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HomeMy WebLinkAboutStormwater Report - 498 CHICKERING ROAD 12/14/2007 PROPOSED RETAIL FA CILI I' NORTH ANDOVER, MASSACCHUSETTS EC VVI E D DEG 2 8 Z007 Nut-,1 f­-\iquuVER PANNING DEPARTMENT PROJECT DRAINAGE , REPORT DATE: NOVEMBER 2 , 2007 REVISED: DECEMBER 14 , 2007 PREPARED FOR: PARK STREET REDEVELOPMENT, LLC 231 Sutton Street— Suite 1B North Andover, MA 01845 +c� Vi' Cn 44# ol Merrimack Engineering Services, Inc. Email: merrengc@iaol.com 66 Park Street Phone: (978)-475-3555 Andover,MA 01810 Fax: (978)-475-7448 PROPOSED RETAIL FA CILI T Y NORTHANDOVEX MASSACHUSETTS < TABLE OF CONTENTS > SECTION 1.0 INTRODUCTION SECTION 2.0 LOCUS MAPS SECTION 3.0 SUMMARY 3.1 Pre vs. Post-Subcatchment Areas SECTION 4.0 STORM DRAINAGE CALCULATIONS Description of Drainage System 4.1 Pre vs. Post-Development Analysis 4.2.1 Pre-Development —2, 10 & 100-Year Storm Event 4.2.2 Post-Development—2, 10 & 100-Year Storm Event 4.3 Storm Drainage Pipe Design The Rational Method 4.3.1 Weighted Runoff Coefficient Calculation 4.3.2 Pipe Design Chart SECTION 5.0 APPENDIX 5.1 Rainfall Data Maps 5.2 National Resources Conservation Service(MRCS)— Soil Description with Classification SECTION 6.0 DRAINAGE AREA MAPS Merrimack Engineering Services, Inc. Phone: (978)475-3555 66 Park Street Andover,MA 01810 Fax: (978)475-7448 PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 1.0 > INTRODUCTION The project consists of a proposed retail facility(total foot print-5,042 S.F.)with appurtenant parking lot and grading, on a 0.72 acre parcel located at 498 Chickering Road(Rte 125),North Andover,MA. The subject parcel is mostly paved with some grass and shrubs areas along the south(Park Street),west and north(Franklin Street)sides of the site.The site is a former gas station and contains a building and canopy to be removed. A new building(retail facility)will be built approximately at the center of the lot,to the east of the existing building.There are no wetlands on the site or within 100' of the site. Topographic elevations at the site range from a high of 138±at the southwest corner of the at Park Street to a low of 123±at northeast corner of the parcel toward Franklin Street,a difference of 15±feet.The parcel is above the 100-year flood elevation of 95.0(Zone AE)as depicted on Flood Insurance Rate Map, Community Panel 250098 0003C, dated June 02, 1993. Soils within the vicinity of the project have been mapped by USDA-NRCS(formerly SCS) and consist of Udorthents smoothed soils(68.5%)and Woodbridge fine sandy loam,which is classified within the SCS Hydrological Soils Group C. For a more detailed description of the soils at this site see Section 5.2 of this report. These calculations will determine Pre-Development and Post-Development runoff rates using the SCS-TR20 Runoff Method,as implemented by the HydroCad computer model.The calculations will be performed for the 2, 10 and 100-year storm event. Merrimack Engineering Services,Inc. Section I —Page 1 Printed: December 14,2007 PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 2.0 > LOCUS MAPS Merrimack Engineering Services,Inc. Section 2-Page 1 Printed: December 14,2007 � 1 r 7 ✓ S+r M in Street " , _UN ��v Itned saGlS C®mmonweanh o fdea�acbuaeli�CdEA ?007 Tele Attar ro 2047E sopa YeahitoJapl c m `; . N 79"D771,70";N` eI'svIt27�(gx3lteamirig,;IllIl�llll+100°1 , PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 2.0 > USGS Map l� f ✓ � �l\��\\WBt6f a ���_ r ✓� Q- r ✓ _ -r �lr iii' . N r � � � ., t�t � \ t i ! / ! ♦�fi rr) 1 J\ 54.2 KA f 17 r \ \ U ICI AL ASP � [ • —<� f �� � i l Ors �� '� < �1 i / � \l� I`t 'JI1 Ile mping R v A i i ~ s.->••- 0 Retl / Sttftn M ` 1i\ \\\ Belt S r a 1 r C ( � r a Site Merrimack Engineering Services, Inc. Section 2—Page 3 Printed: December 14,2007 PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 2.0 > Site Soils Map fSSC}; CC)I1fdi�', MASS�1(;EIU;aCTTS, td _ lit, I F'„el P;iD PlID Pat) 0 ILI ur J € \1 Pali 1)al) Pal: 0 ij nd �`eiq lh'sF§ writcr��Pond '4 Milli PaB ROA- pit (,af Ur \ \ 4den 1'dtES cr,l; r�1) r SITE rou IX WORTH ANDOM r, I'.it3 � E3bU (` lJt •112 Wh H LEA P bb mso O (al3' lit) N,EI HrA C.. }:lit SI{iT_y �r llr ./' ...,.�...� ri j',Eirr .* d �,��rk tIT ! v wrn rt Yal' r�qf J W€, vsts 5�- UU ROA flat) t �7 'El ... ,✓ ... Pit UD—Udorthents, smoothed. WrB—Woodbridge fine sandy loam, 0 to 8 percent slopes. Merrimack Engineering Services, Inc. Section 2—Page 4 Printed: December 14,2007 \ a' u o;r I( `78 l O W 41 i a 00 .. ._.. `. .. 0 a ��' onyx, 5•A'3h9 l..' 0, r-1 ao t5 c rn � ❑ , N v 2r t O (O o O tr6v v Off• a _ av O e0 co w w v X (q O q � Iv ) In U w > m 6 ASK rc: LL a J L 8 His SiHa tqL� IY u t Q�0 €H e��~ ie w a Q W M G Fig r 2'tx J� t o 9 'a �I CN O O a Hy cl. a 7�yr J z Z X T 3�yy ) a LL C14 U � ❑ C d � N ^}i�+�-•j Lo IM pl- z w 4Y v �� 1�4h `t 'R CSC Z, � A X z �H ,�a'.1 j', �~ { >X 1 pw �, 9j�YS,. ,.::•/� �TFt.g,1 vM r Cu) U V] µ ¢ Cl) O o x -- W N CD T o r to r 04 N \ lw- J N \ PR OPOSED RETAIL 1�'A CILI T Y NORTHANDOVER, MASSACHUSETTS < SECTION 3.0 > Summary As indicated in the Introduction,the objective of the project design is to mitigate any increase in storm drainage flow rate as the result of the site modifications. The procedure utilized as follows: 1) The area to be modified is currently paved and was used for gas station in the past.It was determined 31,425 square feet and will be modified with the demolition of the old building,construction with the new retail facility, and re- paving of the site. The runoff rate was calculated during the 2, 10,and 100-year storm and the runoff hydrograph was developed. 2) The runoff from the proposed roof will be directed to the proposed underground detention facility with connection via 12"HDPE pipe to the existing stormwater drainage system.This design will not allow any increase in the runoff rate as a result of the project.The proposed structure has been designed according to generally accepted engineering principles with an emergency outlet to allow flows in excess of 100 year storm. 3) There are catch basins that will collect the proposed site runoff and convey it to the system that currently receives the existing site runoff. The following chart is a summary of pre and post-development peak flow rates for 2, 10 and 100-year storm events of the accumulative design point(Catch Basin RI),as shown on the accompanying drainage plans. Rainfall /Storm Event Structure/ Design Point 2—YR cfs 10—YR cfs 100—YR cfs Pre Post Change Pre Post Change Pre Post Change RI 2.85 1 2.84 -0.01 4.54 4.49 -0.05 6.84 6.75 -0.09 Merrimack Engineering Services, Inc. Section 3—Page 1 Printed: December 14,2007 PROPOSED RETAIL FA CILI T Y NORTHANDOVER, MASSACHUSETTS < SECTION 3.1 > Pre and Post sub-catchment areas The following table shows Pre and Post sub-catchment areas tabulated along with their CN values and Time of Concentration(Tc) Sub- Pre-develop ment Sub- Post-develo ment catchment Areas CN Tc (min) catchment Area (sf) CN Tc min S1 33,573 94 9.7 S1-L 15,833 90 5.0 Sl-U 11,180 98 5.0 S2 5,100 94 5.0 S2 2,513 81 5.0 S3 19,641 83 7.8 S3-G 13,798 79 7.8 S3-I 9,942 98 5.0 Prop. Roof 5,046 98 5.0 Total 58,312 Total 58,312 The following table shows Pre and Post sub-catchment impervious areas with runoff directed to components of existing and proposed drainage systems. Sub- Pre-development Sub- Post-development catchment Impervious Area Drainage catchment Impervious Area Drainage Structure s Structure (sf) S1 26,557 CB-1 S1-L 8,880 CB-1 S1-U 11,180 CB-4 S2 3,900 CB-2 S2 300 CB-2 S3 4,236 CB-3 S3-I 9,942 CB-5 Total 34,693 Total 30,302 Merrimack Engineering Services,Inc. Section 3 —Page 2 Printed: December 14,2007 PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 4.0 > Storm drainage calculations The proposed drainage system is a closed system. Catch basins will be constructed at low points of proposed parking area with connection to the existing stormwater drainage system.Decreases in peak flow will be obtained through the use of an underground detention facility. The closed system will discharge into an underground detention facility which is essentially a 7,500 gallon Commercial Septic Tank,which will serve to detain,store, and transfer the runoff to the existing stormwater drainage system. Pre and Post-Development Drainage Area Maps accompany these calculations. Merrimack Engineering Services,Inc. Section 4—Page I Printed: December 14,2007 PROPOSED RETAIL FA CILI T Y NORTHANDOVER, MASSACHUSETTS < SECTION 4.1 > Pre vs. Post Development Hydrologic Analysis & Design 2, 10 & 100—Year Storm Event Merrimack Engineering Services, Inc. Section 4—Page 2 Printed: December 14,2007 PROPOSED RETAIL FA CILI T Y NORTHANDOVER, MASSACHUSETTS < SECTION 4.2.1 > PRE - DEVELOPMENT— 2, 10, & 100 — Year STORM EVENT Merrimack Engineering Services,Inc. Section 4—Page 3 Printed: December 14,2007 E C) co N cr) ) L � � a � C 'm o U 0 O U tmUC • a 'LD CL CL CL ESQ U U) v .F o U - o N M - co M aa) N IL N et c m rn p Ee M U rn m c �aEo N vn ca 0 o m m .0 -C U C •Q°p LL. r C.a N CY) 0 .0 m 3:m m .-. r cn CO) I c N D M Y C = r � N CY)E ° U � = U U 0 U CD M Co x W W �. W m U 498 Chickering Road Pre Type 111 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 1 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment S1: (Subcatchment 1 -Existing Conditions) Runoff Area=33,573 sf Runoff Depth=2.44" Flow Length=377' Tc=9.7 min CN=94 Runoff=1.85 cfs 0.157 of Subcatchment S2: (Subcatchment 2-Existing Conditions) Runoff Area=5,100 sf Runoff Depth=2.45" Flow Length=212' Tc=5.0 min CN=94 Runoff=0.32 cfs 0.024 of Subcatchment S3: (Subcatchment 3 -Existing Conditions) Runoff Area=19,641 sf Runoff Depth=1.53" Flow Length=400' Tc=7.8 min CN=83 Runoff=0.75 cfs 0.057 of Reach P2: (20'-12" RCP) Peak Depth=0.24' Max Vet=7.1 fps Inflow=1.02 cfs 0.081 of D=12.0" n=0.011 L=20.0' S=0.0370 '/' Capacity=8.10 cfs Outflow=1.02 cfs 0.081 of Reach P3: (56'-12" CSP) Peak Depth=0.38' Max Vet=2.7 fps Inflow=0.75 cfs 0.057 of D=12.0" n=0.024 L=56.0' S=0.0155 '/' Capacity=2.41 cfs Outflow=0.73 cfs 0.057 of Reach R1: (Reach 1 -Catch Basin#1) Inflow=2.85 cfs 0.238 of Outflow=2.85 cfs 0.238 of Reach R2: (Reach 2 -Catch Basin#2) Inflow=1.02 cfs 0.081 of Outflow=1.02 cfs 0.081 of Reach R3: (Reach 3 - Catch Basin#3) Inflow=0.75 cfs 0.057 of Outflow=0.75 cfs 0.057 of Total Runoff Area= 1.339 ac Runoff Volume= 0.238 of Average Runoff Depth= 2.13" 498 Chickering Road Pre Type ///24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 2 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Subcatchment S1: (Subcatchment 1 - Existing Conditions) Runoff = 1.85 cfs @ 12.13 hrs, Volume= 0.157 af, Depth= 2.44" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 2-yr Rainfall=3.10" Area (sf) CN Description 7,016 79 50-75% Grass cover, Fair, HSG C 26,557 98 Paved parking & roofs 33,573 94 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.1 50 0.0600 0.1 Sheet Flow, Subcatchment-1 Woods: Light underbrush n= 0.400 P2= 3.10" 0.2 50 0.0650 5.2 Shallow Concentrated Flow, Subcatchment- 1 Paved Kv= 20.3 fps 0.7 150 0.0337 3.7 Shallow Concentrated Flow, Subcatchment- 1 Paved Kv= 20.3 fps 0.5 57 0.0700 1.9 Shallow Concentrated Flow, Subcatchment- 1 Short Grass Pasture Kv= 7.0 fps 0.2 70 0.0681 5.3 Shallow Concentrated Flow, Subcatchment- 1 Paved Kv= 20.3 fps 9.7 377 Total Subcatchment S1: (Subcatchment 1 - Existing Conditions) Hydrograph 2-- 1 .85 CE] Type III 24-hr 2-yr Rainfall=3.10" Runoff Area=33,573 sf ., Runoff Volume=0.157 of Runoff Depth=2.44" 1- Flow Length=377' o Tc=9.7 min u. CN=94 0 . , 0 2 4 6 8 10 12 1'4 '161 '18 20 22 24 Time (hours) 498 Chickering Road Pre Type 111 24-hr 2-yr Rainfall=3.90" Prepared by Merrimack Engineering Services Page 3 HvdroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Svstems 11/1/2007 Subcatchment S2: (Subcatchment 2 - Existing Conditions) Runoff = 0.32 cfs @ 12.07 hrs, Volume= 0.024 af, Depth= 2.45" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 2-yr Rainfall=3.10" Area (sf) CN Description 1,200 79 50-75% Grass cover, Fair, HSG C 3,900 98 Paved parking & roofs 5,100 94 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.5 50 0.0420 1.6 Sheet Flow, Subcatchment-2 Smooth surfaces n= 0.011 P2= 3.10" 0.1 34 0.0588 4.9 Shallow Concentrated Flow, Subcatchment-2 Paved Kv= 20.3 fps 0.5 60 0.0750 1.9 Shallow Concentrated Flow, Subcatchment-2 Short Grass Pasture Kv= 7.0 fps 0.2 68 0.0555 4.8 Shallow Concentrated Flow, Subcatchment-2 Paved Kv= 20.3 fps 3.7 Direct Entry, (Adjust for min. 5minute Tc) 5.0 212 Total Subcatchment S2: (Subcatchment 2 - Existing Conditions) Hydrograph 0.35 0.32 cfs El Runoff - Type III 24-hr 2-yr 0.3 Rainfall=3.10" 0.25 Runoff Area=5,100 sf Runoff Volume=0.024 of 0.2 -- Runoff Depth=2.45" Flow Length=212' �° 0.15- Tc=5.0 min CN=94 0.1 0.05- 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type H/24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 4 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Subcatchment S3: (Subcatchment 3 - Existing Conditions) Runoff = 0.75 cfs @ 12.12 hrs, Volume= 0.057 af, Depth= 1.53" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 2-yr Rainfall=3.10" Area (sf) CN Description 15,405 79 50-75% Grass cover, Fair, HSG C 4,236 98 Paved parking & roofs 19,641 83 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.3 50 0.0400 0.2 Sheet Flow, Subcatchment-3 Grass: Short n= 0.150 P2= 3.10" 0.9 72 0.0332 1.3 Shallow Concentrated Flow, Subcatchment- 3 Short Grass Pasture Kv= 7.0 fps 0.8 59 0.0305 1.2 Shallow Concentrated Flow, Subcatchment- 3 Short Grass Pasture Kv= 7.0 fps 1.0 81 0.0386 1.4 Shallow Concentrated Flow, Subcatchment- 3 Short Grass Pasture Kv= 7.0 fps 0.4 42 0.0564 1.7 Shallow Concentrated Flow, Subcatchment- 3 Short Grass Pasture Kv= 7.0 fps 0.4 96 0.0428 4.2 Shallow Concentrated Flow, Subcatchment- 3 Paved Kv= 20.3 fps 7.8 400 Total 498 Chickering Road Pre Type 11124-hr 2-yr Rainfall=3.90" Prepared by Merrimack Engineering Services Page 5 HydroCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Subcatchment S3: (Subcatchment 3 - Existing Conditions) Hydrograph 0.8 0.75 Cfs 10 Runoff Type III 24-hr 2-yr 0.7- Rainfall=3.10" 0.6 Runoff Area=19,641 sf Runoff Volume=0.057 of 0.5- Runoff Depth=1.53" .r � 9 th=400' Flow Len 3 0.4 —° Tc=7.8 min 0.3 CN=83 0.2 0.1 0 , 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 11124-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 6 HydroCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach P2: (20'-12" RCP) Inflow Area = 0.568 ac, Inflow Depth = 1.71" for 2-yr event Inflow = 1.02 cfs @ 12.11 hrs, Volume= 0.081 of Outflow = 1.02 cfs @ 12.11 hrs, Volume= 0.081 af, Atten= 0%, Lag= 0.1 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 7.1 fps, Min. Travel Time= 0.0 min Avg. Velocity= 2.3 fps, Avg. Travel Time= 0.1 min Peak Depth= 0.24' @ 12.11 hrs Capacity at bank full= 8.10 cfs Inlet Invert= 115.97', Outlet Invert= 115.23' 12.0" Diameter Pipe n= 0.011 Length= 20.0' Slope= 0.0370 '/' Reach P2: (20'-12" RCP) Hydrograph Inflow Inflow Area=O. 1 .02 cfs 0 outflow 1 e Peak Depth=0.24' Max Vet=7.1 fps D=12.0" N n=0.011 c L=20.0' �- S=0.0370 T Capacity=8.10 cfs 0 . „ 0 2 4 6 8 10 12 14 116 18 20 2t2 24 Time (hours) 498 Chickering Road Pre Type 11124-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 7 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach P3: (56'-12" CSP) Inflow Area = 0.451 ac, Inflow Depth = 1.53" for 2-yr event Inflow = 0.75 cfs @ 12.12 hrs, Volume= 0.057 of Outflow - 0.73 cfs @ 12.13 hrs, Volume= 0.057 af, Atten= 3%, Lag= 0.6 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 2.7 fps, Min. Travel Time= 0.3 min Avg. Velocity= 1.0 fps, Avg. Travel Time= 0.9 min Peak Depth= 0.38' @ 12.12 hrs Capacity at bank full= 2.41 cfs Inlet Invert= 116.89', Outlet Invert= 116.02' 12.0" Diameter Pipe n= 0.024 Length= 56.0' Slope= 0.0155 '/' Reach P3: (56'-12" CSP) Hydrograph Inflow 0.8 Inflow Area=O. 0.73 cfs Outflow 0.7 Peak Depth=0.38' 0.6 Max Vet=2.7 fps D=12.0" 0) 0.5 n=0.024 c 0.4 L=56.0' 0.3 ' S=0.0155 T 0.2 Capacity=2.41 cfs 0.1 pp I OiA „ 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 11l 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 8 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach R1: (Reach 1 - Catch Basin #1) Inflow Area = 1.339 ac, Inflow Depth = 2.13" for 2-yr event Inflow = 2.85 cfs @ 12.12 hrs, Volume= 0.238 of Outflow = 2.85 cfs @ 12.12 hrs, Volume= 0.238 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R1: (Reach 1 - Catch Basin #1) Hydrograph p Inflow 3 Inflow Area-1. 2'85 Cfs p Outflow , 7 } 2 w 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 111 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 9 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach R2: (Reach 2 - Catch Basin #2) Inflow Area = 0.568 ac, Inflow Depth = 1.71" for 2-yr event Inflow = 1.02 cfs @ 12.11 hrs, Volume= 0.081 of Outflow = 1.02 cfs @ 12.11 hrs, Volume= 0.081 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R2: (Reach 2 - Catch Basin #2) Hydrograph Inflow 1 Inflow Area-O. 1 .02 Cfs 0 outflow r �s 0 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 11124-hr 2-yr Rainfall=3.90" Prepared by Merrimack Engineering Services Page 10 HydroCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach R3: (Reach 3 - Catch Basin #3) Inflow Area = 0.451 ac, Inflow Depth = 1.53" for 2-yr event Inflow = 0.75 cfs @ 12.12 hrs, Volume= 0.057 of Outflow = 0.75 cfs @ 12.12 hrs, Volume= 0.057 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R3: (Reach 3 - Catch Basin #3) Hydrograph 0 Inflow 0.8-- 0.75 CAS 0 Outflow Inflow Area=O. 0.7= 0.6 w 0.5- k ..r 3 0.4 O 0.3- 3' 0.2 0.1 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type ///24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 11 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment S1: (Subcatchment 1 -Existing Conditions) Runoff Area=33,573 sf Runoff Depth=3.81" Flow Length=377' Tc=9.7 min CN=94 Runoff=2.81 cfs 0.245 of Subcatchment S2: (Subcatchment 2 - Existing Conditions) Runoff Area=5,100 sf Runoff Depth=3.81" Flow Length=212' Tc=5.0 min CN=94 Runoff=0.49 cfs 0.037 of Subcatchment S3: (Subcatchment 3 -Existing Conditions) Runoff Area=19,641 sf Runoff Depth=2.72" Flow Length=400' Tc=7.8 min CN=83 Runoff=1.34 cfs 0.102 of Reach P2: (20'-12" RCP) Peak Depth=0.32' Max Vet=8.2 fps Inflow=1.76 cfs 0.139 of D=12.0" n=0.011 L=20.0' S=0.0370'/' Capacity=8.10 cfs Outflow=1.76 cfs 0.139 of Reach P3: (56'-12" CSP) Peak Depth=0.53' Max Vet=3.1 fps Inflow=1.34 cfs 0.102 of D=12.0" n=0.024 L=56.0' S=0.01557' Capacity=2.41 cfs Outflow=1.31 cfs 0.102 of Reach R1: (Reach 1 -Catch Basin#1) Inflow=4.54 cfs 0.384 of Outflow=4.54 cfs 0.384 of Reach R2: (Reach 2-Catch Basin#2) Inflow=1.76 cfs 0.139 of Outflow=1.76 cfs 0.139 of Reach R3: (Reach 3 - Catch Basin#3) Inflow=1.34 cfs 0.102 of Outflow=1.34 cfs 0.102 of Total Runoff Area= 1.339 ac Runoff Volume= 0.384 of Average Runoff Depth =3.44" 498 Chickering Road Pre Type 11124-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 12 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Svstems 11/1/2007 Subcatchment S1: (Subcatchment 1 - Existing Conditions) Runoff = 2.81 cfs @ 12.13 hrs, Volume= 0.245 af, Depth= 3.81" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 10-yr Rainfall=4.50" Areas CN Description 7,016 79 50-75% Grass cover, Fair, HSG C 26,557 98 Paved parking & roofs 33,573 94 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.1 50 0.0600 0.1 Sheet Flow, Subcatchment- 1 Woods: Light underbrush n= 0.400 P2= 3.10" 0.2 50 0.0650 5.2 Shallow Concentrated Flow, Subcatchment-1 Paved Kv= 20.3 fps 0.7 150 0.0337 3.7 Shallow Concentrated Flow, Subcatchment-1 Paved Kv= 20.3 fps 0.5 57 0.0700 1.9 Shallow Concentrated Flow, Subcatchment- 1 Short Grass Pasture Kv= 7.0 fps 0.2 70 0.0681 53 Shallow Concentrated Flow, Subcatchment-1 Paved Kv= 20.3 fps 9.7 377 Total Subcatchment S1: (Subcatchment 1 - Existing Conditions) Hydrograph 3 2.81 cfs Runoff ffRainfall=4.50"pe III 24-hr 10-yr Runoff Area=33,573 sf 2 Runoff Volume=0.245 of Runoff Depth=3.81" Flow Length=377' 0 LL Tc=9.7 min CN=94 0 : r 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 11124-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 13 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Svstems 11/1/2007 Subcatchment S2: (Subcatchment 2 - Existing Conditions) Runoff = 0.49 cfs @ 12.07 hrs, Volume= 0.037 af, Depth= 3.81" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 10-yr Rainfall=4.50" Areas CN Description 1,200 79 50-75% Grass cover, Fair, HSG C 3,900 98 Paved parkina & roofs 5,100 94 Weighted Average Tc Length Slope Velocity Capacity Description _ (min) (feet) (ft/ft) (ft/sec) (cfs) 0.5 50 0.0420 1.6 Sheet Flow, Subcatchment- 2 Smooth surfaces n= 0.011 P2= 3.10" 0.1 34 0.0588 4.9 Shallow Concentrated Flow, Subcatchment-2 Paved Kv= 20.3 fps 0.5 60 0.0750 1.9 Shallow Concentrated Flow, Subcatchment-2 Short Grass Pasture Kv= 7.0 fps 0.2 68 0.0555 4.8 Shallow Concentrated Flow, Subcatchment-2 Paved Kv= 20.3 fps 3.7 Direct Entry, (Adjust for min. 5minute Tc) 5.0 212 Total Subcatchment S2: (Subcatchment 2 - Existing Conditions) Hydrograph 0.55- 0.49 cfs Q Runoff 0.5- Type III 24-hr 10-yr 0.45- Rainfall=4.50" 0.4= Runoff Area=5,100 sf 0.35 Runoff Volume=0.037 of 0.3 Runoff Depth=3.81 Flow length=212` : 0'25 e Tc=5.0 min 0.2 e CN=94 0.15 " 0.1 0.05 0 „ 0 2` 4 6 8 1'0 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 11124-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 14 H droCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Subcatchment S3: (Subcatchment 3 - Existing Conditions) Runoff = 1.34 cfs @ 12.11 hrs, Volume= 0.102 af, Depth= 2.72" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 10-yr Rainfall=4.50" Areas CN Description 15,405 79 50-75% Grass cover, Fair, HSG C 4,236 98 Paved parking & roofs 19,641 83 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.3 50 0.0400 0.2 Sheet Flow, Subcatchment-3 Grass: Short n= 0.150 P2= 3.10" 0.9 72 0.0332 1.3 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.8 59 0.0305 1.2 Shallow Concentrated Flow, Subcatchment- 3 Short Grass Pasture Kv= 7.0 fps 1.0 81 0.0386 1.4 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.4 42 0.0564 1.7 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.4 96 0.0428 4.2 Shallow Concentrated Flow, Subcatchment-3 Paved Kv= 20.3 fps 7.8 400 Total 498 Chickering Road Pre Type 11124-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 15 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/112007 Subcatchment S3: (Subcatchment 3 - Existing Conditions) Hydrograph 1 .34 Cfs ❑ Runoff Type III 24-hr 10-yr Rainfall=4.50" Runoff Area=19,641 sf 1 Runoff Volume=0.102 of Runoff Depth=2.72" Flow Length=400` 0 LL Tc=7.8 min CN=83 s _, 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 111 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 16 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/112007 Reach P2: (20'-12" RCP) Inflow Area = 0.568 ac, Inflow Depth = 2.95" for 10-yr event Inflow = 1.76 cfs @ 12.11 hrs, Volume= 0.139 of Outflow = 1.76 cfs @ 12.11 hrs, Volume= 0.139 af, Atten= 0%, Lag= 0.1 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 8.2 fps, Min. Travel Time= 0.0 min Avg. Velocity = 2.6 fps, Avg. Travel Time= 0.1 min Peak Depth= 0.32' @ 12.11 hrs Capacity at bank full= 8.10 cfs Inlet Invert= 115.97', Outlet Invert= 115.23' 12.0" Diameter Pipe n= 0.011 Length= 20.0' Slope= 0.0370 '/' Reach P2: (20'-12" RCP) Hydrograph Inflow Inflow Area=O. 1 .76 CfS 1 Outflow Peak Depth=0.32' Max Vet=8.2 fps D=12.0" N n=0.011 3 1 L=20.0' 0 LL S=0.0370 '/' Capacity=8.10 cfs 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 111 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 17 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach P3: (56'-12" CSP) Inflow Area = 0.451 ac, Inflow Depth = 2.72" for 10-yr event Inflow = 1.34 cfs @ 12.11 hrs, Volume= 0.102 of Outflow = 1.31 cfs @ 12.12 hrs, Volume= 0.102 af, Atten= 2%, Lag= 0.5 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 3.1 fps, Min. Travel Time= 0.3 min Avg. Velocity= 1.2 fps, Avg. Travel Time= 0.8 min Peak Depth= 0.53' @ 12.12 hrs Capacity at bank full= 2.41 cfs Inlet Invert= 116.89', Outlet Invert= 116.02' 12.0" Diameter Pipe n= 0.024 Length= 56.0' Slope= 0.01557' Reach P3: (56'-12" CSP) Hydrograph Inflow Inflow Area=O. 1 .31 cfs Outflow Peak Depth=0.53' Max Vet=3.1 fps 1 D=12.0" 4 n=0.024 L=56.0 S=0.0155 '/' Capacity=2.41 cfs 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type /// 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 18 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach R1: (Reach 1 - Catch Basin #1) Inflow Area= 1.339 ac, Inflow Depth = 3.44" for 10-yr event Inflow = 4.54 cfs @ 12.12 hrs, Volume= 0.384 of Outflow = 4.54 cfs @ 12.12 hrs, Volume= 0.384 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R1: (Reach 1 - Catch Basin #1) Hydrograph Inflow 5- 4.54 cfs Outflow Inflow Area=1. 3 4 JEW v 3- v 3 2- 1 0 0 2 4 6 8 10 12 14 16 16 20 22 24 Time (hours) 498 Chickering Road Pre Type /// 24-hr 90-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 19 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach R2: (Reach 2 - Catch Basin #2) Inflow Area = 0.568 ac, Inflow Depth = 2.95" for 10-yr event Inflow = 1.76 cfs @ 12.11 hrs, Volume= 0.139 of Outflow = 1.76 cfs @ 12,11 hrs, Volume= 0.139 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R2: (Reach 2 - Catch Basin #2) Hyd rog raph Inflow Inflow Area=O. 1 .76 cfs 0 outflow 0 { 0 , . . . r 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type Ill 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 20 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach R3: (Reach 3 - Catch Basin #3) Inflow Area= 0.451 ac, Inflow Depth = 2.72" for 10-yr event Inflow = 1.34 cfs @ 12.11 hrs, Volume= 0.102 of Outflow = 1.34 cfs @ 12.11 hrs, Volume= 0.102 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R3: (Reach 3 - Catch Basin #3) Hydrograph Inflow 1 .34 Cfs El outflow Inflow Area=O. 1- - c 0 ! 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 11124-hr 900-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 21 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment S1: (Subcatchment 1 - Existing Conditions) Runoff Area=33,573 sf Runoff Depth=5.69" Flow Length=377' Tc=9.7 min CN=94 Runoff=4.10 cfs 0.365 of Subcatchment S2: (Subcatchment 2 - Existing Conditions) Runoff Area=5,100 sf Runoff Depth=5.69" Flow Length=212' Tc=5.0 min CN=94 Runoff=0.72 cfs 0.056 of Subcatchment S3: (Subcatchment 3 -Existing Conditions) Runoff Area=19,641 sf Runoff Depth=4.46" Flow Length=400' Tc=7.8 min CN=83 Runoff--2.16 cfs 0.168 of Reach P2: (20'-12" RCP) Peak Depth=0.40' Max Vet=9.3 fps Inflow=2.78 cfs 0.223 of D=12.0" n=0.011 L=20.0' S=0.0370 T Capacity=8.10 cfs Outflow=2.78 cfs 0.223 of Reach P3: (66'-12" CSP) Peak Depth=0.74' Max Vet=3.5 fps Inflow=2.16 cfs 0.168 of D=12.0" n=0.024 L=56.0' S=0.0155 '/' Capacity=2.41 cfs Outflow=2.13 cfs 0.168 of Reach R1: (Reach 1 -Catch Basin#1) Inflow=6.84 cfs 0.588 of Outflow=6.84 cfs 0.588 of Reach R2: (Reach 2 -Catch Basin#2) Inflow=2.78 cfs 0.223 of Outflow=2.78 cfs 0.223 of Reach R3: (Reach 3 - Catch Basin#3) Inflow=2.16 cfs 0.168 of Outflow=2.16 cfs 0.168 of Total Runoff Area= 1.339 ac Runoff Volume=0.688 of Average Runoff Depth = 5.27" 499 Chickering Road Pre Type H/24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 22 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Subcatchment S1: (Subcatchment 1 - Existing Conditions) Runoff = 4.10 cfs @ 12.13 hrs, Volume= 0.365 af, Depth= 5.69" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 100-yr Rainfall=6.40" Area (sf) CN Description 7,016 79 50-75% Grass cover, Fair, HSG C 26,557 98 Paved parking & roofs 33,573 94 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 8.1 50 0.0600 0.1 Sheet Flow, Subcatchment- 1 Woods: Light underbrush n= 0.400 P2= 3.10" 0.2 50 0.0650 5.2 Shallow Concentrated Flow, Subcatchment- 1 Paved Kv= 20.3 fps 0.7 150 0.0337 3.7 Shallow Concentrated Flow, Subcatchment- 1 Paved Kv= 20.3 fps 0.5 57 0.0700 1.9 Shallow Concentrated Flow, Subcatchment- 1 Short Grass Pasture Kv= 7.0 fps 0.2 70 0.0681 5.3 Shallow Concentrated Flow, Subcatchment-1 Paved Kv= 20.3 fps 9.7 377 Total Subcatchment S1: (Subcatchment 1 - Existing Conditions) Hydrog raph 4.10 Cfs El Runoff 4 Type III 24-hr 100-yr Rainfall=6.40" Runoff Area=33,573 sf ,. 3 Runoff Volume=0.365 of Runoff Depth=5.69" Flow Length=377' A vo 2_. Tc=9.7 min CN=94 m} 1 OR . . 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type ///24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 23 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 1 1/1/2007 Subcatchment S2: (Subcatchment 2 - Existing Conditions) Runoff = 0.72 cfs @ 12.07 hrs, Volume= 0.056 af, Depth= 5.69" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 100-yr Rainfall=6.40" Area (sf) CN Description 1,200 79 50-75% Grass cover, Fair, HSG C 3,900 98 Paved parking & roofs 5,100 94 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.5 50 0.0420 1.6 Sheet Flow, Subcatchment-2 Smooth surfaces n= 0.011 P2= 3.10" 0.1 34 0.0588 4.9 Shallow Concentrated Flow, Subcatchment- 2 Paved Kv= 20.3 fps 0.5 60 0.0750 1.9 Shallow Concentrated Flow, Subcatchment- 2 Short Grass Pasture Kv= 7.0 fps 0.2 68 0.0555 4.8 Shallow Concentrated Flow,Subcatchment- 2 Paved Kv= 20.3 fps 3.7 Direct Entry, (Adjust for min. 5minute Tc) 5.0 212 Total Subcatchment S2: (Subcatchment 2 - Existing Conditions) Hydrograph 0.8 - 10.72 cfs Q Runoff 0.7 Type III 24-hr 100-yr Rainfall=6.40" 0.6 Runoff Area=5,100 sf 0.5 Runoff Volume=0.056 of Runoff Depth=5.69 0.4 : Flow Length=212` 0 � Tc=5.0 min 0.3- CN=94 0.2- 0.1 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 111 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 24 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Subcatchment S3: (Subcatchment 3 - Existing Conditions) Runoff = 2.16 cfs @ 12.11 hrs, Volume= 0.168 af, Depth= 4.46" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 100-yr Rainfall=6.40" Area (sf) CN Description 15,405 79 50-75% Grass cover, Fair, HSG C 4,236 98 Paved parking & roofs 19,641 83 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.3 50 0.0400 0.2 Sheet Flow, Subcatchment-3 Grass: Short n= 0.150 P2= 3.10" 0.9 72 0.0332 1.3 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.8 59 0.0305 1.2 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 1.0 81 0.0386 1.4 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.4 42 0.0564 1.7 Shallow Concentrated Flow, Subcatchment- 3 Short Grass Pasture Kv= 7.0 fps 0.4 96 0.0428 4.2 Shallow Concentrated Flow, Subcatchment-3 Paved Kv= 20.3 fps 7.8 400 Total 498 Chickering Road Pre Type ///24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 25 HydroCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Subcatchment S3: (Subcatchment 3 - Existing Conditions) Hydrograph 2.16 cfs 0 Runoff Type III 24-hr 100-yr 2- Rainfall=6.40" Runoff Area=19,641 sf Runoff Volume=0.168 of Runoff Depth=4.46" 3 Flow Length=400` ° LL 1 Tc=7.8 min CN=83 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 111 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 26 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach P2: (20'-12" RCP) Inflow Area = 0.568 ac, Inflow Depth = 4.71" for 100-yr event Inflow = 2.78 cfs @ 12.11 hrs, Volume= 0.223 of Outflow = 2,78 cfs @ 12.11 hrs, Volume= 0.223 af, Atten= 0%, Lag= 0,1 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 9.3 fps, Min. Travel Time= 0.0 min Avg. Velocity= 3.0 fps, Avg. Travel Time= 0.1 min Peak Depth= 0.40' @ 12.11 hrs Capacity at bank full= 8.10 cfs Inlet Invert= 115.97', Outlet Invert= 115.23' 12.0" Diameter Pipe n= 0.011 Length= 20.0' Slope= 0.0370 '/' Reach P2: (20'-12" RCP) Hydrograph El Inflow 3- 2.78 cfs El outflow Inflow Area=O. Peak Depth=0.40' r Max Vet=9.3 fps 2- ©=12.0" n=0,011 c L=20.0' �- S=0.0370 'i' 1 Capacity=&10 cfs 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 111 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 27 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 1111/2007 Reach P3: (56'-12" CSP) Inflow Area = 0.451 ac, Inflow Depth = 4.46" for 100-yr event Inflow = 2.16 cfs @ 12.11 hrs, Volume= 0.168 of Outflow = 2.13 cfs @ 12.12 hrs, Volume= 0.168 af, Atten= 2%, Lag= 0.5 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 3.5 fps, Min. Travel Time= 0.3 min Avg. Velocity= 1.3 fps, Avg. Travel Time= 0.7 min Peak Depth= 0.74' @ 12.11 hrs Capacity at bank full= 2.41 cfs Inlet Invert= 116.89', Outlet Invert= 116.02' 12.0" Diameter Pipe n= 0.024 Length= 56.0' Slope= 0.0155 '/' Reach P3: (56'-12" CSP) Hydrograph Inflow Inflow Area=O. 2.13 cfs ❑ Outflow 2- Peak Depth=0.74' Max Vet=3.5 fps D=12.0" n=0.024 c L=56.0' �- 1 S=0.0155 '/' Capacity=2.41 cfs AM WI&M 0m 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type 11124-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 28 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach R1: (Reach 1 - Catch Basin #1) Inflow Area = 1.339 ac, Inflow Depth = 5.27' for 100-yr event Inflow = 6.84 cfs @ 12.12 hrs, Volume= 0.588 of Outflow = 6.84 cfs @ 12.12 hrs, Volume= 0.588 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R1: (Reach 1 - Catch Basin #1) Hydrograph Inflow 6.84 cfs 0 Outflow 7 - Inflow Area=1 . 6 5- 4- o 3-- 2 0-1 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type ///24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 29 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach R2: (Reach 2 - Catch Basin #2) Inflow Area= 0.568 ac, Inflow Depth = 4.71" for 100-yr event Inflow = 2.78 cfs @ 12.11 hrs, Volume= 0.223 of Outflow = 2.78 cfs @ 12.11 hrs, Volume= 0.223 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R2: (Reach 2 - Catch Basin #2) Hydrograph Inflow 3- 2.78 CfS outflow Inflow Area-0.U90 r 2 O 1 0 . . � 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Pre Type Ill 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 30 IydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 11/1/2007 Reach R3: (Reach 3 - Catch Basin #3) Inflow Area = 0.451 ac, Inflow Depth = 4.46" for 100-yr event Inflow = 2.16 cfs @ 12.11 hrs, Volume= 0.168 of Outflow = 2.16 cfs @ 12.11 hrs, Volume= 0.168 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R3: (Reach 3 - Catch Basin #3) Hyd rog raph Inflow 2.16 cfs 0 Outflow Inflow Area=O. 2- o z 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 4.2.2 > POST - DEVELOPMENT— 2, 10, & 100 — Year STORM EVENT Merrimack Engineering Services,Inc. Section 4—Page 4 Printed: December 14,2007 i C U C co U E C: N .0 , N I` N _ ^ . C -p ` O � N E U � � tIIN O O NUJ J, E O Q N -C M v CL ++ 0 r U (� � U) U " o -' := "U "a N m N U � U) .n 0 0 o 0 -j C-2 o a v o a v, U -0 tm T � N Q 'r. c a co m m v Co a L = 'C o U cn � V N c� C7 U M U c i 00 C 00 c� — � — LJ N l ('7 iwO ` L w- U rn O N Of E M cO 0),C:Eo �- N ("1) U) (V d 5-0 E- a) c°� � p` Q.Q gip. N o "0 T U U = co m W ALE n EE U d' 2 n_ N a N o- a 0) U .a) m m cu O L) +U' ~ U ~ U U a . U' a O � N C N O C C .� C: C O � +' 0 �CU U a O U C Q 7 E O Q I< E O C LL � U M � (� o NQ - -a '� Q N Q p O O v ` U) O — 498 Chickering Road Post - test Type ///24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 31 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment PR: (Proposed building roof) Runoff Area=5,046 sf Runoff Depth=2.87" Tc=5.0 min CN=98 Runoff=0.35 cfs 0.028 of Subcatchment S1-L: (Subcatchment 1 -Proposed Conditions Runoff Area=15,833 sf Runoff Depth=2.07" Flow Length=295' Tc=5.0 min CN=90 Runoff=0.88 cfs 0.063 of Subcatchment S1-U: (Subcatchment 1 - Proposed Conditions Runoff Area=11.180 sf Runoff Depth=2.87" Flow Length=165' Tc=5.0 min CN=98 Runoff=0.78 cfs 0.061 of Subcatchment S2: (Subcatchment 2 - Proposed Conditions) Runoff Area=2,513 sf Runoff Depth=1.39" Flow Length=109' Tc=5.0 min CN=81 Runoff=0.09 cfs 0.007 of Subcatchment S3-G: (Subcatchment 3 - Proposed Conditions Runoff Area=13.798 sf Runoff Depth=1.26" Flow Length=400' Tc=7.8 min CN=79 Runoff=0.43 cfs 0.033 of Subcatchment S3-I: (Subcatchment 3 - Proposed Conditions - I Runoff Area=9,942 sf Runoff Depth=2.87" Flow Length=125' Tc=5.0 min CN=98 Runoff=0.69 cfs 0.055 of Reach P1: (29'-12" HDPE) Peak Depth=0.18' Max Vet=8.1 fps Inflow=0.78 cfs 0.061 of D=12.0" n=0.011 L=29.0' S=0.0697 '/' Capacity=1 1.11 cfs Outflow=0.77 cfs 0.061 of Reach P2: (20'-12" RCP) Peak Depth=0.34' Max Vet=8.5 fps Inflow=1.98 cfs 0.183 of D=12.0" n=0.011 L=20.0' S=0.0370 '/' Capacity=8.10 cfs Outflow=1.97 cfs 0.183 of Reach P3: (56'-12" CSP) Peak Depth=0.28' Max Vet=2.3 fps Inflow=0.43 cfs 0.033 of D=12.0" n=0.024 L=56.0' S=0.01557' Capacity=2.41 cfs Outflow=0.42 cfs 0.033 of Reach P4: (45' - 12" HDPE) Peak Depth=0.10' Max Vet=2.1 fps Inflow=0.08 cfs 0.028 of D=12.0" n=0.011 L=45.0' S=0.0100 T Capacity=4.21 cfs Outflow=0.08 cfs 0.028 of Reach P5: (140'-12" HDPE) Peak Depth=0.19' Max Vet=6.6 fps Inflow=0.69 cfs 0.055 of D=12.0" n=0.011 L=140.0' S=0.0436 '/' Capacity=8.79 cfs Outflow=0.68 cfs 0.055 of Reach P6: (64'-12" HDPE) Peak Depth=0.31' Max Vet=7.4 fps Inflow=1.51 cfs 0.143 of D=12.0" n=0.011 L=64.0' S=0.0313 '/' Capacity=7.44 cfs Outflow=1.50 cfs 0.143 of Reach R1: (Reach 1 -Catch Basin #1) Inflow=2.84 cfs 0.246 of Outflow=2.84 cfs 0.246 of Reach R2: (Reach 2 -Catch Basin #2) Inflow=1.98 cfs 0.183 of Outflow=1.98 cfs 0.183 of Reach R3: (Reach 3 - Catch Basin #3) Inflow=0.43 cfs 0.033 of Outflow=0.43 cfs 0.033 of 498 Chickering Road Post - test Type 11124-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 32 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R4: (Reach 4 -Catch Basin #4) Inflow=0.78 cfs 0.061 of Outflow=0.78 cfs 0.061 of Reach R5: (Reach 5 -Catch Basin #5) Inflow=0.69 cfs 0.055 of Outflow=0.69 cfs 0.055 of Reach R6: (Reach 6 -SDMH) Inflow=1.51 cfs 0.143 of Outflow=1.51 cfs 0.143 of Pond CT: (7,500 Gala Commercial Line Tank) Peak Elev=121.29' Storage=355 cf Inflow=0.35 cfs 0.028 of Outflow=0.08 cfs 0.028 of Total Runoff Area = 1.339 ac Runoff Volume = 0.246 of Average Runoff Depth = 2.21" 498 Chickering Road Post - test Type 11124-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 33 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment PR: (Proposed building roof) Runoff = 0.35 cfs @ 12.07 hrs, Volume 0.028 af, Depth= 2.87" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 2-yr Rainfall=3.10" Area (sf) CN Description 5,046 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Roof runoff Subcatchment PR: (Proposed building roof) Hydrograph 0.35 cfs 0 Runoff 0.35_ Type III 24-hr 2-yr Rainfall=3.10" 0.3 Runoff Area=5,046 sf 0.25 Runoff Volume=0.028 of 0 _Runoff_Depth=.2.87" 3 0.2 Tc=5.0 min LL 0.15= CN=98 0.1= y,s 0.05 ur 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 2-yr RainfaN=3.10" Prepared by Merrimack Engineering Services Page 34 HydroCADD 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S1-L: (Subcatchment 1 - Proposed Conditions - Lower Area) Runoff = 0.88 cfs @ 12.07 hrs, Volume= 0.063 af, Depth= 2.07" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 2-yr Rainfall=3.10" Area (sf) CN Description 6,953 79 50-75% Grass cover, Fair, HSG C 8,880 98 Paved parking & roofs 15,833 90 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.5 50 0.0600 1.8 Sheet Flow, Subcatchment- 1 Smooth surfaces n= 0.011 P2= 3.10" 0.9 245 0.0530 4.7 Shallow Concentrated Flow, Subcatchment- 1 Paved Kv= 20.3 fps 3.6 Direct Entry, Adjust for min. 5 minute Tc 5.0 295 Total Subcatchment S1-L: (Subcatchment 1 - Proposed Conditions - Lower Area) Hydrograph 0.88 Cfs 0 Runoff 0.9_ Type III 24-hr 2-yr 0.8 Rainfall=3.10" r Runoff Area=15,833 sf Runoff Volume=0.063 of IF 0.6- Runoff Depth=2,07" 3 0.5--_ Flow Length=295' $; —° 0.4 Tc=5.0 min l CN 90 0.3-- = 0.2-- 0.1 0 3 cto � 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 35 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S1-U: (Subcatchment 1 - Proposed Conditions - Upper Area) Runoff = 0.78 cfs @ 12.07 hrs, Volume= 0.061 af, Depth= 2.87" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 2-yr Rainfall=3.10" Area (sf) CN Description 11,180 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.6 50 0.0365 1.5 Sheet Flow, Subcatchment 1 - Upper Area Smooth surfaces n= 0.011 P2= 3.10" 0.5 115 0.0365 3.9 Shallow Concentrated Flow, Subcatchment 1 - Upper Area Paved Kv= 20.3 fps 3.9 Direct Entry, Adjust for min. 5 minute Tc 5.0 165 Total Subcatchment S1-U: (Subcatchment 1 - Proposed Conditions - Upper Area) Hydrograph 0.78 cfs 11 Runoff 0.8 Type III 24-hr 2-yr 0.7 Rainfall 3.10" - Runoff Area=11,180 sf 0.6- Runoff Volume=0.061 of 0.5 Runoff Depth=2.87" 0.4- c Flow Length=165' v_ Tc=5.0 min 0.3- CN=98 r 0.2 0.1- 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type Ill 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 36 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S2: (Subcatchment 2 - Proposed Conditions) Runoff = 0.09 cfs @ 12.08 hrs, Volume= 0.007 af, Depth= 1.39" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 2-yr Rainfall=3.10" Area (sf) CN Description 2,213 79 50-75% Grass cover, Fair, HSG C 300 98 Paved parking & roofs 2,513 81 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) -- 2.6 50 0.1400 0.3 Sheet Flow, Subcatchment-2 Grass: Short n= 0.150 P2= 3.10" 0.2 59 0.0555 4.8 Shallow Concentrated Flow, Subcatchment-2 Paved Kv= 20.3 fps 2.2 Direct Entry, (Adjust for min. 5minute Tc) 5.0 109 Total Subcatchment S2: (Subcatchment 2 - Proposed Conditions) Hydrograph 0.09 Cfs 0 Runoff 0.09= Type III 24-hr 2-yir Rainfall=3.10" 0.08= Runoff Area=2,513 sf a-F 0.07 : Runoff Volume=0.007 of 0.06 Runoff Depth=1.39" 3 Flow Length=109' 0.05- ° - Tc=5.0 min �- 0.04 v CN=81 0.03- 0.02 y . 0.01 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type III 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 37 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S3-G: (Subcatchment 3 - Proposed Conditions-Grass & Shrubs) Runoff = 0.43 cfs @ 12.12 hrs, Volume= 0.033 af, Depth= 1.26" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 2-yr Rainfall=3.10" Area (sf) CN Description 13,798 79 50-75% Grass cover, Fair, HSG C Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.3 50 0.0400 0.2 Sheet Flow, Subcatchment-3 Grass: Short n= 0.150 P2= 3.10" 0.9 72 0.0332 1.3 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.8 59 0.0305 1.2 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 1.0 81 0.0386 1.4 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.4 42 0.0564 1.7 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.4 96 0.0428 4.2 Shallow Concentrated Flow, Subcatchment-3 Paved Kv= 20.3 fps 7.8 400 Total Subcatchment S3-G: (Subcatchment 3 - Proposed Conditions-Grass & Shrubs) Hydrograph 0.45- 0.43 cfs Runoff - Type III 24-hr 2-yr 0.4= Rainfall=110" 0.35= Runoff Area=13,798 sf 0.3- Runoff Volume=0.033 of Runoff Depth=1.26 0.25-: Flow Length=400' ° 0.2- Tc=7.8 min 0.15- GN-79 0.1 0.05 - 0- . , 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type /// 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 38 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S3-I: (Subcatchment 3 - Proposed Conditions - Impervious Area) Runoff = 0.69 cfs @ 12.07 hrs, Volume= 0.055 af, Depth= 2.87" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 2-yr Rainfall=3.10" Area (sf) CN Description 9,942 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.6 50 0.0250 1.3 Sheet Flow, Subcatchment 3 - Impervious Area Smooth surfaces n= 0.011 P2= 3.10" 0.4 75 0.0250 3.2 Shallow Concentrated Flow, Subcatchment 3 - Impervious Area Paved Kv= 20.3 fps 4.0 Direct Entry, Adjust for min. 5 minute Tc 5.0 125 Total Subcatchment S3-I: (Subcatchment 3 - Proposed Conditions - Impervious Area) Hydrograph 0.69 cfs p Runoff 0.7 Type III 24-hr 2-yr 0.6- Rainfall=3.10 Runoff Area=9,942 sf 0.5 Runoff Volume=0.055 of -Runoff Depth=2.87" 0.4 - Flow Length=125' 3 - ° Tc--5.O min M 0.3 _ CN=98 0.2- 0.1 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11l 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 39 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P1: (29'-12" HDPE) Inflow Area = 0.257 ac, Inflow Depth = 2.87" for 2-yr event Inflow = 0.78 cfs @ 12.07 hrs, Volume= 0.061 of Outflow = 0.77 cfs @ 12.07 hrs, Volume= 0.061 af, Atten= 0%, Lag= 0.1 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 8.1 fps, Min. Travel Time= 0.1 min Avg. Velocity = 2.7 fps, Avg. Travel Time= 0.2 min Peak Depth= 0.18' @ 12.07 hrs Capacity at bank full= 11.11 cfs Inlet Invert= 121.47', Outlet Invert= 119.45' 12.0" Diameter Pipe n= 0.011 Length= 29.0' Slope= 0.0697 '/' Reach P1: (29'-12" HDPE) Hydrograph Inflow 0.77 cfs El outflow 0.8- Inflow Area=Q. 0.7- Peak Depth=0.18' � Max Vet=8.1 fps 0.6 D='12.0" 0.5 "- n=0.011 0 0.4- L=29.0' U- S=0.0697 '/' 0.3 - fi P Capacity=11.11 cfs 0.2= 0.1 0= 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post -test Type H/ 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 40 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P2: (20'-12" RCP) Inflow Area = 0.975 ac, Inflow Depth = 2.26" for 2-yr event Inflow = 1.98 cfs @ 12.09 hrs, Volume= 0.183 of Outflow = 1.97 cfs @ 12.09 hrs, Volume= 0.183 af, Atten= 0%, Lag= 0.1 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 8.5 fps, Min. Travel Time= 0.0 min Avg. Velocity = 2.9 fps, Avg. Travel Time= 0.1 min Peak Depth= 0.34' @ 12.09 hrs Capacity at bank full= 8.10 cfs Inlet Invert= 115.97', Outlet Invert= 115.23' 12.0" Diameter Pipe n= 0.011 Length= 20.0' Slope= 0.03707' Reach P2: (20'-12" RCP) Hydrograph Inflow 2 Inflow Area=O. 1 .97 cfs 0 Outflow Peak Depth=0.34' ,4 Max Vet=8.5 fps D=12.0" n=0.011 0 1 L=20.0' LL S=0.0370 '/' -`' Capacity=8.10 cfs yN sue: 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type /// 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 41 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P3: (56'-12" CSP) Inflow Area = 0.317 ac, Inflow Depth = 1.26" for 2-yr event Inflow = 0.43 cfs @ 12.12 hrs, Volume= 0.033 of Outflow = 0.42 cfs @ 12.13 hrs, Volume= 0.033 af, Atten= 3%, Lag= 0.9 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 2.3 fps, Min. Travel Time= 0.4 min Avg. Velocity = 0.9 fps, Avg. Travel Time= 1.0 min Peak Depth= 0.28' @ 12.12 hrs Capacity at bank full= 2.41 cfs Inlet Invert= 116.89', Outlet Invert= 116.02' 12.0" Diameter Pipe n= 0.024 Length= 56.0' Slope= 0.0155 '/' Reach P3: (56'-12" CSP) Hydrograph Inflow El 0.45- Inflow Area=O. 0.42 CfS Outflow 0.4" Peak Depth=0.28' 0.35 Max Vc1=2.3 fps -- 0.3 D=12.0" n-0.024 0.25- _ _ 3 L=56.0` _2 0.2 _ �- S=0.0155 '/' 0.15 -Ca pacity=2.41 cfs y 0.1- 0.05 = 0 . AW 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 42 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P4: (45' - 12" HDPE) Inflow Area = 0.116 ac, Inflow Depth = 2.86" for 2-yr event Inflow = 0.08 cfs @ 12.45 hrs, Volume= 0.028 of Outflow = 0.08 cfs @ 12.46 hrs, Volume= 0.028 af, Atten= 0%, Lag= 0.6 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 2.1 fps, Min. Travel Time= 0.4 min Avg. Velocity = 1:1 fps, Avg. Travel Time= 0.7 min Peak Depth= 0.10' @ 12.46 hrs Capacity at bank full= 4.21 cfs Inlet Invert= 118.58', Outlet Invert= 118.13' 12.0" Diameter Pipe n= 0.011 Length= 45.0' Slope= 0.0100 '/' Reach P4: (45' - 12" HDPE) Hydrograph IM Inflow 0.09- _ 0.08 cfs El Outflow Inflow Area=O. 0.08 Peak Depth=0.10' 0.07: Max Vel=2.1 fps _ a 0.06- D=12:0" 0.05' n=0.011 0 0.04 L=45.0' �- S=0.0100 '/' 0.03 Capacity=4.21 cfs 0.02 0.01 - 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type /// 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 43 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P5: (140'-12" HDPE) Inflow Area = 0.228 ac, Inflow Depth = 2.87" for 2-yr event Inflow = 0.69 cfs @ 12.07 hrs, Volume= 0.055 of Outflow = 0.68 cfs @ 12.08 hrs, Volume= 0.055 af, Atten= 2%, Lag= 0.8 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 6.6 fps, Min. Travel Time= 0.4 min Avg. Velocity = 2.2 fps, Avg. Travel Time= 1.1 min Peak Depth= 0.19' @ 12.08 hrs Capacity at bank full= 8.79 cfs Inlet Invert= 125.55', Outlet Invert= 119.45' 12.0" Diameter Pipe n= 0.011 Length= 140.0' Slope= 0.0436 '/' Reach P5: (140'-12" HDPE) Hydrograph Inflow El - Inflow Area=O. 0.68 cfs Outflow 0.7 : Peak Depth=0.19' Max Vet=6.6 fps 0.5-:- D=12.0" ,. 0.4 n=0.011 o L=140.0' a: 0.3 S=0.0436 /' 0.2 _ Capacity=8.79 cfs 0.1 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 44 HydroCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P6: (64'-12" HDPE) Inflow Area = 0.601 ac, Inflow Depth = 2.86" for 2-yr event Inflow = 1.51 cfs @ 12.08 hrs, Volume= 0.143 of Outflow = 1.50 cfs @ 12.08 hrs, Volume= 0.143 af, Atten= 0%, Lag= 0.3 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 7.4 fps, Min. Travel Time= 0.1 min Avg. Velocity = 2.6 fps, Avg. Travel Time= 0.4 min Peak Depth= 0.31' @ 12.08 hrs Capacity at bank full= 7.44 cfs Inlet Invert= 118.02', Outlet Invert= 116.02' 12.0" Diameter Pipe n= 0.011 Length= 64.0' Slope= 0.0313 '/' Reach P6: (64'-12" HDPE) Hydrograph 0 Inflow Inflow Area=O. 1 .50 Cfs El Outflow �p Peak Depth=0.31' Max Vet=7.4 fps D=12.0" N 1 n=0.011 o L=64.0' j �- S=0.0313 '/' 4 Capacity=7.44 cfs Q 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type /// 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 45 HvdroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R1: (Reach 1 - Catch Basin #1) Inflow Area = 1.339 ac, Inflow Depth = 2.21" for 2-yr event Inflow = 2.84 cfs @ 12.09 hrs, Volume= 0.246 of Outflow = 2.84 cfs @ 12.09 hrs, Volume= 0.246 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R1: (Reach 1 - Catch Basin #1) Hydrograph Inflow 3 2.84 cfs 0 Outflow Inflow Area=1 . 4 2 ` O f 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post -test Type 11124-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 46 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R2: (Reach 2 - Catch Basin #2) Inflow Area = 0.975 ac, Inflow Depth = 2.26" for 2-yr event Inflow = 1.98 cfs @ 12.09 hrs, Volume= 0.183 of Outflow = 1.98 cfs @ 12.09 hrs, Volume= 0.183 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R2: (Reach 2 - Catch Basin #2) Hydrograph Inflow 2 Inflow Area=O. 1 .9 cfs Q outflow r N 0 1 0 ' . < < e ' � 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 47 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R3: (Reach 3 - Catch Basin #3) Inflow Area = 0.317 ac, Inflow Depth = 1.26" for 2-yr event Inflow = 0.43 cfs @ 12.12 hrs, Volume= 0.033 of Outflow = 0.43 cfs @ 12.12 hrs, Volume= 0.033 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R3: (Reach 3 - Catch Basin #3) Hydrograph D Inflow 0.45 0.43 cfs outflow Inflow Area=O. 0.4 0.35= 0.3- 0.25_ = ° 0.2 - LL 0.15 0.1-- 0.05 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 48 HydroCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R4: (Reach 4 - Catch Basin #4) Inflow Area = 0.257 ac, Inflow Depth = 2.87" for 2-yr event Inflow = 0.78 cfs @ 12.07 hrs, Volume= 0.061 of Outflow = 0.78 cfs @ 12.07 hrs, Volume= 0.061 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R4: (Reach 4 - Catch Basin #4) Hydrograph 0 Inflow 0.8= Inflow Area=O. 0.78 cfs 0 outflow 0.6 r 0.5 9 c0.4-: £. 0.2- 0.1- 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type /// 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 49 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R5: (Reach 5 - Catch Basin #5) Inflow Area = 0.228 ac, Inflow Depth = 2.87 for 2-yr event Inflow = 0.69 cfs @ 12.07 hrs, Volume= 0.055 of Outflow = 0.69 cfs @ 12.07 hrs, Volume= 0.055 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R5: (Reach 5 - Catch Basin #5) Hydrograph C Inflow 0.7 Inflow Area=O. 0.69 CfS El Outflow _ . 0.6-: 0.5- 0.4 3 o _ M 0.3 A 0.2_ 0.1 0 , ' t 0 1 t i i t s 1 77--f f 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type Ill 24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 50 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R6: (Reach 6 - SDMH) Inflow Area = 0.601 ac, Inflow Depth = 2.86" for 2-yr event Inflow = 1.51 cfs @ 12.08 hrs, Volume= 0.143 of Outflow = 1.51 cfs @ 12.08 hrs, Volume= 0.143 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R6: (Reach 6 - SDMH) Hydrograph Inflow 1 .51 cfs B outflow Inflow Area--J.%)V I C t : 1 o a 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type H/24-hr 2-yr Rainfall=3.10" Prepared by Merrimack Engineering Services Page 51 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Pond CT: (7,500 Gal. Commercial Line Tank) Inflow Area = 0.116 ac, Inflow Depth = 2.87" for 2-yr event Inflow = 0.35 cfs @ 12.07 hrs, Volume= 0.028 of Outflow = 0.08 cfs @ 12.45 hrs, Volume= 0.028 af, Atten= 77%, Lag= 23.0 min Primary = 0.08 cfs @ 12.45 hrs, Volume= 0.028 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 121.29' @ 12.45 hrs Surf.Area= 0 sf Storage= 355 cf Plug-Flow detention time= 41.3 min calculated for 0.028 of(99% of inflow) Center-of-Mass det. time= 39.2 min (795.0 - 755.8 ) # Invert Avail Storage Storage Description 1 118.83' 1,008 cf Custom Stage Data Listed below Elevation Cum.Store (feet) (cubic-feet) 118.83 0 122.33 504 125.83 1,008 # Routing Invert Outlet Devices - 1 Primary 118.83' 1.0" Vert. Orifice/Grate X 2.00 C= 0.600 Primary OutFlow Max=0.08 cfs @ 12.45 hrs HW=121.29' (Free Discharge) L1=Orifice/Grate (Orifice Controls 0.08 cfs @ 7.5 fps) Pond CT: (7,500 Gal. Commercial Line Tank) Hydrograph 0.35 Cfs Inflow El Inflow 'Area=0.116 ac Primary 0.35-= y Peak Elev 12129' NO 0.3 : Storage=355 cf N 0.25_ 3 0.2- u 0.15 { y 0.1 0.08 Cfs 0.05 * j , . i . .. , i . .. i . . t . . � ,. . i . . . � 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 52 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment PR: (Proposed building roof) Runoff Area=5,046 sf Runoff Depth=4.26" Tc=5.0 min CN=98 Runoff=0.51 cfs 0.041 of Subcatchment S1-L: (Subcatchment 1 -Proposed Conditions Runoff Area=15.833 sf Runoff Depth=3.39" Flow Length=295' Tc=5.0 min CN=90 Runoff=1.41 cfs 0.103 of Subcatchment S1-U: (Subcatchment 1 - Proposed Conditions Runoff Area=11.180 sf Runoff Depth=4.26" Flow Length=165' Tc=5.0 min CN=98 Runoff=1.14 cfs 0.091 of Subcatchment S2: (Subcatchment 2 - Proposed Conditions) Runoff Area=2,513 sf Runoff Depth=2.55" Flow Length=109' Tc=5.0 min CN=81 Runoff=0.17 cfs 0.012 of Subcatchment S3-G: (Subcatchment 3 - Proposed Conditions Runoff Area=13.798 sf Runoff Depth=2.37" Flow Length=400' Tc=7.8 min CN=79 Runoff=0.82 cfs 0.063 of Subcatchment S3-I: (Subcatchment 3 -Proposed Conditions -I Runoff Area=9,942 sf Runoff Depth=4.26" Flow Length=125' Tc=5.0 min CN=98 Runoff=1.01 cfs 0.081 of Reach P1: (29'-12" HDPE) Peak Depth=0.22' Max Vet=9.0 fps Inflow=1.14 cfs 0.091 of D=12.0" n=0.011 L=29.0' S=0.0697 '/' Capacity=11.11 cfs Outflow=1.13 cfs 0.091 of Reach P2: (20'-12" RCP) Peak Depth=0.43' Max Vet=9.6 fps Inflow=3.11 cfs 0.288 of D=12.0" n=0.011 L=20.0' S=0.0370 '/' Capacity=8.10 cfs Outflow=3.10 cfs 0.288 of Reach P3: (56'-12" CSP) Peak Depth=0.40' Max Vet=2.8 fps Inflow=0.82 cfs 0.063 of D=12.0" n=0.024 L=56.0' S=0.0155 T Capacity=2.41 cfs Outflow=0.80 cfs 0.063 of Reach P4: (46' - 12" HDPE) Peak Depth=0.11' Max Vet=2.3 fps Inflow=0.10 cfs 0.041 of D=12.0" n=0.011 L=45.0' S=0-0100 ? Capacity=4.21 cfs Outflow=0.10 cfs 0.041 of Reach P5: (140'-12" HDPE) Peak Depth=0.23' Max Vet=7.4 fps Inflow=1.01 cfs 0.081 of D=12.0" n=0.011 L=140.0' S=0.0436 '/' Capacity=8.79 cfs Outflow=0.99 cfs 0.081 of Reach P6: (64'-12" HDPE) Peak Depth=0.37' Max Vet=8.2 fps Inflow=2.19 cfs 0.213 of D=12.0" n=0.011 L=64.0' S=0.0313 '/' Capacity=7.44 cfs Outflow=2.18 cfs 0.213 of Reach R1: (Reach 1 -Catch Basin#1) Inflow=4.49 cfs 0.391 of Outflow=4.49 cfs 0.391 of Reach R2: (Reach 2 - Catch Basin#2) Inflow=3.11 cfs 0.288 of Outflow=3.11 cfs 0.288 of Reach R3: (Reach 3 - Catch Basin#3) Inflow=0.82 cfs 0.063 of Outflow=0.82 cfs 0.063 of 498 Chickering Road Post - test Type I// 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 53 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R4: (Reach 4 -Catch Basin #4) Inflow=1.14 cfs 0.091 of Outflow=1.14 cfs 0.091 of Reach R5: (Reach 5 -Catch Basin #5) Inflow=1.01 cfs 0.081 of Outflow=1.01 cfs 0.081 of Reach R6: (Reach 6 -SDMH) Inflow=2.19 cfs 0.213 of Outflow=2.19 cfs 0.213 of Pond CT: (7,500 Gal. Commercial Line Tank) Peak Elev=122.77' Storage=567 cf Inflow=0.51 cfs 0.041 of Outflow=0.10 cfs 0.041 of Total Runoff Area = 1.339 ac Runoff Volume= 0.391 of Average Runoff Depth = 3.51" 498 Chickering Road Post - test Type 111 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 54 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment PR: (Proposed building roof) Runoff = 0.51 cfs @ 12.07 hrs, Volume= 0.041 af, Depth= 4.26" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 10-yr Rainfall=4.50" Area (sf) CN Description 5,046 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Roof runoff Subcatchment PR: (Proposed building roof) Hydrograph 0.55 e 0.51 cfs Runoff 0.5- Type III 24-hr 10-yr 0.45 Rainfall=4.50" 0.4- Runoff Area=5,046 sf Runoff Volume=0.041 of 0.35 - Runoff-Depth=4.26" �- 0.3: Tc=5.0 min o 0.25- .; LL - _C.N=98 0.2 0.15 0.1 0.05- 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post -test Type 111 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 55 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S1-L: (Subcatchment 1 - Proposed Conditions - Lower Area) Runoff = 1.41 cfs @ 12.07 hrs, Volume= 0.103 af, Depth= 3.39" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 10-yr Rainfall=4.50" Area (sf) CN Description 6,953 79 50-75% Grass cover, Fair, HSG C 8,880 98 Paved parking & roofs 15,833 90 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.5 50 0.0600 1.8 Sheet Flow, Subcatchment- 1 Smooth surfaces n= 0.011 P2= 3.10" 0.9 245 0.0530 4.7 Shallow Concentrated Flow, Subcatchment- 1 Paved Kv= 20.3 fps 3.6 Direct Entry,Adjust for min. 5 minute Tc 5.0 295 Total Subcatchment S1-L: (Subcatchment 1 - Proposed Conditions - Lower Area) Hydrograph 1 .41 cfs Runoff Type III 24-hr 10-yr Rainfall=4.50" 3 Runoff Area=15,833 sf 1_ Runoff Volume=0';103 of Runoff Depth=3.39" 3 Flow Length=295' —° Tc=5.0 min CN=90 " � N 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type Ill 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 56 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S1-U: (Subcatchment 1 - Proposed Conditions - Upper Area) Runoff = 1.14 cfs @ 12.07 hrs, Volume= 0.091 af, Depth= 4.26" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 10-yr Rainfall=4.50" Area (sf) CN Description 11,180 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.6 50 0.0365 1.5 Sheet Flow, Subcatchment 1 - Upper Area Smooth surfaces n= 0.011 P2= 3.10" 0.5 115 0.0365 3.9 Shallow Concentrated Flow, Subcatchment 1 - Upper Area Paved Kv= 20.3 fps 3.9 Direct Entry,Adjust for min. 5 minute Tc 5.0 165 Total Subcatchment S1-U: (Subcatchment 1 - Proposed Conditions - Upper Area) Hydrograph 1 .14 Cfs Runoff Type III 24-hr 10-yr 1 Rainfall=4.50" Runoff Area=11,180 sf f Runoff Volume=0;091 of Runoff Depth=4.26" 3 Flow Length=165' ° Tc=5.0 min ` CN=98 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type H/24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 57 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S2: (Subcatchment 2 - Proposed Conditions) Runoff = 0.17 cfs @ 12.08 hrs, Volume= 0.012 af, Depth= 2.55" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 10-yr Rainfall=4.50" _ Area (sf) CN Description 2,213 79 50-75% Grass cover, Fair, HSG C 300 98 Paved parking & roofs 2,513 81 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 2.6 50 0.1400 0.3 Sheet Flow, Subcatchment- 2 Grass: Short n= 0.150 P2= 3.10" 0.2 59 0.0555 4.8 Shallow Concentrated Flow, Subcatchment-2 Paved Kv= 20.3 fps 2.2 Direct Entry, (Adjust for min. 5minute Tc) 5.0 109 Total Subcatchment S2: (Subcatchment 2 - Proposed Conditions) Hydrograph _ 0.17 cfs Runoff 0.18- Type III 24-hr 10- yp yr 0.16 Rainfall=4.50" 0.14 Runoff Area=2,513 sf N 0.12 - Runoff Volume=0.012 of Runoff-Depth=2.55 0.1- Flow Length=109' 0.08 Tc.-5.0 min ` 0.06" CW81 _ 0.04- 0.02= 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type III 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 58 H droCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer S stems 12/20/2007 Subcatchment S3-G: (Subcatchment 3 - Proposed Conditions-Grass & Shrubs) Runoff = 0.82 cfs @ 12.11 hrs, Volume= 0.063 af, Depth= 2.37" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 10-yr Rainfall=4.50" Areas CN Description 13,798 79 50-75% Grass cover, Fair, HSG C Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 4.3 50 0.0400 0.2 Sheet Flow, Subcatchment- 3 Grass: Short n= 0.150 P2= 3.10" 0.9 72 0.0332 1.3 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.8 59 0.0305 1.2 Shallow Concentrated Flow, Subcatchment- 3 Short Grass Pasture Kv= 7.0 fps 1.0 81 0.0386 1.4 Shallow Concentrated Flow, Subcatchment- 3 Short Grass Pasture Kv= 7.0 fps 0.4 42 0.0564 1.7 Shallow Concentrated Flow, Subcatchment- 3 Short Grass Pasture Kv= 7.0 fps 0.4 96 0.0428 4.2 Shallow Concentrated Flow, Subcatchment- 3 Paved Kv= 20.3 fps 7.8 400 Total Subcatchment S3-G: (Subcatchment 3 - Proposed Conditions-Grass & Shrubs) Hydrograph 0.9 0.82 ds p Runoff 0.8-- Type III 24-hr 10-yr Rainfall=4.50" 0.7 Runoff Area=13,798 sf 0.6, Runoff Volume=0.063'af Runoff Depth=2.37" ,. 0.5 Flow Length=400' 0 0.4_ Tc=7.8 min u 0.3 CN=79 0.2 0.1 0" ; 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 59 H droCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer S stems 12/20/2007 Subcatchment S3-I: (Subcatchment 3 - Proposed Conditions - Impervious Area) Runoff = 1.01 cfs @ 12.07 hrs, Volume= 0.081 af, Depth= 4.26" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 10-yr Rainfall=4.50" Areas CN Description 9,942 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description min feet ft/ft ft/sec cfs 0.6 50 0.0250 1.3 Sheet Flow, Subcatchment 3 - Impervious Area Smooth surfaces n= 0.011 P2= 3.10" 0.4 75 0.0250 3.2 Shallow Concentrated Flow, Subcatchment 3 - Impervious Area Paved Kv= 20.3 fps 4.0 Direct Entry Ad'ust for min. 5 minute Tc 5.0 125 Total Subcatchment S3-I: (Subcatchment 3 - Proposed Conditions - Impervious Area) Hydrograph 1 .01 Cfs Runoff 1- Type III 24-hr 10-yr Rainfall=4.50" Runoff Area=9,942 sf Runoff Volume=0'.081 of Runoff Depth=4.26" Flow Length--125' t 3 Y 0 Tc=5.0 min CN=98 0 ! e ircc . , c , s � c c 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 60 HvdroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P1: (29'-12" HDPE) Inflow Area = 0.257 ac, Inflow Depth = 4.26 for 10-yr event Inflow = 1.14 cfs @ 12.07 hrs, Volume= 0.091 of Outflow = 1.13 cfs @ 12.07 hrs, Volume= 0.091 af, Atten= 0%, Lag= 0.1 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 9.0 fps, Min. Travel Time= 0.1 min Avg. Velocity = 3.0 fps, Avg. Travel Time= 0.2 min Peak Depth= 0.22' @ 12.07 hrs Capacity at bank full= 11.11 cfs Inlet Invert= 121.47', Outlet Invert= 119.45' 12.0" Diameter Pipe n= 0.011 Length= 29.0' Slope= 0.0697 '/' Reach P1: (29'-12" HDPE) Hydrograph Inflow cfs Outflow Inflow Area=0. 1 .13 Peak Depth=0.22' } Max Vet=9.0 fps D=12.0" N n=0.011 3 L=29.0' C- 0 ' S=0.0697 '/' Capacity=11.11 cfsf 0 W, 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 61 H droCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P2: (20'-12" RCP) Inflow Area = 0.975 ac, Inflow Depth = 3.54" for 10-yr event Inflow = 3.11 cfs @ 12.09 hrs, Volume= 0.288 of Outflow = 3.10 cfs @ 12.09 hrs, Volume= 0.288 af, Atten= 0%, Lag= 0.1 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 9.6 fps, Min. Travel Time= 0.0 min Avg. Velocity = 3.4 fps, Avg. Travel Time= 0.1 min Peak Depth= 0.43' @ 12.09 hrs Capacity at bank full= 8.10 cfs Inlet Invert= 115.97', Outlet Invert= 115.23' 12.0" Diameter Pipe n= 0.011 Length= 20.0' Slope= 0.0370 '/' Reach P2: (20'-12" RCP) Hydrograph Inflow 3.10 cfs EJ outflow Inflow area=0. -V 3 P., Peak Depth=0.43' 3 Max Vet=9.6 fps D='12.0" .� 2 n=0.011 3 L=20.0' o - S=0.0370 T 1 Capacity=8.10 cfs 'h< 3 f 0 F , o 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post -test Type 11124-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 62 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P3: (56'-12" CSP) Inflow Area = 0.317 ac, Inflow Depth = 2.37 for 10-yr event Inflow = 0.82 cfs @ 12.11 hrs, Volume= 0.063 of Outflow = 0.80 cfs @ 12.12 hrs, Volume= 0.063 af, Atten= 2%, Lag= 0.6 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 2.8 fps, Min. Travel Time= 0.3 min Avg. Velocity = 1.0 fps, Avg. Travel Time= 0.9 min Peak Depth= 0.40' @ 12.12 hrs Capacity at bank full= 2.41 cfs Inlet Invert= 116.89', Outlet Invert= 116.02' 12.0" Diameter Pipe n= 0.024 Length= 56.0' Slope= 0.0155 '/' Reach P3: (56'-12" CSP) Hydrograph Inflow 0.9 0.80 CfS - El Outflow Inflow Area=O. 0.8= Peak Depth=0.40' 0.7_ Max Vet=2.8 fps 0.6":- D=12.0" - 0 0.5 n=0.024 a 0 0.4 L=56.0` LL - 0.3- S=0.01!55 '/' Capacity=2.41 cfs 0.2 jjjjjj�111111 1!!!! j 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 63 HydroCAD@ 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P4: (45' - 12" HDPE) Inflow Area = 0.116 ac, Inflow Depth = 4.25" for 10-yr event Inflow = 0.10 cfs @ 12.49 hrs, Volume= 0.041 of Outflow = 0.10 cfs @ 12.50 hrs, Volume= 0.041 af, Atten= 0%, Lag= 0.6 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 2.3 fps, Min. Travel Time= 0.3 min Avg. Velocity= 1.2 fps, Avg. Travel Time= 0.6 min Peak Depth= 0.11' @ 12.49 hrs Capacity at bank full= 4.21 cfs Inlet Invert= 118.58', Outlet Invert= 118.13' 12.0" Diameter Pipe n= 0.011 Length= 45.0' Slope= 0.0100 '/' Reach P4: (45' - 12" HDPE) Hydrograph Inflow 0.11 Inflow Area=O. 0.10 cfs El Outflow Peak Depth=0.11' 0.09 . _ Max Vet=2.3 fps ; 0.08- D=12.0 ' N 0.07_ 0.06 . n=0.011 L=45.0` 0 0.05 - U- S=0.0100 7, 0.04 0.03- Capacity=4.21 cfs 0.01 Q 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post -test Type 111 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 64 HydroCADO 7.00 s/n 000899 ©1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P5: (140'-12" HDPE) Inflow Area = 0.228 ac, Inflow Depth = 4.26 for 10-yr event Inflow = 1.01 cfs @ 12.07 hrs, Volume= 0.081 of Outflow = 0.99 cfs @ 12.08 hrs, Volume= 0.081 af, Atten= 2%, Lag= 0.7 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 7.4 fps, Min. Travel Time= 0.3 min Avg. Velocity = 2.5 fps, Avg. Travel Time= 1.0 min Peak Depth= 0.23' @ 12.08 hrs Capacity at bank full= 8.79 cfs Inlet Invert= 125.55', Outlet Invert= 119.45' 12.0" Diameter Pipe n= 0.011 Length= 140.0' Slope= 0.0436T Reach P5: (140'-12" HDPE) Hydrograph Inflow 1 Inflow Area=O. 0 99 cfs 0 Outflow Peak Depth=0.23' Max Vet=7.4 fps D=12.0" . n=0.011 c L=140.0' S=0.0436 '/' Capacity=8.79 cfs u 01j, . . . . .I 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type H/ 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 65 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P6: (64'-12" HDPE) Inflow Area = 0.601 ac, Inflow Depth = 4.26" for 10-yr event Inflow = 2.19 cfs @ 12.08 hrs, Volume= 0.213 of Outflow = 2.18 cfs @ 12.08 hrs, Volume= 0.213 af, Atten= 0%, Lag= 0.3 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 8.2 fps, Min. Travel Time= 0.1 min Avg. Velocity= 2.9 fps, Avg. Travel Time= 0.4 min Peak Depth= 0.37' @ 12.08 hrs Capacity at bank full= 7.44 cfs Inlet Invert= 118.02', Outlet Invert= 116.02' 12.0" Diameter Pipe n= 0.011 Length= 64.0' Slope= 0.0313 '/' Reach P6: (64'-12" HDPE) Hydrograph B Inflow Inflow Area=O. . 2.1 S cfs 0 Outflow 2 Peak Depth=0.37' ;T Max Vet=8.2 fps D=12.0" n=0.011 c L=64.0'_ S=0.0313 '/' Capacity=7.44 cfs t 0 1 1 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 66 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R1: (Reach 1 - Catch Basin #1) Inflow Area = 1.339 ac, Inflow Depth = 3.50" for 10-yr event Inflow = 4.49 cfs @ 12.09 hrs, Volume= 0.391 of Outflow = 4.49 cfs @ 12.09 hrs, Volume= 0.391 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R1: (Reach 1 - Catch Basin #1) Hydrograph p Inflow 5 4.49 Cfs . Outflow Inflow Area=1 . 4 3- 3 F 0 2_ 1 f� 0 , , , , 0 2 4 6 8 10 12 14 16 18 20 i2 24 Time (hours) 498 Chickering Road Post -test Type /// 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 67 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R2: (Reach 2 - Catch Basin #2) Inflow Area = 0.975 ac, Inflow Depth = 3.54" for 10-yr event Inflow = 3.11 cfs @ 12.09 hrs, Volume= 0.288 of Outflow = 3.11 cfs @ 12.09 hrs, Volume= 0.288 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R2: (Reach 2 - Catch Basin #2) Hydrograph --- 0 Inflow 3.1 cfs 0 Outflow Inflow Area=O. 3 s' 2 v Q' 1 x 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type /// 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 68 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer SVstems 12/20/2007 Reach R3: (Reach 3 - Catch Basin #3) Inflow Area = 0.317 ac, Inflow Depth = 2.37 for 10-yr event Inflow = 0.82 cfs @ 12.11 hrs, Volume= 0.063 of Outflow = 0.82 cfs @ 12.11 hrs, Volume= 0.063 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R3: (Reach 3 - Catch Basin #3) Hydrograph D Inflow 0.9 Inflow Area=O. 0.82 CfS Outflow 0.8 - 0.7-- o 3 0.4= 0.3- 0.2 P 0.1 ✓ 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type Ill 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 69 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R4: (Reach 4 - Catch Basin #4) Inflow Area = 0.257 ac, Inflow Depth = 4.26" for 10-yr event Inflow = 1.14 cfs @ 12.07 hrs, Volume= 0.091 of Outflow = 1.14 cfs @ 12.07 hrs, Volume= 0.091 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R4: (Reach 4 - Catch Basin #4) Hydrograph M Inflow 1 .1 4Cfs Q Outflow Inflow Area=j-zut C F� 1 fA x y z 0 W a 0 I r r r I r r I r r r 1 r r r r a c r I 1 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 70 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R5: (Reach 5 - Catch Basin #5) Inflow Area = 0.228 ac, Inflow Depth = 4.26" for 10-yr event Inflow = 1.01 cfs @ 12.07 hrs, Volume= 0.081 of Outflow = 1.01 cfs @ 12.07 hrs, Volume= 0.081 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R5: (Reach 5 - Catch Basin #5) Hydrograph Q Inflow 1 .01 Cfs D outflow Inflow Area-J.440 3 o FL r 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post -test Type /// 24-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 71 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R6: (Reach 6 - SDMH) Inflow Area = 0.601 ac, Inflow Depth = 4.26" for 10-yr event Inflow = 2.19 cfs @ 12.08 hrs, Volume= 0.213 of Outflow = 2.19 cfs @ 12.08 hrs, Volume= 0.213 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R6: (Reach 6 - SDMH) Hydrograph p Inflow 2.19Cfs El Outflow Inflow Area= := 2 W� PS" V 3 0 1_ e f „ . , r. 0 2 4 6 8 10 12 14 1�6 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 10-yr Rainfall=4.50" Prepared by Merrimack Engineering Services Page 72 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Pond CT: (7,500 Gal. Commercial Line Tank) Inflow Area = 0.116 ac, Inflow Depth = 4.26" for 10-yr event Inflow = 0.51 cfs @ 12.07 hrs, Volume= 0.041 of Outflow = 0.10 cfs @ 12.49 hrs, Volume= 0.041 af, Atten= 80%, Lag= 25.1 min Primary = 0.10 cfs @ 12.49 hrs, Volume= 0.041 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 122.77' @ 12.49 hrs Surf.Area= 0 sf Storage= 567 cf Plug-Flow detention time= 51.5 min calculated for 0.041 of(100% of inflow) Center-of-Mass det. time= 49.4 min ( 798.0 -748.6 ) # Invert Avail Storage Storage Description 1 118.83' 1,008 cf Custom Stage Data Listed below Elevation Cum.Store (feet) (cubic-feet) 118.83 0 122.33 504 125.83 1,008 # Routing Invert Outlet Devices 1 Primary 118.83' 1.0" Vert. Orifice/Grate X 2.00 C= 0.600 Primary OutFlow Max=0.10 cfs @ 12.49 hrs HW=122.76' (Free Discharge) t1=0rifice/Grate (Orifice Controls 0.10 cfs @ 9.5 fps) Pond CT: (7,500 Gal. Commercial Line Tank) Hydrograph 0.51 cfs EM Inflow El 0.55-- Inflow Area=0.116 ac Primary 0.5= Peak Elev=122.77' 0.45- Storage=567 cf 0.4 J 0.35--. -- 0.37 0 0.25 U_ 0.2= 0.15= 0.10 cfs 0.1 0.05= Q 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type ///24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 73 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points Runoff by SCS TR-20 method, UH=SCS Reach routing by Stor-Ind+Trans method - Pond routing by Stor-Ind method Subcatchment PR: (Proposed building roof) Runoff Area=5,046 sf Runoff Depth=6.16" Tc=5.0 min CN=98 Runoff=0.73 cfs 0.059 of Subcatchment S1-L: (Subcatchment 1 -Proposed Conditions Runoff Area=15.833 sf Runoff Depth=5.23" Flow Length=295' Tc=5.0 min CN=90 Runoff=2.13 cfs 0.159 of Subcatchment S1-U: (Subcatchment 1 - Proposed Conditions Runoff Area=11.180 sf Runoff Depth=6.16" Flow Length=165' Tc=5.0 min CN=98 Runoff=1.62 cfs 0.132 of Subcatchment S2: (Subcatchment 2 - Proposed Conditions) Runoff Area=2,513 sf Runoff Depth=4.25" Flow Length=109' Tc=5.0 min CN=81 Runoff=0.29 cfs 0.020 of Subcatchment S3-G: (Subcatchment 3 - Proposed Conditions Runoff Area=13.798 sf Runoff Depth=4.03" Flow Length=400' Tc=7.8 min CN=79 Runoff=1.39 cfs 0.106 of Subcatchment S3-I: (Subcatchment 3 - Proposed Conditions - I Runoff Area=9,942 sf Runoff Depth=6.16" Flow Length=125' Tc=5.0 min CN=98 Runoff=1.44 cfs 0.117 of Reach P1: (29'-12" HDPE) Peak Depth=0.26' Max Vet=10.0 fps Inflow=1.62 cfs 0.132 of D=12.0" n=0.011 L=29.0' S=0.0697 '/' Capacity=11.11 cfs Outflow=1.62 cfs 0.132 of Reach P2: (20'-12" RCP) Peak Depth=0.55' Max Vet=10.7 fps Inflow=4.68 cfs 0.435 of D=12.0" n=0.011 L=20.0' S=0.0370 '/' Capacity=8.10 cfs Outflow=4.67 cfs 0.435 of Reach P3: (56'-12" CSP) Peak Depth=0.54' Max Vet=3.2 fps Inflow=1.39 cfs 0.106 of D=12.0" n=0.024 L=56.0' S=0.0155 T Capacity=2.41 cfs Outflow=1.36 cfs 0.106 of Reach P4: (45' - 12" HDPE) Peak Depth=0.12' Max Vet=2.4 fps Inflow=0.13 cfs 0.059 of D=12.0" n=0.011 L=45.0' S=0.0100 T Capacity=4.21 cfs Outflow=0.13 cfs 0.059 of Reach P5: (140'-12" HDPE) Peak Depth=0.27' Max Vet=8.2 fps Inflow=1.44 cfs 0.117 of D=12.0" n=0.011 L=140.0' S=0.0436 '/' Capacity=8.79 cfs Outflow=1.41 cfs 0.117 of Reach P6: (64'-12" HDPE) Peak Depth=0.45' Max Vet=9.0 fps Inflow=3.11 cfs 0.308 of D=12.0" n=0.011 L=64.0' S=0.0313 '/' Capacity=7.44 cfs Outflow=3.10 cfs 0.308 of Reach R1: (Reach 1 -Catch Basin #1) Inflow=6.75 cfs 0.593 of Outflow=6.75 cfs 0.593 of Reach R2: (Reach 2 -Catch Basin #2) Inflow=4.68 cfs 0.435 of Outflow=4.68 cfs 0.435 of Reach R3: (Reach 3 - Catch Basin #3) Inflow=1.39 cfs 0.106 of Outflow=1.39 cfs 0.106 of 498 Chickering Road Post -test Type 111 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 74 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R4: (Reach 4 -Catch Basin #4) Inflow=1.62 cfs 0.132 of Outflow=1.62 cfs 0.132 of Reach R5: (Reach 5 -Catch Basin #5) Inflow=1.44 cfs 0.117 of Outflow=1.44 cfs 0.117 of Reach R6: (Reach 6 -SDMH) Inflow=3.11 cfs 0.308 of Outflow=3.11 cfs 0.308 of Pond CT: (7,500 Gal. Commercial Line Tank) Peak Elev=124.91' Storage=875 cf Inflow=073 cfs 0.059 of Outflow=0.13 cfs 0.059 of Total Runoff Area = 1.339 ac Runoff Volume = 0.594 of Average Runoff Depth =5.32" 498 Chickering Road Post -test Type ///24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 75 HydroCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment PR: (Proposed building roof) Runoff = 0.73 cfs @ 12.07 hrs, Volume= 0.059 af, Depth= 6.16" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 100-yr Rainfall=6.40" Area (sf) CN Description 5,046 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 5.0 Direct Entry, Roof runoff Subcatchment PR: (Proposed building roof) Hydrograph 0.8 - 0.73 Cfs 0 Runoff 0.7 Type 11124 h r 100=yr Rainfall=6.40" 0.6 Runoff Area=5,046 sf x Runoff Volume=0.059 of 0.5-, Runoff Depth=6.16'° 3 0.4= Tc=5.0 min —° CN=98 0.3. 0.2-- 0.1 - 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 900-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 76 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S1-L: (Subcatchment 1 - Proposed Conditions - Lower Area) Runoff = 2.13 cfs @ 12.07 hrs, Volume= 0.159 af, Depth= 5.23" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 100-yr Rainfall=6.40" Area (sf) CN Description 6,953 79 50-75% Grass cover, Fair, HSG C 8,880 98 Paved parking & roofs 15,833 90 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.5 50 0.0600 .1.8 Sheet Flow, Subcatchment- 1 Smooth surfaces n= 0.011 P2= 3.10" 0.9 245 0.0530 4.7 Shallow Concentrated Flow, Subcatchment- 1 Paved Kv= 20.3 fps 3.6 Direct Entry, Adjust for min. 5 minute Tc 5.0 295 Total Subcatchment S1-L: (Subcatchment 1 - Proposed Conditions - Lower Area) Hydrograph 2.13 cfs 0 Runoff Type III 24-hr 400-yr 2 Rainfall=6.40" Runoff Area=15,833 sf' { s� .. Runoff Volume=0'.159 of Runoff Depth=5.23" 3 Flow Length=295' 0 1 Tc=5.0 min LL ' CN=90 ` ',mF 0 e 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type Ill 24-hr 100-yr Rainfall=6.40° Prepared by Merrimack Engineering Services Page 77 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S1-U: (Subcatchment 1 - Proposed Conditions - Upper Area) Runoff = 1.62 cfs @ . 12.07 hrs, Volume= 0.132 af, Depth= 6.16" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 100-yr Rainfall=6.40" _ Area (sf) CN Description 11,180 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.6 50 0.0365 1.5 Sheet Flow, Subcatchment 1 -Upper Area Smooth surfaces n= 0.011 P2= 3.10" 0.5 115 0.0365 3.9 Shallow Concentrated Flow, Subcatchment 1 - Upper Area Paved Kv= 20.3 fps 3.9 Direct Entry, Adjust for min. 5 minute Tc 5.0 165 Total Subcatchment S1-U: (Subcatchment 1 - Proposed Conditions - Upper Area) Hydrograph 1 .62 Cfs Runoff Type III 24-hr 100-yr Rainfal l=6.40" Runoff Area=11,180 sf Runoff Volume=0'.132 of 1 Runoff Depth=6.16" f 3 Flow Length=165' —° Tc=5.0 min v_ CN=98 0 , . . 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type ///24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 78 HydroCAD®7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S2: (Subcatchment 2 - Proposed Conditions) Runoff = 0.29 cfs @ 12.07 hrs, Volume= 0.020 af, Depth= 4.25" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 100-yr Rainfall=6.40° Area (sf) CN Description 2,213 79 50-75% Grass cover, Fair, HSG C 300 98 Paved parking & roofs 2,513 81 Weighted Average Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 2.6 50 0.1400 0.3 Sheet Flow, Subcatchment-2 Grass: Short n= 0.150 P2= 3.10" 0.2 59 0.0555 4.8 Shallow Concentrated Flow, Subcatchment-2 Paved Kv= 20.3 fps 2.2 Direct Entry, (Adjust for min. 5minute Tc) 5.0 109 Total Subcatchment S2: (Subcatchment 2 - Proposed Conditions) Hydrograph 0.3 0.29 cfs 0 Runoff Type III 24-hr 100'-yr 0.25 Rainfall=6.40" Runoff Area=2,51'3 sf ; ^ 0.2 - Runoff Volume=0.020 of Runoff Depth=4.25" ,. Flow Length=109' c 0.15- LL - Tc 5.0 min 0.1 CN,=8.1 0.05 � 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 79 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S3-G: (Subcatchment 3 - Proposed Conditions-Grass & Shrubs) Runoff = 1.39 cfs @ 12.11 hrs, Volume= 0.106 af, Depth= 4.03" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 100-yr Rainfall=6.40" Area (sf) CN Description 13,798 79 50-75% Grass cover, Fair, HSG C Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 4.3 50 0.0400 0.2 Sheet Flow, Subcatchment - 3 Grass: Short n= 0.150 P2= 3.10" 0.9 72 0.0332 1.3 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.8 59 0.0305 1.2 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 1.0 81 0.0386 1.4 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.4 42 0.0564 1.7 Shallow Concentrated Flow, Subcatchment-3 Short Grass Pasture Kv= 7.0 fps 0.4 96 0.0428 4.2 Shallow Concentrated Flow, Subcatchment-3 Paved Kv= 20.3 fps 7.8 400 Total Subcatchment S3-G: (Subcatchment 3 - Proposed Conditions-Grass & Shrubs) Hydrograph 1 .39 cfs Runoff Type III 24-hr 100-yr Rainfall=6.40" �x Runoff Area=13,798 sf' 1 Runoff Volume=0'.106 of 4 Runoff Depth=4.03" Flow Length=400' o Tc=7.8 min CN=79 s. 0 2 4 6 8_'10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 80 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Subcatchment S3-I: (Subcatchment 3 - Proposed Conditions - Impervious Area) Runoff = 1.44 cfs @ 12.07 hrs, Volume= 0.117 af, Depth= 6.16" Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Type III 24-hr 100-yr Rainfall=6.40" Area (sf) CN Description 9,942 98 Paved parking & roofs Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.6 50 0.0250 1.3 Sheet Flow, Subcatchment 3 - Impervious Area Smooth surfaces n= 0.011 P2= 3.10" 0.4 75 0.0250 3.2 Shallow Concentrated Flow, Subcatchment 3 - Impervious Area Paved Kv= 20.3 fps 4.0 Direct Entry, Adjust for min. 5 minute Tc 5.0 125 Total Subcatchment S3-I: (Subcatchment 3 - Proposed Conditions - Impervious Area) Hydrograph 1 .44 cfs Runoff Type 111 24-h r 100-yr -; Rainfall=6.40" Runoff Area 9,942 sf f 1 Runoff Volume=0.117 of {, Runoff Depth=6.16" 3 Flow Length=125' ° Tc=5.0 min ` CN=98 e 0 E 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 81 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P1: (29'-12" HDPE) Inflow Area = 0.257 ac, Inflow Depth = 6.16" for 100-yr event Inflow = 1.62 cfs @ 12.07 hrs, Volume= 0.132 of Outflow = 1.62 cfs @ 12.07 hrs, Volume= 0.132 af, Atten= 0%, Lag= 0.1 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 10.0 fps, Min. Travel Time= 0.0 min Avg. Velocity = 3.3 fps, Avg. Travel Time= 0.1 min Peak Depth= 0.26' @ 12.07 hrs Capacity at bank full= 11.11 cfs Inlet Invert= 121.47', Outlet Invert= 119.45' 12.0" Diameter Pipe n= 0.011 Length= 29.0' Slope= 0.0697 '/' Reach P1: (29'-12" HDPE) Hydrograph Inflow Inflow Area=O. 1 .62 Cfs 0 Outflow Peak Depth=0.26' , Max VeI=10.0 fps r D=12.x" 9 n=0.011 3 L=29.0' - O Afp �- S=0.0697 T Capacity=11.11 cfs 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 82 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P2: (20'-12" RCP) Inflow Area = 0.975 ac, Inflow Depth = 5.35" for 100-yr event Inflow = 4.68 cfs @ 12.09 hrs, Volume= 0.435 of Outflow = 4.67 cfs @ 12.09 hrs, Volume= 0.435 af, Atten= 0%, Lag= 0.1 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 10.7 fps, Min. Travel Time= 0.0 min Avg. Velocity = 3.8 fps, Avg. Travel Time= 0.1 min Peak Depth= 0.55' @ 12.09 hrs Capacity at bank full= 8.10 cfs Inlet Invert= 115.97', Outlet Invert= 115.23' 12.0" Diameter Pipe n= 0.011 Length= 20.0' Slope= 0.0370 '/' Reach P2: (20'-12" RCP) Hydrograph Inflow 5 4.67 cfs 0 Outflow Inflow Area=O. Peak Depth=0.55' 4 Max Vet=10.7 fps D=12.0" 3- - n=0.011 3 L=20.0' 2 S=0.0370 '/' P Capacity=8.10 cfs X 0 4p - -W. , 1 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 83 HydroCAD@)7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P3: (56'-12" CSP) Inflow Area = 0.317 ac, Inflow Depth = 4.03" for 100-yr event Inflow = 1.39 cfs @ 12.11 hrs, Volume= 0.106 of Outflow = 1.36 cfs @ 12.12 hrs, Volume= 0.106 af, Atten= 2%, Lag= 0.5 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 3.2 fps, Min. Travel Time= 0.3 min Avg. Velocity = 1.2 fps, Avg. Travel Time= 0.8 min Peak Depth= 0.54' @ 12.12 hrs Capacity at bank full= 2.41 cfs Inlet Invert= 116.89', Outlet Invert= 116.02' 12.0" Diameter Pipe n= 0.024 Length= 56.0' Slope= 0.0155T Reach P3: (56'-12" CSP) Hydrograph Inflow Inflow Area=O. 1 .36 CfS Outflow Peak Depth=0.54' Max Vet=3.2 fps 1 D='12.0" n=0.024 3 L=56.0' o �- S=0.0155 '/' Capacity=2.41 cfs WINUM 0 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 84 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P4: (45' - 12" HDPE) Inflow Area= 0.116 ac, Inflow Depth = 6.14" for 100-yr event Inflow = 0.13 cfs @ 12.52 hrs, Volume= 0.059 of Outflow = 0.13 cfs @ 12.53 hrs, Volume= 0.059 af, Atten= 0%, Lag= 0.6 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 2.4 fps, Min. Travel Time= 0.3 min Avg. Velocity = 1.4 fps, Avg. Travel Time= 0.5 min Peak Depth= 0.12' @ 12.52 hrs Capacity at bank full= 4.21 cfs Inlet Invert= 118.58', Outlet Invert= 118.13' 12.0" Diameter Pipe n= 0.011 Length= 45.0' Slope= 0.0100 '/' Reach P4: (45' - 12" HDPE) Hydrograph Inflow 0.14 _ 0.13 CfS 0 Outflow Inflow Area=O. 0.12 Peak -De th-0.12 p ' Max Vel-_ .24 f. s p 0.1 D=12.0" N 0.08--_ n=0.011 3 - L=45.0` ;r 0.06- S=0.0100 ,P 0.04- Capacity=4.21 cf , g, 0.02- ,_ 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 85 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P5: (140'-12" HDPE) Inflow Area = 0.228 ac, Inflow Depth = 6.16" for 100-yr event Inflow = 1.44 cfs @ 12.07 hrs, Volume= 0.117 of Outflow = 1.41 cfs @ 12.08 hrs, Volume= 0.117 af, Atten= 2%, Lag= 0.6 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 8.2 fps, Min. Travel Time= 0.3 min Avg. Velocity = 2.7 fps, Avg. Travel Time= 0.9 min Peak Depth= 0.27' @ 12.08 hrs Capacity at bank full= 8.79 cfs Inlet Invert= 125.55', Outlet Invert= 119.45' 12.0" Diameter Pipe n= 0.011 Length= 140.0' Slope= 0.0436 '/' Reach P5: (140'-12" HDPE) Hydrograph Inflow Inflow Area=O. 1..41 CfS 13 Outflow Peak Depth=0.27' ' Max Vet=8.2 fps D=12.0" 1 n=0.011 c L=140.0' S=0.0436 '/' Capacity=8.79 cfs k R E 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 86 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach P6: (64'-12" HDPE) Inflow Area = 0.601 ac, Inflow Depth = 6.15" for 100-yr event Inflow = 3.11 cfs @ 12.08 hrs, Volume= 0.308 of Outflow = 3.10 cfs @ 12.08 hrs, Volume= 0.308 af, Atten= 0%, Lag= 0.3 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Max. Velocity= 9.0 fps, Min. Travel Time= 0.1 min Avg. Velocity = 3.3 fps, Avg. Travel Time= 0.3 min Peak Depth= 0.45' @ 12.08 hrs Capacity at bank full= 7.44 cfs Inlet Invert= 118.02', Outlet Invert= 116.02' 12.0" Diameter Pipe n= 0.011 Length= 64.0' Slope= 0.0313 '/' Reach P6: (64'-12" HDPE) Hydrograph Inflow Inflow Area=O. 3.10 .cfs El Outflow 3 Peak Depth=0.45' f Max Vet=9.0 fps .. D=12.0" . 2 n=0.011 ff. 3 L=64.0' o LL Z=0.0313 '/' 1 Capacity=7.44 cfs 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 87 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R1: (Reach 1 - Catch Basin #1) Inflow Area = 1.339 ac, Inflow Depth = 5.32" for 100-yr event Inflow = 6.75 cfs @ 12.09 hrs, Volume= 0.593 of Outflow = 6.75 cfs @ 12.09 hrs, Volume= 0.593 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R1: (Reach 1 - Catch Basin #1) Hydrograph Inflow - 6.75 .cfs a outflow 7 Inflow Area=1 6- 5 IS- 4 f 3 - 2 � 1 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 88 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R2: (Reach 2 - Catch Basin #2) Inflow Area = 0.975 ac, Inflow Depth = 5.35" for 100-yr event Inflow = 4.68 cfs @ 12.09 hrs, Volume= 0.435 of Outflow = 4.68 cfs @ 12.09 hrs, Volume= 0.435 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R2: (Reach 2 - Catch Basin #2) Hydrograph 0 Inflow 5 4.68 Cfs p Outflow Inflow Area-O..7, 4 0- 0 3 3 o u. 2 5 1 0 i o 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type Ill 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 89 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R3: (Reach 3 - Catch Basin #3) Inflow Area = 0.317 ac, Inflow Depth = 4.03" for 100-yr event Inflow = 1.39 cfs @ 12.11 hrs, Volume= 0.106 of Outflow = 1.39 cfs @ 12.11 hrs, Volume= 0.106 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R3: (Reach 3 - Catch Basin #3) Hydrograph 0 Inflow Inflow Area=O. 1 .39 Cfs p Outflow Yf Q 0 2 4 6 8 10 12 14 ­ '1'6' ' ­1'8­' 20 22 24 Time (hours) 498 Chickering Road Post -test Type 111 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 90 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R4: (Reach 4 - Catch Basin #4) Inflow Area = 0.257 ac, Inflow Depth = 6.16 for 100-yr event Inflow = 1.62 cfs @ 12.07 hrs, Volume= 0.132 of Outflow = 1.62 cfs @ 12.07 hrs, Volume= 0.132 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R4: (Reach 4 - Catch Basin #4) Hydrograph Inflow 1 .62 cfs 0 outflow Inflow Area-L r 3 3 o > u. 0 r S , > , , r , i 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 111 24-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 91 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R5: (Reach 5 - Catch Basin #5) Inflow Area = 0.228 ac, Inflow Depth = 6.16" for 100-yr event Inflow = 1.44 cfs @ 12.07 hrs, Volume= 0.117 of Outflow = 1.44 cfs @ 12.07 hrs, Volume= 0.117 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R5: (Reach 5 - Catch Basin #5) Hydrograph M Inflow 1 .44 Cfs E1 outflow Inflow Area-j.zzu r v o lr jY. 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 92 HydroCAD®7 00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Reach R6: (Reach 6 - SDMH) Inflow Area = 0.601 ac, Inflow Depth = 6.15" for 100-yr event Inflow = 3.11 cfs @ 12.08 hrs, Volume= 0.308 of Outflow = 3.11 cfs @ 12.08 hrs, Volume= 0.308 af, Atten= 0%, Lag= 0.0 min Routing by Stor-Ind+Trans method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Reach R6: (Reach 6 - SDMH) Hydrograph Inflow Inflow Area= 3.11 cfs 0 Outflow 3 N ek. 2 v - & k O LL 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) 498 Chickering Road Post - test Type 11124-hr 100-yr Rainfall=6.40" Prepared by Merrimack Engineering Services Page 93 HydroCADO 7.00 s/n 000899 © 1986-2003 Applied Microcomputer Systems 12/20/2007 Pond CT: (7,500 Gal. Commercial Line Tank) Inflow Area = 0.116 ac, Inflow Depth = 6.16" for 100-yr event Inflow = 0.73 cfs @ 12.07 hrs, Volume= 0.059 of Outflow = 0.13 cfs @ 12.52 hrs, Volume= 0.059 af, Atten= 82%, Lag= 26.8 min Primary = 0.13 cfs @ 12.52 hrs, Volume= 0.059 of Routing by Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs Peak Elev= 124.91' @ 12.52 hrs Surf.Area= 0 sf Storage= 875 cf Plug-Flow detention time= 64.4 min calculated for 0.059 of(99% of inflow) Center-of-Mass det. time= 62.3 min ( 805.2 - 742.9 ) # Invert Avail Storage Storage Description 1 118.83' 1,008 cf Custom Stage Data Listed below Elevation Cum.Store (feet) (cubic-feet) 118.83 0 122.33 504 125.83 1,008 # Routing Invert Outlet Devices 1 Primary 118.83' 1.0"Vert. Orifice/Grate X 2.00 C= 0.600 Primary OutFlow Max=0.13 cfs @ 12.52 hrs HW=124.90' (Free Discharge) t1=Orifice/Grate (Orifice Controls 0.13 cfs @ 11.8 fps) Pond CT: (7,500 Gal. Commercial Line Tank) Hydrograph 0.73 Cfs Inflow 0.8� Primary Inflow Area=0.116 ac . 0.7 ..Peak E lev-124.91' 0.6 Storage=875 cf w 0.5 3 0.4- 0 0.3- 0.2 -- 0.13 cfs 0.1 0 2 4 6 8 10 12 14 16 18 20 22 24 Time (hours) PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 4.3 > Storm Drainage Pipe Design — The Rational Method Merrimack Engineering Services, Inc. Section 4—Page 5 Printed: December 14,2007 PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 4.3.1 > Weighted Runoff Coefficient Calculation Calculation For Runoff Determination For Small Areas Drainage Total Area impervious C=0.90 Grass C=0.20 Sum Structure (ac) Area (ac) CA Area(ac) CA CA CW CB-1 1.179 rO.741 0.667 0.438 0.0876 0.755 0.64 CB-2 0.859 521 0.469 0.338 0.0676 0.537 0.63 CB-3 0.317 - - 0.317 0.0634 0.063 0.20 CB-4 0.257 257 0.231 - - 0.231 0.90 CB-5 0.228 228 0.205 - - 0.205 0.90 Merrimack Engineering Services, Inc. Section 4—Page 6 Printed: December 14,2007 0 C> N M O M O M W 0 0 0 0 0 0 d y P. 07 4a.' Ir) N N Q V 00 h M 0 V: N •a O va N C\ N of [-_ f3, r�� � _1 r O O 'c1• --� a w 0 0 0 0 0 0 0 �i O W .G a,i - � on0000000 0U6 0oo0CD O L) N "O O d- O o', O 0 � i-. It d d0 d0 N c kr; V, vi t 00 z `" U � 0 C:, U O � O � 0 0 Uj -ice Utj h w) kn in V � o 0 0 C) o V � o ° 000 u N 1p Q\ o\ o\ 00000 U OO " NN 00000 in v') N ci �i � � V C� .� Ay'' p� pa � . � G� � A O� N 00 � � Q l� oo [� vi � +' Ga y �+ i I�D kn oo 00 O O > O a\ N O [- kn vl r+ V M r- O > cz N o\ o\ "o o" m C� O 0Ln O D Q , CC y . U U uQ� W '�1 A � `"" UUQ PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 5.0 > APPENDIX Merrimack Engineering Services,Inc. Section 5—Page 1 Printed: December 14,2007 PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 5.1 > RAINFALL DATA MAPS Merrimack Engineering Services,Inc. Section 5 —Page 2 Printed: December 14,2007 PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 5.1 > Rainfall Data Map 2:8' ESSEX FRANKLIN DDLESEX �.2� MI ' L SUFFOLK N11hiPSF11RE / wOAGESTER ov 4�* HA4 VEN 3 6,� RAINFALL DATA MaP, , MST LE' 2=YEAR 2.4 HOUR PRECIPITATION (INCHES) rQ bUKES NANTUCKET » 4 biz d 2 4 3„ 4.4" _ essex ­46" FRANKLIN -` iAipbt:E�EX - � SUFFOLK 4:7' a. NANPSHIRE WQRCESTER.. �pJl" v: NAMt+PEN ,AO R�aI�dFALL. 1��1YA �AAF BAitNST LE 10-YEAR, "Z4.HOUR (?RECIPIT'ATIOtJ wVCNI?5) DUKES d . NANTUCKET, Merrimack Engineering Services, Inc. Section 5—Page 3 Printed; December 14,2007 PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 5.1 > Rainfall Data Map "sue r �" �,-, y, ?� f1s 3.s �.%+ T .'3 � 5✓ < .., r�-� f 3 [ Merrimack Engineering Services, Inc. Section 5—Page 4 Printed: December 14,2007 PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 5.2 > NATIONAL RESOURCES CONSERVATION SERVICE- SOIL DESCRIPTION WITH CLASSIFICATION Merrimack Engineering Services,Inc. Section 5—Page 5 Printed: December 14,2007 PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS Soils description: Woodbridge series soils The Woodbridge series consists of coarse-loamy,mixed,mesic Typic Fragiochrepts. These deep and moderately well drained soils are on uplands.The soils formed in compact glacial till derived mainly from schist and granite. Slopes range from 0 to 25 percent. Woodbridge soils formed in the same kind of material as well drained Paxton soils,poorly drained Ridgebury soils,and very poorly drained Whitman soils.They are similar to the Scituate,and Sutton soils. Woodbridge soils have less sand in the substratum than the Scituate soils.They have a fragipan,which the Sutton soils do not have. Typical pedon of Woodbridge fine sandy loam,3 to 8 percent slopes, in the town of Georgetown,in a field 700 feet southwest of the junction of Andover and West Streets: Ap-0 to 9 inches;very dark grayish brown(l OYR 3/2)fine sandy loam;very weak fine and medium granular structure; friable;many fine roots; 10 percent angular coarse fragments 2 to 20 millimeters in diameter;medium acid; abrupt smooth boundary. B21-9 to 16 inches;yellowish brown(I OYR 5/4)fine sandy loam that fades to light olive brown(2.5Y 5/4)with depth; very weak fine and medium granular structure;friable;common fine roots;many small worm holes filled with very dark grayish brown material from Ap horizon; 10 percent angular gravel;medium acid;clear wavy boundary. B22-16 to 23 inches;olive brown(2.5Y 4/4)fine sandy loam; common fine distinct gray to light gray(5Y 6/1)and yellowish brown(I OYR 5/6)mottles;weak medium subangular blocky structure;friable;few fine herbaceous roots; 10 percent angular gravel,3 percent stones;medium acid;abrupt wavy boundary. A'2-23 to 26 inches; light olive gray(5Y 6/2)fine sandy loam; common fine distinct strong brown(7.5YR 516)and yellowish red(5YR 5/6)mottles;weak medium subangular blocky structure;firm; few fine roots; 15 percent angular and subrounded gravel, 3 percent stones;strongly acid;abrupt wavy boundary. Cx-26 to 60 inches;light olive brown(2.5Y 5/4)fine sandy loam;common fine distinct strong brown(7.5YR 5/6) mottles;moderate to strong thick platy structure; very firm; 10 percent angular gravel,3 percent stones;strongly acid. The depth to the firm or very firm fragipan ranges from 21 to 29 inches.The depth to mottling ranges 16 to 29 inches. The content of coarse fragments in the solum and substratum ranges from 5 to 30 percent.The reaction ranges from strongly acid to medium acid. The surface layer is slightly acid to neutral where limed. The Ap horizon has hue of 10YR,value of 3 or 4,and chroma of 2 or 3.The Al horizon is 1 unit lower in value or chroma or both.The texture of the A horizon is fine sandy loam or loam. The B21 horizon has hue of 7.5YR or I OYR,value of 4 or 5,and chroma of 4 to 6. It is fine sandy loam or loam. The B22 horizon has hue of l OYR or 2.5Y with value and chroma of 4 to 6 and is distinctly mottled. It is sandy loam,fine sandy loam,or loam. Some pedons do not have an A'2 horizon. The Cx horizon has hue of 2.5Y or 5Y,value of 4 or 5,and chroma of 3 or 4. It is sandy loam,fine sandy loam,or loam or thin gravely analogues. Merrimack Engineering Services,Inc. Section 5-Page 6 Printed: December 14,2007 x F Tsa 8 i � k t xs _ o �« 3 0 rn I C ^ O s- Y N � � •Ci O N^• c., Ln I i Ko O _ Z r p a Cd u K g T c y w w 10 y O va � "o n m m o. ...._ „ v q H = 7 O N E V O tA N 6 N H En c Y t7 f p O v � o m 01 r a S J .= .e N d m aq. w u Location: v� ' '. Onncr's Alame: l�'�� � l £� ro� .. MnplPared: Addccss; Installers Tel a: New Puo V_Repslr Date: I Wetlands -- Zone II— SailSdbol LIC2 SoA&mevtOW07311 Q Deep-Obsu vatfpn Hole Logs EleM'atlon Depth Son n6an Soil Twure Sell Color - Sell Mottling. %GrAV 4 Stones,etc Z - � �Jqr" „ 5T Nw=t Material.'�'11i�* Depth e Bed to*,= 6tmtdlie�ZYsurladeHat� � �fieepbtt=fceptlftF�a��HGtiT ��^e`�°� G t— 7,5-� % Val r u .- . tc�t,� • putt MaterW �t 1. Depth to ae+n.ac °` sa.ag ter terra Elm say -- Nit=rt=to F.=EMGtivt_ Date Percolation Tests i Observation Holef Depth of Pere Stut PrMoal: Tinge at 12 Time at 9"' Time at 6" Time(9"-6'�� ' Rate MinlInch = r r Performed BP 6 Witnessed Bt^ �-- o -- PROPOSED RETAIL FACILITY NORTHANDOVER, MASSACHUSETTS < SECTION 6.0 > DRAINAGE AREA MAPS Merrimack Engineering Services,Inc. Section 6—Page I Printed: December 14,2007