signatures by the City Clerk Case #1: Consider Juniper Ridge Drive/151st Avenue Storm Water Modifications City Engineer Jankowski stated in 2000 modifications were made to the storm sewer system along a portion of Juniper Ridge Drive, which included the segment from 15,1 sf Avenue south to the cul~de~sac. A part of these improvements included the construction of an emergency outfall to the Rum River, which would be utilized during extreme precipitation events. A part of the normal operation of the storm water system calls for the ponding of water within a fifty foot drainage and utility easement located along the northerly side of the lot located at 15000 Juniper Ridge Drive. This ponding area also has as its primary discharge point another outlet which flows into the pond located between Tonto and Ute Streets in the adjacent Juniper Woods subdivision. Subsequent to the 2000 project, a garage was constructed on this lot just beyond the easement. During a recent storm event, storm water ponded beyond the easement and came within a couple of feet of the newly constructed garage. Staff performed some survey work and determined that the outlet weir was set at an elevation that would cause water to pond beyond the drainage and utility easement prior to discharging through the emergency outfall to the river. City Engineer Jankowski indicated in view of this, staff has requested the design engineer do a review of the design criteria to determine the extent to which the weir on the emergency outlet should be lowered. It is also anticipated that additional ponding volume will be required within ,the drainage and utility easement to ensure the peak elevation of the 100~year flood will be contained within the easement. It is anticipated that the corrective work will include; lowering the weir elevation, increasing the pond areas volume, and filling and resodding a portion of the yard at 15000 Juniper Ridge Drive. It is anticipated that all work, except the landscaping will be performed by the Public Works Department. The cost of the landscaping work should be less than $1,000. He advised staff recommends that an analysis of the drainage basin be conducted and that necessary corrective actions be taken to ensure that the 100 year precipitation event is contained within the drainage and utility easement at a contracted construction cost not to exceed .$1,000 which shall come from the storm water utility. Chairperson Zimmerman requested clarification that the construction cost will not exceed $1,000. City Engineer Jankowski explained he had anticipated they would mark out where the 100 year bounce is and sod that over. Cooperation would be needed from the property owners to do that. Public Works Director Kapler explained the issue is that this yard is very flat and when the water comes up one inch it goes over about 10 feet. Staff would like to create a plateau effect to keep Public Works Committee/September 21, 2004 Page 8 of 10