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253 DISCUSSION In general, the open fields are well suited to Conventional Type septic systems with both soil depth and gentle, consistent sloping topography and as such should be targeted for the septic drainfield for the school. When determining the area needed for the drainfield, the following equation is used to first determine the amount of drainline: Drainline=# students x student GPD /LTAR/3' trench width x 0.75 accepted system 15,6001f= 1,200 x 13 /0.25 x 3 x .75 This drainline calculation is based upon the following assumptions: • 13 GPD/student is based upon the interpretation of state rule .1949(b) of a day school with showers, no cafeteria • The 0.25 LTAR is a considered a conservative estimate. This rate may change pending additional soil testing, in particular hydraulic conductivity tests, and with input from state and/or county regulators Once the amount of drainline is determined, the area needed for the drainfield is calculated as follows: Area= drainline/ 100 ft. long drainlines x 9-foot center spacing x buffer x repair system 336,960 ft2= 15,600 / 100 x 9 x 1.2 x repair system The area calculation is based on the following assumptions: • 100 ft drainlines, this is general starting point, can be increased or decreased • 20% buffer is factored in to allot for diverging drainline and other site factors • Repair system is using the same drainfield type as the initial system As such, 336,960 ft2 or approximately 7.75 acres will be required for the initial and repair systems. The initial and repair systems do not have to be contiguous. Further, the 168,480 ft2 required for just the initial system can be broken into separate drainfields and/or smaller systems to suit the site design. It should also be noted that the repair area(s) could be placed elsewhere on the property and could be a different system type(i.e. Drip). Additional soil testing would be required to determine the viability of this option. CONCLUSIONS The findings presented herein represent our professional opinion based on our Preliminary Soil and Site Evaluation and knowledge of the current laws and rules governing on-site wastewater systems in Orange County and North Carolina. There appears to be ample soil to accommodate the drainfield needs for a 1,200 student day school. However, once a preliminary site design is completed, additional site and soil investigations should be conducted to determine the septic system particulars.