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HomeMy WebLinkAboutStormwater - 1077 OSGOOD ST 8-7-1990 DRAINAGE SYSTEM ANALYSIS AND DESIGN BUTCHER BOY MALL 1077 OSGOOD STREET NORTH ANDOVER, MASSACHUSETTS MAY 1989 PREPARED BY M. ANTHONY LALLY ASSOCIATES, INC. 100 BELMONT STREET NORTH ANDOVER, MASSACHUSETTS 01845 TABLE OF CONTENTS ITEM PAGE I INTRODUCTION 1 II PROJECT DESCRIPTION 2 III DETERMINATION OF STORMWATER RUNOFF HYDROGRAPHS 5 EXISTING CONDITIONS 5 PROPOSED CONDITIONS (WITHOUT DETENTION) 8 COMPARISON OF EXISTING AND PROPOSED CONDITIONS (WITHOUT DETENTION) 10 IV ON-SITE REMEDIATION OF PEAK RATES OF RUNOFF 15 DESIGN BASIS 15 DETENTION STRUCTURE DESIGN 16 EMERGENCY OVERFLOW FROM DETENTION POND 17 EFFECT OF ON-SITE REMEDIATION ON PEAK RATES OF RUNOFF 17 V IMPACT OF RUNOFF AT DRAINAGE SYSTEM OUTFALL 24 DESIGN OF OUTFALL STRUCTURES 24 PARAMETERS OF WETLAND AT OUTFALL 25 DETERMINATION OF PEAK RATES OF RUNOFF TO WETLAND AT OUTFALL 26 IMPACT OF RUNOFF AT DRAINAGE SYSTEM OUTFALL 30 LIST OF APPENDICES APPENDIX A PLANS APPENDIX Al : SHEET Cl , SITE PLAN APPENDIX A2 : SHEET C2, CLARK STREET PLAN APPENDIX A3 : SHEET C6, DETAILS APPENDIX B COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF, SITE DRAINAGE ANALYSIS, EXISTING CONDITIONS APPENDIX B1 : 2 YEAR, 24 HOUR STORM APPENDIX B2 : 10 YEAR, 24 HOUR STORM APPENDIX B3 : 100 YEAR, 24 HOURS STORM APPENDIX C COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF, SITE DRAINAGE ANALYSIS - WATERSHED NO. 1 , PROPOSED CONDITIONS APPENDIX Cl : 2 YEAR, 24 HOUR STORM APPENDIX C2 : 10 YEAR, 24 HOUR STORM APPENDIX C3 : 100 YEAR, 24 HOUR STORM APPENDIX D COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF, SITE DRAINAGE ANALYSIS - WATERSHED NO. 2, PROPOSED CONDITIONS APPENDIX D1 : 2 YEAR, 24 HOUR STORM APPENDIX D2 : 10 YEAR, 24 HOUR STORM APPENDIX D3 : 100 YEAR, 24 HOUR STORM APPENDIX E COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF, DETENTION POND DESIGN - WATERSHED NO. 1 , PROPOSED CONDITIONS APPENDIX E1 : 2 YEAR, 24 HOUR STORM APPENDIX E2 : 10 YEAR, 24 HOUR STORM APPENDIX E3 : 100 YEAR, 24 HOUR STORM APPENDIX F COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF, DRAINAGE ANALYSIS AT OUTFALL, EXISTING CONDITIONS APPENDIX F1 : 2 YEAR, 24 HOUR STORM APPENDIX F2 : 10 YEAR, 24 HOUR STORM APPENDIX F3 : 100 YEAR, 24 HOUR STORM APPENDIX G COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF, DRAINAGE ANALYSIS AT OUTFALL, PROPOSED CONDITIONS APPENDIX G1 : 2 YEAR, 24 HOUR STORM APPENDIX G2 : 10 YEAR, 24 HOUR STORM APPENDIX G3 : 100 YEAR, 24 HOUR STORM I . INTRODUCTION: The following report describes the drainage analysis performed to determine the stormwater runoff rates which will result from the proposed construction of the Butcher Boy Mall in North Andover, Massachusetts . The analysis includes the design of a detention structure which will mitigate peak rates of stormwater runoff to present levels . The analysis also includes an examination of the effects of the introduction of the stormwater runoff at the outfall of the proposed drainage system. All computations for this report were performed in accordance with the recommendations of the Soil Conservation Service Technical Release 55 , latest edition. Stormwater runoff hydrographs were developed for 2, 10, and 100 (year) storms with a Type III storm distribution. The resultant drainage system design provides for a zero increase in the peak rate of stormwater runoff from the developed project site for a 10 (year) and 100 (year) storm. The introduction of stormwater runoff to the wetland at the outfall from the drainage system will not adversely affect the wetland' s capacity to retain stormwater and provide flood protection. - 1 - II . PROJECT DESCRIPTION: The proposed project site is located in the northeastern portion of the Town of North Andover, MA. The proposed project occupies approximately 5 . 3 (acres) of a 9 . 2 (acre) parcel of land. The parcel is generally bounded northerly and easterly by residential property, southerly by Great Pond Road and Lake Cochichewick, and westerly by Osgood Street (State Highway Route 125 ) . Figure No. 1 , Project Locus and Drainage Routing, shows the general location of the project site. At present, a parking lot and a structure containing a retail facility are located at the southwestern part of the site. The remainder of the site consists chiefly of wooded areas . The existing site consists of approximately twenty percent (200) impervious area. The developed site will contain a larger parking lot extending to the northern, eastern, and western boundaries of the project parcel . The site will contain a structure housing a retail/office facility. The developed site will consist of approximately sixty percent (60%) of impervious area increasing the total impervious area on the site by approximately 2 . 1 (acres) . Sheet C1 , Site Plan, is attached as Appendix Al , and shows the developed site. The existing topography of the site is fairly flat with a slight slope to the south. The majority of the drainage from the existing site is directed toward Great Pond Road and Lake Cochichewick and contributes to the Lake' s watershed. The proposed site will be regraded such that all stormwater in the paved area will be collected by a stormwater collection system to be constructed on site. The collection system will convey the stormwater down Clark Street and overland to an existing wetland. The wetland is drained by an existing stream which eventually discharges to the Merrimack river. The drainage routing of the proposed site is shown in Figure No. 1 , Project Locus and Drainage Routing. Sheet C2, Clark Street Plan, is attached as Appendix A2, - 2 - Ti 1 g �`\ yI , en Vaeyi�'ii1•I,. 1.1 I - i.�� ` �. / BM` �h1 '�\?•�,�(.jj1.64w;� a Hill j . ; bb \ea dol ^ Gravel r con\ ' INT CHANGE 47 !, So w�� Alhlqtig V'� ' Fletd I(i ��_ _HAVERH G9/ 200 II V '' .� Qj �.., r 1 /� �' O 6 8(0 A h StQ!( NTERC`IHAN P > v � I , —.LOP �� i� �F i Vt__ 100_ Vb,4ter7!an s "o so' _ ��-- ZJ� ° t DRAINAGE R O U T glrk r ,\� go 178 ze �. \5 •ground; I/�,x 3�t I l �R illlJ�i .,w ,�- Muol PAI AIRP RT VVVN� :c - �\ - I ^)if PROPOSED DRAINAGE DISCHARGE Pumping i. it ' »w L ` ,v ij. L./ tJ /•' _ _. . - R p. I4 11 � PROJECT LOCUS „ \ ��y ,;� . 1.w `�i„ •� III I. J?5 1P I�� v �IV: ��� ♦�`� 1 1 .�u !\.//I �A5�,; \( j - m o Ir��A��d "--' �i�•`•�r 7AZ0V A otN•• M AAl D O'REILLV , 1 ti J �% I1\\46 llv \`\ �. .•1 ') r\ ___—_-.�-_ �,rrp•}Ra�ah� a - ! v` �1 .-t �1y;�� w �T•:,�.•,o il�l.1\ f� �-�X- „. ' '_��—�® \p\\t}����� %i�}i6cl I® ••,,�,` ��j �Crr i,�,,�' W ,•�, �o��--. LW _ P \" 'Sch r., 11 \�.+u:•��a- , h�. 2 �" o SY IC.4Yne nel �c7Uarhi gL `y k%. • ,32 \� FIGURE O. R0 PROJECT LOCUS DRAINAGE ROUTING 1 �, BUTCHER BOY MALL. ii �� ''� w I\ `,O r�<� NORTH ANDOVER, MA. .. - ----- REF. U,S.GS, SOUTH GROVELAND QUAD. ;� M. ANTHONY LALLY ASSOCIATES MAY, 1989 - 3 - and shows the stormwater collection system from the site to the outfall . Due to the regrading of the site under developed conditions, a portion of the stormwater drainage will be redirected out of the Lake Cochichewick watershed and into the Merrimack River watershed. All undisturbed, non-paved areas of the proposed site will continue to contribute stormwater drainage to the Lake Cochichewick watershed. A detailed description of the existing and proposed drainage characteristics and the drainage system design is contained in the following sections of this report. 4 - III . DETERMINATION OF STORMWATER RUNOFF HYDROGRAPHS : Stormwater runoff hydrographs were developed for 2, 10, and 100 (year) storms with a Type III storm distribution for both existing and proposed site conditions . All computations were performed in accordance with the recommendations of the Soil Conservation Service Technical Release 55 (SCS-TR55 ) , latest edition. Rainfall data for the 24 (hour) storm events was obtained from SCS-TR55 . The watersheds comprising the project site were broken down into subwatersheds based on existing and proposed topography. Existing topographic information was obtained from the USGS South Groveland Quadrangle and from additional survey data. The drainage characteristics of each subwatershed were defined by existing and proposed land use and soil characteristics . Soil data was obtained from the Soil Conservation Service Soil Survey of Essex County, Massachusetts, Northern Part, issued February 1981 . Existing Conditions : The existing site consists of a single watershed area. All of the stormwater runoff from the site watershed contributes to the overall Lake Cochichewick watershed. The delineation of the existing site watershed is shown in Figure No. 2, Existing Drainage Area. The runoff curve number (RCN) defining the drainage characteristics of the existing subwatershed was determined to be 74 . The stormwater runoff was routed directly to the southern boundary of the site with a total time of concentration of 0 . 1 (hours ) . The tabular hydrographs developed for the 2, 10 , and 100 (year) storms are attached as Appendix B, Composite Hydrograph Development for Determination of Peak Rates of Runoff, Site Drainage Analysis, Existing Conditions . The tabular hydrographs showing the stormwater runoff from the site for each storm are shown in Table No. 1 , Tabular Hydrographs, Site Drainage Analysis, Existing Conditions . 5 TABLE NO. 1 TABULAR HYDROGRAPHS SITE DRAINAGE ANALYSIS EXISTING CONDITIONS BUTCHER BOY MALL 1077 OSGOOD STREET NORTH ANDOVER, MASSACHUSETTS 2 YEAR STORM 10 YEAR STORM 100 YEAR STORM TIME DISCHARGE DISCHARGE DISCHARGE (HR) (CFS) (CFS) (CFS) 11 0 . 09 0 . 38 0 .86 11 . 3 0 . 12 0 . 49 1 . 13 11 . 6 0 . 17 0 . 74 1 . 7 11 . 9 0 . 78 2 . 46 5 . 18 12 1 . 3 3 . 62 7 . 31 12 . 1 2 . 87 6 . 89 13 . 03 12 . 2 5 . 19 11 . 37 20 . 47 12 . 3 4 . 25 9 . 2 16 . 44 12 . 4 3 . 01 6. 19 10 . 74 12 . 5 2 . 4 4 . 83 8 . 27 12 . 6 1 . 76 3 . 51 5 .97 12 . 7 1 . 22 2 . 41 4 . 07 12 . 8 0 . 97 1 . 89 3 . 17 13 0 . 82 1 . 57 2 . 61 13 . 2 0 . 68 1 . 3 2 . 14 13 . 4 0 . 63 1 . 19 1 . 95 13 . 6 0 . 6 1 . 12 1 . 83 13 . 8 0 . 56 1 . 04 1 . 7 14 0 . 52 0 . 97 1 . 58 14 . 3 0 . 46 0 . 86 1 . 39 14 . 6 0 . 44 0 . 81 1 . 3 15 0 . 4 0 . 73 1 . 17 15 . 5 0 . 35 0 . 63 1 . 01 16 0 . 29 0 . 54 0 . 85 16 . 5 0 . 26 0 . 46 0 . 73 17 0 . 23 0 . 42 0 . 67 17 . 5 0 . 21 0 . 38 0 . 6 18 0 . 18 0 . 32 0 . 51 19 0 . 16 0 . 28 0 . 44 20 0 . 15 0 . 26 0 . 41 22 0 . 12 0 . 22 0 . 35 26 0 0 0 Ref. Appendices B1 , B2 & B3 - "Hydrograph - Subwatershed No. 111 7 The tabular hydrographs for Watershed No. 1 , showing the stormwater runoff from the site for each storm are shown in Table No. 2, Tabular Hydrographs, Site Drainage Analysis - Watershed No. 1 , Proposed Conditions . The tabular hydrographs developed for Watershed No. 2 (Lake Cochichewick) for the 2, 10, and 100 (year) storms are attached as Appendix D, Composite Hydrograph Development for Determination of Peak Rates of Runoff, Site Drainage Analysis - Watershed No. 2, Proposed Conditions . The tabular hydrographs for Watershed No. 2 showing the stormwater runoff from the site for each storm are shown in Table No. 3, Tabular Hydrographs, Site Drainage Analysis - Watershed No. 2, Proposed Conditions . Comparison of Existing and Proposed Conditions (Without Detention) : To compare the rates of the stormwater runoff from the project site, the total runoff from the site was calculated as the sum of all stormwater leaving the site regardless of runoff routing. Therefore, the total runoff leaving the site under existing conditions is equal to the runoff across the southern border of the site to Great Pond Road and Lake Cochichewick. The total runoff from the site under proposed conditions is equal to the runoff across the southern border as above, plus the runoff collected in the proposed parking lot drainage system and eventually routed to the Merrimack River. All comparisons contained in the following are made on this basis . A comparison of stormwater runoff rates for the existing and proposed conditions without the use of a detention structure shows that there will be an increase in the peak rates of runoff for each of the storm events examined. This increase is due primarily to the increase in impervious area under the proposed site conditions . A comparison of peak rates of stormwater runoff for existing and proposed conditions without the use of a detention structure for a 2, 10, and 100 (year) storm is shown in Table No. 4, Summary Table, Comparison of Peak Rates of Runoff, Without Detention. - 10 - Proposed Conditions (Without Detention) : The proposed, developed site consists of two ( 2) watersheds . One site watershed (Watershed No. 1 ) consists of nine (9 ) subwatersheds and contributes stormwater runoff to the overall Merrimack River watershed. The second site watershed (Watershed No. 2 ) consists of a single subwatershed and contributes stormwater runoff to the overall Lake Cochichewick watershed. The delineation of the developed site watersheds is shown in Figure No. 3, Proposed Drainage Area. Watershed No. 1 represents the portion of the site containing the parking lot and building and all grassed areas draining directly to the parking lot. There is a one to one relationship between subwatersheds and catch basins and each subwatershed is defined as that area which drains to a single catch basin. The RCN defining the drainage characteristcs of each subwatershed was determined to be 98, representing that the subwatersheds are essentially impervious, paved areas . The stormwater runoff from each subwatershed is routed to its respective catch basin and through the proposed on-site drainage system to the outlet from the parking lot across Osgood Street to Clark Street. The time of concentration for each subwatershed is different and is represented in the tabular hydrographs referenced herein. Watershed No. 2 represents the portion of the site which will remain undisturbed or unpaved after development. The watershed consists of a single subwatershed with an RCN equal to that of the existing conditions. The stormwater runoff from this watershed was routed directly to the southern boundary of the site with a total time of concentration of 0 . 03 (hours) . The tabular hydrographs developed for Watershed No. 1 (Merrimack River) for the 2, 10, and 100 (year) storms are attached as Appendix C, Composite Hydrograph Development for Determination of Peak Rates of Runoff, Site Drainage Analysis - Watershed No. 1 , Proposed Conditions . The singular and composite hydrographs contained in Appendix C are cross referenced with Figure No. 3 . 8 TABLE NO. 2 TABULAR HYDROGRAPHS SITE DRAINAGE ANALYSIS - WATERSHED NO. 1 PROPOSED CONDITIONS BUTCHER BOY MALL 1077 OSGOOD STREET NORTH ANDOVER, MASSACHUSETTS 2 YEAR STORM 10 YEAR STORM 100 YEAR STORM TIME DISCHARGE DISCHARGE DISCHARGE (HR) (CFS) (CFS) (CFS) 11 0 . 42 0 . 63 0 . 91 11 . 3 0 . 54 0 . 83 1 . 19 11 . 6 0 . 82 1 . 24 1 . 78 11 . 9 2 . 47 3 . 75 5 . 38 12 3 . 46 5 . 26 7 . 54 12 . 1 6 . 09 9 . 27 . 13 . 31 12 . 2 9 . 49 14 . 44 20 . 73 12 . 3 7 . 61 11 . 59 16. 62 12 . 4 4 . 95 7 . 53 10 . 8 12 . 5 3 . 8 5 . 78 8 . 3 12 . 6 2 . 74 4 . 17 5 . 98 12 . 7 1 . 86 2 . 84 4. 07 12 . 8 1 . 45 2 . 2 3 . 16 13 1 . 19 1 . 81 2 . 6 13 . 2 0 . 98 1 . 48 2 . 13 13 . 4 0 . 89 1 . 35 1 . 94 13 . 6 0 . 83 1 . 27 1 . 82 13 . 8 0 . 77 1 . 18 1 . 69 14 0 . 72 1 . 09 1 . 57 14 . 3 0 . 63 0 . 96 1 . 38 14 . 6 0 . 59 0 . 89 1 . 28 15 0 . 53 0 . 81 1 . 16 15 . 5 0 . 46 0 . 7 1 16 0 . 39 0 . 59 0 . 85 16 . 5 0 . 33 0 . 5 0 . 72 17 0 . 3 0 . 46 0 . 66 17 . 5 0 . 27 0 . 41 0 . 59 18 0 . 23 0 . 35 0 . 5 19 0 . 2 0 . 31 0 . 44 20 0 . 19 0 . 28 0 . 41 22 0 . 16 0 . 24 0 . 34 26 0 0 0 Ref. Appendices Cl , C2 & C3 - "Composite Hydrograph No. 6" - 11 - TABLE NO. 3 TABULAR HYDROGRAPHS SITE DRAINAGE ANALYSIS - WATERSHED NO. 2 PROPOSED CONDITIONS BUTCHER BOY MALL 1077 OSGOOD STREET NORTH ANDOVER, MASSACHUSETTS 2 YEAR STORM 10 YEAR STORM 100 YEAR STORM TIME DISCHARGE DISCHARGE DISCHARGE (HR) (CFS) (CFS) (CFS) 11 0 . 04 0 . 15 0 . 34 11 . 3 0 . 05 0 . 19 0 . 45 11 . 6 0 . 07 0 . 29 0 . 67 11 . 9 0 . 31 0 . 97 2 . 05 12 0 . 51 1 . 43 2 . 89 12 . 1 1 . 13 2 . 72 , 5 . 15 12 . 2 2 . 05 4 . 49 8 . 09 12 . 3 1 . 68 3 . 64 6 . 5 12 . 4 1 . 19 2 . 45 4. 25 12 . 5 0 . 95 1 . 91 3 . 27 12 . 6 0 . 69 1 . 39 2 . 36 12 . 7 0 . 48 0 . 95 1 . 61 12 . 8 0 . 38 0 . 75 1 . 25 13 0 . 32 0 . 62 1 . 03 13 . 2 0 . 27 0 . 51 0 . 84 13 . 4 0 . 25 0 . 47 0 . 77 13 . 6 0 . 24 0 . 44 0 . 72 13 . 8 0 . 22 0 . 41 0 . 67 14 0 . 21 0 . 38 0 . 62 14 . 3 0 . 18 0 . 34 0 . 55 14 . 6 0 . 17 0 . 32 0 . 51 15 0 . 16 0 . 29 0 . 46 15 . 5 0 . 14 0 . 25 0 . 4 16 0 . 12 0 . 21 0 . 34 16 . 5 0 . 1 0 . 18 0 . 29 17 0 . 09 0 . 17 0 . 26 17 . 5 0 . 08 0 . 15 0 . 24 18 0 . 07 0 . 13 0 . 2 19 0 . 06 0 . 11 0 . 18 20 0 . 06 0 . 1 0 . 16 22 0 . 05 0 . 09 0 . 14 26 0 Ref . Appendices Di, D2 & D3 - "Hydrograph Subwatershed No. ill - 12 TABLE NO. 4 SUMMARY TABLE COMPARISON OF PEAK RATES OF RUNOFF WITHOUT DETENTION BUTCHER BOY MALL NORTH ANDOVER, MASSACHUSETTS DRAINAGE PEAK RATE OF RUNOFF STORM EVENT AREA ID* EXISTING PROPOSED NET INCREASE REF. HYDROGRAPHS 2 (Year) Exist.Watershed No. 1 5 . 19 (cfs) -- Table No. 1 it Prop. Watershed No. 1 -- 9 . 49 (cfs) Table No. 2 Prop. Watershed No. 2 -- 2 . 05 (cfs) Table No. 3 TOTAL 5 . 19(cfs) 11 . 54 (cfs) 6 . 35 (cfs) i N 10 (Year) Exist.Watershed No. 1 11 . 37 (cfs) -- Table No. 1 a if Prop. Watershed No. 1 -- 14 . 44 (cfs) Table No. 2 If Prop. Watershed No. 2 -- 4 . 49 (cfs ) Table No. 3 TOTAL 11 . 37 (cfs) 18 .93 (cfs) 7 . 56 (cfs) 100 (Year) Exist .Watershed No. 1 20 . 47(cfs) -- Table No. 1 " Prop. Watershed No. 1 -- 20 . 73 (cfs) Table No. 2 11 Prop. Watershed No. 2 -- 8 . 09 (cfs) Table No. 3 TOTAL 20 . 47 (cfs) 28 . 82 (cfs) 8 . 35 (cfs) * Ref. Figure Nos . 2 & 3 Due to the increase in the peak rates of runoff from the project site under proposed conditions, a stormwater detention structure will be constructed as part of the on-site drainage system. The design of the detention structure is outlined in the following section of this report. 14 IV. ON-SITE REMEDIATION OF PEAK RATES OF RUNOFF: Assuming that no stormwater detention is to be provided, the proposed site development will result in an increase in the existing peak rates of stormwater runoff from the site. Therefore, to mitigate the peak rates of runoff from the site to existing levels, a detention structure will be constructed as part of the on-site drainage system. The peak rates of stormwater runoff will be remediated using a detention structure consisting of two components . A control pipe will be constructed at the discharge of the drainage system from the site across Osgood Street to Clark Street and will restrict the flow of stormwater from the site. The on-site drainage system will surcharge due to the flow restriction at the discharge and the resulting volume of stormwater from the drainage system will be stored in an on-site detention pond. Sheet C1 , Site Plan (Appendix Al ) shows the layout of the control pipe and detention pond. The detention structure was designed to mitigate the peak rates of runoff from the site for a 10 (year) , 24 (hour) storm event to existing levels . The peak rate of runoff from the site under proposed conditions was defined as the sum of the peak rates of runoff from all watersheds comprising the site regardless of runoff routing. The existing peak rate of runoff from the site for a 10 (year) storm was calculated to be 11 . 37 cubic feet per second (cfs) . The proposed peak rate of runoff from the site for a 10 (year) storm with on-site detention was calculated to be 11 . 25 (cfs) . A detailed description of the detention structure design and the resultant peak rates of stormwater runoff is contained in the following sections of this report . Design Basis • The detention structure was designed to mitigate the peak rates of runoff from the site for a 10 (year) , 24 (hour) storm event to - 15 existing levels . The peak rate of runoff from the site under proposed conditions was defined as the sum of the peak rates of runoff from both Watershed Nos . 1 and 2 as defined in Section III of this report. Under proposed conditions, the stormwater runoff from Watershed No. 1 and Watershed No. 2 discharges from the site at two ( 2) different locations . The runoff from Watershed No. 2 discharges overland across the southern border of the site to Great Pond Road. The runoff from Watershed No. 1 discharges through the on-site drainage system across Osgood Street to Clark Street. The proposed total rate of runoff from the site will be controlled by restricting the rate of runoff from Watershed No. 1 . Under existing conditions, the peak rate of runoff from the site for a 10 (year) storm was calculated to be 11 . 37 (cfs) . Under proposed conditions for Watershed No. 2, the peak rate of runoff from the site for a 10 (year) storm was calculated to be 4 . 49 (cfs) . Therefore, in order to maintain the peak rate of runoff for a 10 (year) storm at the existing level, the maximum peak rate of runoff which can be discharged from proposed Watershed No. 1 was calculated to be 6 . 88 (cfs) . Detention Structure Design: The detention structure to be constructed as part of the drainage system consists of two (2) components. A control pipe will be constructed at the discharge of the on-site drainage system and was designed to restrict the stormwater runoff from the proposed Watershed No. 1 at or below 6.88 (cfs) during a 10 (year) storm event. A detention pond will be constructed on the developed site and was designed to receive and store the volume of stormwater which will surcharge from the drainage system due to the restriction imposed by the control pipe. The detention pond will be connected to the on-site drainage system by an overflow pipe from catch basin No. 6. The invert elevation of the overflow pipe and detention pond will be constructed such that a minimum volume of water will surcharge to - 16 the detention pond during a 2 (year) storm event. The control pipe and detention pond are sized such that the maximum water level in the detention pond will be below the low point of the parking lot during a 100 (year) storm event to prevent ponding on the lot. The control pipe consists of 245 ( feet) of 15-inch diameter reinforced concrete pipe. The proposed detention pond will be an earth structure with 3 to 1 side slopes planted with creeping bent grass and the top of the slope planted with indigenous trees for stabilization. A profile of the detention structure is shown in Figure No. 4, Detention Structure Profile. The detention pond and control pipe were sized such that the maximum discharge would be 6 . 88 (cfs) at a water level at elevation 130 . 0 for a 10 (year) storm. The stage-storage-discharge curve for the detention structure is shown' in Figure No. 5, Stage-Storage- Discharge Curve, Detention Structure. Details of the detention pond are shown on Sheet C-6, Details, attached as Appendix A3 . Emergency Overflow from Detention Pond: The detention pond will be constructed such that if the control pipe becomes plugged, stormwater will surcharge from the drainage system to the parking lot. No stormwater will overflow the banks of the detention pond. The top of the detention pond slope will be constructed higher than the high point of the parking lot. If the control pipe becomes plugged, stormwater will pond in the parking lot and eventually flow to Osgood Street via the parking lot entrance. The water will be collected by the Osgood Street drainage system discharging to the wetland west of the project site. Effect of on-Site Remediation on Peak Rates of Runoff: The tabular hydrographs developed for proposed Watershed No. 1 for 2, 10, and 100 (year) storms were routed through the proposed detention structure to determine the effects of the remedial design - 17 i FIGURE NO. 5 STAGE STORAGE DISCHARGE CURVE DETENTION STRUCTURE BUTCHER BOY MALL NORTH ANDOVER,MA 134 i w 132 STORAGE L z 130 Q - w DISCHARGE J W 128 126 1 2 3 4 5 6 7 8 9 10 DISCHARGE (CFS) 0 10 20 30 STORAGE (CU. FT.X 1000) on the peak rates of runoff from the site. A comparison of the resulting peak rates of runoff to the existing conditions are presented in Table No. 5, Summary Table, Comparison of Peak Rates of Runoff, With Detention. The maximum water levels which will result from surcharging the drainage system are presented in Figure No. 6, Maximum Stormwater Elevations . In summary, the peak rate of runoff from proposed Watershed No. 1 for a 10 (year) storm was calculated to be 6 . 76 (cfs) . The resulting peak rate of runoff from the site for a 10 (year) storm under proposed conditions was calculated to be 11 . 25 (cfs) which is comparable to the existing peak rate of runoff for a 10 (year) storm calculated to be 11 . 37 (cfs) . The tabular hydrographs developed for proposed Watershed No. 1 as routed through the detention 8tructure. for the 2, 10, and 100 (year) storms are attached as Appendix E, Composite Hydrograph Development for Determination of Peak Rates of Runoff, Detention Pond Design - Watershed No. 1 , Proposed Conditions . The tabular hydrographs for Watershed No. 1 as routed through the detention structure showing the stormwater runoff from the site for each storm are shown in Table No. 6, Tabular Hydrographs, Detention Pond Design - Watershed No. 1 , Proposed Conditions . 20 TABLE NO. 5 SUMMARY TABLE COMPARISON OF PEAK RATES OF RUNOFF WITH DETENTION BUTCHER BOY MALL NORTH ANDOVER, MASSACHUSETTS DRAINAGE PEAK RATE OF RUNOFF STORM EVENT AREA ID* EXISTING PROPOSED NET INCREASE REF. HYDROGRAPHS 2 (Year) Exist.Watershed No. 1 5 . 19 (cfs) -- Table No. 1 Prop. Watershed No. 1 -- 6 . 07 (cfs) Table No. 6 11 Prop. Watershed No. 2 -- 2 . 05 (cfs) Table No. 3 i TOTAL 5 . 19 (cfs) 8 . 12 (cfs) 2 .93 (cfs) N F- 10 {Year) Exist.Watershed No. 1 11 . 37 (cfs) -- Table No. 1 Prop. Watershed No. 1 -- 6 . 76 (cfs) Table No. 6 If Prop. Watershed No. 2 -- 4 . 49 (cfs) Table No. 3 TOTAL 11 . 37 (cfs) 11 . 25 (cfs) Decrease 100 (Year) Exist.Watershed No. 1 20 . 47 (cfs) -- Table No. 1 it Prop. Watershed No. 1 -- 7 . 70 (cfs) Table No. 6 11 Prop. Watershed No. 2 -- 8 . 09 (cfs) Table No. 3 TOTAL 20 . 47 (cfs) 15 . 79 (cfs) Decrease * Ref. Figure Nos . 2 & 3 TABLE NO. 6 TABULAR HYDROGRAPHS DETENTION POND DESIGN - WATERSHED NO. 1 PROPOSED CONDITIONS BUTCHER BOY MALL 1077 OSGOOD STREET NORTH ANDOVER, MASSACHUSETTS 2 YEAR STORM 10 YEAR STORM 100 YEAR STORM TIME DISCHARGE DISCHARGE DISCHARGE (HR) (CFS) --(CFS) (CFS) 11 0 0 0 11 . 3 0 . 48 0 . 73 1 . 05 11 . 6 0 . 68 1 . 04 1 . 49 11 . 9 1 . 64 2 . 48 3 . 53 12 2 .91 4 . 1 4 . 95 12 . 1 4 . 14 5 . 15 • 5 .96 12 . 2 5 . 39 6 . 08 6 . 51 12 . 3 6 . 01 6. 52 7 . 2 12 . 4 6 . 07 6 . 74 7 . 58 12 . 5 5 .98 6 . 76 7 . 69 12 . 6 5 . 57 6 . 69 7 . 69 12 . 7 4 . 22 6 . 53 7 . 59 12 . 8 1 . 66 6 . 31 7 . 43 13 1 . 32 5 . 48 7 13 . 2 1 . 08 1 . 65 6. 53 13 . 4 0 0 0 13 . 6 0 . 86 1 . 31 1 . 88 13 . 8 0 . 8 1 . 22 1 . 75 14 0 . 75 1 . 13 1 . 63 14 . 3 0 . 67 1 . 03 1 . 47 14 . 6 0 . 61 0 .93 1 . 33 15 0 . 56 0 . 85 1 . 22 15 . 5 0 . 49 0 . 75 1 . 08 16 0 . 42 0 . 64 0 . 92 16 . 5 0 . 36 0 . 55 0 . 78 17 0 . 32 0 . 48 0 . 69 17 . 5 0 . 29 0 . 44 0 . 63 18 0 . 25 0 . 38 0 . 55 19 0 . 22 0 . 33 0 . 47 20 0 . 19 0 . 29 0 . 42 22 0 . 17 0 . 26 0 . 38 26 0 0 0 Ref . Appendices El , E2 & E3, "Hydrograph-Detention Structure No. - 23 APPENDIX E COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF DETENTION POND DESIGN - WATERSHED NO. 1 PROPOSED CONDITIONS CONTENTS : APPENDIX El : 2-YEAR, 24-HOUR STORM APPENDIX E2 : 10-YEAR, 24-HOUR STORM APPENDIX E3 : 100-YEAR, 24-HOUR STORM APPENDIX E1 COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF DETENTION POND DESIGN - WATERSHED NO. 1 PROPOSED CONDITIONS 2-YEAR, 24-HOUR STORM COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF SOIL CONSERVATION SERVICE TR-55 TABULAR HYDROGRAPH METHOD M. ANTHONY LALLY ASSOCIATES PROJECT : BUTCHER BOY MALL NORTH ANDOVER - MA RUN NO.E1 - PROPOSED CONDITIONS - DETENTION POND DESIGN - WATERSHED NO . 1 STORM DATA : TYPE III DURATION 24 ( HR ) FREDUENCY : 2 ( YR ) RAINFALL : 3 . 1 ( IN ) NO . OF SUBWATERSHEDS = `? NO. OF DETENTION STRUCTURES : 1 RESULTS FOLLOW . . . SUrIMARY TABLE - BASIC WATERSHED DATA ------------------------------------- PROJECT : BUTCHER BOY I'IALL NORTH ANDOVER RUN NO.E1 - PROPOSED CONDITIONS - DETEN T I Of\l POND DESIGN - WATERSHED NO . I SUB- DRAINAGE TIME OF TRAVEL DOWNSTREAM TRAVEL 24-HR RUNOFF RUN- INITIAL AREA AREA CONCEN- TIME SUBAREAS TIME RAIN- CURVE OFF ABSTRAC- TRATION THROUGH SUMMATION FALL NUMBER TION SUBAREA TO OUTLET ---------------------------------------------------------------------------------------- - DA TC TT SUMTT P CN O DAtO IA IA/P (SO MI) (HR) (HR) (HR) IINI (IN) (SM-IN) (IN) --------------------------------------------------------------------------------,-------- 1 .0008 .07 0 2 3 .02 3.1 9B 2.87 .0023 .041 .01 2 .0002 .04 .01 3 .01 3.1 98 2.87 .0006 .041 .01 3 .0006 .05 .01 0 3.1 98 2.87 .0017 .041 .01 4 .0005 .02 0 0 3.1 98 2.87 .0014 .041 .01 5 .0003 .06 0 7 8 9 .04 3.1 98 2.87 .0009 .041 .01 6 .0009 .06 0 7 B 9 .04 3.1 98 2.B7 .0026 .041 .01 7 .0005 .06 .02 B 9 .02 3.1 98 2.B7 .0014 .041 .01 8 .0006 .05 .01 9 .01 3.1 98 2.87 .0017 .041 01 9 .0006 .04 .01 0 3.1 98 2.87 .0017 .041 .01 SUMMARY TABLE - DETENTION STRULTWE NO . I _________________________________________ PROJECl : BUTCHER BOY MALL NORTH ANDOVER - MA RUN NO.E1 - PROPOSED CONDITIONS - DETENTION POND DESIGN - WATEkYoED NO . 1 STRUCTURE DESCRIPTION : ON-SITE DETENTION POND INPUT DATA FILE : BBDETPND ' DAT STAGE STORAGE ELEVATION VOLUME DISCHARGE ( FT) (CU FT ) ( CFS ) 126 0 O 126. 1 1 . 26 '02 126 .2 2 '52 . 16 126 .3 3.70 ' 35 126.4 5 .04 '6l 126 .5 6 ' 3 '92 126.6 7' 6 1 . 3 126.7 9 ' 47 1 '69 0B 126.8 12 .51 2. 08 126 .9 17 ' 01 2 . 46 127 21 . 91 2' 79 127 .1 29 '02 3 127.2 42 ' 16 3 '01 127.3 60 ^41 3 '58 127 .4 85 . 05 3' 75 127 .5 116 ' 1B 3'92 127 .6 154. 98 4 ' 00 127 .7 203 '02 4 '23 127 .8 260. 42 4 .38 127. 9 327 . 34 4 ' 52 128 403 '02 4 ' 66 120 . 1 485'72 4 . 0- 12B.2 574 . 19 4 .Y7, 120 .3 666.87 5 '06 128' 4 762 '97 5 , 18 128.5 060. 36 5' 3 128.6 956.69 5 . 42 128 .7 1050 ,22 5 .54 120 ' 8 1141 . 0 &. 65 128.9 1234. 40 5 ' 77 129 1327 . 6 5 . 07 ' ; o i I z I I I o I w I s ^ I I Q _� I M ^ a, C.- U U M a r- � nct i Jl (� u� t`, U r• f7 t'", O 0 CO -.0 t i \ Lrl i`J a, Jr; ::D I T I U D z L7 -0 r,- 'o C, (14 L LEI •01 :,:D C,0 1`4 l > i d 'n 'o 'o 1Z C0 U U (D i 4 . . . . . . . . . . . . . . . . . . . . . . U -C •0 -0 -I�j 10 L' -0 tv r f- ti O O O 'm Oo Cl O CJ O a O7 O co, U U U U D i 1 U) 1 1 I I O i W 1 r JG f !T j O 'id a v !nN U v r? tiCv cr H I LD W i- i nN 0 ?• -.0 r, zi- nu� t� P, ("-a0 'TOtiU � U,l v nGt �-+ U (� Z � 0 � r I � LLL I -: toOr-+ .-i ,-, � c) r- L� unLnnLq . . . . . . . . . . . . . . . . . . . . . . . . Z I Cr D t ct') , ter,." -+ r,JNni ') t.) NNt') J -00,) r t')C, M MO iJ I OJO i v DItSIU Nr 1f7 � Od t7 � UUI - UC^ MUOri !� NL7Li 1NCVh7 l7Uh U OriNN 1- 1 - O U i N CV N ) ct -J' f- C0 O r) 0 t- '0 Ln - OD rJ— CO U7 N 0 z� N U tO r Ln 't [ I - O Q` M W I �> > 1 L—r, n - r,— Ill - M t0 -ONU0 - - N lr -0 r- W^ ?` O *-+ NNt'i :I- Ln -Ot- OOQ- 1 - NtM) tj In -0 -0NMM0` U NNNNNNNNNNC'J I I 1 1 I I I LLJ I G I N t,-) :4- r -0 N M 0, N t,i ztz LO -0 N M 0, i N t'i �. In -Oo N M 0, N ri zl- n -0 1,- CO 0, Qt C] I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . F- 1 Li <1 (I I UUQ Cr- ITO` 0, -)` U (DOOOOOOOOC) NNNNNNNNNNN) I O t > lL I CaNCJNNNNNNMrit'irir) t'i) tltih) t', C7t'i Mhitir^) r- Kir` Q I E- W 1 Z I z I o I U HYDROGRAPH - SUBWATERSHED NO . 1 -------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = .0008 ( SQ MI ) RUNOFF DEPTH = 2.07 ( IN) TIME OF CONCENTRATION = . 07 ( HR ) TRAVEL TIME TO OUTLET = '02 ( HR) INITIAL ABSTRACTION = .041 ( IN ) TABULAR ROUNDING METHOD NO . 1 TIME DISCHARGE DISCHARGE ( HR ) ( CSM/ IN) ( CFS) 11 29 . 07 11 . 3 A '09 11 .6 57 ' 13 11 .9 172 ' 39 12 241 ' 55 12 - 1 425 '98 12. 2 662 1 .52 12.3 531 1 '22 12.4 345 . 79 12 .5 265 ' 6I 12 . 6 191 . 44 12.7 130 '3 12 . 8 101 ' 23 13 83 . 19 13.2 68 ' 16 13. 4 62 . 14 13 . 6 50 . 13 13 -8 54 ' 12 14 50 ' lz 14 . 3 44 ' l 14 .6 41 ' 09 15 37 '08 15. 5 32 . 07 16 27 'O6 16 . 5 23 .u5 17 21 , 05 17 .5 19 .04 18 16 . U4 19 14 20 13 22 11 '03 26 0 0 HYDROGRAPH - SUBWATERSHEU NO . 2 --------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA '0002 ( SO MI ) RUNOFF DEPTH = 2 ' 87 ( IN ) TIME OF CONCENTRATION = ' 04 (HR ) TRAVEL TIME TO OUTLET = ,01 ( HR ) INITIAL ABSTRACTION = '041 ( 1N ) TABULAR ROUNDING METHOD NO . 1 TIME DISCHARGE DISCHARGE (HR) ( CSM/ IN) ( CFS) 11 29 02 ^ 11 .3 38 . 02 11 - 6 57 .03 11 . 9 172 . 1 12 241 . 14 12 . 1 425 .24 12.2 662 .39 12 .3 531 . 3 12. 4 345 -2 12.5 265 . 15 12 . 6 191 . 11 12. 7 130 .07 12 .8 101 . 06 13 83 . O5 13.2 68 ,04 13.4 62 .04 13 . 6 58 ' 03 13.0 54 '03 14 50 .03 14 .3 44 '03 14 . 6 41 .02 15 37 . 02 15.5 32 .02 16 27 .02 16 . 5 23 .01 17 21 . U1 17 .5 19 .01 18 16 ' 01 19 14 ' 01 20 13 '01 22 11 .01 26 0 0 HYDROGRAPH - SUBWATERSHED NO . 3 ________________________________ PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = '0006 ( SO i'lI ) RUNOFF DEPTH = 2 ' 07 ( IN ) TIME OF CONCENTRATION = -05 (HR) TRAVEL TIME TO OUTLET = 0 ( HR) INITIAL ABSTRACTION = .041 ( IN ) TABULAR ROUNDING METHOD NO . 1 TIME DISCHARGE DISCHARGE (HR ) ( CSM/IN) ( CFS ) 11 29 ' D5 11 . 3 07 38 ^ 11 .6 57 ' 1 11 . 9 172 ' 3 12 241 . 41 12, 1 425 ' 77, 12 -2 662 1 ' 14 12-31 531 ' 91 12. 4 345 ' 59 12 .5 265 ' 46 12.6 191 ' 33 12 . 7 130 '22 12 . 8 101 . 17 13 83 ' 14 13 .2 60 ' |2 13 .4 62 . 11 13 .6 59 . 1 13.8 54 '09 14 50 'O9 14 .3 44 . OB 14 .6 41 '07 15 37 'O6 15 .5 32 .06 16 27 ' 05 16 .5 23 . 04 17 21 .04 ' 17 .5 19 -03 18 16 'O3 19 14 -02 20 13 .02 , 22 11 02 26 0 0 HYDROGRAPH - SUBWATERSHED NO . 4 -------------------------------- PROPOSED CONDITIONS WATERSHED DATA : DRAINAGE AREA = '0005 (SO 1,11 ) RUNOFF DEPTH = .2.87 ( IN) TIME OF CONCENTRATION = . 02 (HR) TRAVEL TIME TO* OUTLET = 0 ( HR ) INITlAL ABSTRACTION = .041 ( IN ) TABULAR ROUNDING METHOD NO. 1 TIME DISCHARGE DISCHARGE (HR) ( CSM/ IN ) ( CFS) 11 29 .04 11 . 3 38 .05 ' 11 .6 57 .OB 11 .9 172 .25 12 241 .35 12. 1 425 ' 61 12 . 2 662 . 95 12 .3 ti31 . 76 12 . 4 345 ' 49 12.5 265 ' 38 12 . 6 191 ' 27 12 . 7 130 ' 19 12 - 8 101 ' 14 13 87, 13 . 2 68 13 . 4 62 .09 O8 5B 13.6 ^ 13 .8 54 ' OB 14 50 . 07 14 . 3 44 ' u6 14 .6 41 ' 06 15 37 'O5 15 .5 32 .O5 16 27 'O4 16 .5 23 17 21 ' 03 �3 17 .5 19 . 18 16 . 02 19 14 , u2 20 22 11 '02 26 0 U HYDRO8RAPH - SUBWATERSHED NO . 5 --------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = . 0003 (SQ MI ) RUNOFF DEPTH = 0 .87 ( IN) TIME OF CONCENTRATION = .06 ( HR) TRAVEL TIME TO OUTLET = ' 04 ( HR ) INITIAL ABSTRACTION = . 041 ( IN) TABULAR ROUNDING METHOD NO. 1 TIME DISCHARGE DISCHARGE (HR ) (CSM/ IN ) ( CFS) 11 29 .02 11 . 3 38 . 03 ' 11 .6 57 .05 11 .9 172 . 15 12 241 .21 12. 1 425 . 37 12 . 2 662 '57 12. 3 531 . 46 12 . 4 345 - 3 12 . 5 265 .23 12. 6 191 . 16 12 . 7 130 . 11 12.8 101 .09 13 83 .O7 13 . 2 6B .06 13 . 4 62 .05 . 13 .6 58 05 13 .B 54 . 05 14 50 .O4 14 . 3 44 . 04 14 .6 41 .04 15 37 .D3 15. 5 32 .03 16 27 'O2 16 . 5 23 '02 17 21 '02 17 . 5 19 . 02 1B 16 ' 01 19 14 . O1 20 13 '0i 22 11 '0l 26 0 0 HYDROGRAPH - SUBWATERSHED NO . 6 ------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = . 0009 ( SO MI ) RUNOFF DEPTH = 2 - 07 ( IN) TIME OF CONCENTRATION = . 06 ( HR ) TRAVEL TIME TO OUTLET = ' 01 ( HR ) INITIAL ABSTRACTION = ' 041 ( IN) TABULAR ROUNDING METHOD NO. l TIME DISCHARGE DISCHARGE (HR) (CSM/ IN) ( CFS ) 11 29 ' 07 11 .3 38 . l ' 11 . 6 57 . 15 11 . 9 172 . 44 12 241 .62 12. 1 425 1 . 1 12 . 2 662 1 . 71 12.3 531 1 '37 12. 4 345 .89 12.5 265 .68 12 .6 191 ' 49 12.7 130 ' 34 12 .8 101 ,26 13 83 .21 13.2 68 to 13. 4 62 ' 16 13. 6 50 ' 15 13. 8 54 . 14 14 50 . l3 14 . 3 44 . 11 14 .6 41 . 11 15 37 . 1 15.5 32 .09 16 27 ^O7 16 .5 23 . 06 17 21 ' 05 17 .5 19 ' 05 18 16 ' 04 19 14 '04 20 13 .03 22 11 .03 26 0 O HYDROGRAPH - SUBWATERSHED NO. 7 ---------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = . 0005 ( SO MI ) RUNOFF DEPTH = 2. 87 ( IN ) TIME OF CONCENTRATION = .06 ( HR) TRAVEL TIME TO OUTLET = .02 ( HR ) INITIAL ABSTRACTION = '041 ( IN) TABULAR ROUNDING METHOD NO. 1 TIME DISCHARGE DISCHARGE (HR ) ( CSM/ IN > ( CFB ) 11 29 ' 04 11 . 3 B . O5 11 .6 57 .08 11 . 9 172 ' 25 12 241 .35 12 . 1 425 ' 61 12 . 2 662 . 95 12 . 3 531 ' 76 12.4 345 . 49 12 . 5 265 ' 3B 12 ' 6 191 ' 27 12. 7 130 ' 19 12' 8 101 ' 14 13 83 . )2 13 .2 68 ' l 13 .4 62 ' 09 ' 13. 6 58 U8 13 . 8 54 - 0B 14 50 ' 07 14 . 3 44 'Oa 14 . 6 41 .06 15 37 '0!j 15.5 32 . 05 16 27 '04 16 . 5 23 -03 17 21 .O3 17 .5 19 .03 18 16 .02 19 14 'O2 20 13 -02 22 Al . 02 26 0 0 HYDROGRAPH SUBWATERSHED NO . B ----------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = .0006 (SQ h'II ) RUNOFF DEPTH = 2.07 ( IN) TIME OF CONCENTRATION = .05 ( HR) TRAVEL TIME TO OUTLET = . 01 (HR ) INITIAL ABSTRACTION = .041 ( IN) TABULAR ROUNDING METHOD IVO. 1 , TIME DISCHARGE DISCHARGE (HR) ( CSM/IN) (CFS) 11 29 .05 11 .3 38 .07 11 .6 57 . 1 11 .9 172 • 3 12 241 . 41 12 . 1 425 . 73 12 .2 662 1 . 14 12.3 531 .91 12. 4 345 .59 12.5 265 .46 12.6 191 . 33 12 .7 130 .22 12.B 101 . 17 13 e3 . 14 13.2 6B . 12 13 . 4 62 . 11 13.6 50 . 1 13.B 54 .09 14 50 •09 14 .3 44 .CEO 14 .6 41, • 07 15 37 . 06 15.5 32 .06 16 27 .05 16 .5 23 04 17 21 C)Z 17 .5 19 03 19 16 0- 19 14 0 20 13 .02 22- 26 0 0 HYDROGRAPH - SUBWATERSHED NO. 9 ----------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = '0006 ( 60 MI ) B7 ( IN) RUNOFF DEPTH = 2.97 TIME OF CONCENTRATION = .04 (HR ) TRAVEL TIME TO OUTLET = 0 ( HR ) INITIAL ABSTRACTION = .041 ( IN ) TABULAR ROUNDING METHOD NO. l TIME DISCHARGE DISCHARGE (HR > ( CSM/ IN > ( CFS) 11 29 . O5 38 11 .3 , 07 11 . 6 57 . 1 11 .9 172 .3 12 241 '41 12. 1 425 ' 73 12.2 662 1 . 14 12'3 531 ' 91 12. 4 345 ' 59 12 .5 265 ' 46 12 .6 191 ' 33 12 .7 130 ' 22 12 .8 101 ' 17 13 83 ' 14 13 .2 68 ' 12 13 .4 62 13 '6 13 .8 54 .09 14 50 '09 14 .3 44 '00 14 '6 41 ' 07 15 37 '06 15 .5 32 .Oa ^ 16 27 D5 16 .5 23 .04 17 21 .04 17 .5 19 .03 10 16 .03 19 14 . 02 20 13 '02 22 11 -0Z 26 0 0 COMPOSITE HYDROGRAPH NO . 1 ---------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUBWATERSHED NO . 1 SUBWATERSHED NO . 2 . TIME DISCHARGE (HR) ( CFS) 11 .OB 11 .3 . 11 11 .6 - 16 11 .9 .49 12 .69 12. 1 1 .22 12.2 1 . 9 12.3 1 .52 12. 4 '99 12 .5 .76 12 .6 .55 . 12.7 '37 12.8 .29 13 .24 13.2 . 2 13. 4 . 18 13. 6 ' 17 13 .8 . 15 14 . 14 14 .3 ' 1Z 14 . 6 . 12 15 . 11 15'5 .09 16 ' 0B 16 . 5 . 07 17 . O6 17 . 5 .O5 18 .05 19 .D4 20 ,U4 22 , 03 26 0 COMPOSITE HYDROGRAPH NO. 2 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM : SUBWATERSHED NO. COMPOSITE HYDRO . NO . 1 TIME DISCHARGE (HR ) ( CFS ) 11 . 13 11 . 3 . 17 11 .6 .26 11 .9 .79 12 1 . 11 12. 1 1 .95 12. 2 0.04 12 . 3 2. 44 12 . 4 1 .50 12 .5 1 .22 12.6 . BB 12 . 7 . 6 12 .8 . 46 13 .30 13.2 .31 13. 4 .28 13. 6 .27 13. 8 .25 14 •23 14. 3 •2 14 . 6 . 19 15 . 17 15. 5 . 15 16 . 12 16. 5 . 11 17 • 1 17 .5 .09 18 .07 19 .06 20 .06 22 .05 26 0 COMPOSITE HYDROGRAPH NO. 3 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUBWATERSHED NO. 5 SUBWATERSHED NO. 6 SUBWATERSHED NO. 7 TIME DISCHARGE (HR) ( CFS ) 11 . 14 11 .3 - . 19 11 .6 .2B 11 .9 . 04 12 1 . 17 12. 1 2 .07 12 . 2 3.23 12 . 3 2-59 12 . 4 1 .68 12 . 5 1 .29 12.6 . 93 12 . 7 •63 12.8 .49 13 .4 1T . 2 . ?3 13. 4 . J 13. 6 . 20 13.8 . 26 14 .24 14.3 • L1 14. 6 •2 15 . 18 15 .5 . 16 16 . 13 16.5 . 11 17 . 1 17 .5 .09 18 .OB 19 .07 20 .06 22 .05 26 0 COMPOSITE HYDROGRAPH 1\10 . 4 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUBWATERSHED NO . 8 COMPOSITE HYDRO. NO. 3 TIME DISCHARGE_ (HR) (CFS) 11 . 19 11 . 3 .25 11 . 6 .30 11 . 9 1 . 13 12 1 .59 12. 1 2 . 8 12 . 2 4. 37 12 .3 3 . 5 12 .4 2.29 12. 5 1 .75 12. 6 1 . 26 12. 7 .06 12. 8 . 67 1 55 13. 2 .45 13 . 4 . 41 13. 6 . 38 13 .8 . 36 14 • 33 14. 3 .29 14 .6 .27 15 .24 15.5 .21 16 . 10 16 .5 . 15 17 . 14 17 .5 . 13 18 . 11 19 . 09 20 .09 22 .07 26 0 COMPOSITE HYDROGRAPH NO . 5 ------------------ PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUBWATERSHED NO. 9 COMPOSITE HYDRO. NO . 4 TIME DISCHARGE (HR) ( CFS) 11 .24 11 . 3 .32 11 .6 .47 11 .9 1 .43 12 2 12. 1 3.53 12.2 5.51 12.3 4 . 42 12. 4 2.87 12 .5 2.2 12 .6 1 .59 12 .7 1 .00 12.9 . 04 13 .69 13.2 .57 13 .4 .52 13.6 .49 13. 8 . 45 14 . 42 14.3 . 37 14.6 .34 15 .31 15.5 . 27 16 .22 16.5 . 19 17 . 17 17 . 5 . 16 18 . 13 19 . 12 20 . 11 22 . 09 26 0 COMPOSITE HYDROGRAPH 1\10. 6 --------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUBWATERSHED NO. 4 COMPOSITE HYDRO. NO. 5 COMPOSITE HYDRO. NO. 2 TIME DISCHARGE (HR) ( CFS ) 11 . 42 11 .3 •54 11 .6 . B-12 11 .9 2 .47 12 3 . 46 12. 1 6.09 12. 2 9 . 49 12 .3 7 .61 12. 4 4 .95 12.5 3.8 12 . 6 2 . 74 12. 7 1 .86 12.8 1 . 45 13 1 . 19 13.2 •90 13.4 . 99 13. 6 . 83 13. 0 .77 14 . 72 14 .3 • 6T 14. 6 .59 15 .53 15.5 . 46 16 . 39 16 .5 .33 17 17 .5 .27 18 .23 19 L 20 . 19 22 . 16 26 0 HYDROGRAPH - DETENTION STRUCTURE ND . 1 -------------------------------------- PROPOSED CONDITIONS INPUT : COMPOSITE HYDROGRAPH NO. 6 NET STAGE STORAGE TIME INFLOW OUTFLOW INFLOW ELEVATION VOLUME (HR) (CFS) (CFS) ( CFS) (FT ) ( CU FT ) ------------------------------------------------------------- 11 . 42 0 . 42 126 . 1 1 .5 11 .3 .54 .48 .06 126. 4 4 .65 11 . 6 .82 .68 . 14 126. 5 5.03 11 .9 2.47 1 .64 .83 126 .8 12.2 12 3. 46 2.91 .54 127 . 1 28.52 12. 1 6.09 4 . 14 1 .95 127 . 7 102 . 22 12 .2 9.49 5.39 4 . 1 128 .6 947 . 45 12.3 7 .61 6 .01 1 . 6 129 . 1 2001 12. 4 4 .95 6.07 -1 . 12 129 .2 2398. 15 12.5 3.0 5.90 -2. 10 129 . 1 1903.2-r 12 .6 2.74 5. 57 -2 .83 128.7 1061 .61 12.7 1 . 86 4 . 22 -2.35 127 .7 190. 62 12. 8 1 .45 1 .66 - .21 126 . 7 0.56 13 1 . 19 1 . 32 - . 13 126.6 7 .21 13. 2 .99 1 . 00 - . 11 126.5 6.46 13. 4 .99 0 0 0 13.6 .83 . 06 - .03 1' 5. 95 13.8 .77 . 0 - . 03 126 . 5 5 . 72 14 .72 . 75 - .C) 126. 4 5. 49 14 . 3 .63 .67 - .04 126. 4 5 . 15 14 .6 .59 .61 - .0" 126 . 4 4.97 15 .53 .56 - .0;; 126 . 4 4 .7 15 .5 . 46 . 49 - . 04 126 4 . 36 16 .39 .42 - . 04 126 . ', 4 .01 . 36 - .0-3126 .3 _ .71 16.5 .33 17 .3 . 3,2 - .01 12 6. _,. 5 17 .5 .27 .29 - .01 126 . 3 31. 312 18 .23 .25 - .02 126 .2 3.06 19 .2 .22 - .01 126.2 2.85 20 . 19 . 19 -.01 126.2 2 .74 22 . 16 . 17 - .01 126. 2 2 .50 26 0 0 0 0 0 MAXIMUM DISCHARGE OCCURS C TIME = 12. 4 ( HR) MAXIMUM DISCHARGE = 6.()7 ( CFS ) MAX 1 P1U[,l Fl_FVAT I ON = 129 . 1 8 (FT ) APPENDIX E2 COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF DETENTION POND DESIGN - WATERSHED NO. 1 PROPOSED CONDITIONS 10-YEAR, 24-HOUR STORM COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF SOIL CONSERVATION SERVICE TR-55 TABULAR HYDROGRAPH METHOD M. ANTHONY LALLY ASSOCIATES PROJECT : BUTCHER BOY MALL NORTH ANDOoER - MA RUN NO.E2 - PROPOSED CONDITIONS - DETENTION POND DESIGN - WATPRSHED NO . 1 STORM DATA; TYPE DURATION 24 ( HR ) FREQUENCY : 10 ( YR ) RAINFALL : 4 ' 6 ( IN ) NO . OF SUBWATERSHEDS , 9 NO. OF DETENTION STRUCTURES : 1 RESULTS FOLLOW ' . . SUMMARY TABLE - BASIC WATERSHED DATA ----------------------------- PROJECT : BUTCHER BOY MALL NORTH ANDOVER - MA RUN NO.E2 - PROPOSED CONDITIONS - DETENTION POND DESIGN - WATERSHED NO . 1 SUB- DRAINAGE TIME OF TRAVEL DOWNSTREAM TRAVEL 24-HR RUNOFF RUN- INITIAL AREA AREA CONCEN- TIME SUBAREAS TIME RAIN- CURVE OFF ABSTRAC- TRATION THROUGH SUMMATION FALL NUMBER TION SUBAREA TO OUTLET --------------------------------------------------------------------------------------------------------- DA TC TT SUMTT P CN O DAtO IA IA/P (SO MI) (HR) (HR) (HR) (IN) (IN) (SM-IN) (IN) --------------------------------------------------------------------------------------------------------- 1 OOOB .07 0 2 3 .02 4.6 98 4.36 .0035 .041 .01 2 .0002 .04 .01 3 .01 4.6 98 4.36 .0009 .041 .01 3 .0006 .05 .01 0 4.6 98 4.36 .0026 .041 .01 4 .0005 .02 0 0 4.6 98 4.36 .0022 .041 .01 5 .0003 .06 0 7 8 9 .04 4.6 98 4.36 .0013 .041 .01 6 .0009 .06 0 7 8 9 .04 4.6 90 4.36 .0039 .041 .01 7 .0005 .06 .02 0 9 .02 4.6 98 4.36 .0022 .041 .01 0 .0006 .05 .01 9 .01 4.6 98 4.36 .0026 .041 .01 9 .0006 .04 .01 0 4.6 98 4.36 .0026 .041 .01 SUMMARY TABLE - DETENTION STRUCTURE NO . 1 ----------------------------------------- PROJECT : BUTCHER BOY MALL NORTH HNDOVER - MA RUN NO.E2 - PROPOSED CONDITIONS - DETENTION POND DESIGN - WATERSHED NO . 1 STRUCTURE DESCRIPTION: ON-SITE DETENTION POND INPUT DATA FILE: BBDETPND. DAT STAGE STORAGE ELEVATION VOLUME DISCHAHGE (FT ) (CU FT ) ( CFS) ___________________________________ 126 0 0 126. 1 1 ' 26 .02 126.2 2.52 ' 16 126.3 3' 78 ' 35 126.4 5 . 04 . 61 126.5 6'3 ' 92 126.6 7 . 6 1 ' 3 126. 7 9 ' 47 1 .69 126.8 12, 51 2 ' 08 126.9 17 - 01 2 ' 46 127 21 . 91 2 . 79 127 . 1 29. 82 3 127 .2 42 ' 16 3 ' 01 127 .3 60 .41 3 . 5B 127 . 4 05 '05 3 - 75 127 '5 116 . 18 3 .92 127 .6 154 '98 4 '0B 127 . 7 203 .02 4 .23 127 .8 260 .42 4 .30 127 .9 327 . 34 4 ' 52 128 403 ' 02 4 . 66 120 . 1 485. 72 4 ' 8 128 .2 574 . 19 4 ' 9-r, 128. 3 666 ' 87 5. 06 128. 4 762 ' 97 5' 1O 128'5 060 -36 5 ' 3 120. 6 956 . 69 5 . 42 128 . 7 1050 . 22 5 . 54 120.8 1141 ' 0 5 ' 65 128 . 9 1214 . 40 5 - 77 129 1327 ' 6 5 ' 07 SUMMARY TABLE - DETENTION STRUCTURE NO . 1 ------------------------------------------- (CONTINUED) STAGE STORAGE ELEVATION VOLUME DISCHARGE ( FT ) ( CU FT ) ( CFS ) t29. 1 1920. 65 5 . qo 129 .2 2521 . 37 v . 09 129 .3 1128 . 04 6 . 19 129 .4 3730 . 11 6 . 129 . 5 4049 . 16 6 . 4 129 .6 4961 . 19 6 . 49 129.7 5571 . 41 6 . 59 129 . 0 6190 . 02 6 . 61% 129 .9 6801 . 7 6 . 70 130 7415 . 52 6 . 00 130. 1 8031 . 5 6 . 97 130 .2 0650 . DB 7 . Ob 130 .3 9274 . 54 7 . 15 130. 4 9905 . 56 7 . 24 130.5 10544 . 74 7 130 . 6 11190 . 41 7 . 41 130.7 11901 . 76 7 . ,:i 130. 0 12519 . 04 7 . 50 130. 9 10197 .75 7 . 6% 131 1 B85 .54 7 . 7'5 131 . 1 145W .29 7 . 0 131 .2 15291 . 00 7 .91 131 .3 16000. 96 7 . 99 131 .4 16717 .05 0 .07 131 .5 17475. 04 0 . 15 131 .6 10223 . 97 0 . 23 131 . 7 10983 8 .31, 131 . 0 19752. 49 8 . 30 131 .9 20532 .51 0. 46 132 21.123 . 14 8 . 54 132 . 1 22124 . 45 0 . 61 132 .2 22936 .52 0 . 60 132 . 3 23759 . 4 0 . 76 132.4 24591. 19 132.5 25437 . 94 8 . 9 132. 6 26293. 73 0 . 97 132.7 27160.63 9 .05 132.9 20019 .72 9. 12 132.9 28928.07 9 . 19 133 29020. 74 9.25 HYDROGRAPH - SUBWATERSHED NO. 1 -------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = .0009 ( SO MI ) RUNOFF DEPTH = 4 . 06 ( IN) TIME OF CONCENTRATION = . 07 (HR ) TRAVEL TIME TO OUTLET = .02 ( HR) INITIAL ABSTRACTION = .041 ( IN) TABULAR ROUNDING METHOD NO. 1 TIME DISCHARGE DISCHARGE (HR ) (CSM/ IN) ( CFS ) 11 29 . 1 11 . 3 38 . 13 11 .6 57 .2 11 . 9 172 . 6 12 241 .94 12. 1 425 1 .48 12 .2 662 2 .31 12.3 531 1 . 05 12 .4 345 1 .2 12 .5 265 .93 t2. 6 191 .67 12.7 100 . 45 12 . 8 101 . 35 13 83 .29 13 . 2 68 . 24 13. 4 62 .22 t3 .6 59 . 2 13 . 8 54 . 19 14 50 . 17 14 . 3 44 . 15 14 .6 41 . 14 15 37 . 13 15. 5 32 . 11 16 27 .09 16.5 23 .08 17 21 . 07 17 .5 19 .07 18 16 . 06 19 t4 .05 20 13 .05 22 11 . 04 26 0 0 HYDROGRAPH - SUBWATERSHED NO . 2 -------------------------------- PROPOSED CONDITIONS WATERSHED DATA : DRAINAGE AREA = .0002 ( SQ MI ) RUNOFF DEPTH = 4 ' 36 ( IN ) TIME OF CONCENTRATION = '04 ( HR) TRAVEL TIME TO OUTLET = .01 ( HR) INITIAL ABSTRACTION = '041 ( IN) TABULAR ROUNDING METHOD NO . l TIME DISCHARGE DISCHARGE (HR) ( CSM/ IN ) ( CFS) 11 29 .O3 11 .3 30 .03 11 .6 57 - 05 11 . 9 172 ' l5 12 241 .21 12. 1 425 .37 12 .2 662 '5B 12.3 531 ' 46 12. 4 345 '3 12. 5 265 '23 12. 6 191 ' 17 12 . 7 130 ' 11 12.8 101 '09 13 83 ' O7 13 .2 68 ' 06 13 . 4 62 '05 13 .6 50 ' 05 13. 8 54 -U5 14 50 ' O4 14 . 3 44 '04 14.6 41 '04 15 37 .03 15. 5 32 .03 16 27 . 02 16. 5 23 ' 02 17 21 . 02 17 . 5 19 ' 02 18 16 . U1 19 14 .01 20 13 ' O1 22 11 '0z 26 0 0 HYDROGRAPH - SUBWATERSHED NO . 3 -------------------------------- PROPOSED CONDITIONS WATERSHED DATA, DRAINAGE AREA = '0006 ( SO MI ) RUNOFF DEPTH = 4 . 36 ( IN ) TIME OF CONCENTRATION = ' 05 ( HR ) TRAVEL TIME TO OUTLET = 0 ( HR ) INITIAL ABSTRACTION = .041 ( IN ) TABULAR ROUNDING METHOD NO . l TIME DISCHARGE DISCHARGE (HR) (C5M/ IN) ( CF5) 11 29 'U8 11 . 3 30 . / 11 .6 57 . 15 11 ' 9 172 12 241 ' 63 12 ' 1 425 l ' 1l 12 . 2 662 1 '73 12 .3 531 1 ' 39 12 .4 345 . 9 12.5 265 . 69 12. 6 191 . � 12 .7 130 '34 12 .0 101 . 26 13 83 . 22 13. 2 69 . 18 13.4 62 ' 16 13. 6 58 IS 13 .8 54 . 14 14 50 ' l3 14 .3 44 ' 12 14 .6 41 ' 11 15 37 , 1 15.5 32 . 00 16 27 'O7 16.5 23 ' 06 17 21 '05 17 . 5 19 '05 18 16 ' 04 19 14 . 04 20 13 .03 22 11 .03 26 0 0 HYDROGRAPH - SUBWATERSHED NO. 4 ----------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = .0005 ( SO Ml ) RUNOFF DEPTH = .4 ' 36 ( IN ) TIME OF CONCENTRATION = . 02 ( HR ) TRAVEL TIME TO OUTLET = 0 ( HR ) INITIAL ABSTRACTION = ' 041 ( IN ) TABULAR ROUNDING METHOD NO. 1 TIME DISCHARGE DISCHARGE ( HR) ( CSrll/ lN) ( CFS ) 11 29 .06 11 .3 3B ' 08 11 . 6 57 . 12 11 '9 172 . 38 12 241 .53 12. 1 425 ' 9� 12 . 2 662 1 . 44 12 . 3 531 1 - 16 12 . 4 345 ' 75 12. 5 265 '5B 12 .6 191 . 42 12~ 7 130 . 2B 12. 8 101 . 22 13 83 . 1B 13 .2 60 ' 15 13.4 b2 . 14 13 . 6 58 13. 8 54 - 12 14 50 . 11 14 . 3 44 14 . 6 41 '09 15 37 ' 08 15.5 3� . 07 16 27 '0b 16. 5 23 '05 17 21 .05 17 . 5 19 ' 04 18 16 - 03 19 14 ' O3 20 13 'O3 2� 11 , 02 26 O 0 HYDROGRAPH - SUBWATERSHED NO ' 5 PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = '0003 ( SO MI ) RUNOFF DEPTH = 4 . 36 ( IN) TIME OF CONCENTRATION = .06 ( HR) TRAVEL TIME TO OUTLET = .04 (HR) INITIAL ABSTRACTION = . 041 ( IN) TABULAR ROUNDING METHOD 1\10 . 1 TIME DISCHARGE DISCHARGE (HR) (CSM/IN) ( CFS) 11 29 .04 11 . 3 38 .05 . 11 .6 57 ' 07 11 . 9 172 '23 12 241 . 32 12. 1 425 ' 56 12. 2 662 .87 12.3 531 ' 7 12 . 4 345 . 45 12. 5 265 . 35 12. 6 191 . 25 12. 7 130 ' 17 12 . 8 101 . l3 13 B� ' ll 13. 2 60 . 09 13. 4 62 '013 13.6 58 . OB 13'8 54 - 07 14 50 . 07 14 . 3 44 .06 14. 6 41 ' 05 15 37 ' O5 15. 5 32 ' O4 16 27 ' (.)4 16 '5 23 '03 17 21 ' O3 17 . 5 19 'O2 18 16 'O2 19 14 . U2 20 l3 . 02 22 1 ] 'O1 26 0 u HYDROGRAPH - SUBWATERSHED NO . 6 --------------------------------- PROPOSED CONDITIONS WATERSHED DATA ; DRAINAGE AREA = - 0009 ( SU nl ) RUNOFF DEPTH = 4 ' 36 ( IN ) TIME OF CONCENTRATION = '06 ( HR ) TRAVEL TIME TO OUTLET = - 04 ( HR ) INITIAL ABSTRACTION = ' 041 ( IN ) TABULAR ROUNDING METHOD NO. l TIME DISCHARGE D15CHAR8E (HR) (CSM/IN) ( CFS ) 11 29 . 11 11 . 3 au- ' 15 11 .6 57 '22 11 . 9 172 .68 12 241 -95 12 . 1 425 1 ,67 12 . 2 662 2. 6 12 . 3 531 2 .09 12. 4 345 1 ' 35 12 . 5 265 1 -04 12 .6 191 '75 12. 7 130 '51 12. 8 101 . 4 13 83 '33 13.2 68 '27 13 . 4 62 '24 13. 6 58 '23 13. 0 54 '21 14 50 '2 14 ;3 44 - 17 14 .6 41 . 16 15 37 , l5 15.5 32 ' l3 16 27 . 11 16. 5 23 .09 17 21 '0B 17 .5 19 .07 18 16 .O6 19 14 .05 20 13 .O5 22 11 -04 26 0 0 _ _ HYDRO8RAPH - SUBWATERSHED NO ' 7 -------------------------------- PROpOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = 00O5 ( SQ MI ) RUNOFF DEPTH = 4. 36 (IN ) TIME OF CONCENTRATION = .06 ( HR ) TRAVEL TIME TO OUTLET = '02 ( HR ) INITIAL ABSTRACTION = .041 ( IN ) TABULAR ROUNDING METHOD NO. 1 TIME DISCHARGE DISCHARGE (HR) ( CSM/ IN ) ( CFS ) 11 29 . 06 11 . 3 38 ' 08 11 - 6 57 . 1Z 11 . 9 172 ' 38 12 241 . 53 12 . 1 425 . 93 12. 2 662 1 . 44 12. 3 531 1 ' 16 12 . 4 345 ' 75 12 . 5 26---) ' 58 12 . 6 191 12. 7 l30 - 2B 12 . 8 101 . 22 13 B3 IF, 13 . 2 60 . 15 13 . 4 62 ' 14 13 . 6 5B ' 1J 13. 8 54 ' 12 14 50 ' 11 14 .3 44 ' l 14 . 6 41 . 09 15 37 ' 08 15 . 5 32 '07 16 27 ' O6 16 . 5 23 ' 05 17 21 ' 05 17 . 5 19 ' 04 18 16 .03 19 14 -03 20 13 -03 22 11 ' 02 26 0 0 HYDROGRAPH - SUBWATERSHED NO . 3 --------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = . 0006 ( So 1,11 ) RUNOFF DEPTH = 4 . 36 ( IN ) TIME OF CONCENTRATION = . 05 ( HR ) TRAVEL TIME TO OUTLET = . 01 (HR ) INITIAL ABSTRACTION - . 041 ( IN) TABULAR ROUNDING METHOD 1\10. 1 TIME DISCHARGE DISCHARGE (HR ) ( CSM/ IN) ( CFS ) 11 29 . 08 11 . 3 39 . 1 11 . 6 57 . 15 11 . 9 172 . 45 12 241 .6_3 12 . 1 425 1 . 11 12.2 662 1 .7' 12 . 3 531 1 .39 12.4 345 . 9 12.5 265 . 69 12. 6 191 .5 12 . 7 130 . 34 12 .8 101 .26 13 83 . 2? 13. 2 68 . 18 13 .4 62 . 16 13 . 6 58 . .15 13.8 54 . 14 14 50 . 13 14 . 3 44 , 12 14 .6 41 . 11 15 37 . l 15 . 5 32 i8 16 27 .07 16.5 23 .06 17 21 .01) 17 .5 19 . 0:i 18 16 .04 19 14 .04 20 1'� 0?, 22 1 1 i 26 O C) ' HYDROGRAPH - SUBWATERSHED NO. 9 --------------------------------- PROPOSED CONDITIONS WATERSHED DATA : DRAINAGE AREA = . 0006 ( SO M| ) RUNOFF DEPTH = 4 . 36 ( IN) TIME OF CONCENTRATION = '04 ( HR ) TRAVEL TIME TO OUTLET = 0 ( HR) INITIAL ABSTRACTION = -041 ( IN ) TABULAR ROUNDING METHOD NO. 1 , TIME DISCHARGE DISCHARGE (HR) ( CSM/ IN) ( CFS ) 11 29 . O8 11 . 3 38 . l 11 . 6 57 ' 15 11 - 9 172 '45 12 241 .63 12. 1 425 1 ' 11 12. 2 662 l . 73 12. 3 531 1 .39 12 .4 345 ' 9 12 . 5 265 . 69 12 , 6 191 . 5 12. 7 130 '34 12 .8 101 ' 26 13 07, . 22 13. 2 68 ' 18 13. 4 62 . 16 13. 6 58 . 15 13. 8 54 . 14 14 50 ' 13 14 . 3 44 . 12 14 . 6 41 ' 11 15 37 ' 1 15. 5 32 . 08 16 27 .U7 16. 5 23 .06 17 21 ' OD 17 . 5 19 . 05 18 16 . 04 19 14 . 04 20 13 - O3 22 11 . 03 26 0 0 COMPOSITE HYDROGRAPH NO. 1 ---------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUBWATERSHED NO. 1 SUBWATERSHED NO . 2 TIME DISCHARGE (HR ) ( CFS ) 11 . 13 11 . 3 . 17 11 . 6 .25 11 .9 .75 12 1 .05 12. 1 1 .05 12. 2 2 .a9 12. 3 � .32 12 . 4 1 . 51 12 . 5 1 . 16 12 . 6 .03 12 . 7 .57 12 . 8 . 44 13 .36 13 . 2 . 3 13 . 4 . 27 13 . 6 .25 13 . 0 .24 14 . 22 14 . 3 . 19 14 . 6 . 10 15 . 16 15 . 5 . 14 16 . 12 16. 5 . 1 17 .09 17 . 5 .00 18 .07 19 .06 20 .06 22 .05 26 0 COMPOSITE HYDROGRAPH NO. 2 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUDWATERSHED NO . 3 COMPOSITE HYDRO. NO. 1 TIME DISCHARGE (HR ) ( CFS) 11 .2 11 . 3 .27 11 .6 . 4 11 .9 1 .2 12 1 .68 12 . 1 2.97 12.2 4 .62 12.3 . 3.71 12.4 2.41 12.5 1 .05 12 .6 1 .33 12 . 7 . 91 12 .8 . 71 13 .58 13. 2 . 47 13. 4 .43 13.6 .4 13. 8 . 39 14 . ._, 14 .3 .31 14.6 .29 15 .26 15.5 .22 16 . 19 16 .5 . 16 17 . 15 17 . 5 . 13 18 . 11 19 . 1 20 . 09 22 .08 26 0 COMPOSITE HYDROGRAPH NO . -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUBWATERSHED NO . 5 SUBWATERSHED NO. 6 SUBWATERSHED NO . 7 TIME DISCHARGE (HR) ( CFS ) 11 .22 11 .3 .28 11 .6 •42 11 .9 1 .20 12 1 .79 12 . 1 3. 15 12 .2 4.91 12 .3 3 .94 12 . 4 2.56 12 .5 1 .97 12 .6 1 .42 12 .7 .96 12.8 •75 13 .62 13 . 2 •5 13. 4 .46 13 . 6 . 43 13 .8 . 4 14 .37 14 .3 •33 14 .6 .3 15 .27 15.5 .24 16 • `- 16.5 . 17 17 . 16 17 .5 . 14 18 . 12 19 1 20 • 1 22 .08 26 0 COMPOSITE HYDROGRAPH NO. 4 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM : SUHWATERSHED NO. 8 COMPOSITE HYDRO . NO . TIME DISCHARGE (HR) ( CFS ) 11 .29 11 . 3 .38 11 .6 .57 11 .9 1 .73 12 2. 42 12. 1, 4 .27 12 .2 6 .64 12.3 5 .33 12 . 4 3.46 12 .5 2 . 66 12 .6 1 .92 12 .7 1 . 3 12.B 1 .01 13 . 83 13 .2 . 68 13.4 . 62 13 . 6 . 58 13.8 . 54 14 5 14 .3 • 44 14 .6 . 41 15 . 37 15 .5 • 32 16 . 27 16 .5 17 .21 17 .5 . 19 18 . 16 19 . 14 20 131 22 11 26 0 COMPOSITE HYDROGRAPH NO . 5 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUBWATERSHED NO . 9 COMPOSITE HYDRO. NO . 4 TIME DISCHARGE (HR ) (CFS) 11 .37 11 .3 .4B 11 .6 ~72 11 .9 2 . 18 12 3.05 12 . 1 5 .30 12 '2 0 . 30 12.3 6' 72 . 12 .4 4 . 37 12.5 3 . 35 12 .6 2.42 12.7 1 . 65 12 .8 1 . 28 13 1 '05 13 '2 ' 86 13 .4 .78 13.6 ' 73 13 .8 . 6B 14 .63 14 .3 .56 14 . 6 .52 15 .47 15.5 . 4 16 . 34 16 .5 .29 17 .27 17 .5 '24 18 . 2 19 ' 18 20 . 16 22 . 14 26 0 COMPOSITE HYDROGRAPH NO . 6 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM : SUBWATERSHED NO . 4 COMPOSITE HYDRO. N0 . 5 COMPOSITE HYDRO. NO . 2 TIME DISCHARGE (HR) ( CFS) 11 . 63 11 .3 .83 11 . 6 1 .24 11 .9 3 .75 12 5 .26 12 . 1 9 .27 12.2 14 . 44 12 .3 11 .59 12. 4 7. 5? 12 .5 5. 79 12 .6 4. 17 12. 7 2.84 12.8 2.2 13 1 .81 13. 2 1 .40 13.4 1 .35 13.6 1 .27 13.8 1 . 18 14 1 . 09 14 .3 .96 14 .6 . 89 15 . 81 15.5 . 7 16 .59 16 .5 . 5 17 . 46 17 .5 .41 18 .35 19 .31 20 .28 22 .24 26 0 3 H D I = D I Z m I < X N N N -0 0 10 H O- hJO Oc0 �I �10` 0- 00 A4�, .P (ri (,: (AC4 (4» JhJhJNNNNJ NJJ ' �-'• �-'� µ I C _0 I m 3 13 -I O 1 0 C U U U 0 (4 07 'Cl OJ0 U A W NS � 0- W I •• m U) 1 0 3 I m I m I m 0 1 D s < C7 I 0 1 Ti D D H I 3 (7 1 = x x En 1 >+ m O I H F 4 (� O . . . . . . µ �..-� �--� �-•` �-` N N -p U -1 �-' �-' -0 U C4 µ . . I .. Z O z I I 3 3 I N N (A C4 U -} M O -0 . . . . . . . . . . O 0` 1 C7 71 co 0 I C C D N U U L1 - `OO, 0 C4 t C, M Jj M - '-JU NhJ NJ (A (A 1 7r 3 -z Z7 C 0 LT M ' 4:� "IO W, U ^ -1 0- U -P. I LO 0 -1 -I 1 m m ,0 p I E m -+ I -i m 0 m I 0 1 m r H I = z I Z F,1 Ln 0 i d < n D = n I O zI O -iD C O p — UUC- C 0 000, U N O 1 C O i Z 7J �7 hJ N C C,� 4P U C' J O -0 ° • • 0G7 Ul C, -C (.+ c0 -PMLq 0UC40 - IJtA I N Zm (ACJ Ulm C,3 -CC* J�: hJCJU I co r D 1 -I r 1 - 0 m I ?J 11 11 I Z y I Cl � 1 m H I m U C:.I C4fj UCD µ 1 Z i CJ O C O O O C C C, C 0 p p O r, 0 . . . . .0 v N 0 1 n 7 z 0 I Z µ N � NCJNhJ .r UU � r,4 "J UMM0C4 - - N - CI 1 71rm 1 O n tJ J 0 hJ 0l 1 Cn 0 �l (P. I v I I m i r m C() N N N hJ FJ hJ hJ N N N fJ tJ N N f•J N N hJ hJ hJ N N N N N hJ N N N N I Ti < —I C G- 0- C` UC- Cr0` 0- C- 0` UCP Um -0 0J -40 -0 -0 -0CC 0 0` i —iDfD NC4 'C,4 ! JCS A P AUUUUU C CO L '-CU Ns0` O UFJ 1 - m 1 0 I Z i I i r. r� C� r„ C� p A UU0 0 0 � �lO ru CC, Ln C U f N �JUhJ I CO - - UU UO- < LO µCJC" ci 0 -p UUh•' 0` mC•JU -r-- m I n0 -i (.' C'JUhJN cO 0rA0, --O C4 - • Olt� -Oom I CrO O . . . . • ( i - O 1 Cal hJT-1mmNOWt) pT. 177D - � mm I m I APPENDIX E3 COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF DETENTION POND DESIGN - WATERSHED NO. 1 PROPOSED CONDITIONS 100-YEAR, 24-HOUR STORM ` COMPOSITE HYDROGRAPH DEVELOPMENT FOR DETERMINATION OF PEAK RATES OF RUNOFF SOIL CONSERVATION SERVICE TR-55 TABULAR HYDROGRAPH METHOD M. ANTHONY LALLY ASSOCIATES PROJECT : BUTCHER BOY MALL NORTH ANDOVER - MA RUN NO.E3 - PROPOSED CONDITIONS - DETENTION POND DESIGN - WATERSHED NO . 1 STORM DATA : TYPE DURATION 24 ( HR ) FREQUENCY : 100 ( YR ) RAINFALL : 6.5 ( IN ) NO. OF SUBWATERSHEDS 9 NO. OF DETENTION STRUCTURES : l RESULTS FOLLOW . . . ` SUriMARY TABLE -- BASIC WATERSHED DATA ------------------------------------- PROJECT : BUTCHER BOY h10LL NORTH ANDOVER - I`lA RUN NO.E3 - PROPOSED CONDITIONS DETENTION POND DESIGN - WATERSHED NO . I SUB- DRAINAGE TIME OF TRAVEL DOWNSTREAM TRAVEL 24-HR RUNOFF RUN- INITIAL AREA AREA CONCEN- TIME SUBAREAS TIME RAIN- CURVE OFF ABTIONC TRATION THROUGH SUMMATION FALL NUMBER SUBAREA TO OUTLET ------------------------------------ ------- DA TC TT SUMTT P CN 0 DAID IA IA/P (SO MI) (HR) (HR) (HR) (IN) (IN) (SM-IN) (IN) ---------------------------------------------------------------- 1 .0008 .07 0 2 3 .02 6.5 98 6.26 .005 .041 .01 2 .0002 .04 .01 3 .01 6.5 98 6.26 .0013 .041 .01 3 .0006 .05 .01 0 6.5 98 6.2116 .0038 .041 .01 4 .0005 .02 0 0 6.5 9B 6.26 .0031 .041 .01 5 .0003 .06 0 7 8 9 .04 6.5 90 6.2E .0019 .041 .01 6 .0009 .06 0 7 8 9 .04 6.5 9B 6.26 .0056 .041 .01 7 .0005 .06 .02 8 9 .02 6.5 98 6.20 .0031 .041 .01 8 .0006 .05 .01 9 O1 6.5 98 6.26 .0038 .041 .01 9 .0006 .04 .01 0 6.5 98 6.26 .0038 .041 .01 SUMMARY TABLE - DETENTION STRUCTURE NO . I PROJECT : DUTCHER BOY MALL NORTH ANDOVER -- Mo RUN NO.E3 - PROPOSED CONDITIONS - DETENTION POND DESIGN - WATERSHED NO . 1 STRUCTURE DESCRIPTION : ON-SITE DETENTION FOND INPUT DATA FILE : BBDETPND . DAT STAGE STORAGE. ELEVATION VOLUME DISCHARGE ( FT ) ( CU FT ) ( CFS ) -------------------------------------- 126 0 O 126. 1 1 .26 .02 126 .2 2.52 . 16 126.3 3.70 .35 126.4 5.04 .81 126. 5 6 3 •92 126. 6 7 .6 1 .3 126. 7 9.47 1 .69 126.9 12 . 51 2.00 126.9 17 . 01 2. 46 127 21 . 91 2.79 127 . 1. 29 .82 3 127 .2 42 . 16 3 . 01 127. 3 60. 41 3 .50 127 .4 85 . 05 3. 75 127.5 116 . 1B 3. 92 127 . 6 154 . 90 4.00 127 . 7 203. 02 4 . 23 127 .0 260 .42 4 . 00 127 . 9 327 . 34 4 . 52 120 403. 02 4 .66 120. 1 485 .72 4 . 0 120.2 574 . 19 4 .93 120.3 666. 07 5.06 120.4 762 .97 5. 10 128.5 060. 16 5. 3 129 .6 956.69 5 . 42 128.7 1050 . 22 5. 511 120. 0 1141 . 0 5 . 6`---) 120.9 1271 . 40 0 . 77 129 1327 . E 5. 07 I . I O1 z I W I I u I ly i iY - f i �0 ! -0 > IT > [T OOi� I :ir !lt�i C (- Lrl i d CJ G t�i hJ1NQ n 0 - r1 : Cf� -�jr- OC- 0 N Lp 'u"l 0 ` CD Cr, C- -3 C "off tIti 0 -0r-- O0. T0 N J I Ui I !' ,O -C. w -0 0 -Z. M. CO. OOMOOli.)M. G. O I Lr I i I I I (Il I I I ! z l I O I :11 I V` i - 7 L9 I Cr' O v0 `7 � O ,-i v in N (T rI) t'1 N r- 7 - I CD Li r I t7i• T :r W C, N Cj OT � � � r� O � nNOO` Or'iC n �tnczl � 0, N -0r,- Oi- z • . • • . • • . N"1 - 0 f� U `i O i� !7 i t7 N N t 1 d t'i t� 1 i O i'"')i G7 m 11 I CD :D I M '> d O -i0 0O zl- 0- 0 - 0` L000, 0t'jf'- NCc Ln C'4NNi toC 0 NN I r- OJ I C4NNii t -O O 0 --' tint\ 0n - On -+ OltiNCi� - NC; t- Lnt'i - G- h0ctC4 - 0CTCC) 11 I LO D, - I CT an ri C, J-) - O T 0 -0 N o, 0 -i r N ro n n -0 -0 O O u O - N N ro I- n G N O O O` O 1 I Nt'it'? ct :;I- ln -0 -t r,- 03M0- 0, NNC•4NNNNNNNNN I I I I I I W I Z I J I O 1 m I W 1 (Jr'i drto -OrOT Nto 7' n Or, OO` Nto 'Tn -OI, OO` Nt1 "tn -Orl- 00` F- I Lj1 Cr <1 1 O1 U U v` LT U O, 01, O O O O O O O O O O N N N N N N N N N N t10 I D > LL I id C4 Cl CA CI N CA N N r hi hi Ni 1,0 t'i ti hi t'i r) ti h'i hi to rl i M hj ri t17 to t'i t'r t'i t) N) r) ri tll ri > I G Ln LJ — 1 ri Q I - L!1 1 1 z I 1 O I U U) I HYDROGRAPH - SU8WATERSHED NO . 1 ---------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = .00UB ( SO MI ) RUNOFF DEPTH = 6 ' 26 ( IN ) TIME OF CONCENTRATION = .07 ( HR) TRAVEL TIME TO OUTLET = '02 ( HR ) INITIAL ABSTRACTION = '041 ( IN ) TABULAR ROUNDING METHOD NO . 1 TIME DISCHARGE DISCHARGE (HR) (CSM/ IN) ( CF6 ) 11 29 . l5 11 . 3 3B ' 19 11 .6 57 ' 29 11 . 9 172 ' 86 12 24l 1 .21 12 . 1 425 2' �3 12 . 2 662 3Z 12 .3 531 2 . 66 12 , 4 345 1 . 73 12 . 5 265 1 '33 12 .6 191 . Y6 12. 7 17,0 ,65 12. 8 101 . 51 13 8� . 42 13. 2 68 . 34 13. 4 62 ' � L 13 . 6 59 ' 29 54 . 27 14 50 ' 21) 14 . 3 44 14 . 6 41 ' 21 15 37 . 19 15.5 32 ' 16 16 27 ' 10 16.5 23 ' 12 17 21 ' 11 17 .5 19 ' 1 10 16 ' 08 19 14 . 07 20 13 ' 07 22 11 ' D6 26 0 0 HYDROGRAPH - SUBWATERSHED NO . 2 --------------------------------- PROPOSED CONDITIONS WATERSHED DATA : DRAINAGE AREA = .0002 ( SO mi ) RUNOFF DEPTH = 6 . 26 ( IN) TIME OF CONCENTRATION =_ . 04 ( HR) TRAVEL TIME TO OUTLET = .01 ( HR) INITIAL ABSTRACTION = .041 ( IN ) TABULAR ROUNDING METHOD NO. 1 TIME DISCHARGE DISCHARGE ( HR) (CSM/ IN ) (CFS ) 11 29 .04 11 . 3 30 .05 11 . 6 57 .07 11 .9 172 •22 12 241 12. 1 425 53 12. 2 662 • 83 12. 3 531 .66 12. 4 345 . 43 12. 5 265 . 33 12. 6 191 .24 12. 7 130 . 16 12. 9 101 . 13 13 03 • 1 13 .2 60 .09 13 . 4 62 .00 13 . 6 5e . 07 13 .9 14 .07 14 50 •06, 14 . 3 44 .06 14 . 6 41 .05 15 37 .05 15 .5 02 .014 16 27 .03 16 .5 23, .0- 17 21 .03 17 .5 19 . 02 1B 16 .02 19 14 .02 20 1.= . 02 22 11 . 01 26 0 0 HYDROGRAPH - SUBWATERSHED NO . 3 -------------------------------- PROPOSED CONDITIONS WATERSHED DATA : DRAINAGE AREA = .0006 ( SO M1 ) RUNOFF DEPTH = 6 . 26 ( 1N ) TIME OF CONCENTRATION = . 05 ( HR ) TRAVEL TIME TO OUTLET = 0 ( HR ) INITIAL ABSTRACTION _ . 041 ( IN ) TABULAR ROUNDING METHOD NO . 1 TIME DISCHARGE D T SC_HARGE- ( HR) ( CSM/ IN ) ( CFS ) 11 29 . 11 11 . 3 38 I4 11 . 6 57 . 21 11 . 9 172 .65 12 241 . 91 12. 1 425 1 .6 12. 2 662 2 .49 12. 3 531 1 .99 12. 4 345 1 . 3 12. 5 265 1 12 . 6 191 .72 12 . 7 130 .49 12. 8 101 . 19 13 83 . 31 13 . 2 68 .26 13. 4 62 . 2'-', 13 . 6 58 . 22 13 . 8 54 . 2 14 50 . 19 14 . 3 44 . 17 14 .6 41 . 15 15 37 . 14 15 . 5 32 . 12 16 27 . 1 16. 5 23 . 09 17 21 .08 17 . 5 19 . 07 1B 16 . 06 19 14 . 05 20 13 . 05 22 11 .04 26 0 HYDROGRAPH - SUBWATERSHED NO . 4 -------------------------------- PROPOSED CONDITIONS WATERSHED DATA : DRAINAGE AREA = '0005 lSO MI ) RUNOFF DEPTH = 6 '26 ( IN ) TIME OF CONCENTRATION = - 02 (HR) TRAVEL TIME TO OUTLET = 0 ( HR ) INITIAL ABSTRACTION = ' 041 ( IN) TABULAR ROUNDING METHOD NO. 1 TIME DISCHARGE DISCHARGE ( HR) ( CSM/IN) (CFS ) 11 29 '09 11 '3 38 . 12 11 - 6 57 ' 18 11 ' 9 172 ' 54 12 241 ' 75 12. 1 425 / ' 33 12.2 662 2 ' 07 12.3 531 1 ' 66 12. 4 345 1 '00 12.5 265 . 63 12. 6 191 ' 6 12. 7 130 ' 41 12. 8 101 .32 13 83 ' 26 13. 2 68 . 21 13 . 4 62 ' 19 13.6 58 ' 18 13.8 54 ' 17 14 50 ' 16 14 . 3 44 . 14 14.6 41 - l3 15 37 . l2 15.5 32 ' 1 16 27 .08 16. 5 23 .07 17 21 . 07 17 . 5 19 .06 10 16 .05 19 14 '04 20 13 'O4 22 11 -O3 26 0 0 HYDROGRAPH - SUBWATERSHED NO. 5 -------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = .0003 ( So 1,11 ) RUNOFF DEPTH = 6 .26 ( IN ) TIME OF CONCENTRATION = .06 (HR ) TRAVEL TIME TO OUTLET = . 04 ( HR ) INITIAL ABSTRACTION = .041 ( IN) TABULAR ROUNDING 111ETHOD NO. 1 TIME DISCHARGE DISCHARGE (HR) ( CSI,I/ IN) (CFS) 11 29 .05 11 .3 18 .07 11 . 6 57 . 11 11 .9 172 .32 12 241 .45 12 . 1 425 . 8 12. 2 662 1 .24 12. 3 531 1 12. 4 345 . 65 12 .5 265 . 5 12 .6 191 . 36 12 . 7 130 . 24 12.8 101 . 19 13 8_ . 16 13. 2 6B . 1 3 13. 4 62 . 12 13 .6 58 . 11 13 .8 54 . 1 14 50 09 14 . 3 44 0G 14 .6 41 . 08 15 37 .07 15. 5 3,2 . 06 16 27 05 16 . 5 23 . 011 17 21 . 04 17 . 5 19 . 014 18 16 19 14 . 0-`, 20 1 02 22 1l O? 26 ci .; HYDROGRAPH - SUBWATER5HED NO . 6 --------------------------------- PROPOSED CONDITIONS WATERSHED DATA : DRAINAGE AREA = ' 0009 ( 5O Ml ` RUNOFF DEPTH = 6' 26 ( IN ) TIME OF CONCENTRATION = ' 06 ( HR ) TRAVEL TIME TO OU [LET = ' 04 ( HR ) INITIAL ABSTRACTION = '041 ( 1N ) ' TABULAR ROUNDING METHOD NO. z TIME DISCHARGE DISCHARGE (HR) ( CSM/ lN) (CFS ) 11 29 . 16 11 . 3 38 .21 . 11 . 6 57 ' 32 11 .9 172 ' 97 12 241 1 .36 12. 1 425 2 '�S9 12. 2 662 3 ,73 12 . 3 531 2 '99 12 . 4 345 1 '94 12 . 5 265 1 .49 12 .6 191 1 '08 12 . 7 130 - 73 12.8 101 '57 13 83 . 47 13.2 60 .30 13. 4 62 - 35 13.6 58 . 33 13. B 54 .3 14 50 - 2B 14 . 3 44 ' 25 14.6 41 -23 15 37 . 21 15 . 5 32 . lB 16 27 . 15 16 .5 23 ' 13 17 21 . l2 17 .5 19 . 11 18 16 '09 19 14 .0B 20 13 . 07 22 11 .06 26 0 0 HYDROGRAPH - SUBWATERSHED NO . 7 ________________________________ PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = . 0005 ( SO MI ) RUNOFF DEPTH = 6 .26 ( IN) TIME OF CONCENTRATION = .06 ( HR ) TRAVEL TIME TO OUTLET = .02 ( HR ) INITIAL ABSTRACTION = .041 ( IN ) TABULAR ROUNDING METHOD NO. 1 TIME DISCHARGE DISCHARGE (HR ) ( CSM/ IN) ( CFS) 11 29 . 09 11 . 3 38 ' 12 11 . 6 57 . 10 11 . 9 172 ' 54 12 241 ' 75 12 . 1 425 1 '�3 12 . 2 662 2 '07 12 . 3 531 1 '66 12 .4 345 1 '0H 12'5 265 ' 83 12 .6 191 ' 6 12. 7 130 ' 41 12 . 8 1O1 ' 32 13 83 ' 26 13 . 2 68 - 21 13 . 4 62 ' 19 13. 6 58 ' 10 13 . 8 54 - 17 14 50 - 16 14 . 3 44 . 14 14 .6 41 ' 13 15 37 ' 12 15.5 32 . 1 16 27 .0B 16 .5 23 .07 17 21 .07 17 .5 19 .06 18 16 ' O5 19 14 ' 04 20 13 ' 04 22 11 ,03 26 0 0 _ HYDROGRAPH - SUBWATERSHED NO . 8 PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = .0006 ( SO MI ) RUNOFF DEPTH = 6 . 26 ( IN) TIME OF CONCENTRATION = .05 ( HR) TRAVEL TIME TO OUTLET = . 01 ( HR ) INITIAL ABSTRACTION = . 041 ( IN) TABULAR ROUNDING METHOD 1\10. 1 TI111E DISCHARGE DISCHARGE (HR) ( CSM/ IN) (CFS) 11 29 . 11 11 .3 38 . 14 11 .6 57 .21 11 .9 172 .65) 12 241 .91 12 . 1 425 1 . 6 12 .2 662 2 . 49 12 .3 531 1 . 99 12 .4 345 1 . 3 12 .5 265 1 12 .6 191 .72 12.7 13O . 19 12. 8 101 E3 13 83 13 .2 68 . 26 13 .4 62 2T 13.6 58 . 22 13.8 54 14 50 . 19 14 . 3 44 . 17 14 . 6 41 . 15 15 37 14 15.5 32 . 1< 16 27 . 1 16 . 5 Z . 09 17 21 00 17 .5 19 . 0-7 18 16 . 06 19 14 0`_) 20 1 0`i 22 11 . 04 26 0 0 HYDROGRAPH - SUBWATERSHED NO . 9 --------------------------------- PROPOSED CONDITIONS WATERSHED DATA: DRAINAGE AREA = .0006 ( SO M1 ) RUNOFF DEPTH - 6.26 ( IN) TIME OF CONCENTRATION = . 04 ( HR) TRAVEL TIME TO OUTLET _ 0 ( HR ) INITIAL ABSTRACTION = . 041 ( IN ) TABULAR ROUNDING METHOD NO. 1 TIME DISCHARGE DISCHARGE (HR) ( CSM/ IN) ( CFS ) 11 29 . 11 11 .3 ?B . 14 11 .6 57 .21 11 .9 172 .65 12 241 .91 12 . 1 425 1 .6 12 .2 662 2 . 49 12. 3 531 1 . 99 12. 4 345 1 . 3 12.5 265 1 12.6 191 . 72 12 .7 130 . 49 12 .8 101 .313 13 83 .31 13 .2 60 .26 13. 4 62 .23 13.6 r-� 50 .22 13 .0 54 .2 14 50 . 19 14.3 44 . 17 14 . 6 41 . 15 15 37 . 14 15.5 32 . 12 16 27 . 1 16. 5 23 . 09 17 21 .08 17 . 5 19 .07 1B 16 .06 19 14 .05 20 13 . 05 22 11 .04 26 0 0 COMPOSITE HYDROGRAPH NO. 1 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM. SUBWATERSHED NO. 1 SUBWATERSHED N0 . 2 TIME DISCHARGE (HR ) (CF5 ) 11 . 18 11 . 3 .24 11 . 6 .36 11 . 9 1 .00 12 1 . 51 12. 1 2 . 66 12. 2 4 . 15 12 . 3 3 32 12 . 4 2 . 16 12 . 5 1 . 66 12.6 1 . 2 12 . 7 . 81 12 . 0 .63 13 . 52 13 .2 . 43 13.4 . 39 13.6 .36 1J .8 . 34 14 . 31 14 . 3 .20 14 . 6 . 26 15 . 2S 15. 5 . 2 16 17 16.5 . 14 17 . 1 17.5 . 12 18 . 1 19 . 09 20 .00 22 . 07 26 0 COMPOSITE HYDROGRAPH NO. 2 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM : SUBWATERSHED NO. 3 COMPOSITE HYDRO. NO. 1 TIME DISCHARGE (HR ) ( CFS) 11 .29 11 .3 . 30 11 . 6 . 57 11 . 9 1 .72 12 2. 41 12. 1 4 .26 12. 2 6.63 12. 3 5.32 12. 4 3. 46 12. 5 2 . 65 12.6 1 .91 12 .7 1 . 3 12 .8 1 .01 13 . B3 13.2 . 60 13 . 4 . 62 13 . 6 . 58 I: . 8 . 54 14 .S 14 . 3 .44 14 . 6 . 111 15 3)7 . J 15. 5 .32 16 .27 16.5 . 23 17 . 21 17 . 5 . 19 10 . 16 19 . 14 20 . 13 22 . 11 26 0 COMPOSITE HYDROGRAPH NO . 3 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUBWATERSHED NO . 5 SUBWATERSHED NO . 6 SUBWATERSHED NO. 7 TIME DISCHARGE (HR) ( CFS) 11 .31 11 .3 . 4 11 . 6 .61 11 . 9 1 . 03 12 2 .57 12. 1 4.52 12.2 7 . 05 12. 3 5 . 65 12. 4 3. 67 12.5 2 .02 12.6 2 .03 12.7 1 .30 12. 0 1 .09 13 .00 13 .2 .72 13. 4 .66 13.6 .62 13.0 .57 14 .53 14 . 3 .47 14 . 6 . 44 15 .39 15.5 .34 16 .29 16. 5 .24 17 .22 17 .5 .2 10 . 17 19 . 15 20 . 14 22 . 12 26 O COMPOSITE HYDROGRAPH NO. 4 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SU9WATERSHED NO . 9 COMPOSITE HYDRO. NO . 3 TIME DISCHARGE (HR) (CFS) 11 .42 11 .3 .55 11 .6 .82 11 .9 2. 48 12 3. 47 12 . 1 6. 12 12 .2 9 .53 12 .3 7 .65 12. 4 4 .97 12 .5 3.02 12.6 2 . 75 12 .7 1 .97 12 .8 1 .45 13 1 . 2 13.2 .98 13. 4 .89 13 .6 .04 13 .0 . 78 14 .72 14 .3 .63 14 .6 .59 15 .53 15 .5 .46 16 .39 16 .5 . 33 17 .3 17 .5 . 27 18 . 23 19 . 2 20 . 19 22 . 16 26 0 COMPOSITE HYDROGRAPH NO. 5 --------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUDWATERSHED NO. 9 COMPOSITE HYDRO. NO . 4 TIME DISCHARGE (HR) ( CFS) 11 .53 11 . 3 .69 11 .6 1 .04 11 .9 3 . 12 12 4 .30 12 . 1 7 .72 12 .2 12.02 12 .3 9.64 12.4 6 .26 12 .5 4 .01 12 .6 3.47 12. 7 2.36 12 .8 1 .03 13 1 .51 13.2 1 .23 13.4 1 . 1 3 13 .6 1 .05 13 .0 .90 14 . 91 14 .3 • 8 14 .6 .74 15 .67 15 .5 .50 16 . 49 16.5 .42 17 . 39 17 .5 .35 18 .29 19 .25 20 •24 22 . 2 26 0 COMPOSITE HYDROGRAPH NO. 6 -------------------------- PROPOSED CONDITIONS COMPOSITE OF HYDROGRAPHS FROM: SUBWATERSHED NO . 4 COMPOSITE HYDRO. NO . 5 COMPOSITE HYDRO. NO. 2 TIME DISCHARGE (HR) ( CFS) 11 .91 11 .3 1 . 19 11 .6 1 .78 11 .9 5.38 12 7 .54 12 . 1 13.31 12 .2 20 . 73 12. 3 16 .62 12. 4 10.8 12 .5 8. 3 12 .6 5.90 12 . 7 4 .07 12 .0 3. 16 13 2.6 13.2 2 . 13 13. 4 1 .94 13 . 6 1 .02 13.8 1 .69 14 1 .57 14 . 3 1 .30 14 . 6 1 .20 15 1 . 16 15.5 1 16 . 95 16. 5 .72 17 .66 17 .5 .59 18 . 5 19 . 44 20 .41 22 . 34 26 0 HYDROGRAPH - DETENTION STRUCTURE NO. l -------------------------------------- PROPOBED CONDITIONS INPUT: COMPOSITE HYDROGRAPH NO . 6 NET STAGE STORAGE TIME INFLOW OUTFLOW INFLOW ELEVATION VOLUME (HR) ( CFS) ( CFS) ( CFS) ( FT ) (CU FT ) _____________________________________________________________ 11 .91 O ' 91 126 .3 3 . 27 11 . 3 1 . 19 1 .05 . 14 126. 6 7 .24 11 .6 1 .78 1 . 49 ' 3 126 .7 9 . 56 11 .9 5 . 30 3.53 1 .85 127 '3 65 . 65 12 7 .54 4 . 95 2 . 6 128 '2 597 '61 12 . 1 13 .31 5 .96 7 .34 129 . 1 1839 . 96 12. 2 20. 73 6. 51 14 .22 129.6 5076 .38 12. 3 16. 62 7 .2 9 .42 130 . 4 9681 .32 12.4 10.8 7 .58 3 .23 130.8 12459 . 36 ' 12.5 0.3 7 .69 . 61 130. 9 13365.9 12.6 5.98 7 . 69 -1 .71 130 .9 13368 .29 12 .7 4 .07 7 .59 �3.53 130 .8 12591 . 65 12 .B 3. 16 7 . 43 -4 .26 130.6 11268 ,59 13 2 .6 7 -4 .41 130. 1 6246 .33 13 .2 2. 13 6. 53 -4 .4 129.6 5159.86 1314 1 .94 0 0 0 0 13.6 1 .92 1 .88 - . 06 126.7 10'7 13.8 1 . 69 1 . 75 - .06 126.7 9 .73 14 1 .57 1 .63 - . 06 126.7 8.94 14 .3 1 .38 1 .47 - .09 126.6 B.07 14 .6 1 .28 1 .33 -.05 126 .6' 7 .56 15 1 . 16 1 -22 - .06 126. 6 7 .09 15.5 1 ' 1 .09 -.08 126. 5 6.56 16 .05 . 92 - '08 126 . 5 6.02 16 .5 .72 .78 -.06 126 .4 5.52 ' 17 .66 ,69 - .03 126. 4 5 .25 17 .5 .59 . 63 -.03 126.4 5 18 .5 .55 -.05 126 .4 4.50 47 03 126 3 4 19 . 44 . -~ ~ .25 20 .41 .42 - .02 126. 3 4 .08 22 .34 .38 - .03 126.3 3.79 26 0 0 0 0 0 MAXIMUM DISCHARGE OCCURS @ TIME = 12 .55 ( HR) - MAXIMUM DISCHARGE = 7 .7 ( CFS) MAXIMUM ELEVATION = 130 . 93 ( FT ) A YELLOW FLOWERING DOGWOOD 20' 0 C. (9 REO ID) REINFORCED SUMP EL. _ �1 CONCRETE 12875 HEADWALL FALL SIDE — 1 SLOPES 3_ i DETENTION POND � �p BOTTOM 4 SIDE SLOPES\ TO BELINED W/ CREEPING BENT GRASS NORTr/ERN ARROW WOO /r:> O C R,:-c /29.0 >9a o I3/.0 / 720 �! 133 0 34 0 A DETENTION POND PLAN_ SCALE 1 "=20' A DETENTION POND PLAN SCALE 1 "=20' TOP OF BANK L.=134. 0 r / 24 I NV. 24 RCP EL =129.05 S =0.002 =12900 ti SLOPE- SUMP EL =128.75 -REINFORCED CONCRETE- HEADWALL W/WING WALLS SEE DETAIL SH C-5 DETENTION POND SECTION A-A SCALE: VORT I " = 20