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Potential Rainfall = 13.5" (1.13 ft) Net Rainfall Recharge= 10.8" (0.9 ft). Most rainfall runoff from the impervious areas flow into the unlined stormwater infiltration pond which makes impermeable runoff, permeable. A 20% reduction of the Available Rainfall will be used for Net Rainfall Recharge for that impervious rainfall volume that does not flow to the unlined stormwater basin and/or is lost to evaporation. Pervious areas=65.6 ac: 1.13 ft x 325,851 gals/ac-ft x 65.6 ac x=2,415,468 gals (R1) Impervious areas= 83.7 ac 0.9 ft x 325,851 gals/ac-ft x 83.7 ac=24,546,356 gals runoff from impervious areas entering the stormwater basin and other pervious areas. (b) 149.5 ac x 0.9 ft= 134.6 ac-ft x 325,851 gals/ac-ft=43,843,252 gals rainfall directly as recharge(c) 13.5" - 10.8" =2.7" Lost to runoff from impervious areas and/or evaporation from impervious areas 2.7" x 27,154 gals/ac-in x 149.5 ac= 10,960,712 gals(d) (e)=24,546,356 gals(b)+43,843,252 gals(c)- 10,960,712 (d)=57,428,896(R2) R1 + R2 =R=2,415,468 gals+ 57,428,896 gals= 59,844,364 gals= 183.65 ac-ft III. NITRATE LOADING STUDY FINDINGS A. WASTEWATER FLOW VOLUME PROJECTIONS AND CHARACTERISTICS Wastewater Flow Volume Projections To determine nitrate-nitrogen loading from any project, wastewater flow volumes must be determined as accurately as possible, for the highest reasonable usage. Since the number of onsite employees, customers, visitors, etc. are quite variable over the course of any given year, flow volumes from restroom fixture counts will be used for both the nitrate loading and effluent disposal area design calculations. Ultimately, there are to be 500 onsite people during the crush season, which is approximately four to six months of the year. As referenced, septic tank effluent from all but three standalone buildings will be pumped to a centralized location east of the stormwater basin. The three buildings with standalone OWTS will be Buildings G, G2, and S. These Buildings currently have septic tanks and adjacent effluent disposal areas, which will remain. Found in Appendix E, is a list of fixture counts for each of the referenced Buildings. Taking the highest reasonable use to determine Average Daily Flow(ADF), usage from both toilet and urinal fixture units have been quantified for flow volumes during crush season; the busiest time of any Lyear. ets have been assigned 2 flushes per hour and urinals 4 flushes per hour over a 20 hr Page -6- Chesney Consulting