Agenda - Public Works Committee - 03/21/2017

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Public Works Committee 5. 2. Meeting Date: 03/21/2017 By: Bruce Westby, Engineering/Public Works Title: Consider Recommending Council Approval of City Cost Participation for Looped Watermain Connection through Brookfield 8th Addition Purpose/Background: Purpose: The purpose of this case is to consider recommending City Council approval of City cost participation for a looped watermain connection through Brookfield 8th Addition. Background: Capstone Homes proposes to construct 25 single family homes along an approximately 1,200 foot long cul-de-sac street in Brookfield 8th Addition. This development is in the City's MUSA area and as such is proposed to be served by City water and sanitary sewer. The development plans submitted by Capstone Homes show the 8-inch diameter trunk watermain running through the cul-de-sac and dead -ending at the edge of the plat. Engineering Staff's plan review comments directed the developer to extend the dead-end watermain line approximately 650 feet through an existing City owned right-of-way corridor to the south and to connect the extended watermain to an existing watermain stub north of 166 th Avenue. This would provide a looped trunk watermain system which allows water to be drawn from either end of the trunk line which is preferred to dead-end watermain lines for numerous reasons, which are discussed in more detail below. The developer responded that they can't afford to bear this cost alone, but that they understand the benefits and are agreeable to sharing up to 50% of the costs required to complete this work, to a maximum of $50,000. The estimated cost to extend and connect the 8-inch trunk watermain line, including approximately 500 feet of directional drilled high -density polyethylene (HDPE) watermain and 150 feet of open trenched cast iron pipe (CIP), through the City owned right-of-way between 166th Avenue and Brookfield 8th Addition is approximately $100,000. A 50/50 cost split would therefore result in both parties contributing up to $50,000 for this work. This watermain connection was discussed briefly by the City Council on February 28th. At the time, Council raised concerns that sharing in costs for directed work could set a precedent whereby future developers may request City cost sharing for watermain extensions and connections when requested by the City. However, Staff believes this situation is unique and would not set a precedent for future developer cost -share requests since the requested watermain extension occurs well outside the plat for Brookfield 8th Addition and therefore similar situations are anticipated to be encountered infrequently. The trunk watermain connection will benefit both the City and the developer so City Staff supports a 50/50 cost -share based on dual benefits. Benefits to the City due to a looped water supply system include; 1. Improved public safety response due to increased water pressure and flow rates 2. Improved water quality due to increased water pressure and flow rates 3. Ability to isolate (shut off) fewer homes when maintaining watermain 4. Reduced maintenance costs due to minimal watermain flushing needs Benefits to Capstone Homes due to a looped water supply system include;