Agenda - Public Works Committee - 06/17/2008

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CASE # I UPDATE ON HIGHLANDS AT RIVER PARK POND By: Tim Himmer, Assistant City Engineer Background: Last summer a few residents from the HIGHLANDS AT RNER PARK subdivision approached the City with concerns about a pond that was leaking water. Staff began investigating the issue and fOtmd that the water levels' in the pond were indeed dropping. on a consistent basis for a prolonged period of time, and have continued to do so. The pond was constructed with a bentonite liner, and the City's investigation found areas where this liner may have been damaged by either contractors or residents. It is inconclusive from our research to pinpoint the exact location(s) of the breaches) or when they might have occurred. Staff continued dialogue with the developer (Arc on Development) and a resident (Scott Rothnun) on a strategy to resolve the issue. During those discussions there was consensus from all that there was a problem with the liner, and the ponds ability to retain water. Arcon was reserved to the fact that something needed to be done to remedy the problem, and was open to further investigation of options with the homeowners and staff. A couple of specific ideas were discussed; they included spot repair of the liner at known/suspected breach locations, and the introduction of a chemical sealer (Seepage Control) into. the pond. City assistance (if directed to do so) throughout this process could include filling the pond and maintaining the normal water level for a couple of weeks (if necessary). At the February 2008 Public Works Committee Arcon's escrow security was reduced to $30,000, with the understanding that additional research was to be performed to develop a strategy and schedule to resolve the problem. Since that date additional information has been collected and exchanged on potential solutions. On June 3, 2008 the City received a letter from Arcon stating that due to current market conditions they were not presently in a position to put forth any additional funds, beyond what was currently retained by the City, towards this pond issue. They requested that the City use their current escrow to remedy the situation. Staff has further investigated the option of introducing the chemical sealer and was quoted a price of$30,575 for the product (ESS-13). Observations: There are afew options that could be explored as it relates to Arcon's request to utilize their escrow fund on a potential remedy: 1. Use the retained funds to purchase the ESS-13 product and have City staffintroduce it to the pond according to manufacturer's specifications. This would require staff time and equipment, and potentially filling the pond from the municipal water system. 2. Use the retained funds to purchase the ESS-13 and undertake additional spot repairs to the liner in suspected breach locations utilizing additional funds. What is the source of