C150296 Approval letter - Laserfiche WebLink

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Town of Gypsum May 12, 2009 (UPDATED May 22, 2009) Page 4 of 6 Agenda Item 17a repairs and 1,900 feet of new pipe. Construction estimate for the Ditch improvements is $342,000. Alternative No. 1- No Action - This option is not considered viable since the existing dam and spillway do not meet current dam safety regulations. There would likely be significant loss in storage capacity, if a SEO restriction were placed on the reservoir water level. The Ditch would continue to periodically overtop and ditch failures would occur causing erosion on the hillside below. Alternative No. 2- Repair and rehabilitate the existing dam - This alternative would not increase capacity of the dam; however, it would avoid a potential future SEO restriction. This alternative does not assist with the Town's long term goals for meeting existing and growing water needs. Construction estimate for the dam is $2,150,000 for a total of $2,500,000. Alternative No. 3(SELECTED) - Repair and enlarge dam (685 AF) - This alternative will maximize storage and maintain current SEO rating of the dam. The dam's height could be raised 9.5 feet, to 49 feet. This would raise the crest height of the dam 14.5 feet with the crest width extended to 20 feet. Approximately 254 AF of additional storage (685 AF total) would be added to the reservoir. The outlet pipe would be replaced and the spillway modified. Construction estimate for the dam is $2,820,000 for a total of $3,162,000. Alternative No. 4- Repair and enlarge dam (947 AF) - This alternative will increase storage to the decreed capacity with a dam height increase of 19.5 ft and the crest height 24.5 ft. The dam height would be approximately 59 ft(69 ft total). This alternative requires an increase in several dam safety components and therefore is not cost beneficial. Construction estimate for the dam is $3,653,000 for a total of $3,995,000. Project Cost Estimate LEDE Ditch Construction Engineering/Permitting/Mitigation/Legal $122,000 Construction $183,000 Construction Contingency (20%) $37,000 Subtotal $342,000 LEDE Reservoir Construction Engineering/Permitting/Mitigation/Legal $820,000 Construction $1,667,000 Construction Contingency (20%) $333,000 Subtotal $2,820,000 Total $3,162,000 The cost of the enlargement portion for the Project would be $11,100/AF for the 254 AF of enlargement. Design and permitting is expected to occur in 2009/2010 with pipeline construction starting in late 2009 and dam construction starting in 2011.