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Home My WebLink About2001-06-21 Stormwater Report }t NORTH ANDOVER BUILDING DRAINAGE REPORT 200 SUTTON STREET NORTH 9 MARCH MA 2001 MERRIMACK EPJGIPJEERING SERVICES, Inc. 66 Park Street Andover, Massachusetts 01810 planners 40 engineers 0 surveyors DRAINAGE REPORT NARRATIVE SITE DRAINAGE CALCULATIONS RECHARGEPROPOSED C PRE AND POST DEVELOPMENT DRAINAGE ANALYSIS SUMMARY OF PEAK FLOW RATES FLOODPLAIN COMPENSATION CALCULATIONS CHARTS AND TABLES r NARRATIVE This project site has been designed to accommodate a multi-bay car wash facility which will be serviced with existing Town water and sewerage systems. Access to the site will be from a proposed 25' wide paved driveway from Route 114. On-site parking for up to eight (8) cars will be provided in the rear of the site. The site has also been designed with a dual purpose subsurface drainage storage system to accommodate a detention period of stormwater runoff in order to mitigate a potential increase in the peak rate of runoff. The size of the drainage storage system is large in order to provide required compensatory volume to offset the filling proposed within the 100 floodplain (up to El = 236.1). Also, a subsurface drainage system is proposed to handle all of the roof drainage and to provide ample recharge to groundwater of this uncontaminated runoff water. The volume of recharge is based on the `dead storage' capacity within this system. An elevated outlet pipe, approximately 2 feet above the bottom of the precast concrete structures, will limit the retainable capacity of the volume to be ultimately recharged, after the storm for approximately two or three days henceforth. To ensure that the stormwater runoff from the proposed paved parking areas will not be creating a potential downstream pollution problem, a series of pollution mitigating treatment the design of the site drainage system. Each catch basin measures will be implemented withZn frame and grate will have a"Fossil Filter" installed to retain petroleum based contaminants (hydro-carbons) within its "Filter Medium". Each catch basin will have a 4' deep sump for silt and sand accumulation. The outlet pipe from each basin will have an oil trap or hood to prevent flotables (grease, oil, and debris) from discharging from the catch basin to the downstream waters. With these elements of prevention and pollution mitigation in-place and periodically maintained, the flow of runoff from each catch basin to the subsurface detention facility will be a significantly cleaner and highly treated runoff discharge. The time of detention in these subsurface structures will also allow for further treatment of any minimal pollutants, which get beyond the catch basin treatment measures. Additionally, a "Stormceptor" oil separator unit will be installed at the outlet of the drainage system, prior to stormwater discharge into the Restoration and Wetland Replication Areas. A 30" RCP culvert will be installed at the entrance, adjacent to the existing 30" culvert, to improve hydraulic capacity for drainage flow beneath the proposed driveway from Route 114. An "Operation and Maintenance" Plan is proposed to be implemented from the start of construction, throughout the duration of the construction activity (approximately six months), and periodically on an inspectional or"as necessary" basis after the work is completed and the development is opened for business. PROJECT: PROPOSED ROUTE 114 CAR WASH FACILITY APPLICANT: NORTH ANDOVER BUILDING CORPORATION DATE: MARCH 23, 2001 A SITE DRAINAGE CALCULATIONS USING RATIONAL METHOD Determine peak flow rates to each catch basins; use 10 year storm, time of concentration of 5 minutes, rainfall intensity of 5.3 inches/hour RATIONAL METHOD: Q = CiA Q =Peak Flow Rate (in cubic feet per second) C =Runoff Coefficient Impervious: 0.9 Lawn/Landscaped: 0.3 Wooded/Vegetated: 0.1 i =Rainfall Intensity (in/hr) A=Drainage Area (acres) PIPE FLOW CHARACTERISTICS: n= 0.015, for RCP 0.013, for C.I. 0.011, for.PVC V = Velocity, in feet per second d = depth of flow in pipe, in feet REFER TO "PIPE FLOW CHART", THE"DRAINAGE PLAN", AND SHEETS 4 AND 5 OF THE PLANS FOR ANALYSIS AND DESIGN INFORMATION 1 of 3 AREA "A" (CB #1 to D H#1) C = 0.9 (100% impervious) A= 1080 S.F. = 0.025 Acres Q = 0.9x5.3 x 0.025 = 0.12 CFS use 12" RCP @ S = 0.015 '/1, V=2.2 FPS, d= 0.12 Ft. n AREA "B" (CB #2 to DMH#1) C = 0.9 (100% impervious) A= 3420 SF = 0.079 Acres Q2 = 0.9x5.3 x0.079 = 0.38 CFS use 12" RCP @ S = 0.004 '/1, V= 2.0 FPS, d=0.30 Ft. For: DMH 91 to DMH 42 and DMH 92 to DMH 43 Q = Sum of Flow from CB's#1 and 92 = 0.12 + 0.38 = 0.50CFS use 12" RCP @ S = 0.004 1/1, V= 2.1 FPS, d =0.35 Ft. For: DNM 93 to Detention Facility "C" Q = sum of flow from CB's 1, 2 and 5 = 0.12 +0.38 + 0.53 = 1.03 CFS use 12" RCP @ S = 0.004 1/1, V =2.5 FPS, d= 0.50 Ft. AREA "C" (CB #3 to Detention Facility "B") C = 0.9 (100%Impervious) A= 3840 SF = 0.088 Acres Q3 = 0.9x5.3 x 0.088 = 0.42 CFS (Note: No overflow from `Recharge' Facility Expected) use 12" RCP @ S = 0.008 1/1, V= 2.7 FPS, d = 0.27 Ft. 2 of 3 AREA "D" (CB #4 to Detention Facility "B") C = 0.9 (100%Impervious) A= 12,800 SF = 0.294 Acres Q4 = 0.9x5.3 x0.294= 1.40CFS use 12" RCP @S = 0.031/1, V= 5.8fps, d = .35Ft. AREA "E" (CB 145 TO DMH#3) C= 0.9 (100% impervious) A= 4935 SF = 0.11 Ac Q = 0.9x 5.3 x0.11 = 0.53 CFS use 12" RCP @ S = 0.006 1/1, V= 2.4 FPS, d =0.32 Ft. AREA "F" (Building Roof Drainage to "Recharge" Facility) C = 0.9 (100% impervious) A= 5400 SF = 0.124 Ac Q = 0.9 x 5.3 x 0.124= 0.59 CFS use 6" cast iron rain leader @ S = 0.004 where V= 5.3 FPS, full, flow is full at 1.1 CFS where _c = 0.59 = 0.54; v_= 0.80, v= 0.88 FPS; Qf 1.1 V d= 0.61, d= .61x .5 D = 0Y Refer to the "Hydraulic Elements for Circular Pipe" Chart and the Hydraulics of Sewers" Chart 3 of 3 SUMMARY As a result of the Pre and Post-Development Analysis, there is a net decrease or reduction in the peak rate of runoff from the overall site for the 2, 10, and 100 year storms.. This is in compliance, therefore, with Standard #2 of the Stormwater Management Policy and, in addition, the Planning Board's Site Plan Regulations and Requirements. n The Pre-Development Analysis was done without the Floodway Analysis since the site runoff would be discharging into the wetland or areas subject to flooding, regardless of the floodplain elevation at any given time during the design storm event. The Post-Development Analysis was done in conjunction with the Floodway Analysis in order to determine the outlet flow from the subsurface drainage facilities while affected by the rise of water in the floodplain, which results in a tail water effect,thereby reducing outlet flow capacity. The following chart illustrates the resultant peak flow rates which occur during each storm event at each Design Point and the Total, in summation: PEAK FLOW RATES (CFS) PRE-D POST-D DIFFERENCE DESIGN DESIGN DESIGN DESIGN DESIGN DESIGN STORM POINT POINT POINT POINT POINT POINT EVENT #1 #2 TOTAL #1 #2 TOTAL #1 #2 TOTAL 100 Year (6.5") 1.4 3.16 4.56 0.64 2.88+/- 3.52 -0.76 -0.28+/- -1.04 10 Year (4.5") 0.81 1.85 2.66 0.38 1.77+/- 2.15 -0.43 -0.08 -0.51 2 Year (3.1") 0.42 0.98 1.4 0.2 1.13+/- 1.33 -0.22 +0.15+/- -o.07 1 Year (2.3") 0.22 0.54 0.76 0.11 0.75+ 0.86 -0.11 +0.21+/- +0.10 THE HAESTAD'S FLOW-MASTER I PROGRAM WAS USED FOR DETERMINATION OF FLOW CHARACTERISTICS AT THE STORMWATER DETENTION AND FLOOD STORAGE FACILITIES. (Refer to the "Outflow Capacities" Charts for the resultant flow characteristics). I. The outflow from these facilities will be discharged through a 12" RCP drain pipe into a rip-rap area, then into and through a 3' wide grass-lined treatment Swale to the wetland. A. The 12" RCP pipe is 9 feet in length, with a slope of 0.5%, and n= 0.015, full flow capacity is 2.34 cfs, with V= 3.11 FPS, and Depth = 0.91 feet. From the post-development analysis, the outflow from these facilities reached a maximum flow rate of 0.90 cfs, which occurred during the 10 year storm. B. The grass swale is 3' wide with 4:1 side slopes and a slope of 0.5%, and n = 0.15 (short grass). At a maximum computed flow rate of 0.90 cfs, the velocity will be 0.36 FPS, at a depth of 0.52' in the swale. II. The Flood Storage Facilities will be filled to capacity as the floodplain level rises during the 100 year storm event. There will be 2-12" RC pipes provided for this purpose, at each facility i.e. "high" and "low" stage. The "low" stage has 2 pipes at slope= 0.6%, approximately 12 LF each. At full flow, the peak inflow rate is 2.40 cfs, or 4.8 cfs for both pipes. The "high" stage has 2 pipes at slope = 1.2%, approximately 17 LF each. At full flow, the peak inflow rate is 3.60 cfs, or 7.2 cfs for both pipes. i 1 1 1 A i �1 t t3 U c LD �1 core NO RTk Ar,,J DC-JOG� tvl A m W ES LE Y ST. 2 2 2 A w N w ti co �► ZONE J C�A ZONE X LIMIT OF 238 ZONE Nr' N CO N N a DETAILED STUDY--. 228 ��"� 1 Farm Crossing '?.Q M Nw N ZONE X Stone Walls Mo: N Br J !,)it �I III Ii illl v 1 v U -ram 0 E ! ( y F- i.tc�M. r Ar-1 A. CAR W,--\ S1A q Is �lT� 25Uo96 - Gc:®G C RWx ��v► �'va�. 2, �9�3 114 Z N Gt ZONE X U)� m rt A r -Mill 1011, ��r I ill p�� i ! �� Ii ` ►: . �� ► � ^ M �N , 'WNW I I po ems-°;, ► Q . .� )1r�I j WA FW pro- MO MA pp'l PM PAR 36 Joins sheet 30 a4 N }i�t �, nEYA Kt� iNrA a Oj RI6 Srdk. •\ `.. UD CaB `v .f Rd/{ RdA G� Pb . LWrH y WM ... FbC PcE Sr8 \ r 1 rs� TEE,. RdA_ Pb 1 j \ Se SrB t ?` wE HfD Sr 4 F � dB WrA �: v.. WrB PG m 1 W� r Sri d B o i RIBr Wra. r WrA weA me 11�sC Pa i PaC `r � PaC r dA `'fir Pbd ShB V ! kP , WYB:, �Pa btl F � s t L X YYI& r r� `t t WsP f o ej 1 t..11 ITV A 5 I-�I t Ic�OJ E C -Si TE r Y'; o , �g ESSEX COUNTY, MASSACHUSETTS, NORTHERN PART - SHEET NUMBER 36 o a� OP W aA mP k r t k ,cG A• � �t I I `r '{F9 �r�;tl� WsB' � o u6 T' iy � �V.fl � :;`` 1320 3. cs_ A L. R68• 'r��e ry 700 000 FEE 1 S IL TYPES PARENT DEPTH MATERIAL TO HIGH HYDROLOGIC PERMEABILITY WATER SOIL SYMBOL NAME TEXTURE (IN/HR) (FT) GROUP MC Medisaprists - - - D (deep) RdA Ridgebury F.S.L. <0.2 0-1.5 C Wg Whitman F.S.L. <0.2 0-0.5 D WrC Woodbridge F.S.L. <0.2 1-3 C C SOIL - Consists of nearly level, very poorly drained deposits of organic material, extends to depth of 64 inches or more, generally is black to very dark grayish brown decomposed organic matter. Permeability is moderate to rapid, frequently flooded, with a seasonal high water table at or near the surface. RdA SOIL, - Consists of deep, nearly level, poorly drained soil along drainageways. Subsoil is fine sandy loam, olive and olive brown, mottled, and firm, to a depth of 60 inches or more, slow permeability in substratum, seasonal high water at or near surface. g SO - Consists of deep, nearly level, very poorly drained sandy loam to a depth of 60 inches or more, subsoil is firm, gray, and mottled. Slow permeability in substratum. Seasonal high water table at or near surface. WrC S 1L - Consists of deep, moderately well drained subsoil of friable fine sandy loam, yellowish brown to olive brown, mottled, slow permeability in the substratum, with a seasonal high water table at 1.5 to 3 feet. Y� Appendix A: RUNOFF CURVE E Runoff curve numbers for urban areas] CUI-VE numbe►s for Cover description h}•drologic soil group— Average percent Cover type and hydrologic condition impervious areal A b C D n Fully developed urban areas (vegetation established) Open space (lawns, parks, golf courses, cemeteries, PRC-D etc.)': Poor condition (grass cover < 60%) .............. 68 79 8 _ 89 Fair condition (grass cover 50% to 75%)........... 49 69 ' 79 S1 Good condition (grass cover > 75%) ............... 39 61 Impervious areas: P®5T- O Paved parking lots, roofs, driveways, etc. (excluding right-of-way). ........................• 98 9$ 98 9S Streets and roads: Paved; curbs and storm sewers (excluding right-of-way).................................. 98 98 98 98 Paved; open ditches (including right-of-way) ....... 83 89 92 93 Gravel (including right-of-way) ................... 70 85 89 91 Dirt (including right-of-way) ..................... 72 82 87 89 Western desert urban areas: Natural desert landscaping(pervious areas only)'... 63 77 85 88 Artificial desert landscaping(impervious weed barrier, desert shrub with 1- to 2-inch sand or gravel mulch and basin borders). .............. 96 96 96 a 96 Urban districts: Commercial and business.......................... 85 89 92 94 95 Industrial. 72 81 88 91 93 Residential districts by average lot size: 1/8 acre or less (town houses)...................... 65 77 85 90 92 114 acre ......................................... 38 61 75 83 87 1/3 acre ........................... ...... .... 30 57 72 81 86 1/2 acre ......................................... 25 54 70 80 85 1 acre ........................................... 20 51 68 79 84 2 acres ........................................ 12 46 65 77 82 Developing urban areas Newly graded areas (pervious areas only, no vegetation)-'................................... 77 86 91 94 Idle lands (CN's are determined using cover types similar to those in table 2.2c). 'Average runoff condition,and I, =0.2S. "'The average percent impervious area shown was used to develop the composite CN's. Other assumptions are as follows: impervious areau. are directly connected to the drainage system, impervious areas have a CN of 98, and pervious areas are considered equivalent to open space in goal hydrologic condition. C\"s for other combinations of conditions may be computed using figure 243 or 24. 'CN's shown are equivalent to those of pasture. Composite CN's may be computed for other combinations of open space cover type. 'Composite CN's for natural desert landscaping should be computed using figures 2-3 or 24 based on the impervious area percentage(CN =98)and the pervious area CN. The pervious area CN's are assumed equivalent to desert shrub in poor hydrologic condition. 'Composite CN's to use for the design of temporary measures during grading and construction should be computed using figlu•e 2.3 or 24, based on the degree of development(impervious area percentage)and the CN's for the newly graded pervious areas. This appendix reprinted from S.C.S. TR-55, revised 1986. A-1 CD o a O VALVES OF THE ROUGHNESS COEFFICIENT n (Continued) VALVES OF THE ROUGHNESS COEFFICIENT n (continued) (] 04 Type of channel and description Minimum Normal Maximum Type of channel and description ' Minimum Normal .11nximum mc Z C. EXCAVATED OR DREDGED b. Mountain streams, no vegetation in a. Earth,straight and uniform channel, banks usually steep, trees B 1. Clean,recently completed 0.016 0.018 0.020 and brush along banks submerged at 0 2. Clean,after weathering 0.018 0.022 0.025 high stages Z3. Gravel,uniform section,clean 0.022 0.025 0.030 1. Bottom: gravels, cobbles, and few 0.030 0.040 0.050 4. With short grass,few weeds 0.022 0.027 0.033 boulders C] b. Earth,winding and sluggish 2. Bottom:cobbles with large boulders 0.040 0.050 0.070 1. No vegetation 0.023 0.025 0.030 D-2. Flood plains 2. Grass,some weeds 0.025 0.030 0.033 a. Pasture,no brush 3. Dense weeds or aquatic plants in 0.030 0.035 0.040 1. Short grass 0.025 0.030 0.035 70 c deep channels 2. High grass 0.030 0.035 0.050 1-34. Earth bottom and rubble aides 0.028 0.030 0.035 b. Cultivated areas a 5. Stony bottom and weedy banks 0.025 0.035 0.040 1. No crop C7 P 0.020 0.030 0.040 W �1 6. Cobble bottom and clean sides 0.030 0.040 0.050 2. Mature row crops 0.025 0.035 0.0.65 ny D c. Drugline-excavated or dredged 3. Mature Seld crops R c� 0.030 0.010 0.050 tip CC' 1. No vegetation 0.025 0.028 0.033 c. Brush s^a Ij 2. Light brush on banks 0.035 0.050 0.060 1. Scattered brush, heavy weeds 0.035 0.050 0.070 d. Rock cuts 2. Light brush and trees,in winter 0.035 0.050 0.060 .� 1. Smooth and uniform 0.025 0.035 0.040 3. Light brush and trees,in summer .0- 0.060 0.030 C 2. Jagged and irregular 0.035 0.040 0.050 4. Rfedium to dense brush,in winter 0.045 0.070 0.110 7 e. Channels not maintained, weeds and 5. Medium to dense brush,in summer 0.070 0.100 0.160 1 brush uncut d. Trees a 1. Dense weeds,high as flow depth 0.050 0.080 0.120 1. Dense willows,summer,straight 0.110 0.150 0.200 gn 2. Clean bottom,brush on sides 0.040 0.050 0.080 2. Cleared land with tree stumps, no 0.030 0.040 0.050 3. Same,highest stage of flow 0.045 0.070 0.110 sprouts - 4. Dense brush,high stage 0.080 0.100 0.140 3. Same as above, but with heavy 0.050 0.060 0.080 oD. NATURAL STREAMS growth of Sprouts D-1. Minor streams (top width at flood stage 4. Heavy stand of timber,a few down 0.080 0.100 0.120 <100 ft) trees,little undergrowth,flood stage RQ a. Streams on plain below branches 1. Clean,straight,full stage,no rifts or 0.025 0.030 0.033 5. Same as above,but with flood stage 0.100 0.120 0.160 u deep pools reaching branches \O 2. Same na above,but more stones and 0.030 0.035 0.040 D-3. Major streams (top width at flood stage Cr weeds >100 ft). The n value is less than that �. 3. Clean, winding, some pools and 0.033 0.040 0.045 for minor streams of similar description, shoals because banks offer less effective resistance. 4. Same as above,but some weeds and 0.035 0.045 0.050 a. Regular section with no boulders or 0.025 0.060 F stones brush x 5. Same as above, lower stages, more 0.040 0.048 0.055 b. Irregular and rough section 0.035 0.100 E ineffective slopes and sections 6. Same as 4,but more stones 0.045 0.050 0.060 a 7. Sluggish reaches,weedy,deep pools 0.050 0.070 (. 080 8. Very weedy reaches, deep pools, or 0.075 0.100 0.150 t~iI floodways with heavy stand of tim- ber and underbrush Appendix A: RUNOFF CURVE NUMBERS (continued) Runoff curve numbers for arid and semiarid rangelands' Curve number_ for Cover description hydrologic soil group— Hydrologic Cover type condition2 A3 B C D Herbaceous—mixture of grass, weeds, and Poor 80 87 93 lo:v-growing brush, with brush the Fair 71 81 89 minor element. Good 62 74 85 Oak-aspen—mountain brush mixture of oak brush, Poor 66 74 79 aspen, mountain mahogany, bitter brush, maple, Fair 48 57 63 and other brush. Good 30 41 48 Pinyon-juniper—pinyon,juniper, or both; Poor 75 85 89 grass understory. Fair 5S 73 80 Good 41 61 71 Sagebrush with grass understory. Poor 67 80 85 Fair 51 63 70 Good 35 47 55 Desert shrub—major plants include saltbush, Poor 63 77 85 88 greasewood, creosotebush, blackbrush, bursage, Fair 55 72 ` 81 86 palo verde, mesquite, and cactus. Good 49 68 79 84 Aver age runotT condition, and I;, = 0.2S. For range in humid regions, use table 2-2c. 'Poor: <30% ground cover(litter, grasp,and bru;' over�tory). Fuir: .30 to 7W( ground cover. Good: >7U�/r ground cover. Curer: numbers for group A have been develop d only for desert shrub. This appendix reprinted from S.C.S. TR-55, revised 1986. A-4 Appendix A: RUNOFF CURVE NUMBERS (continued) Runoff curve numbers for other agricultural lands' Curve numbers for Cover description h.drulogic soil group— Hydrologic n Cover type condition A B C D Pasture, grassland, or range—continuous Poor 68 79 86 89 forage for gtazing.2 Fair 49 69 t9 L"'_� Good 39 61 80 Meadow—continuous grass, protected from — 30 58 71 78 grazing and generally moNved for hay. Brush—bi-ush•weed-grass mixture %%ith brush Poor 43 67 77 83 the major element.a Fair 35 56 70 77 Good 430 48 65 73 Woods—grass combination (orchard Poor 57 73 82 86 or tree farm).$ Fair 43 65 76 82 Good 32 58 72 79 Wpods.s Poor 45 66 77 83 Fair 36 60 73 79 Good 430 55 70 77 Farmsteads—buildings, lanes, driveways, — 59 74 82 86 and surrounding lots. 'Average runoff condition,and I;, — 0.2S. 211o0): <5 0%ground cover or heavily grazed with no mulch. Fur-: 50 to 75% ground cover and not heavily grazed. Good: >75%ground cover and lightly or only occasionally graced. 31'our: <50%ground cover. Fair:• 50 to 75%ground cover. Guod: >75%ground cover. 'Actual curve number is ley than 30; use CN = 30 for runoff computations. 5CN's shown were computed for areas with 501/v woods and 50% grass(pasture)cover. Other combinations of conditions may be computed from the CN's fur woods and pasture. 'Poor: Forest litter, small lives, and brush are destroyed by heavy grazing or regular binning. Fair: Woods are grazed but not biped, and some forest litter covers the soil. Goa(: Woods are protected from grazing, and litter and brush adequately cover the soil. This appendix reprinted from S.C.S. TR-55, revised 1986. A-3 Appendix A: RUNOFF CURVE NUMBERS Runoff curve numbers for urban areast Curve numbers for Cover description hydrologic soil group— Average percent Cover type and hydrologic condition impervious areal A P C D A Fully developed urban areas (vegetation established) Open space (lawns, parks, golf courses, cemeteries, PRC-D etc.): Poor condition (grass cover < 50%) .............. 68 79 86- 89 Fair condition (grass cover 50% to 75%)........... 49 69 79 Good condition (grass cover > 75%) ............... 39 61 Impervious areas: Paved parking lots, roofs, driveways, etc. (excluding right-of-way). ......................... 98 98 98 98 Streets and roads: Paved; curbs and storm sewers (excluding right-of-way).................................. 98 98 98 9S Paved; open ditches (including right-of-way) ....... 83 89 92 93 Gravel (including right-of-way) ................... 70 85 89 91 Dirt (including right-of-way) ..................... 72 82 87 89 Western desert urban areas: Natural desert landscaping(pervious areas only)'... 63 77 85 S8 Artificial desert landscaping(impervious weed barrier, desert shrub with 1- to 2-inch sand or gravel mulch and basin borders). .............. 96 96 96 96 Urban districts: Commercial and business.......................... 85 89 92 94 95 Industrial........................................ 72 81 88 91 93 Residential districts by average lot size: 1/8 acre or less (town houses)................... 65 77 85 90 92 1/4 acre ......................................... 38 61 75 83 87 1/3 acre ........................... 30 57 72 81 86 1/2 acre ........... .............................. 25 54 70 80 85 1 acre ........................................... 20 51 68 79 84 2 acres ....................... 12 46 65 77 82 Developing urban areas Newly graded areas (pervious areas only, no vegetation)s......... ........................... 77 86 91 94 Idle lands (CN's are determined using cover types similar to those in table 2-2c). 'Average runoff condition, and % =0.2S. rI'he average percent impervious area shown was used to develop the composite CN's. Other assumptions are as folio%%-;:impervious areas. are directly connected to the drainage system, impervious areas have a CN of 98, and pervious areas are wnsidered equivalent to open space in good hydrologic condition. CN's for other combinations of c-onditiuns may be euinputed using figure 241 or 2A. 'CN's shown are equivalent to those of pasture. Composite CN's may be computed for other combinations of open space cover type. 'Composite CN's for natural desert landscaping should be computed using figures 2-3 or 2-4 based on the impervious area percentage(CN = 98)and the pervious area CN. The pervious area CN's are assumed equivalent to desert shrub in pour hydrologic condition. 'Composite CN's to use for the design of temporary measures during grading and construction should be computed using figlu•e 2.3 or 2A, based on the degree of development(impervious area percentage)and the CN's for the newly graded pervious areas. This appendix reprinted from S.C.S. TR-55, revised 1986. A-1 Appendix G: VELOCITY FACTORS The TR-55 Shallow Concentrated Flow procedure and the NEH-4 Upland Method are both published as a chart of velocity vs. slope for various surfaces. Both charts are based on the same equation (see page 4) and make use of a velocity factor, Kv, determined by the surface type. HydroCAD provides the following predefined surface types for use with this equation.' The first two surfaces (paved and unpaved) are the basis for TR-55 Figure 3-1, and the factors are taken from TR-55, Appendix F [11 p.F-1]. The remaining surfaces are taken from NEH-4 Figure 15.2 [10 p.15-8] with the factors derived from that chart. (Some descriptions have been abbreviated.) For other surfaces or conditions, HydroCAD also allows the direct entry of Kv. Surface Description Kv Paved 20.3282 Unpaved 16.1345 Grassed Waterway 15.0 Nearly Bare & Untilled 10.0 Cultivated Straight Rows 9.0 Short Grass Pasture 7.0 Woodland 5.0 Forest*w/Heavy Litter .2.5 9 These factors are for a fractional slope (rise/run) and a velocity in feet per second. A-19 Appendix F: SHEET FLOW ROUGHNESS COEFFICIENTS When using the TR-55 Sheet Flow procedure for calculating time of concentration[11 p.3-3], HydroCAD provides the following table of roughness coefficients. This information is taken directly from TR-55 Table 3-1, with slight abbreviation of the descriptions. If you decide to substitute other roughness coefficients, note that these values are specifically for sheet flow, and may be larger than the regular Manning's number for a comparable surface. Surface Description n Smooth surfaces .011 Fallow .05 Cultivated: Residue< =20% .06 Cultivated: Residue>20% .17 Grass: Short .15 Grass: Dense .24 Grass: Bermuda .41 Range .13 Woods: Light underbrush .40 Woods: Dense underbrush .80 A-18 Appendix E: CULVERT ENTRANCE LOSS COEFFICIENTS Entrance Loss Coefficients. Type of Structure and Design of Entrance Coefficientke Pipe,Concrete Projecting from fill,groove end. . . . . . . . . . . . . . . . . . . . . . . 0.2 Projecting from fill,sq.cut end. . . . . . . . . . . . . . . . . . . . . . . 0.5 Headwall or headwall and wingwalls Grooveend of pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.2 Square-edge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 Rounded(radius= 1/1213) . . . . . . . . . . . . . . . . . . . . . . . 0.1 Mitered to conform to fill slope . . . . . . . . . . . . . . . . . . . . . . 0.7 End-Section conforming to fill slope*. . . . . . . . . . . . . . . . . . . . 0.5 Pipe,or Pipe-Arch,Corrugated Metal Projecting from fill(no headwall) . . . . . . . . . . . . . . . . . . . . . 0.9 Headwall or headwall end wingwalls Square-edge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 Mitered to conform to fill slope . . . . . . . . . . . . . . . . . . . . . . 0.7 End-Section conforming to fill slope*. . . . . . . . . . . . . . . . . . . 0.5 Box, Reinforced Concrete Headwall parallel to embankment(no wingwalls) Square-edged on 3 edges. . . . . . . . . . . . . . . . 0.5 Rounded on 3 edges to radius of 1/12 barrel dimension. . . . . . . 0.2 Wingwalls at300 to 750 to barrel Square-edged at crown. . . . . . . . . . . . . . . . . . . . . . . . . . 0.4 Crown edge rounded to radius of 1/12 barrel dimension . . . . . . 0.2 Wingwalls at 100 to 300 to barrel Square-edged at crown. . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 Wingwalls parallel (extension of sides) Square-edged at crown. . . . . . . . . . . . . . . ....... . . . . . . . 0.7 •Note: "End Section conforming to fill slope", made of either metal or concrete,are the sections commonly available from manufacturers. From limited hydraulic tests they are equivalent In operation to a headwall In both Inlet and outlet control. Some end sections, Incorporating a closed taper 'have a superior hydraulic per• I ormance. This table reprinted from the CONCRETE PIPE HANDBOOK, Copyright 1981 by the American Concrete Pipe Association, with the permission of the publisher. A-17 Circular Channel Analysis & Design Solved with Manning' s Equation Open Channel - Uniform flow Worksheet Name : Outflow Capacities Comment : Discharge Pipe From Drainage Facilities , Solve For Actual Depth Given Input Data : Diameter. . . . . . . . . . 1 .00 ft Slope. . . . . . . . . . . . . 0 .0050 ft/ft Manning' s n. . . . . . . 0 . 015 Discharge . . . . . . . . . 0 .90 cfs Computed Results : Depth. . . . . . . . . . . . . 0 .45 ft Velocity. . . . . . . . . . 2 . 65 fps Flow Area. . . . . . . . . 0 .34 sf Critical Depth. . . . 0 .40 ft Critical Slope . . . . 0 . 0076 ft/ft Percent Full . . . . . . 44 . 74 Full Capacity. . . . . 2 .18 cfs QMAX @. 94D. . . . . . . . 2 .35 cfs Froude Number. . . . . 0 .80 (flow is Subcritical) Open Channel Flow Module, Version 3 . 16 (c) 1990 Haestad Methods, Inc . * 37 Brookside Rd * Waterbury, Ct 06708 Trapezoidal Channel Analysis & Design Open Channel - Uniform flow Worksheet Name : Grass-lined Swale Description: outflow from Drainage Facilities to Wetland Solve For Discharge Given Constant Data; Bottom Width. . . . . . . 3 . 00 Z-Left . . . . . . . . . . . . . 4 .00 Z-Right . . . . . . . . . . . . 4 . 00 Mannings In' . . . . . . . 0 .150 Channel Slope. . . . . . 0 .0050 Jariable Input Data Minimum maximum Increment By Channel Drepth OF.0 or 0.70 0 . 10 VARIABLE COMPUTED COMPUTED --------------------------- --------------------------- Bottom Z-Left Z-Right Mannings Channel Channel Channel Velocity Width (H:V) (H:V) In' Slope Depth Discharge fps ft ft/ft ft cfs Unable to compute this instance. 3 . 00 4 .00 4 .00 0 .150 0 . 0050 0 . 10 0 .05 0 .14 3 .00 4 . 00 4 .00 0 .150 0 .0050 0 . 20 0 .16 0 .21 3 .00 4 . 00 4 .00 , 0 .150 0 . 0050 0 . 30 0 .33 0 .26 3 . 00 4 . 00 4 . 00 0 .150 0 . 0050 0 .40 0 .57 0 .31 3 . 00 4 . 00 4 . 00 0 .150 0 .0050 0 .50 0 . 87 0 .35-0- 3 .00 4 . 00 4 .00 0 . 150 0 . 0050 0 . 60 1 .25 0 .39 3 . 00 4 . 00 4 . 00 0 .150 0 .0050 0 . 70 1 . 70 0 .42 A G41oaAY F. F.S. //? per";,71551W6 ilelocl_//V 0 f 5 /rps Open Channel Flow Module, Version 3 . 16 (c) Haestad Methods, Inc . * 37 Brookside Rd * Waterbury, Ct 06708 Circular Channel Analysis & Design Solved with Manning' s Equation Open Channel - Uniform flow Worksheet Name: Outflow Capacities Description: Inflow from Floodplain to Storage Facilities Solve For Actual Depth Given Constant Data; Diameter_ . _ _ . . . . . . . 1 .00 Slope . . . . . . . . . . . . . . 0 .0060 "LOW STAGE Mannings n. . . . . . . . . 0 . 015 Variable Input Data Minimum Maximum Increment By Discharge 0. 00 2.40 0 . 30 VARIABLE COMPUTED COMPUTED COMPUTED Diameter Channel Mannings Discharge Depth Velocity Capacity ft Slope In' cfs ft fps Full ft/ft cfs ------------------------------------------------------------------- Unable to compute this instance. 1 . 00 0 .0060 0 .015 0 . 30 0 .24 2 . 08 2 .39 1 .00 0-0060 0 .015 0 _60 0__34 2 .53 2.39 1 . 00 0 . 0060 0 . 015 0 . 90 0 .43 2 . 83 2 .39 1 . 00 0 . 0060 a. 015 1 . 20 0 . 50 3 . 05 2 .39 1 . 00 0 .0060 0 .015 1 . 50 0 .57 3 .22 2 .39 1 .00 0 .0060 0 . 015 1 -80 0_65 3 .34 2 . 39 1 . 00 0 .0060 0 . 015 2 . 10 0 . 73 3 .43 2 .39 1 . 00 0 . 0060 0 .015 2 .40 0 . 82 3 .47 2 .39 Open Channel Flow Module, Version 3 . 16 (c) Haestad Methods, Inc . * 37 Brookside Rd * Waterbury, Ct 06708 Circular Channel Analysis & Design Solved with Manning' s Equation Open Channel - Uniform flow Worksheet Name: Outflow Capacities Description: Inflow from Floodplain to Storage Facilities Solve For Actual Depth Given Constant Data; Diameter. . . . . . . . . . . 1 .00 Slope . . . . . . . . . . . . . . 0 .0120 "HIGH " ST4GE Mannings n. . . . . . . . . 0 .015 Variable Input Data Minimum Maximum Increment By Discharge 0 . 00 3 . 60 0 . 40 VARIABLE COMPUTED COMPUTED COMPUTED ------------------------------ Diameter Channel Mannings Discharge Depth Velocity Capacity ft Slope 'n' cfs ft fps Full ft/ft cfs Unable to compute this instance. 1 . 00 0 . 0120 0 . 015 0 .40 0 .23 2 .89 3..38 1 . 00 0 . 0120 0 .015 0 . 80 0 .33 3 . 52 3 .38 1 . 00 0 . 0120 0 . 015 1 .20 0 .41 3 . 94 3 .38 1 . 00 0 . 0120 0 . 015 1 . 60 0 :48 4 .25 3 . 38 1 . 00 0 . 0120 0 . 015 2 . 00 0 .55 4 .49 3 . 38 1 . 00 0 . 0120 0 . 015 2 .40 0 . 62 4 . 67 3 . 38 1 . 00 0 . 0120 0 . 015 2 . 80 0 . 69 4 . 81 3 .38 1 . 00 0 . 0120 0 . 015 3 .20 0 . 78 4 . 90 3 .38 1 . 00 0 . 0120 0 . 015 3 . 60 0 . 90 4 . 85 3 .38 Unable to compute this instance. Open Channel Flow Module, Version 3 . 16 (c) Haestad Methods, Inc . * 37 Brookside Rd * Waterbury, Ct 06708 Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 6.50 IN (100-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 14 PROPOSED BUILDING ROOF AREA PEAK= .76 CFS @ 11.98 HRS, VOLUME= .06 AF PERCENT CN SCS TR-20 METHOD 100 .00 98 IMPERVIOUS ROOF SURFACE TYPE III 24-HOUR TOTAL AREA = .12 AC RAINFALL= 6 .50 IN SPAN= 0-24 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW ACROSS MIDDLE OF ROOF .7 Smooth surfaces n=.011 L=50 ' P2=3 .1 in s=.02 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW ACROSS ROOF TO GUTTERS .7 Unpaved Kv=16.1345 L=100' s=.02 ' / ' V=2 .28 fps Total Length= 150 ft Total Tc= 1.4 SUBCATCHMENT 14 RUNOFF PROPOSED BUILDING ROOF AREA .75 .70 AREA= . 12 AC .65 Tc= 1 .4 MIN .60 CN= 98 .55 r-, SCS TR-20 METHOD } .45 TYPE III 24-HOUR 40 RAINFALL= 6.50 IN 35 PEAK= .76 CFS 3 .30 @ 11 .98 HRS J .25 UOLUME= .06 AF L- .20 . 15 10 05 tD CO m N V �D M m N V - - N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 6.50 IN (100-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems REACH 1 COMBINED FLOWS. .@ DESIGN POINTS #1 & #2. . . Qin = 3 .59 CFS @ 12 .15 HRS, VOLUME= .55 AF Qout= 3 .52 CFS @ 12 .17 HRS, VOLUME= .55 AF, ATTEN= 2., LAG= 1.1 MIN DEPTH END AREA DISCH (FT) (SQ-FT) (CFS)_ 5 ' x 2 ' CHANNEL STOR-IND+TRANS METHOD A 0 .00 0 .00 0.00 SIDE SLOPE= .05 1 / ' PEAK DEPTH= .26 FT .20 1.80 1.79 n= .04 PEAK VELOCITY= 1.2 FPS .40 5 .20 7 .61 LENGTH= 20 FT TRAVEL TIME _ .3 MIN .60 10 .20 18.87 SLOPE= .01 FT/FT SPAN= 0-24 HRS, dt=.1 HRS .86 19.09 43 .73 1.20 34 .80 97.59 1.60 59 .20 198.42 2 .00 90 .00 347 .06 REACH 1 INFLOW & OUTFLOW COMBINED FLOWS . . @ DESIGN POINTS # 1 & #2 . . . 3.6 3.4 5' x 2' CHANNEL 3.2 SIDE SLOPE= .05 .0 2.8 n=.04 L=20' S=.e1 2.6 2.4 STOR-IND+TRANS METHOD ^ LO 2.2 UELOCITY= 1 .2 FPS 2.e TRAUEL= .3 MIN 1 .8 1 .6 Qin= 3.59 CFS 0 1 .4 Qout= 3.52 CFS 1 1 .2 LAG= 1 . 1 MIN IL 1 .0 8 .6 .4 .2 B.em N V tD N m N V tD M m N Q - - - - - N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 6.50 IN (100-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems POND 1 SUBSURFACE DETENTION FACILITY "B" & "C" Qin = 4.64 CFS @ 12 .00 HRS, VOLUME= .37 AF Qout= 1.54 CFS @ 12 .26 HRS, VOLUME= .36 AF, ATTEN= 67`0, LAG= 15 .9 MIN ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD (FT) (SF) (CF) (CF) PEAK STORAGE = 4102 CF n 232 .3 0 0 0 PEAK ELEVATION= 233 .5 FT 232 .4 2435 122 122 FLOOD ELEVATION= 238.0 FT 232 .8 2435 974 1096 START ELEVATION= 232 .3 FT 233 .0 4712 715 1810 SPAN= 0-24 HRS, dt= .1 HRS 234 .0 4712 4712 6522 Tdet= 49 MIN ( .36 AF) 235 .0 4712 4712 11234 236 .0 4712 4712 15946 236.2 4712 942 16889 236.7 2277 1747 18636 236.8 10 114 18750 238 .0 10 12 18762 # ROUTE INVERT OUTLET DEVICES 1 P 232 .3 ' 8" CULVERT n=.013 L=6' S=.0051 / ' Ke=.S Cc=. 9 Cd=.6 POND 1 INFLOW & OUTFLOW SUBSURFACE DETENTION FACILITY "B" & "C" 4.5 LEE :::��233 ETHOD 4.0 02 CF ,5 FT 3.5 4 CFS 3.0 4 CFS .9 MIN U 2.5 3 2.0 0 J 1 .5 1 .0 .5 0.Bm N V QD CO m N V l0 M m N IT -- - - - - N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 6.50 IN (100-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HVdroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems POND 2 ROOF DRAINAGE "RECHARGE" FACILITY Qin = .76 CFS @ 11.98 HRS, VOLUME= .06 AF Qout= .70 CFS @ 12 .02 HRS, VOLUME= .05 AF, ATTEN= 7%, LAG= 1.9 MIN ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD (FT) (SF) (CF) (CF) PEAK STORAGE = 801 CF 234 .4 0 0 0 PEAK ELEVATION= 236 .9 FT 234 .5 324 16 16 FLOOD ELEVATION= 238 .4 FT 235 .5 324 324 340 START ELEVATION= 234.4 FT 236 .5 324 324 664 SPAN= 0-24 HRS, dt=.1 HRS 236 .9 324 130 794 Tdet= 130.9 MIN ( .05 AF) 237 .0 24 17 811 237 .4 12 7 818 238 .4 2 7 825 # ROUTE INVERT OUTLET DEVICES 1 P 236 .5 ' 6" CULVERT n=.013 L=10 ' S=.0031/ ' Ke=.5 Cc=.9 Cd=.6 2 P 234 .4 ' EXFILTRATION Q= .01 CFS at and above 234 .5 ' 3 P 236 .5 ' 6" CULVERT n=.013 L=15' S=.021/' Ke=.5 Cc=.9 Cd=.6 POND 2 INFLOW & OUTFLOW ROOF DRAINAGE ''RECHARGE'' FACILITY .75 70 STOR-IND METHOD 65 PEAK STOR= 801 CF 6e PEAK ELEU= 236.9 FT 55 .5e Qin= .76 CFS c, .45 Gout= .70 CFS 4e LAG= 1 .9 MIN .35 � 30 .25 .20 15 � 1e .05 e.Be N V 0 M m N m I �0 M m N V TIME (hours) . Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 4.50 IN ( 10-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 11 PAVEMENT & LANDSCAPING AT ENTRANCE ROAD PEAK= .38 CFS @ 12 .14 HRS, VOLUME= .03 AF PERCENT CN SCS TR-20 METHOD 74 .00 74 AREAS TO BE LANDSCAPED & PLANTED TYPE III 24-HOUR 26 .00 98 DRIVEWAY ENTRANCE AT RTE.114 RAINFALL= 4.50 IN 100 . 00 80 TOTAL AREA = .17 AC SPAN= 0-24 HRS, dt=.1 HRS Method Comment Tc (min) TR-55 SHEET FLOW TOWARD THE FRONT OF THE SITE 11.0 Grass: Dense n=.24 L=50 ' P2=3 .1 in s=.01 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW FLOW TO DESIGN POINT #1 2 .4 Grassed Waterway Kv=15 L=300 ' s=.02 / ' V=2 .12 fps Total Length= 350 ft Total Tc= 13 .4 SUBCATCHMENT 11 RUNOFF PAUEMENT & LANDSCAPING AT ENTRANCE ROAD .36 34 LRAINFN . 17 AC 32 .4 MIN 30 80 .28 .26 METHOD Lo .24 4-HOUR `} .22 4.50 IN U .20 . 18 .38 CFS 3 . 16 O . 14 . 14 HR5. 12 .03 AF L- 10 08 .06 .04 .02 e.0 em N V l0 0C) m N V N m N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 4.50 IN ( 10-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 12 DRIVEWAY AND PAVEMEMT AREAS PEAK= 2 .72 CFS Q 11.99 HRS, VOLUME= .22 AF PERCENT CN SCS TR-20 METHOD 100 . 00 98 AREAS TO BE PAVEMENT TYPE III 24-HOUR TOTAL AREA = .61 AC RAINFALL= 4.50 IN SPAN= 0-24 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW ACROSS DRIVEWAYS & PAVEMENT AREA .9 Smooth surfaces n=.011 L=50 ' P2=3 .1 in s=.01 '/ ' SHALLOW CONCENTRATED/UPLAND FLOW TO CB'S,THEN TO S.D.F."B" & "C" 1.6 Paved Kv=20.3282 L=200 ' s=.01 '/ ' V=2 . 03 fps Total Length= 250 ft Total Tc= 2 .5 SUBCATCHMENT 12 RUNOFF DRIUEWAY AND PAUEMEMT AREAS 2.6 AREA= .61 AC 2.4 Tc= 2.5 MIN 2.2 CN= 98 2.0 1 8 SCS TR-20 METHOD 1 6 TYPE III 24-HOUR 1 RAINFALL= 4.50 IN .4 3 1 .2 PEAK= 2.72 CFS O 1 .0 @ 11 .99 HRS _I 8 UOLUME= .22 AF 6 4 2 0.BCD N V �D CD CD N V W CD m N V -- - - - - N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 4.50 IN ( 10-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 13 LAND RESTORATION & WETLAND REPLACEMENT PEAK= .80 CFS @ 12 .14 HRS, VOLUME= .07 AF PERCENT CN SCS TR-20 METHOD 67 .00 74 AREA TO BE LANDSCAPED TYPE III 24-HOUR 33 .00 80 AREA TO BE LANDSCAPED RAINFALL= 4 .50 IN n 100 .00 76 TOTAL AREA = .42 AC SPAN= 0-24 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW OVER LANDSCAPED & NATURAL AREAS 11.0 Grass: Dense n=.24 L=50' P2=3 .1 in s=.01 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW IN SWALE,WITHIN REPLACED WETLAND 2 .2 Grassed Waterway Kv=15 L=200' s=.01 '/ ' V=1.5 fps CHANNEL FLOW IN SWALE ,TO DESIGN POINT #2 .2 a=8 sq-ft Pw=5 ' r=1.6' s=.006 ' / ' n=.04 V=3 .94 fps L=40 ' Capacity=31.5 cfs Total Length= 290 ft Total Tc= 13 .4 SUBCATCHMENT 13 RUNOFF LAND RESTORATION & WETLAND REPLACEMENT .80 .75 AREA:: .42 AC .7e Tc= 13.4 MIN .65 CN= 76 .60 .55 SCS TR-20 METHOD LO .50 TYPE III 24-HOUR `'- .45 RAINFALL= 4.50 IN U 40 3 35 PEAK= . 1 CFS O 30 @ 12. 14 HRS 25 UOLUME= .87 AF LL .2e . 15 1e 05 0.00 C N V 0 O7 m N V �-0 M m N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 4.50 IN ( 10-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 14 PROPOSED BUILDING ROOF AREA PEAK= 52 CFS @ 11.98 HRS, VOLUME= .04 AF PERCENT CN SCS TR-20 METHOD 100 . 00 98 IMPERVIOUS ROOF SURFACE TYPE III 24-HOUR TOTAL AREA = .12 AC RAINFALL= 4 .50 IN SPAN= 0-24 HRS, dt=.l HRS Method Comment To (min) TR-55 SHEET FLOW ACROSS MIDDLE OF ROOF .7 Smooth surfaces n=.011 L=50 ' P2=3 .1 in s=.02 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW ACROSS ROOF TO GUTTERS .7 Unpaved Kv=16.1345 L=100 ' s=.02 / ' V=2 .28 fps Total Length= 150 ft Total To= 1.4 SUBCATCHMENT 14 RUNOFF PROPOSED BUILDING ROOF AREA 50 LIUNFAAA . 12 AC .451 .4 MIN 4098 .35 METHOD Ln 24-HOUR .30 4.50 IN .25 .52 CFS 3 .20 .98 HRSO .04 AF . 15 . 1e .05 e.e em N V 0 07 m N V �D N m N Q N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 4.50 IN ( 10-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5.11 000899 (c) 1986-1999 Applied Microcomputer Systems REACH 1 COMBINED FLOWS. .@ DESIGN POINTS #1 & #2. . . Qin = 2 .15 CFS @ 12 .15 HRS, VOLUME= .35 AF Qout= 2 .15 CFS @ 12 .17 HRS, VOLUME= .35 AF, ATTEN= 0`0, LAG= 1.1 MIN DEPTH END AREA DISCH (FT) (SQ-FT) (CFS) 5' x 2 ' CHANNEL STOR-IND+TRANS METHOD n 0 .00 0. 00 0.00 SIDE SLOPE= .OS 1/ 1 PEAK DEPTH= .21 FT .20 1.80 1.79 n= .04 PEAK VELOCITY= 1 .1 FPS .40 5.20 7.61 LENGTH= 20 FT TRAVEL TIME _ .3 MIN .60 10.20 18. 87 SLOPE= .01 FT/FT SPAN= 0-24 HRS, dt=.l HRS . 86 19. 09 43 .73 1.20 34. 80 97.59 1.60 59.20 198.42 2 .00 90.00 347.06 REACH 1 INFLOW & OUTFLOW COMBINED FLOWS - @ DESIGN POINTS # 1 & #2 . . . 2.0 5' x 2' CHANNEL 1 8 SIDE SLOPE= .05 '/' n=.04 L=20' S=.81 1 .6 1 4 STOR-IND+TRANS METHOD LO UELOCITY= 1 , 1 FPS U 1 .2 TRAUEL= .3 MIN 1 .e Qin= 2. 15 CFS 0 .8 Qout= 2. 15 CFS LAG= 1 . 1 MIN .6 4 .2 0.0 N V 0 OJ m N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 4.50 IN ( 10-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 11 000899 (c) 1986-1999 Applied Microcomputer Systems POND 1 SUBSURFACE DETENTION FACILITY "B" & "C" Qin = 2 .73 CFS @ 12 .00 HRS, VOLUME= .25 AF Qout= 1.03 CFS @ 12 .28 HRS, VOLUME= .24 AF, ATTEN= 62%, LAG= 16.5 MIN ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD (FT) (SF) (CF) (CF) PEAK STORAGE = 2610 CF 232 .3 0 0 0 PEAK ELEVATION= 233 .2 FT 232 .4 2435 122 122 FLOOD ELEVATION= 238 .0 FT 232 .8 2435 974 1096 START ELEVATION= 232 .3 FT 233 .0 4712 715 1810 SPAN= 0-24 HRS, dt=.1 HRS 234 .0 4712 4712 6522 Tdet= 51.1 MIN ( .24 AF) 235 .0 4712 4712 11234 236 .0 4712 4712 15946 236 .2 4712 942 16889 236 .7 2277 1747 18636 236 .8 10 114 187SO 238 .0 10 12 18762 # ROUTE INVERT OUTLET DEVICES 1 P 232 .3 ' 8" CULVERT n=.013 L=6' S=.005 ' / ' Ke= .5 Cc=.9 Cd=.6 POND 1 INFLOW & OUTFLOW SUBSURFACE DETENTION FACILITY "B" 8 "C" 2.6 STOR-IND METHOD 2.4 PEAK STOR= 2610 CF 2.2 PEAK ELEU= 233.2 FT 2.0 - Qin= 2.73 CFS LO 1 '8 Qout= 1 .03 CFS +� 1 .6 LAG= 16.5 MIN U 1 4 3 1 .2 O I .0 IL B .6 .4 .2 0.Bm N V �D M m N V tD Co m NN IT N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 4.50 IN ( 10-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 11 000899 (c) 1986-1999 Applied Microcomputer Systems POND 2 ROOF DRAINAGE "RECHARGE" FACILITY Qin = .52 CFS @ 11.98 HRS, VOLUME= .04 AF Qout= .30 CFS @ 12 .13 HRS, VOLUME= .03 AF, ATTEN= 43%, LAG= 8 .8 MIN ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD (FT) (SF) (CF) (CF) PEAK STORAGE = 745 CF n 234 .4 0 0 0 PEAK ELEVATION= 236.7 FT 234 .5 324 16 16 FLOOD ELEVATION= 238.4 FT 235 .5 324 324 340 START ELEVATION= 234 .4 FT 236 .5 324 324 664 SPAN= 0-24 HRS, dt=.l HRS 236.9 324 130 794 Tdet= 174 .2 MIN ( .03 AF) 237 .0 24 17 811 237 .4 12 7 818 238 .4 2 7 825 # ROUTE INVERT OUTLET DEVICES 1 P 236 .5' 6" CULVERT n=.013 L=10' S=.0031/ ' Ke=.S Cc=. 9 Cd=.6 2 P 234 .4 ' EXFILTRATION Q= .01 CFS at and above 234 .5 ' 3 P 236 .5' 6" CULVERT n=.013 L=15 ' S=.021/' Ke=.5 Cc=.9 Cd=.6 POND 2 INFLOW & OUTFLOW ROOF DRAINAGE ''RECHARGE'' FACILITY .50 LEE THOD .45 45 CF .7 FT .40 .35 2 CFS 0 CFS U .30 8 MIN 25 0 20 15 10 .05 - - - - 0.0 am N V �D Co m N V �D M m N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 3.10 IN ( 2-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 11 PAVEMENT & LANDSCAPING AT ENTRANCE ROAD PEAK= .20 CFS Q 12 .15 HRS, VOLUME= .02 AF PERCENT CN SCS TR-20 METHOD 74 . 00 74 AREAS TO BE LANDSCAPED & PLANTED TYPE III 24-HOUR 26.00 98 DRIVEWAY ENTRANCE AT RTE.114 RAINFALL= 3 .10 IN n 100 .00 80 TOTAL AREA = .17 AC SPAN= 0-24 HRS, dt= .l HRS Method Comment Tc (min) TR-55 SHEET FLOW TOWARD THE FRONT OF THE SITE 11.0 Grass: Dense n=.24 L=50' P2=3 .1 in s=.01 ' / , SHALLOW CONCENTRATED/UPLAND FLOW FLOW TO DESIGN POINT #1 2 .4 Grassed Waterway Kv=15 L=300 ' s=.02 ' / ' V=2 .12 fps Total Length= 350 ft Total Tc= 13 .4 SUBCATCHMENT 11 RUNOFF PAUEMENT & LANDSCAPING AT ENTRANCE ROAD . 19 18 AREA= 17 AC 17 Tc= 13.4 MIN . 16 CN= 80 . 15 . 14 SCS TR-20 METHOD L 12 TYPE III 24-HOUR 11 RAINFALL= 3. 10 IN 10 09 PEAK= .20 CF5 .08 e 12. 15 HRS CD .07 UOLUME= .02 AF .06 05 .04 .03 .0z .01 0.0 0m N v 0 m m N v 0 co m N IT N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 3.10 IN ( 2-YR) 27 Mar 01 Prepared by Merrimack Engineering Services H droCAD 5 .11 000899 c 1986-1999 Lp lied Microcomputer S stems SUBCATCHMENT 12 DRIVEWAY AND PAVEMENT AREAS PEAK= 1. 86 CFS @ 11.99 HRS, VOLUME= .15 AF PERCENT CDT SCS TR-20 METHOD 100.00 98 AREAS TO BE PAVEMENT TYPE III 24-HOUR TOTAL AREA = .61 AC RAINFALL= 3 .10 IN SPAN= 0-24 HRS, dt=.l HRS Method Comment Tr (min) TR-55 SHEET FLOW ACROSS DRIVEWAYS & PAVEMENT AREA 9 Smooth surfaces n=.011 L=50' P2=3 .1 in s= .01 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW TO CB'S,THEN TO S.D.F. "B" & "C° 1.6 Paved Kv=20 .3282 L=200 ' s=.01 ' / , V=2 .03 fps Total Length= 250 ft Total Tc= 2 .5 SUBCATCHMENT 12 RUNOFF DRIUEWAY AND PAUEMEMT AREAS 1 .8 AREA= .61 AC 1 .7 LRINF .5 MIN 1 .5 8 1 .5 1 .4 ETHOD 1 .3 ,o 1 .2 -HOUR ti- 1 . 1 . 10 IN U 1 .0 `J 9 86 CFS O •8 99 HRS 6 . 15 AF 4 .3 .2 . 1 0.0CS) N V 0 co m N V D W m N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 3.10 IN ( 2-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 13 LAND RESTORATION & WETLAND REPLACEMENT PEAK= .38 CFS @ 12 .16 HRS, VOLUME= .04 AF PERCENT CN SCS TR-20 METHOD 67.00 74 AREA TO BE LANDSCAPED TYPE III 24-HOUR 33 .00 80 AREA TO BE LANDSCAPED RAINFALL= 3 .10 IN s 100 .00 76 TOTAL AREA = .42 AC SPAN= 0-24 HRS, dt=.1 HRS Method Comment Tc (min) TR-55 SHEET FLOW OVER LANDSCAPED & NATURAL AREAS 11.0 Grass: Dense n=.24 L=50' P2=3 .1 in s=.01 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW IN SWALE,WITHIN REPLACED WETLAND 2 .2 Grassed Waterway Kv=15 L=200 ' s=.01 ' / ' V=1.5 fps CHANNEL FLOW IN SWALE ,TO DESIGN POINT #2 .2 a=8 sq-ft Pw=S ' r=1.6' s=.006 ' / ' n=. 04 V=3 .94 fps L=40 ' Capacity=31.5 cfs Total Length= 290 ft Total Tc= 13 .4 SUBCATCHMENT 13 RUNOFF LAND RESTORATION & WETLAND REPLACEMENT .38 .36 AREA= .42 AC .34 Tc= 13.4 MIN .32 .30 CN= 76 .28 r .26 SCS TR-20 METHOD Jl .24 TYPE III 24-HOUR q- .22 RAINFALL= 3, 10 IN .20 18 PEAK= .38 CFS :3 . 16 e 12. 16 HRS O . 14 J 12 VOLUME= .04 AF L 10 .e8 06 e4 .ez 0.00 N Q N m N V �D 07 m N IT - -- - N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 3.10 IN ( 2-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 11 000899 (c) 1986-1999 Applied Microcomputer Svstems SUBCATCHMENT 14 PROPOSED BUILDING ROOF AREA PEAK= .36 CFS @ 11.98 HRS, VOLUME= .03 AF PERCENT CN SCS TR-20 METHOD 100 .00 98 IMPERVIOUS ROOF SURFACE TYPE III 24-HOUR TOTAL AREA = .12 AC RAINFALL= 3 .10 IN SPAN= 0-24 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW ACROSS MIDDLE OF ROOF .7 Smooth surfaces n=.011 L=50' P2=3 .1 in s=.02 '/ ' SHALLOW CONCENTRATED/UPLAND FLOW ACROSS ROOF TO GUTTERS .7 Unpaved Kv=16 .1345 L=100' s=.02 '/ ' V=2 .28 fps Total Length= 150 ft Total Tc= 1.4 SUBCATCNMENT 14 RUNOFF PROPOSED BUILDING ROOF AREA .34 32 AREA= . 12 AC .3e Tc= 1 .4 MIN .28 CN= 98 .26 r, 24 SCS TR-20 METHOD .22 TYPE III 24-HOUR U` 20 RAINFALL= 3. 10 IN 18 16 PEAK= .36 CFS 3 . 14 C' 11 .98 HRS O J . 12 UOLUME= .03 AF . 10 .08 ,06 .e4 .02 B.e Bm N V tD co m N V �D M m N IT N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 3.10 IN ( 2-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems REACH 1 COMBINED FLOWS. .@ DESIGN POINTS #1 & #2. . . Qin = 1 .33 CFS @ 12 .16 HRS, VOLUME= .22 AF Qout= 1.33 CFS @ 12 .18 HRS, VOLUME= .22 AF, ATTEN= 0%, LAG= 1.2 MIN DEPTH END AREA DISCH (FT) (SQ-FT) (CFS) 5' x 2 ' CHANNEL STOR-IND+TRANS METHOD r 0 .00 0 .00 0 .00 SIDE SLOPE= .05 '/ ' PEAK DEPTH= .15 FT .20 1.80 1.79 n= .04 PEAK VELOCITY= 1.0 FPS .40 5 .20 7 .61 LENGTH= 20 FT TRAVEL TIME _ .3 MIN .60 10 .20 18 .87 SLOPE= .01 FT/FT SPAN= 0-24 HRS, dt=.l HRS .86 19 .09 43 .73 1.20 34 .80 97 .59 1 .60 59.20 198 .42 2 .00 90 .00 347 .06 REACH 1 INFLOW & OUTFLOW COMBINED FLOWS . . @ DESIGN POINTS # 1 & #2 . . . 1 .3 1 2 5' x 2' CHANNEL 1 1 SIDE SLOPE= .05 '/' n=.04 L=20' S=.01 1 .0 .9 STOR-IND+TRANS METHOD L B VELOCITY= i FPS `-- TRAVEL= .3 MIN u 7 .6 Qin= 1 .13 CFS o 5 Qout= 1 .33 CFS LL 4 LAG= 1 .2 MIN 3 .2 1 0.Om N V D N m N C D OJ m N V TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 3.10 IN ( 2-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems POND 1 SUBSURFACE DETENTION FACILITY "B" & "C" Qin = 1.87 CFS @ 11.99 HRS, VOLUME= .16 AF Qout= .76 CFS @ 12 .20 HRS, VOLUME= .16 AF, ATTEN= 60%, LAG= 12 .1 MIN ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD (FT) (SF) (CF) (CF) PEAK STORAGE = 1700 CF 232 .3 0 0 0 PEAK ELEVATION= 233 .0 FT 232 .4 2435 122 122 FLOOD ELEVATION= 238.0 FT 232 . 8 2435 974 1096 START ELEVATION= 232 .3 FT 233 . 0 4712 715 1810 SPAN= 0-24 HRS, dt=.l HRS 234 .0 4712 4712 6522 Tdet= 54 .7 MIN ( .16 AF) 235 .0 4712 4712 11234 236 .0 4712 4712 15946 236 .2 4712 942 16889 236.7 2277 1747 18636 236.8 10 114 18750 238 .0 10 12 18762 # ROUTE INVERT OUTLET DEVICES 1 P 232 .3 ' 8" CULVERT n=.013 L=6' S=.0051 / ' Ke=.S Cc=.9 Cd=.6 POND 1 INFLOW & OUTFLOW SUBSURFACE DETENTION FACILITY ''B" & "C'' 1 .8 1 .7 LKR ETHOD 1 .6 00 CF 1 .5 33 FT 1 .4 1 .3 7 CFS Lo 1 .2 76 CFS `-'- 1 ' 1 . 1 MIN U 1 .e 9 3 .8 O 7 J .6 LL .5 .2 0.BN N IT 0 00 CJ/ N V w N m N Q fV N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 3.10 IN ( 2-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems POND 2 ROOF DRAINAGE "RECHARGE" FACILITY Qin = .36 CFS @ 11.98 HRS, VOLUME= .03 AF Qout= .02 CFS @ 13 .40 HRS, VOLUME= .02 AF, ATTEN= 93%, LAG= 84 .8 MIN ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD (FT) (SF) (CF) (CF) PEAK STORAGE = 674 CF n 234 .4 0 0 0 PEAK ELEVATION= 236.5 FT 234 .5 324 16 16 FLOOD ELEVATION= 238 .4 FT 235 .5 324 324 340 START ELEVATION= 234.4 FT 236 .5 324 324 664 SPAN= 0-24 HRS, dt=.l HRS 236 .9 324 130 794 Tdet= 251.3 MIN ( . 02 AF) 237 .0 24 17 811 237.4 12 7 818 238 .4 2 7 825 # ROUTE INVERT OUTLET DEVICES 1 P 236.5' 6" CULVERT n=.013 L=10' S=.0031/ ' Ke=.5 Cc=.9 Cd=.6 2 P 234 .4 ' EXFILTRATION Q= .01 CFS at and above 234 .5 ' 3 P 236.5 ' 6" CULVERT n=.013 L=15 ' S=.021/ ' Ke=.5 Cc=.9 Cd=.6 POND 2 INFLOW & OUTFLOW ROOF DRAINAGE ''RECHARGE'' FACILITY LELE .34 .32 ETHOD 3e 74 CF 28 .5 FT ,26 .24 6 CFS `- .22 2 CFS U 20 .8 MIN v . 18 16 - PE 14 . 12 � 10 .08 .06 .04 02 - - - -0.0 Bm M m N V �D CO m N V - - - - - N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 2.30 IN ( 1-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 11 PAVEMENT & LANDSCAPING AT ENTRANCE ROAD PEAK= .11 CFS @ 12 .16 HRS, VOLUME= .01 AF PERCENT CN SCS TR-20 METHOD 74 .00 74 AREAS TO BE LANDSCAPED & PLANTED TYPE III 24-HOUR 26 . 00 98 DRIVEWAY ENTRANCE AT RTE.114 RAINFALL= 2 .30 IN 100 . 00 80 TOTAL AREA = .17 AC SPAN= 0-24 HRS, dt=.1 HRS Method Comment Tc (min) TR-55 SHEET FLOW TOWARD THE FRONT OF THE SITE 11.0 Grass: Dense n=.24 L=50 ' P2=3 .1 in s=.01 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW FLOW TO DESIGN POINT #1 2 .4 Grassed Waterway Kv=15 L=300 ' s=.02 ' / ' V=2 .12 fps Total Length= 350 ft Total Tc= 13 .4 SUBCATCHMENT 11 RUNOFF PAUEMENT & LANDSCAPING AT ENTRANCE ROAD . 10 AREA= . 17 AC .09 Tc= 13.4 MIN CN= 80 08 SCS TR-20 METHOD � e7 TYPE III 24-HOUR `- .06 RAINFALL= 2.30 IN U 05 PEAK= . 11 CFS :3 04 @ 12. 16 HRS J UOLUME= .01 AF L- .03 .02 ei 0.8em N 0 N m N [f D co m N Q TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 2.30 IN ( 1-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 12 DRIVEWAY AND PAVEMEMT AREAS PEAK= 1.37 CFS @ 11.99 HRS, VOLUME= .11 AF PERCENT CN SCS TR-20 METHOD 100 .00 98 AREAS TO BE PAVEMENT TYPE III 24-HOUR TOTAL AREA = .61 AC RAINFALL= 2 .30 IN SPAN= 0-24 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW ACROSS DRIVEWAYS & PAVEMENT AREA .9 Smooth surfaces n=.011 L=50' P2=3 .1 in s=.01 ' / , SHALLOW CONCENTRATED/UPLAND FLOW TO CB'S,THEN TO S.D.F. "B" & "C" 1.6 Paved Kv=20.3282 L=200' s=.01 '/ ' V=2 .03 fps Total Length= 250 ft Total Tc= 2 .5 SUBCATCHMENT 12 RUNOFF DRIUEWAY AND PAUEMEMT AREAS 1 .3 AREA= .61 AC 1 .2 Tc= 2.5 MIN 1 . 1 CN= 98 1 .e 9 SCS TR-20 METHOD LO TYPE III 24-HOUR B U RAINFALL= 2.30 IN 7 v 6 PEAK= 1 .37 CFS o .5 e 11 .99 HRS J 4 UOLUME= . 11 AF L� 3 .2 1 0 B� N V lD CO m N V lD M m N Q - -- -- - N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 2.30 IN ( 1-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5.11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 13 LAND RESTORATION & WETLAND REPLACEMENT PEAK= .19 CFS @ 12 .18 HRS, VOLUME= .02 AF PERCENT CN SCS TR-20 METHOD 67 .00 74 AREA TO BE LANDSCAPED TYPE III 24-HOUR 33 .00 80 AREA TO BE LANDSCAPED RAINFALL= 2 .30 IN 100 . 00 76 TOTAL AREA = .42 AC SPAN= 0-24 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW OVER LANDSCAPED & NATURAL AREAS 11.0 Grass : Dense n=.24 L=50' P2=3 .1 in s=.01 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW IN SWALE,WITHIN REPLACED WETLAND 2 .2 Grassed Waterway Kv=15 L=200 ' s=.01 1 / ' V=1 .5 fps CHANNEL FLOW IN SWALE TO DESIGN POINT #2 .2 a=8 sq-ft Pw=S' r=1.6 ' s=.006 / ' n=.04 V=3 .94 fps L=40' Capacity=31.5 cfs Total Length= 290 ft Total Tc= 13 .4 SUBCATCHMENT 1 .3 RUNOFF LAND RESTORATION & WETLAND REPLACEMENT . 18 17 AREA= .42 AC . 16 Tc= 13.4 MIN . 15 CN= 76 . 14 . 13 SCS TR-20 METHOD Ln . 12 TYPE III 24-HOUR `+- . II RAINFALL:: 2.30 IN U . 10 v .09 PEAK= . 19 CFS 3 .08 o .07 @ 12. 18 HRS J .06 VOLUME= .02 AF 05 e4 03 .02 .01 e.e em N IT �D co m N 0 co m N V TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 2.30 IN ( 1-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 14 PROPOSED BUILDING ROOF AREA PEAK= .26 CFS @ 11.98 HRS, VOLUME= .02 AF PERCENT CN SCS TR-20 METHOD 100 .00 98 IMPERVIOUS ROOF SURFACE TYPE III 24-HOUR TOTAL AREA = .12 AC RAINFALL= 2 .30 IN SPAN= 0-24 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW ACROSS MIDDLE OF ROOF .7 Smooth surfaces n=.011 L=50 ' P2=3 .1 in s=.02 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW ACROSS ROOF TO GUTTERS .7 Unpaved KV=16.1345 L=100 ' s=.02 / ' V=2 .28 fps Total Length= 150 ft Total Tc= 1.4 SUBCATCHMENT 14 RUNOFF PROPOSED BUILDING ROOF AREA .26 .24 AREA= . 12 AC .22 Tc= 1 .4 MIN 20 CN= 98 18 SCS TR-20 METHOD 16 TYPE III 24-HOUR - 14 RAINFALL= 2.30 IN 12 PEAK= .26 CFS 3 O 10 @ 11 .98 HRS J 08 VOLUME= .02 AF 06 e4 .02 0.00 1 -,j N N N V �-o 07 m N V - - - - N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 2.30 IN ( 1-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5.11 000899 (c) 1986-1999 Applied Microcomputer Systems REACH 1 COMBINED FLOWS. .@ DESIGN POINTS #1 & #2. . . Qin = .86 CFS @ 12 .18 HRS, VOLUME= .15 AF Qout= . 86 CFS @ 12 .20 HRS, VOLUME= .15 AF, ATTEN= 0%, LAG= 1.0 MIN DEPTH END AREA DISCH (FT) (SQ-FT) (CFS) 5' x 2 ' CHANNEL STOR-IND+TRANS METHOD 0 .00 0. 00 0.00 SIDE SLOPE= .05 ' / ' PEAK DEPTH= .10 FT .20 1. 80 1.79 n= .04 PEAK VELOCITY= 1.0 FPS .40 5.20 7.61 LENGTH= 20 FT TRAVEL TIME _ .3 MIN .60 10.20 18.87 SLOPE= .01 FT/FT SPAN= 0-24 HRS, dt=.l HRS .86 19.09 43 .73 1.20 34. 80 97.59 1.60 59.20 198.42 2 .00 90.00 347.06 REACH 1 INFLOW & OUTFLOW COMBINED FLOWS - @ DESIGN POINTS #1 & #2 . . . .85 8e 5' x 2' CHANNEL .75 SIDE SLOPE= .05 '/' 7e n=.04 L=20' S=.81 ,65 .60 STOR-IND+TRANS METHOD 55 VELOCITY= I FPS .50 TRAUEL= .3 MIN 45 40 Qin= .86 CFS 3 .35 Gout= .86 CFS 1 30 LAG= 1 MIN 20 . 15 . 10 .05 e.eem N 0 M m N IT �D m N N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 2.30 IN ( 1-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5.11 000899 (c) 1986-1999 Applied Microcomputer Systems POND 1 SUBSURFACE DETENTION FACILITY "B" & "C" Qin = 1.38 CFS @ 11.99 HRS, VOLUME= .12 AF Qout= .57 CFS @ 12 .19 HRS, VOLUME= .12 AF, ATTEN= 59%, LAG= 11.9 MIN ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD (FT) (SF) (CF) (CF) PEAK STORAGE = 1290 CF 232 .3 0 0 0 PEAK ELEVATION= 232 .9 FT 232 .4 2435 122 122 FLOOD ELEVATION= 238 .0 FT 232 . 8 2435 974 1096 START ELEVATION= 232.3 FT 233 .0 4712 715 1810 SPAN= 0-24 HRS, dt=.1 HRS 234 .0 4712 4712 6522 Tdet= 58 .4 MIN ( .12 AF) 235 .0 4712 4712 11234 236 .0 4712 4712 15946 236 .2 4712 942 16889 236.7 2277 1747 18636 236 .8 10 114 18750 238.0 10 12 18762 # ROUTE INVERT OUTLET DEVICES 1 P 232 .3 ' 8" CULVERT n=.013 L=6 ' S=.0051 / ' Ke=.5 Cc=.9 Cd=.6 POND 1 INFLOW & OUTFLOW SUBSURFACE DETENTION FACILITY "B" & "C" 1 .3 LELE ETHOD 1 .2 90 CF 1 . 1 2.9 FT 1 .0 9 38 CFS 57 CFS U B .9 MIN 7 3 .6 � .5 3 0.BN N V lD -CO m N V 0 M m N V - - - -- - N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 2.30 IN ( 1-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems POND 2 ROOF DRAINAGE "RECHARGE" FACILITY Qin = .26 CFS @ 11.98 HRS, VOLUME= .02 AF Qout= .01 CFS @ 9.90 HRS, VOLUME= .01 AF, ATTEN= 96%, LAG= 0 .0 MIN ELEVATION AREA INC.STOR CUM.STOR STOR-IND METHOD (FT) (SF) (CF) (CF) PEAK STORAGE = 482 CF n 234 .4 0 0 0 PEAK ELEVATION= 235.9 FT 234 .5 324 16 16 FLOOD ELEVATION= 238.4 FT 235 .5 324 324 340 START ELEVATION= 234.4 FT 236 .5 324 324 664 SPAN= 0-24 HRS, dt=.l HRS 236 .9 324 130 794 Tdet= 271.7 MIN ( .01 AF) 237 .0 24 17 811 237 .4 12 7 818 238 .4 2 7 825 # ROUTE INVERT OUTLET DEVICES 1 P 236.5' 6" CULVERT n=.013 L=10 ' S=.0031/ ' Ke=.5 Cc=.9 Cd=.6 2 P 234.4 ' EXFILTRATION Q= .01 CFS at and above 234.5' 3 P 236.5 ' 6" CULVERT n=.013 L=15 ' S=.021/ ' Ke=.5 Cc=.9 Cd=.6 POND 2 INFLOW & OUTFLOW ROOF DRAINAGE ''RECHARGE'' FACILITY .26 .24 STOR-IND METHOD 22 PEAK STOR= 482 CF 20 PEAK ELEU= 235.9 FT . 18 Qin= .26 CFS to 16 Qout= .01 CFS 14 LAG= 0 MIN . 12 0 10 J .08 06 .04 .02 - - - - - - - - - - - - - - - - - - 0.0 em N V �D co m N V �D OD m N V - -- - - -- N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) Page 1 TYPE III 24-HOUR RAINFALL= 6.50 IN Prepared by Merrimack Engineering Services 26 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems WATERSHED ROUTING 14 12 ZL 1 OSUBCATCHMENT ❑ REACH POND LINK SUBCATCHMENT 11 = DRIVEWAY & PARKING IN FRONT OF BLDG. -> REACH 1 SUBCATCHMENT 12 = DRIVEWAY AND PAVEMEMT AREAS -> POND 1 SUBCATCHMENT 13 = LAND RESTORATION & WETLAND REPLACEMENT -> REACH 1 SUBCATCHMENT 14 = PROPOSED BUILDING ROOF AREA -> POND 2 REACH 1 = COMBINED FLOWS. .@ DESIGN POINTS #1 & ##2 . . . -> POND 1 = SUBSURFACE DETENTION FACILITY "B" & "C" -> REACH 1 POND 1 secondary = SUBSURFACE DETENTION FACILITY "B" & "C" -> REACH 1 POND 2 = ROOF DRAINAGE "RECHARGE" FACILITY -> POND 1 Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 6.50 IN (100-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 11 PAVEMENT & LANDSCAPING AT ENTRANCE ROAD PEAK= .64 CFS @ 12 .14 HRS, VOLUME= .06 AF PERCENT CN SCS TR-20 METHOD 74 .00 74 AREAS TO BE LANDSCAPED & PLANTED TYPE III 24-HOUR 26.00 98 DRIVEWAY ENTRANCE AT RTE.114 RAINFALL= 6.50 IN 100 .00 80 TOTAL AREA = .17 AC SPAN= 0-24 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW TOWARD THE FRONT OF THE SITE 11.0 Grass: Dense n=.24 L=50' P2=3 .1 in s=.01 1/ 1 SHALLOW CONCENTRATED/UPLAND FLOW FLOW TO DESIGN POINT #1 2 .4 Grassed Waterway Kv=15 L=300 ' s=.02 / ' V=2 .12 fps Total Length= 350 ft Total Tc= 13 .4 SUBCATCHMENT 11 RUNOFF PAUEMENT & LANDSCAPING AT ENTRANCE ROAD .60 AREA= . 17 AC .55 Tc= 13.4 MIN .50 CN= 80 45 SCS TR-20 METHOD tn .40 TYPE III 24-HOUR U .35 RAINFALL= 6.50 IN 30 PEAK= .64 CFS 3 O .25 e 12. 14 HRS -1 20 UOLUME= .06 AF 15 10 .05 0.0 Bm N V �D OJ m N IT, � m N Cf' N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 6.50 IN (100-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 12 DRIVEWAY AND PAVEMENT AREAS PEAK= 3 .95 CFS @ 11.99 HRS, VOLUME= .32 AF PERCENT CN SCS TR-20 METHOD 100 .00 98 AREAS TO BE PAVEMENT TYPE III 24-HOUR TOTAL AREA = .61 AC RAINFALL= 6.50 IN SPAN= 0-24 HRS, dt=.1 HRS Method Comment Tc (min) TR-55 SHEET FLOW ACROSS DRIVEWAYS & PAVEMENT AREA .9 Smooth surfaces n=.011 L=50 ' P2=3 .1 in s=.01 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW TO CB'S,THEN TO S.D.F. "B" & "C" 1.6 Paved Kv=20.3282 L=200 ' s=.01 '/ ' V=2 .03 fps Total Length= 250 ft Total Tc= 2.5 SUBCATCHMENT 12 RUNOFF DRIVEWAY AND PAUEMEMT AREAS 3.8 3.6 LRAINF5 .61 AC 3.4 .5 MIN 3.2 98 3.0 2.8 METHOD 2 4 24-HOUR U 2.2 .58 IN 2.0 1 .8 .95 CFS � 1 .6 .99 HRS01 z .32 AF 1 .0 .8 6 .4 .2 0.am N V tD m N Q �D 07 m N V - - -- - N N N TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (POST-D) TYPE III 24-HOUR RAINFALL= 6.50 IN (100-YR) Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5.11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 13 LAND RESTORATION & WETLAND REPLACEMENT PEAK= 1.44 CFS @ 12 .14 HRS, VOLUME= .13 AF PERCENT CN SCS TR-20 METHOD 67 .00 74 AREA TO BE LANDSCAPED TYPE III 24-HOUR 33 .00 80 AREA TO BE LANDSCAPED RAINFALL= 6 .50 IN n 100 . 00 76 TOTAL AREA = .42 AC SPAN= 0-24 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW OVER LANDSCAPED & NATURAL AREAS 11.0 Grass: Dense n=.24 L=50' P2=3 .1 in s=.01 ' / ' SHALLOW CONCENTRATED/UPLAND FLOW IN SWALE,WITHIN REPLACED WETLAND 2 .2 Grassed Waterway Kv=15 L=200 ' s=.01 '/ ' V=1.5 fps CHANNEL FLOW IN SWALE ,TO DESIGN POINT #2 .2 a=8 sq-ft Pw=5 ' r=1.6 ' s=.006 / ' n=.04 V=3 .94 fps L=40 ' Capacity=31 .5 cfs Total Length= 290 ft Total Tc= 13 .4 SUBCATCHMENT 1 .3 RUNOFF LAND RESTORATION & WETLAND REPLACEMENT 1 .4 13 AREA= .42 AC 1 2 Tc= 13.4 MIN 1 1 CN= 76 1 0 SCS TR-20 METHOD Lo .9 TYPE III 24-HOUR `U g RAINFALL:: 6.50 IN v 7 3 .6 PEAK= 1 .44 CFS CD @ 12. 14 HRS -i 5 UOLUME= . 13 AF li .4 3 .2 1 0.0 N V �D 0D m N V tD M m N V - - - - - N N N TIME (hours) 100 YEAR FLOG PLAIN ELEVATION ANALYSIS The calculated 100 year floodplain level between Route 114 and Chestnut Street, inclusive of the property at 740 Turnpike Street, has been determined, by hydrological analysis, to be at an elevation of 236.10, based on the results of the HEC-2 Floodway Analysis. The 100 year floodplain elevation on the southerly side of Route 114 adjacent to Jasmine Plaza has been previously determined to be at elevation 236.74. This difference in elevation of 0.64' is indicative of a hydraulic gradient which occurs in order to maintain continuous flow through the existing 42" RCP culvert under Route 114, during the peak of the 100 year storm event. The culvert is functional during the submergence and tailwater condition, resulting in a reduced rate of flow through the pipe at the peak of the area wide flooding. FLOODPLAW FILLING AND COMPENSATORY REPLACEMENT VOLUME The proposed volume of F000dplain Filling is based on calculation of the difference of the grades between existing conditions and proposed development conditions. The existing grades are determined based on an actual field survey of the property. The"Existing Conditions" plan shows the spot shot elevations and the elevation contours. The development plans show the filling required associated with the building siting and parking areas, confined within proposed retaining walls. On this plan there is also a strip of land which is proposed to excavated and reconstructed for both wetland replacement and land restoration, which will provide a more aesthetic and natural appearance between the developed portion of the parcel n and the existing wetland. Within the 100 year floodplain, up to Elevation 236.1, an overall net increase of filling versus removal volumes has resulted in provisions for on-site floodplain compensatory storage being designed as part of the proposed site development. The following chart shows a breakdown of areas indicative of the difference between pre and post conditions on a vertical increment basis, as determined by planimetered and AutoCAD measurements. ELEVATION AREA(SQ. FT.) 237 37,240 Filling 236 25,338 Filling 235 7,661 Filling 4,875 Removal 2,786 Filling 234 10,010 Removal 233 Not Computed 232 4,800 Removal 231.6 No Alteration The following graph indicates a plot or depiction of the charted information, obtained from the measurements indicated above, used to compute the volumes of wetland filling and compensatory replacement. This is necessary in order to determine the size and number of structures which will be needed for the placement of the flood storage facilities on the site. NORTH AT,�DOJEJQ, U(LDlt & CZ)kP MERRIMACK ENGINEERING SERVICES JOB_ V) SHEET NO. 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DETERMINE SIZE AND CAPACITY OF STAGED FLOOD STORAGE FACILITIMS FOR COMPENSATORY FLOODPLAIN REPLACEMENT EL 236.1 - 235.3 (Upper Stage) Volume= 0.8' x 27,000 + 16,000 = 17,200 Cu. Ft. 2 El = 235.3 - 234.74 (Lower Stage) Volume= 0.55' x 16,000 + 1,000 = 4,675 Cu, Ft. 2 Upper Stage -Based on Concrete Systems Inc. # of twin cell box culvert structures required @ 4' inside height by 2 Y-10" overall width invert of structures @ 232.3 invert of 6" PVC outlet pipe @ 232.4 each structure is 7' - 3 1/2" long, effective width of 19.83' Determine Linear Feet of Twin Cell Box Culverts and# of Structures Required: 17,200 Cu. Ft. = 19.83' x L 9236.1 - 232.4) L =235' Use 4 End Sections @ 6' - 6 1/2" Each (26.2') and 29 Open Section @ 7' - 3 1/2" (211.5') Total Area= 21.83' x 239.4' = 5226.1 Sq. Ft. Lower Stage - Based on Concrete Systems, Inc. Use 4' inside height structures, 21'-10" overall width (9' - 4" outside width) invert of structures at 232.3 invert of 6" PVC outlet pipe @ EL= 232.4 Determine Liner Feet of Twin Cell Box Culvert System and Total Number of Structures Required: 4675 Cu. Ft. = 19.83' X L x (235.3 - 232.4) L = 82' Use 2 End Sections @ 6' - 6 '/2" Ea. (13.l')O and 10 Open Sections @ 7' - 3 1/2" Ea. (73') Total Length= 86.1' Total Area= 21.83' x 86.1' = 1880 Sq. Ft. a POST-DEVELOPMENT DRAINAGE ANALYSIS Proposed subsurface stormwater runoff detention facility is designed to mitigate any increase in the peak rate of runoff due to pre-to post- development ground surface conditions. Pond 41 is a proposed subsurface detention system consisting of 66 precast n concrete box culvert structures laid out in two (2) separate groups at the rear of the site, beneath the proposed pavement within the driveway and parking areas. These structures will serve a"dual purpose" as an "upper-stage" flood storage facility for the higher intensity storm events. The surface runoff from the site to be collected by the site drainage system will be discharged into these two groups using three pipe connections. For modeling purposes, the runoff will be handled by one large subsurface detention"pond", combining facilities "B" and "C" as a single ponding facility. Flood storage facility "A", a"lower-stage" flood storage facility, will be used solely for accommodation of compensatory flood storage as necessary to offset the proposed floodplain filling. The stored water in facility `B" will flow into facility "C", through an 8" pipe. Then, the combined volume of stored water in facility "C" will be discharged through a 10" pipe, which will have an 8" flap valve installed inside to prevent flood waters from backing up into facility `B". The total surface area of the combined detention system is calculated: Facility "B": 22' x 115' = 2530 SF Facility "C": 22' x 123' = 2706 SF 5236 SF Use a factor of 0.9, to account for a 10% reduction in storage volume capacity due to the volume of the concrete walls. Therefore, the incremental storage volume is computed to be: 0.9 x 5236 =4712 cu. ft. per vertical foot. The invert of the 10" outlet pipe from facility "C" is set at 232.3. Add 0.05' to determine the invert of the 8" flap valve inside the 10" pipe. Use an invert of 232.35 for the 8" flap valve at the outlet pipe from this structure. Any potential for infiltration or exfiltration has been neglected from the analysis due to minimal impact or significance. The structures will be installed with gasketed joints to prevent or minimize any infiltration or exfiltration. The roof drainage from the car wash facility will be collected and piped to a "recharge" facility, and infiltrated over a period of up to three (3) days, depending on the duration and intensity of the rainfall event. NOKTH AN06VGK Z\FTE Ht-j CAP WA5H " 10-22 Drainage and Erosion Control 1)5e L 5. inches per hour- or to yr sizrryl 10.0 Qnd T'C = 5 rninutC5 _ 9.0 8.0 7.0 6.0 5.0 n 4.0 3.0 2.0S 1.5 s FREQUENCY (YRS. ) IN- 0 .9 .7 N .6 U C .4 } z .. Z 2 W _ z 15 J J Q lJ 1 Z .09 ' Q 08 cr .07 06 .05 .04 .03 .02 .01 5 6 7 8 9 10 15 20 30 40 50 60 2 3 4 5 6 8 10 12 18 24 (MINUTES) DURATION (HOURS) a Figure 10- . Intensity — Duration — Frequency Curve for Boston, MA 60,L N 22 JOB MERRIMACK ENGINEERING SERVICES SHEET NO OF 2) Prof mloul Engirmrs ® Land Surveyors e Planners CALCULATED BY C' D e==" DATE 66 Park Street ac-v, .3 -01 ANDOVER, MASSACHUSETTS 01810 CHECKED BY DATE qt4t)475.3555 SCALE RErOMMENDED RUNOFF COEFFICIENTS (C) FOR RATIQNAL ME i T HOD T 15Y OVERALL Cj4AFlAC-ER OF AREAl DESCRIPTION OF AREA RUNOFF COEFFICIENTS BUSINESS DOWNTOWN 0.70 to las0 7 NEIGHBORHOOD 0.50 to 0. RESIDENTIAL 0.30 to 0.50 SINGLE-FAMILY 0.40 to 0,60 MULTI-FAMILY, DETACHED 0.60 to 0.75 MULTIFAMILY. ATTACHED OM to 0.40 0. RESIDENTIAL (SUBURBAN) 50 to 0.70 APARTMENT I INDUSTRIAL 0.50 to 0.80 UGHT 0.60 to 0.90 HEAVY 0.10 to 0.25 PARKS, CEMETERIES OM to 0.25 PLAYGROUNDS 020 to 0.35 RAILROAD YARD 0.10 to 0.30 UNIMPROVED 0.15 to 0-25 WOODLAND 0.10 to 0.80 CULTIVATFO 0.10 SWAMP, MARSH TABLE 10-2.02F RECOMMENDED RUNOFF COEFFICIENTS _(C) FOR RATIONAL NIETHOD (FOR SURFACE TYPE) CHARAC'T_tR OF SURFACE I RUNOFF COEFFICIENTS PAVEMENT ASPLiAL11C AND CONCRETE 0.70 to 0.95 9 R i CX 0.-jj to 0.0-5 RCCFS LAWNS, SANDY SOIL 0.CIS to 0.10 FLAT. 2 PERCENT 0.10 to 0.1.5 AVERAGE. 2 TO 7 PERCENT 0.15 to 0-m S-.c--P 7 PERCENT LAWNS. HEAVY SOIL 0.13 to 0.117 FLAT, 2 PERCENT 0.18 to 0.-- AVERAGE, 2 TO 7 0E.RC!NT :5 7 PERCENT 0.m *0 0. JOB NOR1:I4 Ap4c>oVEP 6L1 ILDlf-�G CoiAp' MERRIMACK ENGINEERING SERVICES SHEET NO. OF Professional Engineers ® Land Surveyors ® Planners 66 Park Street CALCULATED BY DATE ®4 ANDOVER MASSACHUSEITS 01810 REL/ : 3 78g �475-3555 CHECKED 8Y DATE SCALE gt 1.... ._.. .... . ....: .. .' ...... ......:. . I .....................:........... k .. fi I HYDRAULICS OF SEWERS ................. ...._ ................ ....... �hfl� Values of / n - and " ( f .................................... 10.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.9 3.0 3.2 3.4 3.6 .......... .................... variable with defer ®' ® . ......................._....€ 0.9 ----x,7 constant L ._. .`.. ®®Independent of n,( 0.8 Darcy-Weisbach ® i Friction factor,/ ® ® f �0,7 0.6 ° Discharge, Hydraulic radiusR 0.5 V/anninjrk W ® i � 'S 0.4 ®®® ® Velocity,V 0.3 ® _. .. ... 02 .... .. ...... r I 0.1 �® ® e 0 0.1 0.2 03 0.4 0.5 0.6 0.7 0.0 0.9 1.0 1.1 13 .13 Hydraulic elements V , Q A, and R FIGURE a yd ul®c-elements graph for circular sewers. e JOB NOfZT l ND-Z)V,'--R MERRIMACK ENGINEERINGVICES SHEET NO. Of Professional Engineers • Land Surveyors • Planners pp �`^ -S 66 Park Street CALCULATED BY f? DATE ANDOVER, MASSACHUSETTS 01810 (4!P ) 75-3555 CHECKED BY DATE SCALE . .........i...........i.........:... : Q ....j...........�.__..... d2 CHART 3 V� �® ® o 0 ®h AL 1 .......... ...........1 --�-- 1 ®®%�rN ®t 00% i ® 0°VL h o p® �, o \ 1) v ® f .. ... ...... op'r'pfi _ 4 ' cz ...'.._.... W ® N,I VIIA Nil pp 0 ................. .... . htu ® �... 7E ® Op u v° o 0p m 0 . \ � V a \ o �! cm —' .......:.......... 0 0 0000 ®® � h O W1 1* m W 4Q: t, 4 h I /0' + U Sd_4 -A - AJ10 73A PIPE L —INCH12 e MERRIMACK ENUINLERING 5MICES, INC. JOB 111QIj H AODOVER QkJlL9W6 C09? I s ' ! ® Park Street SNEET"o of ANDOVER, MASSACHUSETTS 01810 CALCULATED By �' � - DATE (975) 475-3555 CHECKED BY DATE_ SCALE �l 5 U ( 7-1 f I F" EE�- C PA c tTIES - CL\LVE1� � � FC 0'-3 c 4 p a C HYDRAULICS OF SEWERS !-,� o f3 Q C I<t�I a t� A 1 1500 2.400 ®. 0.5 0.a d q.� 2.000 0.3 1,000 1.w0 0.006 06goo 02 0.007 1 A00 ® 0.7 0.00! 0.1 0.o1 0.8 0.05 0.f 0 BOO Soo0.05 400 14 10.04 20WO No 20 0.� 0.03 200 IS g 0.02 100 0.03 so 10 1.5 OA1 60 1� f o 0 ® &a Lo 0=6 40 60 7a t s EQ1 y f 0 D04 1m 50 60 s 25 a i 0A3 .., ., 54 8.010 so a_.. 44 4 N j.1 - ®. r 0.002 j r i•. Ocom 10 o S u a g -0.0006 c S c $ 24 �` a'c ` N DAM i 10 m 21 i• c a 0.0004 5 ® 0.0003 $ 4 6 b 15 g,y _ 0.4 0.0002 3 5 ® 12 OS 2 ' 00 10 /'Y 0.6 6 0. 01 ® 0.7 7 0-00003 2 0 0. 0.00004 1A 0' CAOMS QC f CA lb 4 � 10 0. Le o� 0.4 CA : 03 0=1 CA mm if 4 0.000003 DAMON als Ott s to GURE 22-Al4pummt ekam for Manningfommula for pipe flow. 6 PROPOSED "RECHARGE" FACILITY Determine the Recharge Volume Required, per Standard 93 of the Stormwater Management Policy. Total Recharge Volume; based on total proposed impervious pavement area, contributing to the Site Drainage System. To CB 91 1,080 sq. ft. CB #2 3,420 CB 43 3,840 CB 94 12,800 CB 95 4,950 Portion of proposed driveway contributing to Offsite: 41' x 35' 1,435 to existing catch basin on Route 114 which will not be treated Total Impervious Area= 27,525 sq. ft. of pavement, which is the net increase in impervious area. Minimum Recharge Volume= 27,525 sq. ft. x 0.10" =229.4 cu. ft. 12 Which represents the minimum volume of surface runoff required, by regulations, to be recharged on the site, based on Hydrologic Soil Group "C", as indicated on the U.S.D.A. Soil Maps for this site. PERMEABILITY Permeability, or rate of infiltration, is based on an actual percolation test rate of 5 minutes per inch, and using 0.3 inches per hour, to be conservative: Soil Contact Surface Area of Recharge Facility bottom: 30' x 12' = 360 s.f sidewall: say 1' high x 2x(30' +12') = 84 s.f. 444 s.f. Compute rate of Infiltration, I: I= 0.3 in/hr x 1 ft./12 in x 444 s.f. x 1 hr./60 min = 0.18 c.f./min = 135 gal/min Over a period of up to 3 days, the volume capacity of recharge, V, to be expected is calculated: V,,= 1.35 gal/min x 60 min/hr x 24 hr/day x 3 days V,,= 5,824 gallons (778 c.f) This number, being the maximum feasible recharging capacity determinant value, for comparison with the calculated recharge volume to be discharged into the recharge facility from the building roof top area, is greater that the Minimum Required Recharge Volume of 229.4 c.f. Therefore, the recharge time will be about 1 day. To recharge the "full" volume (648 c.f,, as calculated below) it will take approximately 2.5 days. The proposed Recharge Facility will consist of just 6 precast concrete"Jumbo" dry wells, butted together, and will be set at least two feet above the Seasonal High Water Table. These structures will be H-20 rated, with a 6" thick reinforced concrete top slab. The capacity of the"Recharge" Facility to be provided is based on storage volume, infiltration rate and volume, and overflow provisions when evaluating and designing a Recharge Facility proposed under pavement. This facility will be capable of storing roof drainage up to a depth of 2' inside the structures, before any water would be discharged through the outlet pipe proposed. This total volume would be ultimately recharged over a longer period of time. The Storage Capacity when "full" is approximated, by calculation, to be: 30' x 12' x 0.9 x 2' = 648 c.f. In order to achieve this volume of runoff from the roof area, it will require a rainfall of approximately 0.7 inches, based on the facility being empty or "dry" prior to the storm, not including the volume absorbed during the storm as infiltration or recharge. At times, there will be overflow from the recharge facility into the subsurface detention facility during the higher•intensity storm events. From the analysis of the 100 year storm (6.5 inches in 24 hours), it was necessary to provide two (2) 6" C.L.D.I. overflow drain pipes from the Recharge facility, in order to prevent an overload surcharge within the structure. Therefore, there should be no occurrence when the capacity of the recharge facility could be exceeded, given these conditions as designed. Refer to Subcatchment 914 (Roof Drainage) and Pond 42 (Recharge Facility) in the Post-Development Drainage Analysis for detailed data from the four (4) storm events. 10'-0" J it•---J� I I I I 1 I -i 24" DIA INSPECTION COVER �- -i E•� I , I , 1 i �J �- 1 , �I it j I 1 1 1 6'-0" J I� 1 , I , I , I , I , I I 1 , I , PLAN VIEW 1" TAPER 4" TOP 6" H-20 (4) 6" DIA INLET (3'-0" H-20) ,O\ ,O\ ,Q, \�D,, r�, '�, 2'-D" \ , 1 , , , 11011 \ , \ , 11011 11011 [Ea 'O' 'O' ,O, 'Q' ' ` 'Q` ,0, 0 , , t , t , 101 10 11 3 DRAINAGE HOLES 4" TO 2 1/2" DIA TAPER SECTION VIEW ITEM NO. DW-JDW STANDARD DW-JDWH H-20 NOTES: Sllgi/A 1. CONCRETE: 4,000 PSI MINIMUM AFTER 28 DAYS. 2. ALSO AVAILABLE IN H-20 LOADING. CONCRETE PRODUCTS, INC. DRY WELL JUMBO P.O. BOX 520 - 773 SALEM ST., ROUTE 62 NO. WILMINGTON, MA 01887 PAGE C3 TEL. (508) 658-2645 FAX. (508) 658-0541 SOIL DATA TEST PIT #1 TEST PIT #2 _2 236.0 —4" 236.4 ROOT MAT 253.8 ROOT MAT 0 — — — 0 MIXED FILL OF 2„ 236.1 F.S.L. 235.7 BROKEN LEDGE 10% MIXED FILL „ AND 3 DIAM. CONC. n 50% BROKEN LEDGE 5 YR 5/3 20 F.S.L. G1 2.5 N 234.4 48" T0. 2' DIAMETER MOTTLES 231.8 36" 5Y 4 4,5Y 4 1 233.1 L.S. 5Y 4 1 EVIDENCE OF A&B 231 3 50 VERY FINE SAND 231.9 54" 5Y 6/1, W/POCKETS 5 Y 6//2 (30%) OF F/M SAND & F/M SAND 10 Y 5/8 (10%) L.V.F. SAND 84" 228.8 78" 2.5Y 5 6 MOTTLES 229.6 WATER AT 18" WATER AT 18" (PERCHED) EL.= 234.9 EL.= 234.5 TEST PIT #3 TEST PIT ##4 0„ 234.8 0 MIXED 234.4 MIXED FILL „ FILL 232.3 VARIES TO Ap 25 F.S.L. 36 ' 46"(5Y 5/1 AT 36") B 48 F.S.L2 1 230.4 231.8 F/M SAND WITH „ V.F. SAND 5Y 5/1 10Y 4/4 POCKETS OF F.S.L. 58229.6 (ALL M&F) AND C WITH POCKETS OF RAVELLY SAND M—SAND & F.S.L. 5Y 5/2 2.5Y 5/6 MOTTLES 226.3 102' 225.9 102 WATER A- d6" (EL=231.0) WATER AT 37" (EL=231.3) S.H.W.T. AT 36" (EL=231.8) S.H.W.T. AT 26" (EL=232.2) TEST PIT ##5 TEST PIT ##6 0" 235.3 0" 235.7 22" FILL - 233.5 Ap F.S.L. A F.S.L. 10Y 2/1 5" - 235.3 A B 35" F.S.L. 10Y 5/1 232.4 w F.S.L. 42" 2:5Y 5/6 MOTTLES 231.8 12" Cl L.S. 234.7 L.S., 5% GRAVEL 5% COARSE C 5% COBBLES FRAGMENTS 50% - 10Y 5/8 36 C2 F.S.L. 232.7 50% - 5Y 5/1 MASS. & FIRM 108" 226.3 48" MOTTLED 231.7 WATER AT 58" (EL=230.5) NO WATER (EL=---) S.H.W.T. AT 35" (EL=232.4) S.H.W.T. AT 36" (EL=232.7) PERC TEST (P-5). LEGEND F/M FINE TO MEDIUM 0" 235.2 F.S.L. FINE SANDY LOAM L.S. LOAMY SAND 14 MMIN.RATE= L.V.F. LOAMY VERY FINE USE 5 MIN./M IN.IN DROP M&F MASSIVE AND FIRM U PERC RATE S.H.W.T. SEASONAL HIGH WATER TABLE 40" 231.8 56" 230.5. WATER AT 52" (EL=230.9) DEEP TEST HOLE EVALUATIONS CONDUCTED 4/5/99 & 4/12/99 BY LES GODIN, SOIL EVALUATOR. PERC. TESTS CONDUCTED 4-12-99 BY LES GODIN. PPRE-DEVELOPMENT DRAINAGE ANALYSIS Data for RTE 114 CAR WASH - NORTH ANDOVER (PRE-D) TYPE III 24-HOUR RAINFALL= 6.50 IN Prepared by Merrimack Engineering Services 27 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems WATERSHED ROUTING 1 2 Fil OSUBCATCHMENT ❑ REACH A POND LINK SUBCATCHMENT 1 = RUNOFF TO DESIGN POINT #1 -> REACH 1 SUBCATCHMENT 2 = RUNOFF TO DESIGN POINT #2 -> REACH 1 REACH 1 = SUMMARY OF COMBINED FLOWS - SUBCATS #1 & 2 -> r Data for RTE 114 CAR WASH - NORTH ANDOVER (PRE-D) TYPE III 24-HOUR RAINFALL= 6.50 IN(100-YR STORM) Prepared by Merrimack Engineering Services 26 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 1 RUNOFF TO DESIGN POINT #1 PEAK= 1.40 CFS @ 12 .22 HRS, VOLUME= .13 AF PERCENT CN SCS TR-20 METHOD 100 .00 79 EXIST. BRUSH - FAIR - H.S.G. "C" TYPE III 24-HOUR TOTAL AREA = .43 AC RAINFALL= 6.50 IN n SPAN= 10-20 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW SURFACE RUNOFF 14 .1 Woods: Light underbrush n=.4 L=50' P2=3 .1 in s=.015 SHALLOW CONCENTRATED/UPLAND FLOW OVERLAND FLOW TOWARD WETLAND 5.4 Woodland Kv=5 L=200' s=.015 '/' V=.61 fps CHANNEL FLOW SWALE TO DESIGN POINT #1 0.0 a=6 sq-ft Pw=.4' r=15 ' s=.02 1 / 1 n=.06 V=21.3 fps L=20' Capacity=127 .8 cfs Total Length= 270 ft Total Tc= 19.5 SUBCATCHMENT 1 RUNOFF RUNOFF TO DESIGN POINT # 1 1 ,4 1 .3 AREA= .43 AC 1 .2 Tc= 19.5 MIN 1 1 CN= 79 r-, 1 .0 SCS TR-20 METHOD LO .9 TYPE III 24-HOUR `u .8 RAINFALL= 6.50 IN .7 3 6 PEAK= 1 .40 CFS @ 12.22 HRS I 5 UOLUME= . 13 AF LL .4 3 .2 . 1 0.0 TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (PRE-D) TYPE III 24-HOUR RAINFALL= 6.50 IN(100-YR STORM) Prepared by Merrimack Engineering Services 26 Mar 01 HydroCAD 5 11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 2 RUNOFF TO DESIGN POINT #2 PEAK= 3 .16 CFS @ 12 .21 HRS, VOLUME= .30 AF PERCENT CN SCS TR-20 METHOD 15 .00 84 EXIST. BRUSH - FAIR - H.S.G. "D" TYPE III 24-HOUR 85 .00 79 EXIST BRUSH - FAIR - H.S.G. "C" RAINFALL= 6.50 IN 100 .00 80 TOTAL AREA = .93 AC SPAN= 10-20 HRS, dt= .1 HRS Method Comment Tr- (min) TR-55 SHEET FLOW OVER VEGETATED SURFACE 14 .1 Woods: Light underbrush n=.4 L=50' P2=3 .1 in s=.015 SHALLOW CONCENTRATED/UPLAND FLOW TOWARD THE WETLANDS 4 .4 Short Grass Pasture Kv=7 L=250' s=.018 ' / ' V=.94 fps CHANNEL FLOW INTO THE EXISTING WETLAND 0 .0 a=6 sq-ft Pw=.4' r=15' s=.05 ' / ' n=.06 V=33 .68 fps L=20' Capacity=202 .1 cfs Total Length= 320 ft Total Tc= 18.5 SUBCATCHMENT 2 RUNOFF RUNOFF TO DESIGN POINT #2 3.e AREA= .93 AC 2.8 Tc= 18.5 MIN 2.6 CN= 80 2.4 2.2 SCS TR-20 METHOD Lo 2.0 TYPE III 24-HOUR 1 .8 RAINFALL= 6.50 IN 1 .6 1 4 PEAK= 3. 16 CFS 0 1 .2 @ 12.21 HRS -i 1 B L UOLUME= .3e AF 8 .6 4 .2 0.0� CV r''1 V LO tD m TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (PRE-D) TYPE III 24-HOUR RAINFALL= 6.50 IN(100-YR STORM) Prepared by Merrimack Engineering Services 26 Mar Ol HydroCAD 5 11 000899 (c) 1986-1999 Applied Microcomputer Systems REACH 1 SUMMARY OF COMBINED FLOWS - SUBCATS #1 & 2 Qin = 4.56 CFS @ 12 .21 HRS, VOLUME= .43 AF Qout= 4 .54 CFS @ 12 .22 HRS, VOLUME= .43 AF, ATTEN= 1%, LAG= .5 MIN DEPTH END AREA DISCH (FT) (SQ-FT) (CFS) 20' x 3 ' CHANNEL STOR-IND+TRANS METHOD 0 .00 0 .0 0 .00 SIDE SLOPE= .1 ' / ' PEAK DEPTH= .11 FT .30 6 .9 12 .96 n= .04 PEAK VELOCITY= 1.9 FPS .60 15 .6 43 .91 LENGTH= 30 FT TRAVEL TIME = .3 MIN .90 26 .1 92 .30 SLOPE= .015 FT/FT SPAN= 10-20 HRS, dt=.l HRS 1.29 42 .4 183 .20 1.80 68 .4 354 .85 2 .40 105 .6 642 .82 3 .00 150 .0 1035.18 REACH 1 INFLOW & OUTFLOW SUMMARY OF COMBINED FLOWS - SUBCATS # 1 & 2 4.5 20' x 3' CHANNEL 4.0 SIDE SLOPE= . 1 '/' 3.5 n=.04 L=30' S=.e15 STOR-IND+TRANS METHOD � 3.0 VELOCITY= 1 .9 FPS u 2.5 TRAVEL= .3 MIN :3 2.e Qin= 4.56 CFS 0 Gout= 4.54 CFS J 1 .5 LAG= .5 MIN 1 .e 5 0.am _ N v in �o m M m TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (PRE-D) TYPE III 24-HOUR RAINFALL= 4.50 IN (10-yr Storm) Prepared by Merrimack Engineering Services 26 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 1 RUNOFF TO DESIGN POINT #1 PEAK= .81 CFS @ 12 .23 HRS, VOLUME= .08 AF PERCENT CN SCS TR-20 METHOD 100 .00 79 EXIST. BRUSH - FAIR - H.S.G. "C" TYPE III 24-HOUR TOTAL AREA = .43 AC RAINFALL= 4 .50 IN SPAN= 10-20 HRS, dt=.1 HRS Method Comment Tc (min) TR-55 SHEET FLOW SURFACE RUNOFF 14.1 Woods: Light underbrush n=.4 L=50 ' P2=3 .1 in s=.015 SHALLOW CONCENTRATED/UPLAND FLOW OVERLAND FLOW TOWARD WETLAND 5.4 Woodland Kv=5 L=200' s=.015 1/' V=.61 fps CHANNEL FLOW SWALE TO DESIGN POINT #1 0.0 a=6 sq-ft Pw=.4' r=15 ' s=. 02 '/ ' n=.06 V=21.3 fps L=20 ' Capacity=127.8 cfs Total Length= 270 ft Total Tc= 19.5 SUBCRTCHMENT 1 RUNOFF RUNOFF TO DESIGN POINT # 1 .60 .75 AREA= .43 AC .70 Tc= 19.5 MIN 65 CN= 79 .60 .55 SCS TR-23 METHOD In .50 TYPE III 24-HOUR U 45 RAINFALL= 4.50 IN .40 3 .35 PEAK= .81 CFS o .30 e 12.23 HRS -J .25 UOLUME= .08 AF if 20 . 15 . 10 .05 O.eOm _ N Q M M m TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (PRE-D) TYPE III 24-HOUR RAINFALL= 4.50 IN (10-yr Storm) Prepared by Merrimack Engineering Services 26 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 2 RUNOFF TO DESIGN POINT #2 PEAK= 1 .85 CFS @ 12.22 HRS, VOLUME= .17 AF PERCENT CN SCS TR-20 METHOD 15 .00 84 EXIST. BRUSH - FAIR - H.S.G. "D" TYPE III 24-HOUR 85 .00 79 EXIST BRUSH - FAIR - H.S.G. "C" RAINFALL= 4.50 IN 100 .00 80 TOTAL AREA = .93 AC SPAN= 10-20 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW OVER VEGETATED SURFACE 14 .1 Woods: Light underbrush n=.4 L=50 ' P2=3 .1 in s=.015 SHALLOW CONCENTRATED/UPLAND FLOW TOWARD THE WETLANDS 4 .4 Short Grass Pasture Kv=7 L=250 ' s=.018 '/ , V=.94 fps CHANNEL FLOW INTO THE EXISTING WETLAND 0 .0 a=6 sq-ft Pw=.4 ' r=15' s=.05 / ' n=.06 V=33 .68 fps L=20' Capacity=202 .1 cfs Total Length= 320 ft Total Tc= 18.5 SUBCATCHMENT 2 RUNOFF RUNOFF TO DESIGN POINT #2 1 .8 1 ,7 AREA= .93 AC 1 .6 Tc= 18.5 MIN 1 .5 CN= 80 1 .4 _ 1 .3 SCS TR-20 METHOD ,n 1 .2 TYPE III 24-HOUR 1 . 1 U 1 .0 RAINFALL= 4.50 IN 9 3 .g PEAK= 1 .85 CFS CD .7 @ 12.22 HRS -I .6 UOLUME= . 17 AF Lj- .5 .4 .3 2 . 1 0.Bm N M Q' Ln lD r co M m TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (PRE-D) TYPE III 24-HOUR RAINFALL= 4.50 IN (10-yr Storm) Prepared by Merrimack Engineering Services 26 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems REACH 1 SUMMARY OF COMBINED FLOWS - SUBCATS #1 & 2 Qin = 2 .66 CFS @ 12 .22 HRS, VOLUME= .25 AF Qout= 2 .64 CFS @ 12 .23 HRS, VOLUME= .25 AF, ATTEN= 1%, LAG= .5 MIN DEPTH END AREA DISCH (FT) (SQ-FT) (CFS)_ 20 ' x 3 ' CHANNEL STOR-IND+TRANS METHOD n 0 .00 0 .0 0.00 SIDE SLOPE= .l 1 / ' PEAK DEPTH= .06 FT .30 6 .9 12 .96 n= .04 PEAK VELOCITY= 1.9 FPS .60 15 .6 43 .91 LENGTH= 30 FT TRAVEL TIME = .3 MIN .90 26 .1 92 .30 SLOPE= .015 FT/FT SPAN= 10-20 HRS, dt=.1 HRS 1.29 42 .4 183 .20 1. 80 68 .4 354 .85 2 .40 105 .6 642 .82 3 .00 150 .0 1035 .18 REACH i INFLOW & OUTFLOW SUMMARY OF COMBINED FLOWS - SUBCATS # 1 & 2 2.6 2.4 20' x 3' CHANNEL 2 2 SIDE SLOPE= . 1 '/' n=.04 L=30' S=.015 2.0 1 .8 STOR-IND+TRANS METHOD c 1 6 UELOCITY= 1 .9 FPS 1 4 TRAVEL= .3 MIN 1 .2 - Q i n= 2.6'6 CFS 3 Qout= 2.64 CFS 1 .8 LAG= .5 MIN 6 4 2 0.0 TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (PRE-D) TYPE III 24-HOUR RAINFALL= 3.10 IN Prepared by Merrimack Engineering Services 26 Mar 01 HydroCAD 5.11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 1 RUNOFF TO DESIGN POINT #1 PEAK= .42 CFS @ 12 .24 HRS, VOLUME= .04 AF PERCENT CN SCS TR-20 METHOD 100 .00 79 EXIST. BRUSH - FAIR - H.S.G. "C" TYPE III 24-HOUR TOTAL AREA = .43 AC RAINFALL= 3 .10 IN SPAN= 10-20 HRS, dt=.l HRS Method Comment Tc (min) TR-55 SHEET FLOW SURFACE RUNOFF 14.1 Woods: Light underbrush n=.4 L=50 ' P2=3 .1 in s=.015 '/' SHALLOW CONCENTRATED/UPLAND FLOW OVERLAND FLOW TOWARD WETLAND 5 .4 Woodland Kv=5 L=200' s=.015 '/ ' V=.61 fps CHANNEL FLOW SWALE TO DESIGN POINT #1 0 .0 a=6 sq-ft Pw=.4 ' r=15 ' s=.02 / ' n=.06 V=21.3 fps L=20' Capacity=127 .8 cfs Total Length= 270 ft Total Tc= 19.5 SUBCATCHMENT 1 RUNOFF RUNOFF TO DESIGN POINT # 1 .40 AREA= .43 AC 35 Tc= 19.5 MIN CN= 79 '30 SCS TR-20 METHOD Ln 25 TYPE III 24-HOUR U RAINFALL= 3. 10 IN v 20 PEAK= .42 CFS e 12.24 HR5 01 . 15 UOLUME= .04 AF 10 05 e.eem _ N m TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (PRE-D) TYPE III 24-HOUR RAINFALL= 3.10 IN Prepared by Merrimack Engineering Services 26 Mar 01 HydroCAD 5.11 000899 (c) 1986-1999 Applied Microcomputer Systems SUBCATCHMENT 2 RUNOFF TO DESIGN POINT #2 PEAK= .98 CFS @ 12 .22 HRS, VOLUME= .09 AF PERCENT CN SCS TR-20 METHOD 15 .00 84 EXIST. BRUSH - FAIR - H.S.G. "D" TYPE III 24-HOUR 85 .00 79 EXIST BRUSH - FAIR - H.S.G. "C" RAINFALL= 3 .10 IN 100 .00 80 TOTAL AREA = .93 AC SPAN= 10-20 HRS, dt=.1 HRS Method Comment Tc (min) TR-55 SHEET FLOW OVER VEGETATED SURFACE 14 .1 Woods: Light underbrush n=.4 L=50 ' P2=3 .1 in s=.015 SHALLOW CONCENTRATED/UPLAND FLOW TOWARD THE WETLANDS 4 .4 Short Grass Pasture Kv=7 L=250 ' s=.018 '/ ' V=.94 fps CHANNEL FLOW INTO THE EXISTING WETLAND 0 .0 a=6 sq-ft Pw=.4' r=15' s=.05 1/ 1 n=.06 V=33 .68 fps L=20' Capacity=202 .1 cfs Total Length= 320 ft Total Tc= 18 .5 SUBCPTCHMENT 2 RUNOFF RUNOFF TO DESIGN POINT #2 95 .90 AREA= .93 AC 85 Tc= 18.5 MIN 80 CN= 80 .75 .7e SCS TR-20 METHOD LO .65 .60 TYPE III 24-HOUR U 55 RAINFALL= 3. 10 IN 50 45 PEAK= .98 CFS 40 e 12.22 HRS o .3e UOLUME= .09 AF L 25 2e 15 10 .e5 0.00 TIME (hours) Data for RTE 114 CAR WASH - NORTH ANDOVER (PRE-D) TYPE III 24-HOUR RAINFALL= 3.10 IN Prepared by Merrimack Engineering Services 26 Mar 01 HydroCAD 5 .11 000899 (c) 1986-1999 Applied Microcomputer Systems REACH 1 SUMMARY OF COMBINED FLOWS - SUBCATS #1 & 2 Qin = 1 .40 CFS @ 12 .23 HRS, VOLUME= .14 AF Qout= 1 .39 CFS @ 12 .24 HRS, VOLUME= .14 AF, ATTEN= 1%, LAG= 5 MIN DEPTH END AREA DISCH (FT) (SQ-FT) (CFS) 20 ' x 3 ' CHANNEL STOR-IND+TRANS METHOD 0.00 0 .0 0 .00 SIDE SLOPE= .1 '/' PEAK DEPTH= .03 FT .30 6 .9 12 .96 n= .04 PEAK VELOCITY= 1.9 FPS .60 15 .6 43 .91 LENGTH= 30 FT TRAVEL TIME = .3 MIN .90 26 .1 92 .30 SLOPE= .015 FT/FT SPAN= 10-20 HRS, dt=.l HRS 1.29 42 .4 183 .20 1.80 68 .4 354.8S 2.40 105 .6 642 .82 3 .00 150 .0 103S.18 REACH 1 INFLOW & OUTFLOW SUMMARY OF COMBINED FLOWS - SUBCATS # 1 8 2 1 .4 1 .3 20' x 3' CHANNEL 1 .2 SIDE SLOPE= . 1 '/' 1 . 1 n=.04 L=38' S=.015 _ 1 ,0 STOR-IND+TRANS METHOD Ln 9 UELOCITY= 1 .9 FPS u 8 TRAUEL= .3 MIN v 7 3 .6 Qin= 1 .40 CFS O 5 Qout= 1 .39 CFS LL .4 LAG= .5 MIN .3 .2 . 1 0.0 N M Ln N TIME (hours)