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Home My WebLink AboutDesign Plans and Drainage Report South Annex Parking - PLN General - 3/31/1999 • 03/31/1999 14: 29 3606923802 MIKE WNEK PAGE 02 .... '.. .�:r••:.,,.x....r.��....��. .._.._ :.ay,.;;_>,z;.:.�._.... �i•�i.8;::'','.ii;,i�ii<ia _ - --r.,': " _._.. ..,•...r,. ,:-.:rl. ....-.._��..::� r,_..r.�'re':::.,!n.�4::xr !., _'rir:� r.� .._11:_.... ..., �..III,Y....11:_ • 1.l.Il ... ,.�:�..,...1...:i.;.- ci.�. r..Y ,r'4:...1'.:.1:.'L'F'. .. ... .__ .:........,ul,.�.. .1.._....._. i r, �.. $o a Design Plans & DrAwcaftinage Repold (previous versions dated February 9, 1999 should be discarded) South of Annex Parking - Belfair Krueger / Johnson Mason County prepared for, Jack Johnson P.O. Box 1119 Belfair, WA 98528 360-275-5400 March 31, 1999 CONTENTS Site Plan Page 1 Details Page 2 Detention Plan Page 3 Basin Plan Page 4 Drainage Narrative Page 5 Detention Calculations Page 6-7 Basin Calculations Page 8 USGS Topo Map Page 9 Downstream Pipe Capacity Page 10-11 Water Quality Narrative, Calc's Page 12-14 Project Number: 230 By the seal and signature here affixed, ! certify that the enclosed report was s r accomplished by myself, and that / am currently a registered engineer of good R V standing in the r I[7,R'S 7i 1 : State of Washington. �_....� ' 03/31/1999 14:29 3606923802 MIKE WNEK PAGE 03 SECTION 29, T 23 N, R 1 W, W.M. o / / looll �Q /4 / � 4 / X. �� \ EXISTING BUILDING, / Q NC, Q. \ TYPICAL co SP E J 'PROPOSED: \ g .-AREA`. \\ / ~ X. CUT-OFF DITCH \\ O OVERFLOW DITCH, — — 0. ELEVATION 50.5 Cv i u� 0 E t!) SEE NOTE NOTES fill 1. PROVIDE LOCAL RUNOFF GRADING ROM TMEASSURE THADETENTION POND. Ic PARKING AREA AN NOT BYPASS THE All l / I 2. THE CONTRACTOR SHALL VERIFY flit ELEVATIONS FOR GRAVITY FLOW FROM THE NEW CATCHBASIN TO THE POND, / I I FROM THE 2" OUTLET PIPE TO THE I J I I BIOSWALE, AND THEN TO THE HIGHWAY DITCH; PRIOR TO COMMENCING I I (n I CONSTRUCTION. O I I 3, SEED AND FERTILIZE ALL DISTURBED - 4R RE CONSTRUCT ECONSTRUCT EXISTING CUT-OFF Q DITCH FOR I F-- I I AND SIDES WITH WSOD, LINE BOTTOM BOTTOM WIDTH 2 w ' 0. --� � (/I SIDE SLOPES 3:1 � wEn TOTAL DEPTH = 1.1' a GRADE - 1Z r I I LENGTH = 60' (BEYOND HWY R/W) 0lei I I I - - -- _ __—_— _ _ I L - - -7 ld I1 F y F c� oxi ��a 0,5' FREE$oAF.D `MA$• 2 - OR SEC-n SWRLE 4 '{ = 15` s PIPE TEE, 6oT}} EA 5 OPE►J� EELS. o v a IL gig, w WAsli5b ROCK I p�TA 1 l_ pUTI._ T P1 P POND I NO SLA►�� i a� W 2 Q �1O Acc \ \ cLP \ \ m I 50 I \ BELFAIR LOC PL I A \ I \A � A \ z I SEPTIC SYSTEM I X ��,w� ` a�yb$ .c��.�....mod.. � \ L4 loe L _ \ 54 �,/ L \ � I �, loll Z �l /� Qg� \ isz \ Ile / �N \ Prepared By. SCALE:f' - 60' elisions: Prepared for. DETENTION PLAN WCHAEL F. WNEK, P.E. CA,E os—oa—oo JACK JOHNSON CONSTRUC71ON (A SOUTH OF ANNEX PARKING — BELFAIR Caws a►w DOWEM awc�a er NFw P.O. BOx 1179 ORM SR-3 a�rt, BELFAIR 1005 NwrtTON. A �WA. WM1 MFw BELFAIR, WA 98528 YA90N COUNTY wASHNCTON (310)692-3802 auwN BY: MFW 760-275-5400 FAX-275-6400 \ m y efGFq� U / % \ \ �jr- I Z m. pp �\~� 2��1 T— J I i \\ _ �,G� �\ BELFAIR LOG PL I \\ Iv 1 m I C'i 1 I \\NQ ----SEPTIC SYSTEM ---� � \\+y\\ \ / v o \ � _ _--J sz � -------- I — ----------� \ �z.. / \ I /Z. Prepared By SCALE-1' 100' ewsons: Prepared for. DRAINAGE PLAN MICHAEL F. WNEK, P.E. JACK JOHNSON CONSTRUCTION SOUTH OF ANNEX PARKING - BELFAIR �W� CHECKED r. MFW P.O. BOX 1119 SR-3, BELFAIR 1Xa DRIVE BREMERTp6 WA, W311 DESIGN BY MFw BELFAIR, WA 98528 MASON COUNTY WASNINOTON 1 (310)ee2-3i02 �1M/BY: MFWBY: MFW 360-275-5400 FAX-275-6400 South of Annex Parkin - Belfair March 5, 1999 DESIGN PLANS & DRAINAGE REPORT Project: 230 DRAINAGE NARRATIVE PROJECT DESCRIPTION: Parking lot paving. The area to be paved was recently cleared and graveled under a previous Mason County grading permit. PROJECT LOCATION: South of County Annex Building, east of SR-3 in Belfair. EXISTING DRAINAGE DESCRIPTION: All drainage in the area eventually flows to the roadway ditch and underground storm system along SR-3. The drainage crosses under the highway south of the project (see page 4). DOWNSTREAM DRAINAGE: The downstream drainage route is depicted on page 4. Calculations verify that the existing drainage facilities have adequate capacity to handle basin flows for the 100-year event (Page 8-11). EXISTING TOPOGRAPHY: Topography within the project parcel is relatively flat, with no slopes in excess of 5% within the work area. SOILS: Soils in the general area consist of glacial outwash, and are considered to be Hydrological Soil Group "A" for hydrology calculations. The local soils within the project parcel are saturated in the winter; more characteristic of Group "C" soils. For site detention calculations, curve numbers for Group "C" soils are used; for basin calculations, curve numbers for Group "A" soils are used. LAND USE: The existing condition for site detention calculations is second growth timber. The proposed condition is asphalt pavement and grass. DRAINAGE CONCEPT: The purpose of this design is to provide a detention system for the parking lot paving. The design needs to be functional yet simplistic, due to the small area involved. In the future, if building construction takes place on the site, 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 (0.39 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. Hydrology calculations for detention are on pages 6 & 7. 230\storm\230_Drain-Report_2.doc 5 03;31/1999 14:29 3606923802 MIKE WNEK PAGE 04 w nox r 2 ot.A' .powo 70 SC DO* DETENTION CALCULATIONS BASIN SUMMARY BASIN ID! EXOOO NAME: EXISTING CONDITION, 6-MONTH SBUH METHODOLOGY TOTAL AREA., , ....; 0.39 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . .. : TYPEIA PERVIOUS AREA PRECIPITATION. . .. : 2,35 inches AREA..: 0.39 Acres TIME INTERVAL._. . : 10.00 min CN... .: 81.00 TIME OF CONC..... 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0120 AREA. .: 0.00 acres CN. . '' : 98.00 PEAK RATE., 0.06 cfs VOL: 0.03 Ac-ft TIME: 480 min ---------------------------------------------------- _----.,---------- BASIN TD: EX002 NAME: EXISTING CONDITION, ?-YEAR SBUH METHODOLOGY TOTAL AREA.. . .. ._: 0.39 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE.. .-: TYPElA PERVIOUS AREA PRECIPITATION-.; 3.50 inches AREA_'. 0.39 Acres TIME INTERVAL....: 10.00 min CN. -- ,-* 61.00 TIME OF CONC.. ... 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA..-. 0.00 Acres CN.. * 98.00 PEAK RATE; 0.14 cfs VOL: 0.06 Ac-ft TIME: 480 min ----------------------------------------------------------------------- BASIN ID: EX010 NAME: EXISTING CONDITION, 10-YEAR SBUH METHODOLOGY TOTAL AREA. ,. . . . . : 0.39 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE TYPEIA PERVIOUS AREA PRECIPITATION. . .. : 4.80 inches AREA.. : 0.39 Acres TIME INTERVAL. ...: 10.00 min CN.. .. : 81.00 TIME OF CONC. . ... 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA..: 0.00 Acres CN... . : 98.00 PEAK RATE; 0.24 cfs VOL: 0.09 Ac-ft TIME: 480 min ----------------------------------------------------------------------- BASIN ID: F_X100 NAME: EXISTING CONDITION, 100-YEAR 55UH METHODOLOGY TOTAL AREA.. ... . .: 0.39 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE.. . .: TYPEIA PERVIOUS AREA PRECIPITATION.. ..: 7.00 inches AREA. .: 0.39 Acres TIME INTERVAL. . . . : 10.00 min CN.. . .: 81.00 TIME OF CONC.. :..: 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF; 0.20 AREA. .: 0.00 Acres CN.. . .: . 96.00 PEAK RATE: 0.43 cfs VOL: 0.16 Ac-ft TIME: 480 min ----------------------------------------------------------------------- BASIN ID: PROOO NAME: PROPOSED CONDITION, 6-MONTH SBUH METHODOLOGY TOTAL AREA_.__ . .. . 0.33 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . .. : TYPEIA PERVIOUS AREA PRECIPITATION.. .. : 2.35 inches AREA. .: 0.13 Acres TIME INTERVAL.. ..: 10.00 min CN..... 86-00 TIME Or CONC. .... ! 6,00 min IMPERVIOUS AREA ABSTRACTION COEFF; 0.20 AREA. .. 0.26 Acres CN.... : 98.00 PEAK RATE! 0.16 cfs VOL: 0,06 Ac-ft TIME. 480 min ----------------------------------------------------------------------- BASIN ID: PRO02 NAME: PROPOSED CONDITION, 2-YEAR 55UK METHODOLOGY TOTAL AREA... . . . . : 0.39 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE. . . . : TYPEIA PERVIOUS AREA PRECIPITATION. . .. : 3.50 inches AREA. .: 0.13 Acres TIME INTERVAL. ..,: 10.00 min CN.. .. : 86,00 TIME OF CONC... .. 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA..: 0.26 Acres CN. ... : 96.00 PEAK RATE; 0.25 cfs VOL: 0.09 Ac-ft TIME: 460 min ----------------------------------------------------------------------- BASIN ID: PRolo NAME: PROPOSED CONDITION, 10-YEAR SBUH METHODOLOGY TOTAL AREA... . . .. : 0.39 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE... . : TYPEIA PERVIOUS AREA PRECIPITATION. .. . : 4.80 inches AREA.., * 0.13 Acres TIME INTERVAL... . : 10.00 min CN....: 86.00 TIME OF CONC.. ,, . : 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA..: 0.26 Acres CN.. .. . 98.00 PEAK RATE: 0.36 cfs VOL: 0.13 Ac-ft TIME: 480 min ----------------------------------------------------------------------- BASIN ID: PRIOO NAME: PROPOSED CONDITION, 100-YEAR SBUH METHODOLOGY TOTAL AREA--._. . ... 0.39 Acres BASEFLOwS, 0.00 cfs RAINFALL TYPE... .: TYPEIA PERVIOUS AREA PRECIPITATION....: 7.00 inches AREA.. : 0.13 Acres TIME INTERVAL....: 10.00 min CN... . : 66.00 TIME Or CONC. .. . . 6.00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA. . : 0.26 Acres CN. .. ... 98.00 PEAK RATE: 0.54 cfs VOL; 0.20 Ac-ft TIME; 480 Min ----------------------------------------------------------------------- 6 03/31/1999 14:29 3606923802 MIKE WNEK PAGE 05 So uth.bf u�. DETENTION CALCULATIONS HYDROGRAPH SUMMARY PEAK TIME VOLUME HYD RUNOFF OF or Contrib NUm RATE PEAK HYDRO Azea cfs min. cf-AcFt Acres 1 0.060 480 1185 cf 0.39 2 0.141 480 2419 cr 0.39 3 0.245 480 3977 cf 0.39 4 0.432 460 6803 Cf 0.39 5 01155 480 2532 cr 0.39 6 0.250 480 4073 cf 0.39 7 0.359 480 5855 cf 0.39 a 0.545 480 8913 cf 0.39 9 0.084 510 2532 cf 0.39 10 0.110 520 4073 cf 0.39 11 0.134 550 5855 cf 0.39 12 0.164 570 8913 cf 0.39 . STAGE STORAGE TABLE TRAPEZOIDAL BASIN ID No. TRAP Description: TRAPEZOIDAL BASIN Length: 62.00 ft. Width- 4.00 ft. Side Slope 1: 3 Side Slope 3: 3 Side Slope 2: 3 Side Slope 4: 3 Infiltration Rate; 0.00 min/inch STAGE <----STORAGE----> STAGE <----STORAGE--- STAGE <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --AC-Ft- (ft) ---cf--- --AC-Ft- (tt) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- �4;777--- 48.10 26.792 0.0006 48.90 392.33 0.0090 49.70 1053 0.0242 50.50 2045 0.0469 48.20 57.616 0.0013 49.00 458.00 0.0105 49.80 1158 0-0266 50.60 2194 0.0504 48.30 92.544 0-0021 49.10 528.35 0.0121 49.90 1268 0.0291 50.70 2349 0.0539 48.40 131-65 0.0030 49.20 603-46 0,0139 50.00 1384 0.0318 50.80 2510 0.0576 46-50 173.00 0.0040 49.30 683.38 0.0157 50.10 IS05 0.0346 50-90 2677 0.0615 48.60 222.67 0.0051 49.40 768.21 0-0176 50-20 1632 0.0375 51.00 2650 0.0654 48.70 274.74 0.0063 49.50 858.00 0,0197 50.30 1764 0.0405 51.00 2850 0-0654 STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. DCS Description; DISCHARGE CONTROL STRUCTURE Outlet Elev: 4B.00 Klev- 48.00 ft Orifice Diameter; 2.0000 in. STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) ---cfs-- ------- (ft) .--_cfs-- ------- ------------- ---------------------------- 48.00 0,0000 48.80 0.0971 49-60 0.1373 50.40 0.1682 48.10 0.0343 48.90 0,1030 49.70 0.1415 50.50 0.1716 48.20 0-0465 49,00 0.1085 49.80 0.1456 50.60 0.1,750 48.30 0.0595 49.10 0.1138 49.90 0.1496 50.70 0,1784 48.40 0,0687 49.20 0.1189 50.00 0.1535 50.80 0.1816 49.50 0.0769 49.30 0.1238 50.10 0.1573 50.90 0.1849 45.60 0.0841 49.40 0.1284 50.20 011610 51.00 0.1880 48.70 0.0908 49.50 0.1329 50.30 0.1646 LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> STORAGE PEAK --------DESCRIPTION---------;> (cfs) (cfs) --id- --id- <-STAGE> id VOL (cf) DISCHARGE --------------------6-MONTH .. ... . ... .. .. . .. . .. . .. 0.06 0.16 TRAP DCS 48.60 9 223.27 0.08 cfs 2-YEAR . . . .. . . .... . .. . . . .. . ... 0.14 0.25 TRAP DCS 49-03 10 476.04 0.11 cfs IQ-yz&R . . .. . ..... .. . .. . .. . .. 0.24 0.36 TRAP DCS 49,51 11 970.27 0.13 cfs 100-YEAR .. . ... .. . .. . .. . 0.43 0.54 TRAP DCS 50.29 12 1734.96 0.16 cfs South of Annex Parkin - Belfair March 5, 1999 DESIGN PLANS & DRAINAGE REPORT Project:230 BASIN CALCULATIONS BASIN SUMMARY BASIN ID: BASIN NAME: 100-YEAR BASIN FLOW SBUH METHODOLOGY TOTAL AREA.......: 24.00 Acres BASEFLOWS: 0.00 cfs RAINFALL TYPE....: TYPElA PERVIOUS AREA PRECIPITATION....: 7.00 inches AREA..: 21.00 Acres TIME INTERVAL....: 10.00 min CN....: 42.00 TIME OF CONC.....: 49.40 min IMPERVIOUS AREA ABSTRACTION COEFF: 0.20 AREA..: 3.00 Acres CN..... 98.00 TcReach - Sheet L: 300.00 ns:0.8000 p2yr: 3.50 s:0.3300 TCReach - Shallow L: 700.00 ks:3.00 s:0.2000 TCReach - Channel L: 600.00 kc:5.00 s:0.0250 PEAK RATE: 3.10 cfs VOL: 3.43 Ac-ft TIME: 490 min 8 6 13t4rVw� °�s-z = o" A-Z O0 -5 -dam xi oo£I(04z ` 13 -Coe '-f oOL '4 ooz Xo�ddb C .,A o � �;kA IQ :yaw S(I of 1•�3d W 1 poo'OSo `I = ,00L x ,00s' ,000`1 M .1 ado-L s hs n s ,,,��-� u►sbg ' xv 3, MIla gyp' • � s • le lb � • i • P i * f i fir✓ �__,...._. t i • • 4 � . . r • i E>oW J STfZ P)F F- CApAe-1 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Figure III-2. 1 - Nomograph for Sizing Circular Drains Flowing Full 1000 900 800 .0001 700 2.0 600 .0002 500 0003 Minimum 400 •0004.0005 .0001 Allowable Velocit Y .0006 iFlowinq� 300 � Full) 3.0 120 N •0008� .0002 �L^1 108 9 .000000 63 200 0 0004 9 °c .002 .0005 -84 / 0~_ 4.0 78 x 72 O .003 .0008 0066 W .001 5.0 100 80 o .006 O go so 5 00 .002 o / Z48 .01 / 6.0 70 60 42 004' c cn vi pc 7.0 u. Z 36 0 •00U- W 50 0066 a Z / 3Uj 40 30 .008 w 8.0 w .0 .01 O LL a27 J Ob0 _ 9.0 a .06 cc 30 w 24 � .08 020 > 10.04 l O21C .10 uj .030 20 0.18 0 D40 w 15 > .060 .080 12 -- .100 9 10 9 8 SAMPLE USE 7 CFS 8 24" dia. CMP @ 2% slope yields 20.0 6 P1PE 17cfs @ 5.2 FPS velocity (n s 0.024) 5 Fu U- 6 4 RNC Values per Manning's Equation Q m ( 1.49) AR'A s 3 n 30.0 This table can be converted to other"n"values by applying 2 formula: 40.0 01 n1 02 n2 111-2-8 FEBRUARY, 19 DoW ASTR -AM PIPE CAPAc" STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN _1 Figure III-2.14 - Headwater Depth for Smooth Interior Pipe Culverts With Inlet Control } 80 - ,0,000 I— 168 I- 8,000 EXAMPLE ( I) (2) (3) -- 156 D•4Z .ncnee 1s feel 6. ENTRANCE TYPE - 6,000 6_ Q.120 c,s — 144 i— 5,000 -`-- 5 - SQUARE EDGE WITH �- 4.000 HEADWALL r 132 r,w' nw 6. 5. 0 Net — 3,000 5 4, %- 120 lr) 2.5 0.e 4. 2,000 106 I 15I 2.2 7.7 4.-- 1 i - 36 1,000 3 ' , PLAN i- 800 GROOVE ENO WITH 84 - -- HEADWALL 600 / _ _ _ 2. 2 i Soo r • N 72 400 / 2. _ - 300 z z 60 u 200 Uj PLAN l2� 0 54 GROOVE END a a PROJECTING W 48 / W _ 100 > / cr 80 -j x 4 2 a 60 a 10 1.0 o N 50 HW SCALE ENTRANCE 10 W - 40 D TYPE W 9 W 3fi 30 (,) sore,••N• sour i 9 33 h4ohell #O .9 Q Q - 20 (1) G,o•w ew1 .116cz W - 30 esaa.ell Z 8 8 Isl (reeve end 8 - 27 praletr e� 10 6 To use %care (2) or 131 Drelec, 21 5 norreon,ony ro—aeale- 4il,reen 1 4 -6 rrr�$$er . it sa/n• e n J er.�'+Ticares,o,!,ever e• a• 1 ..•'� 3 iioetrefed. - .6 6 18 ~� ♦—-- 2 ,`flVLET 15 ORE _ CAQAG�T`� 5 5 — 12 ADEQu>A`t II— — FEBRUARY, 1 2 03/31/1999 14: 29 3606923802 MIKE WNEK PAGE 06 _ t y;''1'.. 1 i — i`�.Jtil t iE��;d b., ; _ry'•^jLs'".. ��11�iAl1.�T1 �.�M�� it - WATER QUALITY NARRATIVE CONCEPT: Water quality features will be provided via the implementation of a bioswale. The bioswale will be located downstream of the detention pond. The rainfall event used for the 6-month storm calculation is 67% of the 2-year, 24-hour storm. The bioswale design criteria includes: checking for water quality criteria for the 6- month storm, and stability parameters for the 100-year event. Water quality criteria: maximum flow depth of 3 inches (0.25 feet), maximum velocity of 1.0 feet per second, minimum residence time of 5 minutes. Stability criteria: maximum velocity of 3.5 feet per second, 1 foot of freeboard above high water. The 6-month event was added to the hydrology calculations for the detention pond. There is no requirement to "match" the before and after peak flows for this event. However since the bioswale is downstream of the pond, the hydrology calculations portray how the peak flow of the 6-month event will be attenuated by the pond, so that the bioswale can be properly sized. The bioswale calculations are based on procedures outlined in the Kitsap County Stormwater Management design manual; which recommends using a Manning's coefficient of 0,200 for the 6-month event, and 0,035 for the 100-year event. Calculation sheets are attached. 12 03/31/1999 14:29 3606923802 MIKE WNEK PAGE 07 Trapezoidal Channel Analysis & Design Open Channel . Uniform flow Worksheet Name: 6-MONTH Comment : BZOSWALE, 6-MONTH Solve For Depth Given Input Data: Bottom Width. . . . . 2 . 00 ft Left Side Slope. . 3 . 00 : 1 (H:V) Right Side Slope. 3 . 00 : 1 (H:V) Manning' s n. . . . . . 0 . 200 Channel Slope. . . . 0 . 0100 ft/ft Discharge. . . . . . . . 0 . 08 cfs Computed Results : Depth. . . . . . . . . . . . 0 . 16 ft velocity. . . . . . . . . 0 .20 fps Flow Area. . . . . . . . 0 .41 SE Flow Top Width. . . 2 . 99 ft Wetted Perimeter. 3 . 04 ft Critical Depth. . . 0 . 04 ft Critical Slope. . . 1 . 8074 ft/ft Froude Number. . . . 0 . 09 (flow is SubCritical) RESiDEt0ce 'nN� (moo LF - 0. 2.0 -f't/.Sec = 30o sec.," Open Channel Flow Module, Version 3 . 21 (c) 1990 Haestad Methods, Inc. * 37 Brookside Rd * Waterbury, Ct 06708 13 Trapezoidal Channel Analysis & Design Open Channel - Uniform flow Worksheet Name : 100-YEAR Comment : BIOSWALE, 100-YEAR Solve For Depth Given Input Data: Bottom Width. . . . . 2 . 00 ft Left Side Slope. . 3 . 00 :1 (H:V) Right Side Slope. 3 . 00 :1 (H:V) Manning 's n. . . . . . 0 . 035 Channel Slope. . . . 0 . 0100 ft/ft Discharge. . . . . . . . 0 . 16 cfs Computed Results : Depth. . . . . . . . . . . . 0 . 09 ft velocity. . . . . . . . . 0 . 78 fps Flow Area. . . . . . . . 0 ,20 sf Flow Top Width. . . 2 .54 ft Wetted Perimeter. 2 , 57 ft Critical Depth. . . 0 . 06 ft Critical Slope. . . 0 . 0482 ft/ft Froude Number. . . . 0 .49 (flow is SubCritical) Open Channel Flow Module, Version 3 . 21 (c) 1990 Haestad Methods, Inc_ * 37 Brookside Rd * Waterbury, Ct 06708 �4 C Phone:(360)427-9670 Ext.450 Jerry W.Hauth,PE,PLS MFax:(360)427-8425 Director A O , S V DEPARTMENT OF PUBLIC WORKS ON COURTHOUSE BLDG 1, 411 NORTH 5TH STREET TP.O.BOX 1850 SHELTON,WASHINGTON 98584 N Y March 17, 1999 WSDOT Olympic Region Headquarters Attention: Brad Lindgren 5720 Capitol Blvd Tumwater, WA 98501 Re: Stormwater Plan for Jack Johnson's Belfair Annex Dear Brad, Enclosed please find a copy of the design plans and drainage report for the Kruger/Johnson parking annex paving in Belfair, Washington. Please feel free to contact me at County extension 461 if there's anything more I should request of the applicant, or contact them directly; Jack Johnson (360) 275-5400 (FAX) 275-6400 I'll be requiring an Operation & Maintenance Covenant instrument to be created to cover the constructed facilities. Thanks for your help. Sincerely, AL N A. TAHJ , County Hydraulic Engineer encl: Design Plans & Drainage Report prepared by Michael Wnek AT:at wP�s-��ittcv \�cu cws��sdot—fol• cvc