Agenda - 08-06-1990 - Laserfiche WebLink

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L Harding Hughes, Zr. :anuary 14, 1987 Page 2 necessary valves, fire hydrants and taps, as well as 1,000 feet of 8 -inch PVC line and four fire hydrants for the school's internal use. This alternative does not, provide for fire protection flow capacity by the Town of Hillsborough water system. 150 guidelines require that 3,000 GPM be deliverable to the school as fire flow, yet that rate cannot be supplied given the restrictions in the existing water distribution system. Residual pressures would fall well below the 20 psi minimum level in several sections of the line at that flow rate. Therefore, we recommend that an on -site tank be erected at the school for the sole purpose of providing an adequate fire flow. The total cost for providing water service and on -site fire protection is $368,280. A breakdown of the unit prices used to develop this estimate is given in Table 1. Domestic & Fire Protection Flows Provided by Town of Hillsborou h Water System A second option is available for providing fire protection as well as water service to the school site. The sections of 6-inch main between Woodsedge and Wildwood must be replaced with a new 12 -inch main to reduce the friction losses generated during a fire demand at the school. Installation of a 12 -inch line from Wildwood to the school site is estimated to cost $420,280, but would preclude the necessity of an elevated storage tank. A breakdown of the unit prices used to develop this estimate is given in Table 2. Sewer Service Extension of Town of Hillsborough sewer service to the proposed site may or may not be available. Beyond the technical aspects of introducing sewage from the site into the existing system, two problems are present that must be considered by the School Board in conjunction with the Town Board before service can be extended. The first problem involves capacity of the existing system. Although the existing system is capable of handling the additional waste volumes from the proposed school, future influx from development tributary to the system may exceed capacity. Previous to the School Board's request, Mr. James Freeland had requested sewer service to a proposed development south of I -85 along NC 86. At this time, however, estimates of waste volume from the development are not available beyond that for a proposed motel. Final analysis of the extension of sewer service to the school site, therefore must be held pending more definitive information from Mr. Freeland. The second problem is that the Town of Hillsborough currently has a moratorium on the construction of additional sewage pump stations. Since the extension of sewer service to the school site requires installation of such a pumping station, this may present a strong roadblock. Looking at the current system capacity without regard to the potential commercial development proposed by Mr. Freeland, several locations in the existing system could act as control points for designing the expansion for the school site. As outlined by Dr. Lunsford the school will house 700 students and be equipped with a cafeteria, resulting in a sewage discharge of 10,500 GPD (average). Current capacity at the Woodsedge pump station totals 87,250 GPD. This reduces to an average daily capacity of 34,900 GPD after applying a 2.5 peaking factor, with current and future development potential in the park totaling 23,975 GPD average (175 GPD /unit). Excess capacity of 10,925 GPD average thus exists at Woodsedge, allowing for the 10,500 GPD average influx from the proposed school. A similar situation exists at the Wildwood pumping station, where current and future influx to the system will total 83,675 GPD 30