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2 <br />Design and Construction Cost Considerations <br />Both of the design options will accomplish the original design goal of providing sewer service to <br />Area D1 of the Buckhorn-Mebane EDD. The design and construction of Option 1 would be the <br />less expensive option. The design costs for Option 1 are already a part of the contract amount <br />of $192,000, as noted above. For design Option 2, there would be additional design costs. <br />Though many parts of the design process are similar, designing a gravity sewer system is more <br />intricate work than designing a force main. However, HUA has stated its additional design costs <br />for a gravity sewer line north of Bowman Road would not cause the total contract amount to <br />exceed the original $200,000 cap placed in the design contract. This means that the maximum <br />design cost differential would be $8,000. <br />When considering the construction cost differential between the two design options, only the <br />portions of the two design options that are different will be outlined in this abstract. The majority <br />of the project will remain unchanged regardless of which of these design options is chosen. <br />The current construction estimate for the roughly 1.8 miles of sewer force main along the north <br />side of Bowman Road in Option 1 is .approximately $475,000. The construction of a gravity <br />sewer line is much more expensive than construction of a force main. The work goes slower <br />because precise slopes have to be maintained and often the excavation is deeper than for a <br />force main. In addition, because of the need to follow the natural topography, the length of the <br />line is longer. The current construction estimate for the roughly 2.2 miles of gravity sewer outfall <br />north of Bowman Road in Option 2 is approximately $1,150,000. To put this into perspective, <br />the total estimated cost for construction of Phase 2 water and sewer infrastructure is <br />approximately $3,000,000 for Option 1, so choosing to construct the gravity outfall in Option 2 <br />would represent about a 23% increase in the construction costs. <br />Benefits of a Gravity Outfall in Option 2 <br />As was noted above, choosing to construct a gravity outfall along Bowman Road will add to the <br />design and construction costs. However, it also adds functionality and flexibility to the sewer <br />design. The gravity outfall would be installed in Area "A" (shown on Attachment 1, 423 acres) <br />which was recently added to the County's utility primary service area in the Water and Sewer <br />Management, Planning, and Boundary Agreement (WASMPBA). The gravity outfall would <br />serve the dual purpose of transporting sewer flow from the Phase 2 area of the EDD and <br />allowing property owners in this 423 acre area access to public sewer. Also, because the <br />length of force main would be reduced substantially, the pump station upgrades necessary to <br />pump the wastewater to Mebane's Southeast Regional Pump Station could be less robust, e.g. <br />smaller horsepower pumps could be used to pump the same amount of wastewater. <br />If Option 1 is chosen and a force main is constructed along Bowman Road, there would be no <br />access to public sewer for Area A. If service is desired, a gravity sewer outfall would eventually <br />have to be designed and constructed to serve these properties at a later date. The design and <br />construction costs for the gravity sewer as a stand-alone project would be approximately $1.25 <br />million. In addition, once the gravity sewer outfall was in place, the force main along Bowman <br />Road would most likely be taken out of service and abandoned and the initial $475,000 for the <br />force main construction would have been spent on infrastructure that is no longer in use. <br />Another point to consider is the current development activity in the area around the Southeast <br />Regional Pump Station, west of Area A. If the County had a viable design for a gravity sewer <br />outfall that connected to the SE Regional Pump Station, there is the potential for developers <br />interested in this area to help fund the construction of this portion of the sewer infrastructure. It <br />is much more feasible for a developer to pay for several hundred feet of sewer line extension to <br />