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I I I Council Meeting Minutes June 12, 1995 Page 7 Council Business. continued Staff feels the ponding area should not be eliminated. Elimination of the pond may make it easier for the developer to sell these lots, however, if Ulteig's calculations were in error, Pond 3/4 could overflow onto adjacent developed lots. Benke verified that the proposal involves a 40 ft. extension of Pond 3/4. Mattila noted that Pond 3/4 would be dredged and deepen to pull more water. Proper confirmed that Maurie Anderson, Park Director, reviewed the proposal and spoke to adjacent property owners. Proper said it is agreed upon that Pond 3/4 be enlarged to compensate for a small piece of wetland which needs to be mitigated, however, he opposes decreasing Pond 2. Benke verified that Pond 3/4 would be enlarged to compensate for the wetland, but the developer proposes to eliminate half of Pond 2. Proper said a town home resident stated that recent rains flooded the area beyond Pond 3/4 and spread into the park and town home area. It was found that the outlet to Pond 2 was plugged and inoperable. The proposal may look good on paper, but in reality there is much water coming into the area and the loss of Pond 2 should not be allowed. Benke asked if Pond 2 was not plugged, would flooding had been worse. Proper senses the flooding would have been worse, and feels this issue should have been addressed before construction than now because 90 % of the homes are now built and the affected areas are privately owned. Keith Harstad, applicant, said Pond 2 was never intended to be a pond and is a swale; it became a pond when the outlet was plugged. He feels running a pipe further west would decrease the swale's depth and deal with erosion problems. Some town home residents are willing to live without a walkout basement. When the swale is unplugged, the water runs directly into Pond 3/4 which is designed to hold water and has an overflow outlet. The City installed a restrictor on Pond 3/4 which reduces the flow rate by 35 %; but to solve the problem the restrictor should be removed to increase flow out of Pond 3/4. The proposal will improve the neighborhood appearance because the swale will not appear so deep. He feels Proper is mistaken that the swale is a pond. Benke said the outlet is intended to drain the swale dry, however, the swale was designed to provide peak storage during heavy rains as a temporary pond. Harstad disagrees, and feels in its present state the swale is dry. Benke said the proposal states the swale will be regraded. Proper confirmed that a 6~inch flow restrictor was to be installed in Pond 2, but was not due to confusion of what end feature to use. He feels Pond 2 should not be left in its current state. Ulteig Engineer Charlie Melcher's calculations show a IS-inch pipe would provide drainage to create a pond level lower than its current state. Benke noted the original plan showed a flow restrictor in Swale 2. Melcher said the original plan included a flow restrictor which was never installed. According to Ulteig's analysis, a larger orifice would reduce the level of ponding and additional fill would shift the existing contours. Benke confirmed that Pond 3/4 has orifice control, but Swale 2 does not. Proper said the original Ulteig proposal stated installation of a 9- inch orifice on Swale 2, but the current proposal recommends a lO-inch orifice, he questioned which size should be used. Melcher said the 1991 plan proposed a 10- inch orifice. Proper said the contractor related incorrect information of a 9-inch orifice to the City's consultant which then incorrectly determined an 8-inch orifice. Council Business Innsbruck Park Estates Ponding Area Report 95-104