Wednesday, May 5, 2004

Report: Pye Lake fix will cost Fayetteville $700K+ By JOHN MUNFORD jmunford@TheCitizenNews.com An engineering study of the flood plain around Pye Lake on Fayetteville’s northwest side has determined that the primary cause of flooding downstream from the lake is “inadequate normal spillway capacity.” The report, which will be discussed at Thursday night’s Fayetteville City Council meeting, said other factors contributing to the problem include “undersized structures under Cornwallis Way.” Even though the dam is in sub-standard condition, it still reduces downstream flows by about 20 percent, according to the report prepared for the city by Integrated Science and Engineering of Fayetteville. The report offers several options for making improvements to the area, three of which would eliminate flooding downstream of the dam for the privately-owned Pye Lake. Cost estimates for those scenarios run from between $704,000 to $740,000 for four options. A fifth plan, tabbed at $1.38 million, would involve purchasing and removing homes that could not be removed from the 100-year floodplain by making improvements downstream of the lake. The council may consider paying for the repair projects by using funds from the city’s stormwater utility program, officials have said. The study was undertaken after the state’s Safe Dams program determined the Lake Pye dam had several structural problems that could result in the loss of life downstream should the dam be breached. Three of the options presented by ISE in a 12-page letter to City Engineer Don Easterbrook will eliminate flooding downstream of the dam, the firm concluded. Several homes in the area were damaged by flooding in June last year when the area received heavy rains overnight. Included in the three options that would totally eliminate downstream flooding are improvements to the dam, estimated at $490,000 to $575,000; construction of a forebay to reduce sedimentation from upstream sources, estimated at $150,000 to $175,000; and construction of wetlands, estimated at $30,000 to $60,000. Two of the scenarios would involve decreasing the size of the dam so it no longer falls under the jurisdiction of the Safe Dams program, according to the report. “The implication for the city is that designing the dam to city standards and lowering the dam by approximately 2.3 feet, or designing the dam to (Safe Dams program) standards, with a lowered normal pool, results in very similar downstream discharges during flood events,” the report stated. Two of the proposed options would cause the lake to be “significantly smaller” than it is currently, the report stated. ISE also pointed out that the city could later construct a boardwalk to make Lake Pye a park and nature area. Costs for that project were not considered in any of the options presented by the firm because they focused on what was needed for flood control only, wrote ISE engineers Charles D. Absher and Richard A. Greuel.