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Jager response letter to Staff.01.31.95 Stephen L. Jager Architect 7 0 C h r i s t a n h e r Drive • Enfield. CT 0 6 0 6 2 F o n j F a x 2.03.763. 825 January 31, 1995 REA �f� ❑USE VARIANCE NO. James Martin, Planner 0SIGN Town of Queensbury / I, 531 Bay Road Queensbury, NY 12804-9725 RE: Jeffrey & Debra Godnick - AV 71-1994 Dear Jim, Per Planning Board Resolutions of January 17, 1995, 1 would like to respond to those comments: 1. The Owner intends to install a new on site sewage disposal system per Town of Queensbury Building and Codes Department and Board of Health regulations "Chapter 136, Sewers and Sewage Disposal'. 2. Size of residence and paved areas have been reduced on revised site plan to reduce impervious area and increase permeable area. I have spoke to RIST-FROST to discuss their concerns and have addressed those in a letter dated January 31, 1995. 3. No items under this number. 4. No comment. If you have any questions, please call me. Sincerely, Stephen L. Jager Architect cc: John Lapper, Esq. Jeffrey & Debra Godnick, Owners Stephen L. Jager Architect 0 Chrisfocher Drive • E n 1 1 e I d. CT 0ti_ 082 • For 1Faz 203._'G3. 1825 December 28, 1994 Revised January 31, 1995 Project: Storm water Runoff Calculations & Drywell Design For Jeffrey and Debra Godnick RR1 Box 1759 Lake George, NY 12843 - Design drywell to accommodate post-development runoff and driveway runoff. - Post-development runoff = Proposed impervious - Existing impervious sq. ft. = 5,404 sq ft - 4,821 sq ft = 583 sq ft + driveway 2,070 sf = 2, 653 sq ft - Existing surfaces, C = 0.35 for runoff coefficient - Proposed surfaces, C = 1.0 for runoff coefficient - Q =CiA, where C = runoff coefficient where i = rainfall intensity at 50 year storm where A = difference between post-development and existing development square footage - For very small areas, Tc s 5 min. RUNOFF CALCULATION VoIT,c.f. (cubic feet) _ (1.0 - 0.35)(i, in/hr)(2653 sf)(1 ft./12 in)(T, min)(1 hr/60 min) i, see chart - 50 year storm. T (time) i in/hr VoIT cf 5 min 7.5 89 10 min 6.0 143 20 min 4.3 205 30 min 3.3 236 40 min 2.7 258 c;FR-�Af7cyT 60 min 1.9 272 120 min 1.1 315 240 min 0.7 401 J' . �l 1 of 5 q 02282� yO OF NE December 28, 1994 Revised January 31, 1995 Project: Storm water Runoff Calculations For Jeffrey and Debra Godnick RR1 Box 1759 Lake George, NY 12843 Try a 8 ft dia precast concrete drywell 4 ft. deep CAST IRON GRATE& FRAME SLOPE PRECAST COVER GEOTEXTILE r FABRIC ALL AROUND STONE i ENVELOPE i r3 4-0" 6 t d CRUSHED STONE °v ENVELOPE, CLEAN, 2 1.4, L (WASHED), MIN 2"-3" SIZE, POROSITY 1 b APPROX. 0.35 MAX HIGH GROUND WATER BELOW BOTTOM OF STONE 10'-0" r, =5'-0" 15,,0„ 1-2 =T-6„ SECTION THRU DRYWELL NOT TO SCALE A. Storage Volume = void volume of stone + void volume of drywell Void Volume of Stone =(n(h) (r,2 + r22 + (ri x r2)] -n r32 h2)0.35 3 =15 (52 + 7.52 + (5x7.5)] - n424�0.35 3 = 147 cf Volume of Drywell = n r32 h2 Volume of Drywell = n (42)(4) Storage Volume = 147 cf + 201 cf = 348 cf ` , / 2of5 `; cFSr�, ozzE20.1 y0 FOF N December 28, 1994 Revised January 31, 1995 B. Storage Area of Stone Envelope Surface, sq. ft. _ [n (r, + r2) x ide slope length TT r12 _ [n (5 + 7.5) x 2.52+ 511n52 = 298 sf C. Infiltration Rate ( perc rate of 2.5 minAnch, sandy loam) estimate For 6" x 12" x 12" = 1/12 cf = 0.01111 cf/sf/min Std. perc hole 2.5(3sf) Infiltration rate = 298 sf x .01111 cf/sf/min =3.31 cf/min i 3of5 � FOF t`Ir�TJ ALBANY, NEW YORK 1903-1950 20.0 150 NO REQi IENCY A LYS S B ME FHOD 10.0 EX73EM VA UES 4FrE3 G MBEL 80 6.0 40 O 2.0 S r{HX z 2: 0.6 } r 06 u� r 2 0.4 J J Q LL Z 3 02 01 0.08 006 004 0.02 5 10 15 20 30 40 50 60 2 3 4 5 6 8 10 12 18 24 MINUTES HOURS DURATION 4 of 5 0'2az1'` FOF December 28, 1994 Revised January 31, 1995 PLOT- INFLOW /OUTFLOW HYDROGRAPHS FOR 2653 SF INCREASE IN IMPERMEABLE AREA & 8 FT DIA X 4 FT DEEP DRYWELL (AS DETAILED) 600540 �f 480 j .... 420 DRYWELL CAPACITY PROVIDED AT INFILTRATION RATE=3.31 CF/MIN - -- 360 348 300 - DRYWELL REQUIRED INFLOW CAPACITY } 240 (INCREASED RUNOFF) 180 i.. 120 0 0 510 20 30 40 60 2HRS 4 HRS TIME CONCLUSION-A SINGLE 8 Fr DIA X 4 Fr DEEP DRYWELL WITH STONE ENVELOPE WILL HAVE ADEQUATE CAPACITY TO ACCEPT AND INFILTRATE THE INCREASED RUNOFF FROM 2653 SF OF ADDITIONAL IMPERMEABLE AREA DUE TO 50 YEAR STORM AND SOIL CAPABILITIES AS NOTED. 5 of 5