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E. SURFACE WATER INFORMATION AND CALCULATIONS NLS§ 3.2. As referenced, the subject facility occupies an APN with an acreage of 11.07 acres. The actual facility only encompasses 4.82 acres in area. An area size of 3.13 acres is the actual batch plant facility and 1.69 acres directly to the east is where stormwater runs to from the batch plant area, as I directly observed after a heavy rainfall. The proposed leachfield area is 0.24 acres of the 3.13 acres. These land use areas are delineated in an aerial photo found in Appendix F. The following Mass Balance Approach utilizes these area delineations correlated with Available Rainfall and Net Rainfall Recharge, which were provided by the EHD consultant, Norman Hantzsche, PE. Available Rainfall = 17.85" (1.49 ft) Net Rainfall Recharge = 8.82" (0.735 ft) Pervious/runoff area comparable to a Retention Basin area = 1.69 ac: 1.69 ac + 0.24 ac (LF Area) = 1.93 ac x 325,851 gals/ac-ft x 0.735 ft = 462,236 gals (R1) Impervious areas: Buildings/batch plant/compacted/paved = 3.13 ac - 0.24 ac = 2.89 ac 1.49 ft x 325,851 gals/ac-ft = 485,518 gals/ac x 2.89 ac = 1,403,147 gals runoff from buildings/batch plant/compacted/paved areas entering the 1.69 ac area (b) 1.69 ac x 0.735 ft = 1.24 ac-ft x 325,851 gals/ac-ft = 404,756 gals rainfall directly onto runoff area (c) 17.85" - 8.82" = 9.03" Lost to evaporation from runoff area 9.03" x 27,154 gals/ac-in x 1.69 ac = 414,389 gals (d) (e) = 1,403,147 gals (b) + 404,756 gals (c) -414,389 (d) = 1,393,514 (R2) RI + R2 = R = 462,236 gals + 1,393,514 gals = 1,855,750 gals = 5.70 ac-ft Page -5- Chesney Consulting