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HomeMy WebLinkAboutDrainage Report South of Annex Parking - PLN General - 2/9/1999 02/09/1993 21:42 360b923802 MIKE WNEK PAGE 02 � .:1-::a .:...T•t•_. ...p•:n f'a';l�i c:^: ::::.iy:.mw'.•;•i:"� - �3� _ Jy'y.f�'i i=i�.'•.'.M'e.i'��4".:::�:-^��_• -_fir^ ....-._.. _ dM^_ - " _.:y��=��..�- ':"-__'I«w -----_ - � ,r^i L..:w•.��.....r:..�lrgy,..n y.�f.w. 'i'�•,�e, tF "_.•',:�aMb� .� :�:Y -_ Tx51 �i'•� .Ildilr2 ~F••+r�• �v`'.o:r'-•�., Sri��.� - �.q J•i', n, �• • ...yrCl.Ia.•..•I....nI�L::I••1�11LI:��I�� a7M'aw __aC.� - R! ..5 'u:5,•. r�^� 0 LP. - 'Ir• oA•'I. •�":i.�rl.....:�:::�.�:a_ ���ic - ]�i'``.- Yj - ..,'.�.�`=,��2 Ci•i':•.�[•.r p - '�^•1 :•!( ~�a?-' 'ter n- _,. ...�.aL•; �•�S'^I.�:�r.i..21 ri;mlC;I:.M1O-cca.ems •:v��4Y� i.[:^ i"'yi v•.:1_^. .:d.w >_}� 7/ I^I m +i j:..._.-...• rru+K°°-•�i• _ ..,� 1 �:.. -.. _... .oa. .s... ".I£ „?- _ •,yag• y ,.i>. .:::. ji•x:..:l n•:f::.:Hlrn'4••'►}---�-rc� Y.r..%:.%-:..�:. Q:~'Y- -.qi"�.:r., ifl." e•`x��.-'e fir:.:'_`:_•: 7. `�'sw. •�,'�:a..:-'... ':W I ;r'91T. ,P-:7= _.r'T_��J ��.qn.•-•G""• ` �,� _. •. .�:"v.!•F'. x�" -I�i_ � �!a .!. ��a.• .te'Fj,�,�.j n•=•:ri ai4- la3a� - L4I - 001 ';�o Drainage Report South of Annex Parking - Belfair Krueger / Johnson Mason County plA 10: Jack Johnson P.O. BOX 11le 6eWair, WA QG 3W275-5 T a �1� ;Ii'r Project Number, 230 p� wa ,4 By(hp seal and signature hem atTlxed, 0 E c.0 oti I certify that the enclosed report was S� Isn °G� gaco shad by myself, and that I am /aNaL � aun�►tt��� roplsten�d enylrteur qly p►oad ,_----...� - .�.... standing!n the State of Washington. 315 6 31311?9 b2/09/1999 21.42 3b8b92JUU2 MIKE WNEK PAGE 03 i :ti: _ _ ua __ -`r�r5�_ �.r..g�y., _e,ex-... 'fir,.-�- • r ,t•,i• _ _ v. a n.:m..r..v�:,c n• "s•�'_ _ __.._:_.._ RINAGE NARR&ME PROJECT DESCRIPTION: Parking lot paving for possible future site development PROJECT LOCATION: South of County Annex Building on east side of SR-3 in Belfair. EXISTING DRAINAGE DESCRIPTION: All drainage in the area eventually flows to the roadway ditch along SR-3. The drainage crosses under the highway south of the project via a storm pipe system. EXISTING TOPOGRAPHY: Topography within the project parcel is relatively flat, with no slopes in excess of 5%within the work area. SOILS: Soils consist of glacial till, and are considered to be Hydrological Soil Group "C" for hydrology calculations. LAND USE_ The existing condition is second growth timber, with Curve Number = 81. The proposed condition is asphalt pavement; CN = 98. DRAINAGE CONCEPT: The purpose of this design is to provide a temporary detention system for the parking lot paving. The design needs to be functional yet simplistic. In the future, if building construction takes place, additional storm detention design will be required. Future detention systems will probably need to be underground tanks, due to the limitation of the site. Since the discharge point for the parcel drainage is the highway ditch, the detention concept calls for restricting discharges from the paved site to 100% of the discharge rates of the natural site; for the 2-year, 10-year, and 100-year storm events. Since the effected area is small (0.20 acres), the detention "pond" amounts to a trench with a single pipe discharge. Since only one "orifice" is used, the proposed system actually over-detains for the larger storm events. 2301atorrn1290_Drain-Report.doc MIKE WNEK PAGE 04 WEN BASIN SUMMARY BASIN 70: EX002 NAME; EXISTING CONDITION, 2-YRAR SBUH METHODOLOGY TOTAL AREA_._____: 0-20 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE....: TYPEIA PERVIOUS AREA PRECIPITATION....: 3.50 inches AREA..; 0.20 Acres TIME INTERVAL__-_! 10-00 min Cx...... 81.00 TIME OF CONC..... 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA..: 0.00 Acrea CN....: 98.00 PEAK RATE., 0-07 cfs VOL: 0-03 Ac-fr, TIME, 480 min BASIN IV: EX010 W?JwM: EXISTING CONDITION, 10-YEAR SBUH METHODOLOGY TOTAL AREA.......: 0.20 Acres BASEFLOWS: 0-00 cfs RAINFALL TYPE--: TYPEIA PERVIOUS AREA PRECIPITATION....; 4.80 inches AREA..: 0.20 Acres TIME INTERVAL....: 10.00 min cly--..! 01.00 TIME OF CONC..... 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA_! 0.00 Acres CN... ': 98.00 WEAX RATE! 0.13 cfs voLt 0-05 49-ft TIME: 480 min BASIN ID: EXIOU NAME: EXISTING CONDITION, 100-YEAR $SUN METHODOLOGY TOTAL AREA........ 0.20 Acres BASEFLOWS, 0.00 cfs RAINFALL TYPE....: TYPEIA PERVIOUS Anth PRECIPITATION..__: 7-00 inchea AREA..: 0.20 Acres TIME INTERVAL....: 10.00 min CN....; 01.00 TIME OF CONC..... 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF- 0.20 AREA..; 0.00 Acres CN...': 90-00 PEAK RATE: 0.22 cfs VOL: 0.08 Ac-ft TIMES 450 min BASIN ID: PRO02 NAME; PROPOSED CONDITION, 2-YEAR SBUH METHODOLOGY TOTAL AREA.......: 0.20 Acres DASEFLOWS: 0.00 cfs RAINFALL TYPE....: TYPEIA PERVIOUS AREA PRECIPITATION....: 3.50 inches AREA..; 0.00 Acres TIME INTERVAL....: :0.00 min CR....: 81-00 TIME OF CONC._.: 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF.- 0.20 AREA..: 0.20 acres c1q....' 98.00 PEAR RATE: 0-15 CfS VOL: 0.05 Ac-ft TIME; 400 min BASIN To! PROID NAME. PROPOSED CONDITION, 10-YEAR SBUH METHODOLOGY TOTAL AREA_______: 0.20 Acres BASEFLOWS; 0.00 cts RAINFALL TYPE....: TYPEIA PERVIOUS AREA PRECIPITATION.._.: 4.80 inches AMA..: 0.00 acres TIME INTERVAL..... 10.00 min CN....: 81.00 TIME OF CONC-----! 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF; 0.20 AREA.-- 0.20 Acres CN....; 98.00 PEAK RATE. 0.70 cfs VOL: 0.06 AC-ft TIME: 400 min BASIN ID: FRIOO NAME: PROPOSED CONDITION, 100-YEAR SBUH METHODOLOGY TOTAL AREA....... . 0.20 Acres BASEFLOWS.'* 0.00 cfs RAINFALL TYPE....: TYPEIA PERVIOUS AREA PRECIPITATION....: 7.00 inches AREA..: 0.00 Acres TTKE INTERVAL-,,.I . 10-00 min Chi..,.: ol-QQ TIME OF CONQ_._..; 6.00 rain IMPERVIOUS AROA ABSTRACTION QQEFV; 4.20 ARE4. 0.20 Acres 00 PEAK PATE., 0-29 cts VOLS 0.13 Ac-ft TINXI 1 480 rda 1 02/0'J/1WJ 21;42 3bdbJ23802 MIKE WNEK PAGE 05 -I 3 .6- ­.V 'Rr wo 1 g 1h: HYDROGRAPH SUMMARY PEAK TIME VOLUME HYD RUNOFF or OF Contrib NUM RATE PEAK HYDRO Area cf5 min cf-ACFt Acres ----------- 0.072 480 1240 cf 0.20 0.126 480 2040 cr 9.20 0.222 480 348E of 0120 4 0.145 400 2371 of 0.20 5 0-201 400 3313 cf 0.20 6 0.294 490 4909 of 0-20 7 0.060 530 7371 of 0.20 0 0.071 560 3313 cf 0.20 9 0.086 570 4908 cf 0.20 STAGE STORAGE TABLE TRAPEZOIDAL BmuN 11) No- WRAP Description; TRAPEZOIDAL BASIN Length? 45-Do ft- Width: 4.00 ft. Side Slope l; 3 Sias Slope 3: 3 Side Slope 2! 3 Side Slope 4: 3 Infiltration Rate: 0.00 min/inch STAGE STAGE <----STORAGE----> STAGE <---- STAGE <----,5T1 'RA" (ft) --Ac-rt- (ft) ---cf­ --AC-Ft- (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- ---------------------------- ---------- ------- 1.0.0 0 0.0000 0.0000 10-80 244.z2 0.o056 11.60 713.47 0-0164 12.40 1445 0,0332 1.0.10 19.482 0.0004 10-90 299.82 0,0067 11.70 789.79 0.0101 12.50 1556 0.0357 10,20 41,976 0.0010 11-00 339.0D 0.0070 11.80 070.26 0.0200 12.60 1673 0.0384 10.30 67.554 0.0016 11.10 391.84 0.0090 11.90 954.98 0.0219 12.70 1794 0.0412 10.40 96-288 0,0022 11.20 448.42 0,0103 12-00 1044 0.0240 12-60 1920 0.0441 1.0.50 128.25 U.0029 11.30 508-79 0.0117 12.10 1137 0-0261 12.90 2051 0.0471 10-60 163.51 0.0030 11.40 573.05 0.0132 12.20 1235 0.0284 13.00 2187 0.0302 10.70 702-15 0.0046 11.50 641-25 0-0147 12.30 1338 0-0307 STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. DCS Description! DISCHARGE CONTROL STRUCTURE Outlet Eltv; 10.00 Elev: 9.75 ft Orifice Diameter; 1.5000 in. STAGE <--DISCHARGE___> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfa-- ------- (ft) ---cfs-- ------- (ft) ---CfN-- ------- -------------------- ----------- --------- ------------ 10.00 0.0000 10.80 0-0546 11.60 0.0772 12.40 0.0946 10.10 0.0193 10.90 0.0579 11.70 0,0796 12.50 0.0965 10-20 0.0273 11.00 0.0611 11.00 0-0819 12.60 0.0905 10.30 0.0334 11-10 0.0640 11.90 0.0042 1z.70 0.1003 1.0-40 0-0396 11.20 0.0669 12.00 0.0063 12.00 0.1022 10.50 0.0432 11-30 0.0696 12-10 0.0095 12.90 0.1040 10.60 0-0473 11.40 0.0722 12.20 0.0906 13-00 0.1058 1.0.70 0.0511 11-50 0.0748 12.30 0.0926 LEVEL POOL TABLE SUMMARY ]MATCH XNFLON -STO- -DIS- STORAGE PEAK <--------DESCRIPTION----------> (eta) (Cts) --id- --id- <-GTAGE> id VOL (cf) OUT(cfs) 2-YEAR ....................... 0.07 0.15 TRAP DCS 10.96 7 321.04 0106 10-YEAR ...................... 0-13 0.20 TRAP DCS 11.36 9 549-45 0.07 IOU-YEAR ..................... 0.22 0.29 TRAP DCS 11.98 9 1027.53 0.09 2 02/09/1999 21:42 3bUb923802 MIKE WNEK PAGE �06 AWE$ SF-t-FAiR akaWW AM* WOW 02--69--99 M X.W. 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