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Home My WebLink AboutAddendum to Drainage Study 1999 ADDENDUM TO DRAINAGE STUDY FOR NORTH ANDOVER COMMERCE CENTER CLARK STREET NORTH ANDOVER, MASSACHUSETTS January 20, 1999 Prepared For: ' One Clark North Andover, LLC 121 Middle Street Portland, Maine 04101 Prepared By: Appledore Engineering, Inc. 600 State Street, Suite D. Portsmouth, New Hampshire 03801 (1275-ds'i.doc) North Andover Commerce Center Clark Street North Andover, Massachusetts TABLE OF CONTENTS 1.0 Summary 2.0 Calculation Methods 3.0 Pre-Development Condition 4.0 Post-Development Condition Appendix A: Supporting Calculations Pre-Development Calculations Post-Development Calculations Post-Development On-site Structure Analysis Appendix B. Charts, Etc. North Andover Commerce Center Table of Contents Clark Street North Andover, Massachusetts 1.0 - SUMMARY This Drainage Study was completed to assess the pre and post-development runoff rates for the proposed development and to assess the proper function of the detention pond used to mitigate adverse impacts of runoff and sediment due to development. 2.1 - Pre- and Post-Development Flow Comparison: All of the runoff from the impervious areas currently enters a closed drainage system and discharges directly the wetland along the northern property line. Almost all of the post development runoff will enter a constructed wetland prior to discharging to the wetland. This constructed wetland will provide stormwater treatment as well detention to mitigate peak flows. Table 1 compares pre and post-development peak runoff rates for the 1-year, 2-year, 10-year, and the 100-year storm events. As detailed in Table 1 the drainage system has been designed to reduce the post-development runoff rate for all four stormwater events. Due to the significant development on the existing site and the reduction in building footprint, very little detention is required. TABLE 1 COMPARISON OF PRE- AND POST-DEVELOPMENT FLOWS STORM EVENT (cfs) CONDITION 1-YR 2-YR 10-YR 100-YR Pre-Development 20.56 26.07 44.26 69.40 Northerly Property Line Post-Development 14.30 20.40 37.45 60.03 Northerly Property Line North Andover Commerce Center Summary Clark Street North Andover, Massachusetts 2.0 - CALCULATION METHODS The design storms analyzed in this study are the 1-year, 2-year, 10-year, and 100-year storm events. The Soil Conservation Service TR20 model(') was utilized to predict the peak runoff rates from these storm events. A Type III storm pattern was utilized in the model. The time of concentration was computed utilizing the TR55 time of concentration worksheets. Drainage structures were sized for the 25-year storm utilizing peak run off rates from the TR-20 method. Structure Subcatchments were identified and stormwater flows were routed through the system. Hydraulics calculations for the drainage structures were analyzed for inlet and outlet control, maximum headwater and discharge velocity for the 25-year storm event using a computer program entitled "Dodson Hydraulics Library"(3) References: 1. Microcomputer Implementation of the Mainframe Fortran Program: TR-20, Project Formulation Hydrology, by Soil Conservation Services, distributed by Haested Methods, Waterbury, CT. 2. Massachusetts Department of Environmental Protection, Stormwater Management Policy, Volume 1, and 2. 3. The Dodson Hydraulics Library, 1987, Dodson & Associates, Houston, TX I North Andover Commerce Center Calculation Methods Clark Street North Andover, Massachusetts 3.0 - PRE-DEVELOPMENT CONDITION: The pre-development condition is characterized by one (1) catchment area. This watershed is depicted on the Pre-Development Watershed Plan attached to this report. North Andover Commerce Center Pre-Development Condition Claris Street North Andover, Massachusetts 4.0 - POST-DEVELOPMENT CONDITION The post-development condition is characterized by three (3) watershed areas. The post-development analysis will allow for a direct comparison between the pre- and post-development peak runoff rates to assess the impact of the project, The three (3) watershed areas are depicted upon the attached Post-Development Watershed Plan. North Andover Commerce Center Post-Development Condition Clark Street North Andover, Massachusetts APPENDIX A PRE-DEVELOPMENT CALCULATIONS •:*r++**x*iYxxx*********#rrr+++Yxx***##rxii+++******.+:xrr+++}+++r+++YY}*YY* i TR 20 5/N * HMVersion 3.40 `1'R 24 * ➢ate 1/19/99 * Time 10;11:12 Project Formulation Hydrology * Input file 1275PRE.IN * Output file 1275PRE.OUT x } xxxxxxx xxxxxx xxxxx xxxxx x x x x x x xx x x x x x x x x xxxxxx x x x x x x x x x x x x x x x xx x x x x xxxxxxx xxxxx Full Microcomputer implementation by Haestad Methods, Ina, 37 Brookside Road * Waterbury, Connecticut 06708 * (203) 755-1666 LIST OF INPUT DATA FOR TR--20 HYDROLOGY****************** '.. TR--2 0 SUMMARY '. 'LE 1275 N. ANDOVER 'LE PRE-DEVELOPMENT RAINFL 7 .25 0.0 .0025 .005 .0075 .010 .0125 .015 .0175 .020 .023 .026 .0285 .031 .034 .037 .040 .043 .0465 .050 .0535 .057 ,0605 .064 .068 .072 .076 .080 .084 .089 .094 .100 .107 .115 .122 .130 ,139 .148 .157 .167 ,178 .189 .202 .216 .231 .250 .271 .298 .345 .500 .655 .702 .729 .751 .769 .785 .798 .611 .823 .834 .844 .653 .862 .870 .878 .8B6 .893 .900 .906 .911 .916 .920 .924 .928 .932 .936 .940 .944 .9475 .951 .954 .957 ,960 .963 .966 .969 .972 .975 .978 .981 .9835 .986 .9885 .991 .9935 .996 .998 1.000 1.00 1.00 1.00 ENDTBI, RUNOFF 1 001 1 0.03154966 84.8 0,1792 ENDATA INCREM 6 0.1 COMPUT 7 001 001 0.0 2.6 1,0 7 2 01 01 ENDCMP 1 '.. COMPOT 7 001 001 0.0 3.1 1.0 7 2 01 02 ENDCMP 1 COMPUT 7 001 001 0.0 4.5 1.0 7 2 01 10 ENDCMP 1 COMPDT 7 001 001 0.0 5.3 1.0 7 2 01 25 RNDCMP I COMPUT 7 001 001 0.0 6.4 1.0 7 2 01 99 ENDCMP 1 ENDJOS 2 r**++*+x+++++++++++**rrrxr***END OF BO--80 LIST***txx*++++*x*rxrr+++x++xx++++++ :0 XEQ 1/19/99 N. ANDOVER JOB 1 SUMMARY REV 09/01/83 DEVELOPMENT PAGE 4 4MARY TABLE 1 - SELECTED RESULTS OF STANDARD AND EXECUTIVE CONTROL INSTRUCTIONS IN THE ORDER PERFORMED (A STAR(*) AFTER THE PEAK DISCHARGE TIME AND RATE (CPS) VALUES INDICATES A FLAT TOP HYDROGRAPH A QUESTION MARK(?) INDICATES A BYbROORAPH WITH PEAK AS LAST POINT.) -TION/ STANDARD RAIN ANTEC MAIN PRECIPITATION PEAK DISCHARGE MJCTURE CONTROL DRAINAGE TABLE MOIST TIME ------------------------- RUNOFF -------------------------------------- ID OPERATION AREA COND INCREM BEGIN AMOUNT DURATION AMOUNT ELEVATION TIME RATE RATE (SQ MI) (HR) (HR) (IN) (HR) (IN) (FT) (HR) (CFS) (CSM) ALTERNATE I STORM 1 HCTION 1 RUNOFF .03 7 2 .10 ,0 2.60 24.DO 1.25 ------ 12.25 20.5E 651,6 ALTERNATE 1 STORM 2 F.CTION 1 RUNOFF .03 7 2 .10 .0 3.10 24.00 1.66 ---- 12.25 26.07 826.3 ALTERNATE 1 STORM 10 ECTION 1 RUNOFF .03 7 2 .10 .0 4.50 24.00 2.90 --- 12.23 44,2E 1403.0 ALTERNATE 1 STORM 25 ECTION 1 RUNOFF .03 7 2 ,10 .0 5.30 24.00 3.64 --- 12.22 = 1737.9 ALTERNATE 1 STORM 99 ECTION 1 RUNOFF .03 7 2 .10 .0 6.40 24.00 4.67 --- 12.21 E69.40) 2199.6 o xEQ 1/19/99 N. ANDovER JOB 1 SUMMARY REV 09/01/83 DEVELOPMENT PAGE 5 MARY TABLE 3 - DISCHARGE (CFS) AT XSECTIONS AND STRUCTURES POR ALL STORMS AND ALTERNATES CTION/ DRAINAGE UCTURE AREA STORM NUMBERS. ......... D (SQ MI) 1 2 10 25 99 ECTION 1 .03 '... ALTERNATE 1 20.56 26,07 44.26 54.83 63,40 ',. NORTH ANDOVER COMMERCE CENTER NORTH ANDOVER, MASSACHUSETTS PRE-DEVELOPMENT WATERSHED #1 CALCULATED BY: BM CHECKED BY: BM Tc = 1.67L^0.8 1 0001CN -9 ^0.7 DATE: JANUARY 18, 1999 1,900S^0.5 C AREA SOIL NAME acres PRODUCT AND COVER sq. mi. OF HYDROLOGIC GROUP DESCRIPTION x % CN X AREA GROUPC WOODS,GOOD 70 22,50 1575.00 GROUP C LAWN,000D 74 22.10 1635.40 GROUP D WETLAND 80 8.90 712.00 IMPERVIOUS PAVEMENT 98 25.40 2489.20 IMPERVIOUS sUILDiNG 98 21.10 2067.80 TOTALS = 100.0 88479.40 USE GN POST-DEVELOPMENT WATERSHED AREA= 0.03154966 Square Miles CN = 84.8 L= 1,704 Ft. S = 4.80 % Worksheet 3: Time of concentration (Tc) or travel time (Tt) BY Date Checked Date _ Location Circle one: resen Developed Circle one: Tc TC through subarea NOTES: Space for as many as two segments per flow type can be used for each worksheet. Include a map, schetsatic, or description of flow segments- Include to T only) Segment ID Sheet flow (App c 1. Surface description (table 3-1) .• U _ 2. Manning's roughness coeff., n (table 3-1) '•• 3. Flow length, L (total L < 300 ft) f r- �CaO in 4. Two-yr 24-hr rainfall, P2 .. . .........'•".. �• 5. Land slope, s ..... '• . ft/ft f�Z 0.8 hr � •C�ZC1` C2� 0.007 (nL) Compute, T 6. Tt P 0.5 s0.4 t 2 Segment ID Shallow concentrated flow p (paved or unpaved) ..••• �� ri1 lX 7. Surface description (p // 8. Flow length, L ..•......r..s............•... ft ` �� ft/ft 9. Watercourse slope, S V (figure 3-1) ....... ft/s 10. Average velocity, L Compute Tt hr l/�5 CJ y 11. TC 3600 V Segment IA Channel flow 12. Cross sectional flow area, a ft2 13. Wetted perimeter, pw ....................... ft a Com ute r ft 14. Hydraulic radius, r P p w ft/ft 15. Channel slope, s 16. Manning's roughness coeff., n ••••••• .•... .. 2/3 sl/2 17. V 1.49 r ftlS Compute V ....... n L ........ . .. . . . ..... EC ......... . 1$. Flow length, { L Compute Tt ...... hr 19. Tt 3600 V hr 20. watershed I./ or subarea Tc or Tt (add Tt in steps 6, 11 , and 19) ...••• l off` D-3 y�w .....n •IT fT T'1 r!' �nn•...a M_(l .Tone I986) POST-DEVELOPMENT CALCULATIONS I * TR 20 SIN * HMVersion 3.40 TR 20 * Fate 1/19/99 * Time 10:11:59 Project Formulation Hydrology * Input file 1275POST.IN * Output file 1275POST.OUT + * x xxxxxxx xxxxxx xxxxx xxxxx x x x x x x Xx x x x x x x x x xxxxxx x x x x x x x x x x x x x x x xx x x x x xxxxxxx xxxxx Full Microcomputer Implementation by Haestad Methods, Inc, . .. 37 Brookside Road * Waterbury, Connecticut 06708 * (203) 755-1666 LIST OF INPUT DATA FOR TR-20 HYi3ROLOGY****************** f0 TR--20 SUMMARY :TLE 1275 N. ANDOVER .TLE PRE-DEVELOPMENT RAINFU 7 .25 ! 0.0 ,0025 .005 .0075 .010 3 .0125 .015 .0175 .020 .023 d .026 .0285 .431 .034 .037 3 .040 .043 .0465 .050 .0535 3 .057 .0605 .064 .068 .072 3 .076 .D80 .084 .089 .094 3 .100 .107 .115 .122 .130 3 .139 .148 .157 .167 .178 3 .189 .202 .216 .231 .250 3 ,271 ,298 .345 .500 .655 3 .702 .729 .751 .769 785 3 .798 .811 .823 .834 .844 3 .853 .862 ,870 .878 .886 3 .893 ,900 .906 .911 .916 3 .920 .924 .928 .932 .936 3 .940 .944 .9475 .951 .954 3 .957 .960 .963 .966 .969 3 .972 .975 .978 .981 .9835 3 .986 .9685 .991 .9935 .996 3 .998 1.000 1.00 1.00 1.00 3 EN➢TBI, 3 STRUCT 01 3 107.0 0.0 010000 3 108.0 1.10 0.2887 3 110.0 21.0 0.9536 3 112.0 30.3 1.7207 ) ENDTEL 5 RUNOFF 1 001 1 0.01096716 89,7 0.1738 5 RUNOFF 1 002 2 0.00142709 97.5 0.0334 5 RUNOFF 1 003 3 0.01916491 80.5 0.1753 G ADDHYD 4 101 1 2 4 5 RSSVOR 2 01 4 5 5 ADDHYD 4 102 3 5 6 ENDATA 7 INCREM 6 0.1 7 COMPUT 7 DD1 102 0.0 2.6 1.0 7 2 01 01 ENDCMP 1 7 COMPUT 7 001 102 0.0 3.1 1.0 7 2 01 02 ENDCMP 1 7 COMPUT 7 001 102 0.0 4.5 1,0 7 2 01 10 ENDCMP 1 7 COMPUT 7 001 102 0.0 5.3 1.0 7 2 01 25 ksittttt**tk+*k*****BO-80 LIST OF INPUT DATA (CONPINUF D]+**+*t***+************ ENDCMP 1 COMPUT 7 001 102 0.0 6.4 1.0 7 2 01 99 ENDCMP 1 FNDJOB 2 s*****k********t*k*k*k**k*k**END OF 80-80 LIST+++++t+++tt+ttt tt+++t+t++tttttt+ I 20 XEQ 1/19/99 N, ANDOVER JOB 1 SUMMARY REV 09/01/83 DEVELOPMENT PAGE 7 MMARY TABLE I - SELECTED RESULTS OF STANDARD AND EXECUTIVE CONTROL INSTRUCTIONS IN THE ORDER PERFORMED' (A STAR(*) AFTER THE PEAK DISCHARGE TIME AND RATE (CFS) VALUES INDICATES A FLAT TOP HYDROGRAPHI, A QUESTION MARK(?) INDICATES A HYDROGRAPH WITH PEAK AS LAST POINT.) CTION/ STANDARD RAIN ANTEC MAIN PRECIPITATION PEAK DISCHARGE RUCTURE CONTROL DRAINAGE TABLE MOIST TIME ----------------------------------- RUNOFF --------------------------------------- ID OPERATION AREA # COND INCREM BEGIN AMOUNT DURATION AMOUNT ELEVATION TIME RATE RATE (SQ MI) (HR) (HR) (IN) (HR) (IN) (FT) (HR) (CFS) (CSM) ALTERNATE 1 STORM I :ECTION 1 RUNOFF .01 7 2 .10 .0 2.60 24.00 1.60 ------ 12.23 8.58 782.3 ECTION 2 RUNOFF .00 7 2 .10 .0 2.60 24.00 2.28 ----- 12.15 1.57 1096.4 SECTION 3 RUNOFF .02 7 2 .10 .0 2.60 24.00 .R9 --- 12,26 10,05 524,2 IECTION 101 ADDHYD .01 7 2 .10 .0 2.60 24.00 1.68 --- 12.18 10.04 809.9 'RUCTURE I RESVOR .01 7 2 .10 .0 2.60 24.00 1,6E O8.41 12.43 5.17 417.4 '.. IECTION 102 ADDHYD .03 7 2 .10 .0 2.60 24.00 1.25 ---- 12.29 4.30 -' 453.1 ALTERNATE I STORM 2 SECTION 1 RUNOFF .01 7 2 .10 .0 3.10 24.00 2.06 --- 12.22 10.87 991.3 1ECTION 2 RUNOFF .00 7 2 .10 .0 3.10 24.00 2.77 --- 12,15 ilea 1317.7 SECTION 3 RUNOFF .02 7 2 .10 .0 3.10 24.00 1.36 --- 12.25 13.75 717.3 SECTION 101 ADDHYD .01 7 2 .10 .0 3.10 24.00 2.14 12.18 12.65 1020.7 'RUCTURE i RESVOR .01 7 2 .10 .0 3.10 24.00 2.12 108.E 12.40 7.46 601.E SECTION 102 ADDHYD .03 7 2 .10 .0 3.10 24.00 1.66 --- 12.2E 0. 00� 646.4 ALTERNATE I STORM 10 SECTION 1 RUNOFF .01 7 2 .10 .0 4.50 24.00 3,38 --- 12.20 17.32 1579.7 SECTION 2 RUNOFF ,00 7 2 .10 .0 4.50 24.00 4.15 --- 12.15 2.75 1928.3 ;ECTION 3 RUNOFF .02 7 2 .10 .0 4.50 24.00 2.51 ---- 12.24 23.B5 1244.5 SECTION 101 ADDHYD .01 7 2 .10 .0 4.50 24.00 3.47 --- 12.17 19.99 1613.1 `RUCTURE I RESVOR .01 7 2 .10 .0 4.50 24.00 3.43 09.24 12.37 13.47 1066.8 SECTION 102 ADDHYD .03 7 2 .10 .0 4.50 24.00 2.67 ----- 12.26 3 .45 1186,8 ALTERNATE I STORM 25 SECTION 1 RUNOFF .01 7 2 .10 .0 5.30 24.00 4.15 --- 12.19 21.00 1919.0 SECTION 2 RUNOFF .00 7 2 ,10 .4 5.30 24.00 4.94 --- 12.15 3,25 2276.1 SL-'CTION 3 RUNOFF .02 7 2 .10 ,0 5.30 24.00 3.21 --- 12.23 30.16 1573.E 3ECTION 101 ADDHYD .01 7 2 .10 ,0 5.30 24.00 4.24 --- 12.17 24.17 1950.4 CRUCTURE 1 RESVOR .01 7 2 .10 .0 5,30 24.00 4.20 109.5 12,36 16.64 1342.8 SECTION 102 ADDHYD .03 7 2 .10 .0 5.30 24.00 3.60 --- 12.2E r47.04 1490.5 ALTERNATE 1 STORM 99 SECTION 1 RUNOFF .01 7 2 .10 .0 6,40 24.00 5.22 --- 12.19 26.03 2373.E 3ECTION 2 RUNOFF .00 7 2 .10 .0 6.40 24.00 6.03 ----- 12.15 3.93 2753.5 20 XEQ 1/19/99 N. ANDOVER JOB 1 SUMMARY REV 09/01/83 DEVELOPMENT PAGE 8 MMARY TABLE 1 - SELECTED RESULTS OF STANDARD AND EXECUTIVE CONTROL INSTRUCTIONS IN THE ORDER PERFORMED (A STAR(*) AFTER THE PEAK DISCHARGE TIME AND RATE (CFS) VALUES INDICATES A FLAT TOP HYDROGRAPH A QUESTION MARK(?) INDICATES A HYDROGRAPH WITH PEAK AS LAST POINT.1 CTION/ STANDARD RAIN ANTEC MAIN PRECIPITATION PEAK DISCHARGE 'RUCTURE CONTROL DRAINAGE TABLE MOIST TIME --------------------------- RUNOFF ---------------------------------------- ID OPERATION AREA It COND INCREM BEGIN AMOUNT DURATION AMOUNT ELEVATION TIME RATE RATE (SQ MI) (HR) (HR) (IN) (HR) (IN) IFT) (HR) (CM (CSM) ALTERNATE 1 STORM 99 :SCTION 3 RUNOFF .02 7 2 .10 .0 6.40 24.00 4.21 ------ 12.22 38.95 2032.2 E?CTION 101 ADDEEYD .01 7 2 .10 .0 6.40 24.00 5.31 ----- 12.17 29.89 2411.9 'RtUCTURE 1 RESVOR .01 7 2 .10 .0 6.40 24.00 5.26 109.9 12.36 20.79 1677.3 IECTION 102 ADDHYD .03 7 2 .10 .0 6.40 24.00 4.62 ---- 12.26 60.03 1902.0 i .2.0 XEQ 1/19/99 N. ANDOVER JOB 1 SUMMARY REV 09/01/83 DEVELOPMENT PAGE 9 iMMARY TABLE 3 - DISCHARGE (CFS) AT XSECTIONS AND STRUCTURES FOR ALL STORMS AND ALTERNATES IECTION/ DRAINAGE 'RUCTURE AREA STORM NUMBBRS.......... ID (So MI) 1 2 10 25 99 STRUCTURE 1 '01 ALTERNATE 1 5.17 7.46 13.47 16,64 20.79 :SECTION 1 .01 ALTERNATE 1 8.58 10.87 17.32 21.00 26.03 :SECTION 2 .00 ALTERNATE 1 1,57 1.88 2.75 3,25 3.93 :SECTION 3 .02 ALTERNATE 1 10.95 13.75 23.85 30.16 38,95 :SECTION 101 .01 ALTERNATE 1 10,04 12.65 19.99 24.17 29.89 :SECTION 102 .03 ALTERNATE 1 14.30 20.40 37.45 47.04 60.03 NORTH ANDOVER COMMERCE CENTER NORTH ANDOVER, MASSACHUSETTS POST-DEVELOPMENT WATERSHED #1 CALCULATED BY: BM CHECKED BY: BM Te = 1.67L"0.8 1 Q00/CN -9 "0.7 DATE: JANUARY 18, 1999 1,900S"0.5 C AREA SOIL NAME acres PRODUCT AND COVER sq. mi. OF HYDROLOGIC GROUP DESCRIPTION x % CN X AREA GROUP C WOODS,GOOD 701 4.20 294.00 GROUP C LAWN,GOOD 74 24.70 1827.80 GROUP D WETLAND 80 6.60 528.00 IMPERVIOUS PAVEMENT 98 45.50 4459.00 IMPERVIOUS BUILDING 98 19.00 1862.00 TOTALS =j 100.0 88970.80 USE CN = 89 7 POST-DEVELOPMENT WATERSHED AREA= 0.01096716 Square Miles CN = 89.7 L= 1,310 Ft, S = 6.48 % i i NORTH ANDOVER COMMERCE CENTER NORTH ANDOVER, MASSACHUSETTS POST-DEVELOPMENT WATERSHED #2 CALCULATED BY: BM CHECKED BY: BM Tc = 1.67L"0.8 1 000/CN -9 ^0.7 DATE: JANUARY 18, 1999 1,900S^0.5 C AREA 501E NAME acres PRODUCT AND COVER sq. mi. OF HYDROLOGIC GROUP DESCRIPTION x % CN XAREA GROUP C WOODS,GOOD 70 0.00i, 0.00 GROUP C LAWN,GOOD 74 2.20 162.80 GROUP D WETLAND 80 0.00 0.00 IMPERVIOUS PAVEMENT 98 97.80 9584.40 IMPERVIOUS BUILDING 981 0.00 0.00 TOTALS 100.00 9747.20 USE GN POST-DEVELOPMENT WATERSHED AREA= 0.00142709 Square Miles CN = 97.5 L= 230 Ft. S= 2.00 % NORTH ANDOVER COMMERCE CENTER NORTH ANDOVER, MASSACHUSETTS POST-DEVELOPMENT WATERSHED#3 CALCULATED BY: BM CHECKED BY: BM Tc = 1.67L^0.8 1 0001CN -9 ^0.7 DATE: JANUARY 18, 1999 1,900S^0.5 C AREA SOIL NAME acres PRODUCT AND COVER sq. mi. OF HYDROLOGIC GROUP DESCRIPTION x % CN X AREA GROUP C WOODS,GOOD 70 50.20 3514.00 GROUP C LAWN,GOOD 74 3.80 281.20 GROUP D WETLAND 80 14.20 1136.00 IMPERVIOUS PAVEMENT 98 11.20 1097.60 IMPERVIOUS BUILDING 98 20.60 2018.80 TOTALS =1 100.0 88047.60 USE CN 80.5 POST-DEVELOPMENT WATERSHED AREA= 0.01916491 Square Miles CN = 80.5 L= 1,245 Ft. S = 6.80 % Worksheet 3: Time of concentration Uc) or travel time (TO By Date 1_1 � 99 Fro ject Checked Dace Location Circle one: present ,eloped') -' Circle one: Tc TL through subarea pgpS; Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic, or description of flow segments- Include to T only) Segment ID Sheet flow (Applicablec 1. Surface description (table 3-1) ....... 2. Manning's roughness coefE., n (table 3-1) '.• • ..... ft 6-0 3. Flow length, L (total L < 300 ft) 4. Two-yr 24-hr rainfall, P2 ... ...•••• ••. .•..• in �• ft/ft . C� 5. Land slope, s ....... ..... ... ...... ... . .. ... 0.007 (nL)0.8 Compute, Tt ...... hr 6. Tt ' P 0.5 s0.4 2 Segment ID Shallow concentrated flow 7, Surface description (paved or unpaved) ..... �.1• � ur ft C B. Flow length, L ........ ..................... l ft/ft 9. Watercourse slope, s V (figure 3-1) ... .. ...... ft/s 10. Average velocity, B + - 0./6oZ L Compute Tt ...... hr 11• Tt w 3600 V Segment ID Channel flow 2 12. Cross sectional flow area a ......... ...... ft ft 13. wetted perimeter, P. ........... ""•" a Compute r ft 14. Hydraulic radius, r p p w ...... ...... ft/ft 15. Channel slope, s ....... .. ...... i6. Manning's roughness coeff., n ..... . .. ••"' 1.49 r�/3 sl/2 ft/s 17• V Compute V ..•••• • n �, f t 18. Flow length, a L Compute T ...... hr .. t 19. Tt 3600 V hr / 3 20. Watershed or subarea c T or Tt (add Tt in steps 6, 11 , and 19) D-3 .,, I"" r� c• ,a F� JiinP 1986) _ Woriksheet 3: Time of concentration (Tc) or travel time (Tt) ny - Date Project � - Checked Date Location Circle one: Present evelope SST Circle one: Tc Tt through subarea NOTES: Space for as many as two segments per flow type can be used for each uorksheet. Include a map, schematic, or description of flaw segments• (Applicable to x only) Segment ID • Sheet flow {ApP c 1. Surface description (table 3-1) 2. Manning's roughness coeff., n (table 3-1) '.. total L < 300 ft) ... ....... ft /,L/? 3. Flow length, L { _ 4. Two-yr 24-hr rainfall, P2 in , •.. . .. ... f t/f t 4 S. Land slope, 0.007 (nL)0.8 Compute Tt . .. ... hr 6. Tt ' .P 0.5 s0.4 2 Shallow concentrated flow Segment ID P (paved or unpaved) f7LJL� 7. Surface descri tion (p ' ft / 8. Flow leng L th, .. ....•• ••...... 9. Watercourse slope, s ft/ft V (figure 3-1) ........... ft/s 10. Average velocity, + C/l L Compute Tt ...... hr dJt 11. it - 3600 V Segment ID Channel flan 2 12. Cross sectional flow area, a ............••• ft ft 13. Wetted perimeter, pW a Compute r ....... ft 14. hydraulic radius, r VW ft/ft 15. Channel slope, s 16. Haaning's roughness coeff., n 49 r2/3 sl/2 1. Compute ...... ft/s 17• V a pute V . n L ft 18. Flow length, } L Compute T ...... hr 19• Tt - 3600 V t or subarea T or Tt (add Tt in steps 6, 11 , and 19) .- hr 20. Watershed c 7.C)3 D•3 t,T TD r-, .dune 19$6) Worksheet 3: Time of concentration (Tr) or travel time (Tt) D a C e � Project �VCi� f � j J �--= Checked Date ---�-- Location Circle one: Present eveloped Circle one: Tc Tt through subarea Hpg; Space for as many as two segments per flow type can be used for each worksheet. Include a map, schematic, or description of flow segments. Sheet flow (Applicable to Tc only) Segment ID 1. Surface description table 3-1) ........... - •Ol 2. Manning's roughness coeff., n (table 3. Flow length, L (total L < 300 ft) .......... ft 4. Two-yr 24-hr rainfall, P2 .................. in S. Land slope, s ... .,... .. . ... ftlft -C� 0.007 (nL)0.8 compute. Tt ...... hr 6. Tt ' .P 0.5 s0.4 2 Shallow concentrated flow Segment ID 7. Surface description (paved or unpaved) ..... 8. Flow length, 9. Watercourse slope, s .. ......... .. .......... fl/f: V f1 ure 3-1) ........... ft/s 10. Average velocity, ( 8 k L hr Compute Tt .• E1. Tt 3600 V Segment ID Channel flow 12. Cross sectional flow area, a ••.......••.... ft2 rimeter, ft 13. Netted pe � Pw ...................... a� compute r ..••••• ft .. 14• Hydraulic radius, r p P w 15. Channel slope, s ..... ..................... ft/ft 16. Manning's roughness coeff., n 1.49 r�/3 s1/2 ...... ft/s 17. V a Compute V . n 18. Flow length, L ........ ........... . ......... ft f L Compute T ...... hr 19. Tt 3600 t and 19) hr f 20. Watershed or subarea Tc or TC (add Tt in steps 6, ll, D-3 _s L",z Tt+no 14RFi1 i PIPE CULVERT ANALYSIS COMPUTATION OF CULVERT PERFORMANCE CURVE January 19, 1999 NORTH ANDOVER INLET(POND) TO DMH AEI 1275 PROGRAM INPUT DATA: DESCRIPTION VALUE -------------------------------------------------------------------- Culvert Diameter (feet) ................ ... ... .... ....... 2.00 FHWA Chart Number (1,2 or 3) ........ ............. ....... 1 Scale Number on Chart (Type of Culvert Entrance) ........ 3 Manning`s Roughness Coefficient (n-value) ............... 0.0120 Entrance Loss Coefficient of Culvert Opening........ .... 0.50 Culvert Length (Peet) ..................... .............. 22.0 Culvert Slope (feet per foot) ................ .... ....... 0.0090 PROGRAM RESULTS: Flow Tailwater Headwater (ft) Normal Critical Depth at Outlet Rate Depth Inlet Outlet Depth Depth outlet Velocity (cEs) (ft) Control Control (ft) (ft) (ft) (fps) ------------------------------------------------------------- E30.3 0,00 0.49 0.99 0.30 0.36 0.36 2.13 2.00 2.80 3.00 1.49 1.64 2.00 6.68 2.70 4.33 5.00 2.00 1.87 2.30 9.64 PIPE CULVERT ANALYSIS COMPUTER PROGRAM Version 1.7 Copyright (c)1986 ', Dodson & Associates, Inc., 7015 W. Tidwell, #107, Houston, TX 77092 (713) 895--8322. All Rights Reserved. PIPE CULVERT ANALYSIS COMPUTATION OF CULVERT PERFORMANCE CURVE January 15, 1999 north andover outlet sturcture-dmh PROGRAM INPUT DATA: DESCRIPTION VALUE -------------------------------------------------------------------- Culvert Diameter (feet) ........................... ...... 3.00 FHWA Chart Number (1,2 or 3) ............................ 1 Scale Number on Chart (Type of Culvert Entrance)........ 3 Manning's Roughness Coefficient (n-value),, ,,,,,,,, ,,,,, 0.0120 Entrance Loss Coefficient of Culvert Opening...... ...... 0.50 Culvert Length (feet) ...... ....................... ...... 78.0 Culvert Slope (feet per foot) .................... ....... 0.0050 PROGRAM RESULTS: Flow Tailwater Headwater (ft) Normal Critical ❑epth at Outlet Rate ➢epth Inlet Outlet Depth Depth Outlet Velocity (cfs) (ft) control Control (ft) (ft) (ft) (fps) -------------------------------------------------------------------- 10.0 1,80 1.37 1.67 0.90 1,00 1.80 2,26 - 20.0 2.20 2.03 2.07 1.30 1.43 2.20 3.60 30.0 2.60 2.59 2.76 1.66 1.77 2.60 4.61 40.0 3.10 3.13 3,69 2.00 2,06 3.00 5.66 50,0 3.70 3.66 4.85 2.41 2,30 3.00 7.07 PIPE CULVERT ANALYSIS COMPUTER PROGRAM Version 1.7 Copyright (c)1986 Dodson & Associates, Inc„ 7015 W. Tidwell, #107, Houston, TX 77092 (713) 895-8322. All Rights Reserved. PIPE CULVERT ANALYSIS COMPUTATION OF CULVERT PERFORMANCE CURVE January 15, 1999 north andover dmh - headwall PROGRAM INPUT DATA: DESCRIPTION VALUE '.. ------------------------------------------------------------------- Culvert Diameter (feet) .... ......... . ............... .... 3.00 FHWA Chart Number (1,2 or 3) ......... ................... 1 Scale Number on Chart (Type of Culvert Entrance) ........ 3 Manning's Roughness Coefficient (n-value) ............ ... 0.0120 Entrance Loss Coefficient of Culvert Opening......... ... 0.50 Culvert Lengtb (feet) .................... ........ ... .... 35.0 Culvert Slope (feet per foot) ......... .. ......... .. .... 0.0050 PROGRAM RESULTS: - Flow Tailwater Headwater (ft) Normal Critical Depth at Outlet Rate Depth Inlet Outlet Depth Depth Outlet Velocity (cfs) (ft) Control Control (ft) (ft) (ft) (fps) -------------------------------------------------------------------- 10.0 0.00 1.37 1.68 0.90 1.00 1,00 4.85 20.0 0.00 2.03 2.26 1.30 1.43 1.43 5.99 30.0 0.00 2.59 2.69 1.66 1.77 1.77 6.89 40.0 0.00 3.13 3.21 2.00 2,06 2.06 7.73 50.0 0.00 3.66 3.81 2.41 2.30 2.30 B.59 PIPE CULVERT ANALYSIS COMPUTER PROGRAM Version 1.7 Copyright (c)1986 Dodson & Associates, Inc., 7015 W. Tidwell, #107, Houston, TX 77092 (713) 895-8322. All Rights Reserved. TRAPEZOIDAL CHANNEL ANALYSIS NORMAL DEPTH COMPUTATION January 19, 1999 PEMBRGBNCX SPTLLWA ELEVATION 115.9 AEI 1275 PROGRAM INPUT DATA: DESCRIPTION VALUE ', ---------------------------------- ---------------------------------- Flow Rate (cubic feet per second) ..................... . . 30.0 Channel Bottom Slope (feet per foot)................. ... 0.0005 Manning's Roughness Coefficient (n-value) ............... 0.0300 Channel Side Slope - Left Side (horizontal/vertical) .... 2.00 Channel Side Slope - Right Side (horizontal/vertical) ... 2.00 Channel Bottom Width (feet) ..................... ..... .. . 25.0 PROGRAM RESULTS; DESCRIPTION VALUE ------------------------------__------------------------------------- Normal Depth (feet) ..................................•. , 1.04 Flaw Velocity (feet per second)..... .................... 1.07 Froude Number (Plow is Sub-Critical) .................... 0.192 Velocity Head (feet) .................................... 0.02 Energy Head meet) -...-...... ............... ...... . 1,06 Crass-Sectional Area of Flow (square feet)............. . 29.10 Top Width of Flow (feet) ... .... ... ................... ... 29.15 TRAPEZOIDAL CHANNEL ANALYSIS COMPUTER PROGRAM, Version 1.3 (c) 1986 Dodson & Associates, Inc., 7015 W. Tidwell, #107, Houston, TX 77092 (713) 695-8322. A manual with equations & flow chart is available. APPENDIX B TABLE 6-6 -- ROUGHNESS COEFFICIENTS (MANNING'S n) FOR SHEET FLOW Surface Descri tion n Smooth surfaces (concrete, asphalt, 0. 011 gravel, or bare soil) 0. 05 Fallow (no residue) Cultivated soils: 0. 06 Residue cover <20% 0. 17 Residue cover >20% Grass: 0. 15 Short grasses 0. 24 Dense grasses Woods: 0. 40 Light underbrush 0. 80 Dense underbrush Note: When selecting n, consider cover tofatheheight of about 0. 1 ft. This is the only part plant cover that will obstruct sheet flow. Source: USDA Soil conservation Service 6-25 .50 — I I I 1 I I I 1 I .20 l i 9 1 E I I I E 1 1 i IliffillW 11 I I i I II1 I .� .10 p omil 06 r I I I I 1 1 Ql , .04 I ; , O 1 t I ! I I ! F1711 I I I I I 1 I 1 3 I if-III 1 l I ! 1 I ! E i ! l I III 1 l t 1 1 I 1 11 1111111 I 1 I I •02 1 1 1 l a I 1 IIII I i 1 1 1 1 , �, II I ( Il1 = � : 111 .01 I I I ' � � I I I i ' '• 11 1 1 I ` l.i 1111 'pill Elf 005 ZI : I 11 1 I1 III I 1 2 4 6 10 20 Average velocity, ft/sec FIGURE 6-14 AVERAGE VELOCITIES FOR ESTIMATING TRAVEL TIME FOR SHALLOW CONCENTRATED FLOW Source: USDA Soil Conservation Service &27. JOB- 141 APPLEDORE ENGINEERING, INC. SHEET NO. OF 600 State Street, Suite D PORTSMOUTH, NH 03801 CALCULATEDBY DATE (603) 433-8818 CHECKED BY DATE SCALE . e a y ' Z o . z o !w. o :. .� . /�� Ca?s c�e.4.0 . s7zi2•�� 4,7, X PIPE CULVERT ANALYSIS COMPUTATION Or CULVERT PERFORMANCE CURVE January 19, 1999 '.. NORTH ANDOVER DMI1 5 - DMH 4 AEI 1275 PROGRAM INPUT DATA: DRSCRIPTION VALUE -------------------------------------------------------------------- Culvert Diameter (feet) ....... .......................... 1.25 PHWA Chart Number (1,2 or 3) .......................... .. 1 Scale Number on Chart (Type of Culvert Entrance) ........ 1 Manning`s Roughness Coefficient (n-value) ......... . ... .. 0.0120 Entrance Loss Coefficient of Culvert Opening....... ..... 0.50 Culvert Length (feet) ..... . ............ ............ ..... 86.0 Culvert Slope (feet per foot) ............ ......... ...... 0.0300 PROGRAM RESULTS: Plow Tailwater Headwater (ft) Normal Critical depth at Outlet Rate Depth Inlet Outlet Depth Depth Outlet Velocity (cfs) (ft) control control (ft) (ft) (Et) (fps) __--__.-___.__.------------------------------------------------------ 8.0 4,00 2.53 3.53 0.74 1.11 1.25 6.52 PIPE CULVERT ANALYSIS COMPUTER PROGRAM Version 1.7 Copyright (c)1986 Dodson & Associates, Inc_ 7015 W. Tidwell, #107, Houston, T% 77092 {713) 995-8322. All Rights Reserved. ca r ,1-41 PIPE CULVERT ANALYSIS COMPUTATION OF CULVERT PERFORMANCE CURVE January 19, 1999 NORTH ANDOVER CB 8 -- DMH AEI 1275 PROGRAM INPUT DATA; DESCRIPTION VALUE '.. -------------------------------------------------------------------- Culvert Diameter (feet) ................. ................ 1,00 FHWA Chart Number (1,2 or 3) .. ...... ...... .......... .... 1 Scale Number on Chart (Type of Culvert Entrance) ........ 1 Manning`s Roughness Coefficient (n-value) ............... 0.0120 Entrance Loss Coefficient of Culvert Opening............ 0.50 Culvert Length (feet) ........ ...................... ..... 6.0 Culvert Slope (feet per foot) .......... ............ ..... 0,1080 PROGRAM RESULTS: Flow Tailwater Headwater (ft) Normal critical Depth at Outlet Rate Depth inlet Outlet Depth Depth Outlet Velocity (cfs) (ft) Control Control (ft) (ft) (ft) (fps) ___-___..______ ____....------------------------------------------- 4.0 3.50 1.70 3.52 0.39 0.85 1.00 5.09 PIPE CULVERT ANALYSIS COMPUTER PROGRAM Version 1.7 Copyright (c)1986 Dodson & Associates, Inc., 7015 W. Tidwell, #107, Houston, TX 77092 (713) 895-8322. All Rights Reserved. 4 PIPE CULVERT ANALYSIS COMPUTATION OF CULVERT PERFORMANCE CURVE January 19, 1999 NORTH ANDOVER CE 9 - DMH 5 AEI 1275 PROGRAM INPUT DATA: DESCRIPTION VALUE -------------------------------------------------------------------- Culvert Diameter (feet) ................ .... ............. 1.00 F11WA Chart Number (1,2 or 3) ............................ 1 Scale Number an Chart (Type of Culvert Entrance) ....... , 1 Manning's Roughness Coefficient (n-value) ............... 0.0120 Entrance Loss Coefficient of Culvert Opening........ . ... 0.50 Culvert Length (feet) ... ............ .................... 114.0 Culvert Slope (feet per foot). . ..................... .... 0.0050 PROGRAM RESULTS: Flow Tailwater Headwater (£t) Normal Critical Depth at Outlet Rate Depth Inlet Outlet Depth Depth outlet Velocity (cfs) (ft) Control Control (ft) (ft) (ft) (fpsl -------------------------------------------------------------------- 4.5 3.50 1.98 G7 1.00 0.69 1.00 5.73 PIPE CULVERT ANALYSIS COMPUTER PROGRAM Version 1.7 Copyright (c)1986 Dodson & Associates, Inc., 7015 W. Tidwell, 0107, Houston, TX 77092 (713) 895-8322. All Rights Reserved. TSS REMOVAL WORKSHEET North Andover Commerce Center North Andover Massachusetts AE111275 Best Management Practice Proposed : Constructed Wetland DEP Credit = 80% TSS removal = 1 x 0.8 = 0.8 (80%) TSS removal required = 80% * This does not include optional credit for parking lot sweeping as proposed in our Operation and Maintenance plan.