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HomeMy WebLinkAboutStormwater Report - 200 CHICKERING ROAD 2/7/1997 r1Q, 6 I99 �N STO WATER MANAGEMENT REPORT FOR OLD TOWN VLLA GE RETAIL PRO.)ECT 200 CHICKERING ROAD NORTHAADOVER, MASSACHUSETTS 01845 1M HF#45996 PREPARED FOR: SCOTT COMPANIES 12 ROGERS ROAD HAVERHILL,MASSACHUSETTS 01.835 PREPARED BY MON` HR6 CIVIL SIONAL MHF Nd. a6a�.`i Design r1 ult t , In ENGINEERS ® PLANNERS ® SURVEYORS 12-B Manor Parkway, Salem, N.H. 03079 FEBRUA4Y(4,"90P :" 3gj1#97 REVISED APRIL 30, 1997 REVISED MAY 14, 199 7 TABLE OF CONTENTS A. NARRATIVE 1 - 5 B. HYDROLOGIC SITE ANALYSIS 6- 9 PRE AND POST DEVELOPMENT CONDITIONS C UNDERGROUND DETENTION SYSTEMDESIGN 10 D. STORMWATER BEST MANAGEMENT PRACTICES 11 - 19 APPENDICES APPENDIX A PRE AND POST DEVELOPMENT HYDROGRAPHS NO DETENTION 2, 10, 100 YEAR DESIGN STORM APPENDIX B POST DEVELOPMENT HYDROGRAPHS WITH DETENTION 2, 10, 100 YEAR DESIGN STORM APPENDIX C UNDERGROUND DETENTIONSYSTEMDESIGN - DESIGN CRITERIA - OUTFLOWHYDROGRAPHS 2, 10,100 YEAR DESIGNSTORM APPENDIX D SCS DATAIRAINFALL MAPS 2, 10, 100 YEAR DESIGN STORM APPENDIX E MISCELLANEOUS PIPE CHARTSINOMOGRAPHS APPENDIX F BMP DESIGN - OUTLET PROTECTION DESIGN - LEVEL SPREADER DESIGN - TREATMENT SWALE DESIGN - ROOF INFILTRATION DESIGN - CULVERT ANALYSIS -EXISTING 12"INLET APPENDIX G "INFILTRATOR CHAMBER" SYSTEMDATA STORMWA TER MANA GEMEYT REPORT FOR OLD TOWN VILLAGE RETAIL PROJECT A. Narrative. 1. Objective The objective ofthis report is to evaluate the impact of the proposed rommercial/r-etail development project with respect to on-site-and-off-site stormwater runoff- Comparison of the pre-development stormwater runoff to the post-development stormwater runoff is made and_a_proposed stormwater man__agemen system-is-designed-to attenuate any_ increases in stormwater runoff due to the proposed development of the project site. The report includes supporting-calculations,tables_and charts_utilizedfor the pre-and-post development stormwaterrurwff-analysis and-the-design-ofthe-proposedstormwater management system and stormwater drainage system for the proposed development. 2. Project Description The proposed development is located just south of the intersection of Farrwood Avenue with State Route 125, also known as Chickering Road in the Town of North Andover, Massachusetts. The property is further identified by the Town Assessor's Maps as Lot 35 &46 on Map 46. The proposed project consists-of approximately 78,53 1 sf of land which. will be-utilized for the development ofacommer_cial/retailbuilding with approximately 16,900 sf of gross floor area_ Associated improvements,for the proposed project include- driveway/access with parking, landscaping,lighting,utilities and an on-site stormwater collection=system and subsurface stormwater management system. See Figure 1, Project Location Map. The topography of the site is slightly sloping from the southern property corner near Chickering Load to the northern property corner at Tan wood Avenue. Elevation of the site ranges from 202 feet to 188 feet. 3. Existing Drainage Conditions. The existing site_currently sheet flows runoff to shallow-concentrated flow to the existing stormwater drainage system inFarrwoodAvenue located.atthe project site's northwestern property corner_ In order to.analyze the pre and post.development stormwater runoff from the site, two design points were selected for the analysis of the stormwater - 1- Figure 1. Project Location Map. OSLO PCP'oEMy COMMON U SS ° Q 1- <i CN ° VpFN TFR Al, Of WOpp Z� / 125 z �G Q qL � �� } � OV ON SITE ?� erP �Q� GO KINGSTON SST P� 61) Ac BREWSrER m SON C°��= USHA/fT r I p i�) ',... O 0 114 Q 133 a z w o LOCATIO MAP (NOT TO SCALE) MHF Design Consukanty,lire Proposed Commercial Retail Development C:19591REPORTI.DOC runoff from the site. Design point 1 was designated as the catch basin on Farrrwood Avenue approximately 150 feet to the west of the.site and_design point 2 was designated as the Existing 12"inlet pipe under the existing parking area to the west of the site. Leak runoff rates for the project site for the pre-development conditions are based_on_the_runoff rates for the existing on-site soil types, the on-site tributary areas, and the time of concentration for each area analyzed in the on-site watershed. Calculations for time of concentration for each subcatchment area are included in Appendix D of the report . Pre-development peak flows are generated-for the site under existing conditions so that they can be.compared with those rates calculated under post-development.conditions. Further,existing peak runoff rates establish the peak rate of outflow from the site.to achieve a zero increase in runoff from the post-development-site. Analysis is performed using.the USDA SCS Type III,24-hour storm distribution and the design return periods for the 2-year,l0-year, and 100-year storm events. 4. Proposed Drainage Conditions. The stormwater runoff generated as a result of the proposed development will be collected on-site via a closed drainage system_ The.drainage system will collect and detain runoff in underground detention systems and release it to a proposed treatment Swale and level spreader. Each catch basin will collect the storm runoff-and route the runoff through its discharge piping to the downstream catch basin or drainage.manhole. The discharge piping(storm drainage system), in conjunction with the_underground detention systems, has been sized to produce,at the point of system outfall,a zero.increase in proposed runoff as compared to existing runoff from the project site. Storage.of peak flows in excess of the capacity of the discharge storm drainage will be provided for at each catch basin in the proposed subsurface stormwater management systems. The-subsurface stormwater management systems consist of 4 separate underground detention systems. These systems provide runoff storage volume for the 100-year design storm at each catch basin. In addition, stormwater runoff is pretreated through the use of deep sump hooded catch basins and sediment collection systems prior to entering the underground detention systems. 5. Stormwater Runoff. Methodology This analysis-evaluates the impact of the proposed commercial/retail development project with respect to pre and post-development stormwater runoff_ Comparison of the pre-development stormwater runoff to the post-development stormwater runoff is made - 3 - and a proposed stormwater management system is designed to attenuate any increases in stormwater runoff due to the proposed development of the project site. The pre and.post development stormwater runoff rates for the project site are determined for the 24 hour duration,USDA-SC S Type III rainfall distribution, for the 2-year, 10-year and 100-year recurrence intervals. Stormwater runoff analysis is based on the USDA-SCS methods as described in "Urban Hydrology for Small Watersheds" 2nd Ed. (TR-55)and "Program for Project Formulation Hydrology" (TR-20 Computer Program) as well as the stage/storage indication method for routing. Interior storm drainage design is based on the discharge hydrographs for each basin. The discharge hydrographs for the 10-year return period are utilized along with "Hydraulic Design of Highway Culverts" charts to ensure adequate capacity, and cleansing velocity given the selected pipe sizes, slopes and pipe materials. Peak discharge hydrographs for the overall project site were calculated for the pre and post development conditions. Runoff curve numbers were determined for the various hydrologic soil groups and land uses for both the pre and post development conditions. The coefficient of runoff for each area used was a weighted average based on land use and area. Times of concentrations for both the pre and post development conditions were determined based on current land use and topography. Calculations for runoff curve numbers and times of concentration for each subcatchment area can be found in Appendix D of the report. In the case of the hydrologic analysis for post development conditions for the project site, it was assumed that the time for rainfall to travel from the most hydraulically remote point to the proposed outlet structure was 6.0 minutes (inlet time of 5.0 minutes plus 1.0 minute for travel through the drainage system to the outlet) for design purposes, which would be a minimum "worst case" situation. Since the runoff would be directed to storm inlets and concentrated in a closed drainage system with a short hydraulic length and since each catchment area is relatively small in extents this assumption is reasonable. The hydrologic soil group that exist within the proposed project site is Woodbridge fine sandy loam, HSG C. The soil type was determined by locating the project boundaries on the soil survey map of the "Soil Survey Essex County, Massachusetts Northern Part" USDA SCS Sheet 30. The runoff factors were based on the figures in Tables 6-4.1 thru 6-4.3. See Appendix D. The project site is divided into subcatchment areas which are tributary to the proposed catch basin inlets in order to develop inflow hydrographs for each of the inlets. This is done so that discharge piping and storage piping may be sized, outflow hydrographs generated, summed and routed all to the point of discharge_ The hydrograph at the point of discharge is then compared with the existing, pre-development peak rates of runoff for the relative design storms to ensure that there will be zero increase in runoff above the existing rates. -4 - i 6. Summary. The results of the detailed analysis for comparison of the pre and post development runoff rates, stormwater management and the onsite drainage systems design are provided in the following sections of this report. The following tables summarize the results of this report: Table l: Site Analysis: Pre & Post-Development Peak Rates of Runoff A. DESIGN POINT 1 FARRWOOD AVENUE CATCH BASIN Design Storm Recurrence Interval 2-year 10-year 100-year Pre-development Conditions 2.0 cfs 3.8 cfs 6.1 cfs Post-development Conditions 2.0 cfs 3.8 cfs 6.1 cfs B. DESIGN POINT 2 EXISTING 12"INLET PIPE Design Storm Recurrence Interval 2-year 10-year 100-year Pre-development Conditions 2.2cfs 5.1 cf 9.Ocfs Post-development Conditions 5.1 cfs 9.1 cfs 14.1 cfs Table 2: Stormwater Management : Pre & Post-Development Design B. DESIGN POINT 2 EXISTING 12"INLET PIPE Design Storm Recurrence Interval 2-year 10-year 100-year Pre-development Conditions 2.2 cfs 5.1 cfs 9.0 cfs Post-development Conditions 2.2 cfs 5.1 cfs 8.2 cfs with Subsurface Detention System A stormwater management system consisting of underground detention systems with controlled release of collected stormwater runoff from the project site limits the peak rate of runoff from the 100-year design storm to slightly less than the existing rate of runoff from the site. The effect of the control release and storage of the peak inflows to the collection system is a zero increase of runoff from project site for the 100-year design storm. Discharge of runoff from the system is proposed to outlet to a flared end section with a rip rap outlet for erosion protection, thence through a grassed treatment swale to a grassed level spreader before continuing downstream to the adjacent wetland area. In addition, an underground system has been designed for the roof drainage for infiltration of the roof drainage as required under the Stormwater Management Policy and based on the design for total infiltration, no runoff from the roof areas is included in the overall peak - 5 - flow rate calculated for the post development conditions. All of these measures are considered "Best Management Practices" (BMP's) for stormwater management and erosion control and are described in more detail in Section D, Stormwater Best Management Practices. In addition, analysis of the pre and post development flows for the 100 year design storm event on the existing 12" inlet pipe (design point 2) revealed that no increase of flooding would result under post development conditions. As a conservative measure, the existing 10" CMP that is located downstream of the existing 12"RCP inlet pipe, was used as the control outlet for design point 2. Design point 2 was modeled as a detention basin(Reservoir 5) based on the existing 10"CMP being used as the outlet. Based on the analysis of the predevelopment condition for the 2 year design storm event, it was determined that this area experienced an overtopping of the design point and flowed overland to the existing drainage system in Farrwood Road. Therefore, a second outlet was modelled at design point 2 based on this condition. The second outlet was modelled as a broad crested weir. Using the two outlets at design point 2, the peak flow rates for the pre and post development conditions under the 2, 10 and 100 year design storm were generated. The results of the analysis indicate that there is virtually no increase to the ponding elevations at design point 2 under post development conditions. Results of this analysis are summarized below and peak flow hydrographs for the pre and post development conditions are located on the following pages. PONDING ELEVATION (FT) DESIGN STORM 2 yr 10 yr 100 yr Predevelopment Conditions 185.87 186.11 186.36 Postdevelopment Conditions 185.87 186.12 186.32 Hydrographs for this analysis can be found on the following pages. Design criteria used in the analysis of the existing area as a detention pond (Reservoir 5) can be found in Appendix C of this report. Additionally, it should be noted that no infiltration credit was taken for the proposed underground detention systems or the treatment Swale, and based on the infiltration rate for the project soils, the increase flow rate would be accommodated through infiltration under actual conditions. - 6 - r 00 O LO N 00 �-I Ln r-i �-I N N 0 O [� Ln N O Ln Ln Ln Ln a) co OD ao O oo ao ww j^1 ri -4 ` I m r CD ao N LO Ln �) C) x a� (y H 14 Ln N 0 ° O I— LO N O �- 00 00 O� OC) Go co a �4, N � 04 i ,-� Ln N it N r-i i ? w Ln rt , o A 0 o Q O Lo r-I lfl N [� co OD OD OD co rn z N e-1 O OD l0 N rl ?-I � x � v N r � -r-� H �-I O Ln rr A, O O ° C9 N (� l9 oc) co O 00 OD 0c) LO a 2 cy't Ln r-1 2 N W Ln W � O r1 t r V O -L / I i $ O O l9 N l— F— lq Ln CC) CC) CC) CC) co OD a N N l� Ln C\' ,Q II o N W l� 4 O O � O Ln sa g CD � o T) ,---i C- cc) cc) 00 00 00 CC) � N B. Hydrologic Site Analysis 1. Hydrologic Drainage Analysis Basis: Stormwater runoff analysis is based on the IJSDA-SCS methods as described in "Urban Hydrology for Small Watersheds" 2nd Ed. (TR-55) and "Program for Project Formulation Hydrology" (TR-20 Computer Program) as well as the stage/storage indication method for routing. Interior storm drainage design is based on the discharge hydrographs for each basin. The discharge hydrographs for the 10-year return period are utilized along with "Hydraulic Design of Highway Culverts" charts to ensure adequate capacity, and cleansing velocity given the selected pipe sizes, slopes and pipe materials. Software which combines these methodologies as well as others typically used in the estimation of peak runoff rates and the hydrographs has been utilized for this analysis and design. The software is "Hydrographs for Windows" Version 5.1 by Intelisolve. The program takes input developed by utilizing TR-55 worksheets for the estimation of times of concentrations, composite curve numbers and various TR-55 figures and charts which have been included in this report. 2. Watershed/Drainage Area Data (Project Situ Total site area: See Exhibits A, B and C Storm Distribution: SCS, 24-hour, Type M. Return Period/Precipitation: 2-year/3.0", 10-year/4.6", 100-year/6.5" 3. Existing Conditions (Base Input Data/Development of Peak Flow Hydrograpw Present Conditions Summary of Peak Runoff Rates: Table 3: Site Analysis: Pre-Development Peak Rates of Runoff Design Storm Recurrence Interval 2-year 10-year 100-year A. Design Point 1 Farrwood Avenue Catch Basin Pre-development Conditions 2.Ocfs 3.8 cfs 6.1 cfs B. Design Point 2 Existing 12"inlet pipe Pre-development Conditions 2.2cfs 5.1 cfs 9.0 cfs USDA-SCS TR55: Worksheet 2: Runoff curve number and runoff See Appendix D for generation of RCN values and tc's for each tributary subcatchment area as depicted on Exhibits A,B and C. - 7 - Watershed Data: Storm No.1 Storm N9.2 Storm No.3 Frequency, yr. 2 10 100 Rainfall, P (24-hr), in 3.0 4.6 6.5 The time of concentration(tc) for the existing conditions was computed using the SCS method and worksheets. See Appendix D for Tc worksheet calculations. 4 Proposed Conditions (Base Input Data/Development of Peak Flow Hydrograph) Proposed Conditions Summary of Peak Runoff Rates: Table 4: Site Analysis: Post-Development Peak Rates of Runoff A DESIGN POINT 1 FARRWOOD AVENUE CATCH BASIN Design Storm Recurrence Interval 2-year 10-year 100-year Post-development Conditions 2.0 cfs 3.8 cfs 6.1 cfs B DESIGN POINT 2 EXISTING 12"INLET PIPE Design Storm Recurrence Interval 2-year 10-year 100-year Post-development Conditions 5.1 cfs 9.1 cfs 14.1 cfs USDA-SCS TR55: Worksheet 2: Runoff curve number and runoff See Appendix D for generation of RCN values for each tributary subcatchment area as depicted on Exhibits A,B and C. Watershed Data: Storm No.1 Storm No.2 Storm No.3 Frequency,yr. 2 10 100 Rainfall,P (24-hr), in 3.0 4.6 6.5 USDA-SCS TR55: Worksheet 3: Time of concentration (Tc) or travel time(Tt) The time of concentration(tc)for the existing conditions was computed using the SCS method and worksheets. See Appendix D for Tc worksheet calculations. For the individual subcatchment areas tributary to each catch basin, it is assumed that due to the short travel time to any inlet of the proposed storm drainage system and the short hydraulic length of closed conduit that the travel time or Tc will be less than or equal to 5 minutes. - 8 - 5. Comparison of Existing and Proposed Peak Runoff Rates The following summary tables are taken from the analysis and design reports which appear in the Appendices. Differences between Existing and Proposed Peak Rates of Runoff(w/o detention system): A. DESIGN POINT 1 FARRWOOD AVENUE CATCH BASIN Design Storm Recurrence Interval 2-year 10-year 100-year Pre-development Conditions 2.0 cfs 3.8 cfs 6.1 cfs Post-development Conditions 2.0 cfs 3.8 cfs 6.1 cfs Increase in Peak Rates of Runoff 0 cfs 0 cfs 0 cfs (w/o detention system) B. DESIGN POINT 2 EXISTING 12"INLET PIPE Design Storm Recurrence Interval 2-year 10-year 00-year Conditions 2.2 cfs 5.1 cf 9.0 cfs Post-development Conditions 5.1 cfs 9.1 cfs 14.1 cfs Increase in Peak Rates of Runoff 2.9 cfs 4.0 cfs 5.1 cfs (w/o detention system) For peak flow data for pre and post development conditions without detention, See Appendix A. Differences between Existing and Proposed Peak Rates of Runoff(w/detention system): B. DESIGN POINT 2 EXISTING 12"INLET PIPE Design Storm Recurrence Interval 2-year 10-year 100-year Pre-development Conditions 2.2 cfs 5.1 cfs 9.0 cfs Post-development Conditions 2.2 cfs 5.1 cfs 8.2 cfs with Subsurface Detention System Increase in Peak Rates of Runoff 0 cfs 0 cfs 0 cfs (with detention system) For peak flow data for post development conditions with detention, see Appendix B. - 9 - C. Underground Detention System Design 1 Introduction The design for the proposed underground detention system will utilize a system known as "The Infiltrator Chamber", which consists of a series of chambers that are interlocked together on a bed of crushed gravel or stone and backfilled with gravel and stone having a stone void ratio of approximately 35%. Each chamber is 15" high and is 2.83 feet by 6.25 feet. See Appendix G for design data on "Infiltrator Chamber" systems. The proposed drainage system for the project will incorporate four underground detention systems consisting of 50 chambers per system. Each underground detention system will provide approximately 1100 cubic feet of available storage per system. The chamber systems are designed to work in series and hydrographs for each system are generated and added to the next system in line. The design of the proposed underground systems will accommodate the additional runoff associated with a 100 year design storm event. In addition,the 2 and 10 year design storm event is also routed through the proposed systems. The computerized program "Hydrographs for Windows" as described above was utilized to analyze the proposed drainage system and series of underground detention systems. The proposed site is delineated into the various subcatchment areas as shown on Exhibit C, and peak flow hydrographs are generated for each subcatchment area. Inflow hydrographs to each system are generated and the outlet pipes from each system are sized to maximize the storage volume provided for each system. The design of the underground detention system and the outflow hydrographs for each system can be found in Appendix C of this report. The design criteria used for the proposed conditions hydrology and analysis of the drainage system can be found in Appendix B of this report. In addition to the underground systems for the paved area, two underground infiltration systems are proposed for the roof drainage. Design for this system consists of 2 foot diameter pipe which roof drainage is tied into and the design of the system assumes the roof drainage to be entirely infiltrated for all design storm events based on the calculated flow associated with the exfiltration as calculated based on Darcy' Law where Q=kiA. An emergency overflow pipe is provided from each system and tied into the proposed parking_lot drainage system. Design calculations for the roof drainage infiltration system can be found in Appendix F of this report. - 10 - D. Stormwater Best Management Practices 1. Introduction The proposed project consists of approximately 78,531 ft2 of land which will be utilized for as the site for a commercial/retail building with approximately 16,900 ft2 of gross floor area. Associated improvements for the proposed project include driveway/access ways with parking, landscaping, lighting, utilities and an on-site stormwater collection system and subsurface stormwater management system. The proposed drainage facilities for the site, including the erosion and stormwater management controls have been designed under the guidelines of the Stormwater Management Standards established by the Stormwater Management Policy as promulgated by the Commonwealth of Massachusetts, Executive Office of Environmental Affairs, Department of Environmental Protection. Under the Stormwater Management Policy,there are nine (9) specific standards which are used to satisfy regulatory requirements under the Policy. The proposed stormwater management controls established as part of the site design meet or exceed those minimum standards and provide for the attenuation of stormwater runoff for both quality and quantity issues. Best management practices for erosion control and site stabilization during construction will be employed on the site to minimize soil erosion and to protect the adjacent wetland areas from impacts associated with the proposed development during and after construction. The use of erosion and sediment control silt fencing around the perimeter of the proposed work will ensure on-site containment of sediment as well as control the extent of disturbed area. At the storm system outfall, the use of outlet protection in the form of a riprapped apron will ensure that sediment controls are not overwhelmed by sudden flows of stormwater which may contain sediment from the site. Additionally, at inlets to the proposed storm drainage system, the use of a combination system will be utilized. This system will consist of placing filter fabric under the inlet grating of catch basins and continuing the fabric up and over the remainder of the inlet area to the basin and placing on top of the filter fabric a layer of crushed stone to add additional filtering of any sediment laden runoff and to secure the filter fabric in place during construction of the proposed project. 2. Proposed Stabilization/Treatment The proposed project will utilize both temporary and permanent erosion control and treatment measures for control of stormwater runoff. Temporary erosion control measures such as silt fence, hay bales, erosion control blanket and mulch will be used - 11 - ` during the construction of the project to minimize intrusion of soil erosion and will remain in place until permanent stabilization is accomplished. Other measures for sedimentation and erosion control as well as water quality protection will include provisions for sumps in all catch basins for capturing sediment laden stormwater runoff. In addition, the underground detention systems will provide for additional treatment of sediment control. 3. Stormwater Runoff Treatment The design of the project incorporates the use of sumps and oil/gas hoods on the outlets of the drainage system which will add to the efficiency of catch basins in the removal of pollutants associated with stormwater flows from the paved areas. Additional permanent stormwater control measures which have been designed for the site are described in more detail as follows: A. Sediment Collection Systems The provision of sediment collection systems will provide for the pretreatment of stormwater runoff prior to entering the individual underground detention systems. Stormwater runoff from each catch basin is routed through the sediment collection system prior to entering the underground detention system for each area. The sediment collection system has been designed in conjunction with the deep sump catch basins to provide for the prescribed volume of runoff as determined under the standards established by the Stormwater Management Policy. Design of the sediment collection systems can be found in E of this report. B. Underground Stormwater Detention System The provision of the underground detention systems will provide for the ability to attenuate the quality and quantity issues associated with stormwater pollutants. Stormwater pollutants may include sediments, heavy metals, hydrocarbons, salts, and fertilizers. The natural renovation capabilities of soil can remove many of these pollutants. The design of the proposed underground detention system does not account for any infiltration, however, because the systems are placed on a gravel bed and are surrounded by gravel fill material, infiltration of stormwater will occur and will provide for a high rate of removal of many of those Stormwater borne pollutants. The systems are designed to be at least 1 foot above seasonal high water levels which were observed by onsite test pit investigations. In addition to the water quality measures provided for by the underground detention systems, water quantity issues are also addressed through their use. The goal of the underground detention systems are to store runoff during peak storm conditions and slowly meter the outflow into the downstream drainage system. The design provides for a - 12 - "zero increase" with respect to the additional runoff associated with the proposed development for the 100 year design storm event. In addition. runoff from paved areas is routed through a smaller set of infiltrators designated as sediment collection systems which have been designed to accommodate the runoff volume of 0.5" from the tributary impervious area. This smaller system will provide for removal of TSS as required and is recommended by the manufacturer. The use of deep sump catch basins and the sediment collection systems will provide for approximately 80 % removal rate of stormwater borne sediment based on the TSS removal design rates outlined by the EPA. C. Outlet Protection Outlet protection for the proposed drainage outfall consists of a rip rap lined apron placed between the outlet of the proposed drainage system and the downstream treatment Swale. Outlet protection prevents erosion or scour at the outlets of storm sewers, culverts, paved waterways or other lined channels or pipes by reducing the velocity of the flow from the pipe or channel. Design of the outlet protection for this project can be found in Appendix F of this report. D. Grassed Treatment Swale Grassed or vegetated swales are either natural or constructed broad channels with dense vegetation that are designed to treat runoff and dispose of it safely into a natural drainage system. Grassed treatment swales are also effective in the removal of sediment and other water borne pollutants and can be effective in the removal of total suspended solids (TSS). Vegetated swales improve water quality by the treatment and removal of pollutants from stormwater runoff, increase the infiltration of runoff and reduce potential erosion from the discharge of runoff. For effective treatment, the swale has been designed to provide for a low velocity so as to provide for the settlement of the waterborne pollutants associated with stormwater runoff. The proposed treatment Swale design for this site is located in Appendix F of this report. E. Level Spreader Design A level spreader is an outlet constructed at zero percent grade across the slope that allows concentrated runoff to be discharged at non-erosive velocities into natural or man-made areas that have existing vegetation capable of preventing erosion. A level spreader change concentrated flow into sheet flow and then outlets it onto stable areas without causing erosion. Design of the level spreader for this project is located in Appendix F of this report. - 13 - 4. Operation and Maintenance Plan An effective Site Operation and Maintenance Plan is essential for the proper operation of the stormwater management systems that are designed to provide for water quality and quantity measures. The stormwater management system owner will be the same as the current owner of the property and will be responsible for implementation of the operation and maintenance plan for the site. As with any development for this type of use, a maintenance company is employed to deal with the routine operation for the facility including maintenance of the building, trash disposal, snow removal and landscaping. Some of these items are routinely done on a weekly, monthly or seasonal basis. The maintenance company employed for the site will be responsible for implementing the operation and maintenance procedures outlined herein for the stormwater management systems. Routine and non-routine maintenance tasks which are part of these procedures are defined and listed for the Operation and Maintenance Plan and the schedule for the proposed maintenance plan is outlined in this report. It is also suggested that the Operation and Maintenance Procedures for this site be made part of the conditions of approval for the Order of Conditions that may be issued for this project and a copy be put on file with the Town of North Andover. In addition, maintenance and inspection reports prepared for the owner as part of this project can also be submitted to the Town of North Andover, if required. L PARKING LOT SWEEPING Sweeping of the parking lots shall be done early in the spring season once the snow has melted. This early sweeping will remove much of the sand and other debris that is often left as a result of snow plowing. Snow removal from the site or placement of snow outside of paved areas will also prevent sand and debris accumulation in the paved areas and reduce the amount of materials that could potentially enter the storm drainage system. Accumulated sediment in non-paved areas from snow storage areas shall be removed as well. In addition, sweeping of the parking areas shall be done in the fall after the majority of the leaf drop occurs but prior to the first snowfall. II LITTER CONTROL Litter control involves removing litter such as leaves, lawn clippings, pet wastes, and trash from parking lots and landscape areas before materials are transported into the on-site drainage systems. There are several ways to control litter. An effective program of trash and garbage collection will reduce the amount of material entering surface waters. Lawn - 14 - clippings and leaves will be removed from the site as part of the landscaping maintenance program. Weekly maintenance of the landscape areas of the site will commence in the early spring months and continue through the summer and taper off to twice a month through the fall months into early winter. Recycling programs will be encouraged by the individual tenants and a recycling container will be provided in the centralized trash enclosure area of the site. In addition, the trash receptacle for the entire site has been located in one area to minimize the amount of trash receptacles onsite, thereby reducing the potential for litter. Trash and recylables removal will be on an as-needed basis, depending on the amount of materials generated by the tenants of the site. Litter collection in the parking areas will be done weekly. In addition to litter control,the use of fertilizers, pesticides and herbicides shall be limited on the site. Proper pesticide and fertilizer application shall be encouraged, including proper timing and application reduction. Buffer areas between the landscape areas and the downstream wetland areas are provided. The specific limits of the fertilizers, pesticides and herbicides to be used on-site will be provided by the landscape maintenance company. III. CATCH BASIN CLEANING The removal of sediments and associated pollutants and trash occurs only when inlets or sumps are cleaned out,therefore regular maintenance of the catch basin sumps is essential to the longevity of the stormwater drainage system. The more frequent the cleaning, the less likely sediments and trash will be resuspended and discharged downstream to the drainage system. Frequent cleaning also provides more volume for future storms and enhances overall performance. In areas of potentially high sediment accumulation such as parking lots, inlets should be inspected frequently, and cleaned as necessary, after every major storm event. Minimum requirements for cleaning of inlets and sumps for catch basins as recommended under the Stormwater Management-policy are four times a year. However, for this site, the recommended inspection and cleaning schedule will be every two months or as needed based upon inspection. IV. SEDIMENT COLLECTION SYSTEMS Sediment collection systems have been provided at the downstream end of each catch basin inlet in the parking lot. These systems are designed to provide for sediment collection of stormwater prior to entering the underground detention systems. Removal of sediment and associated pollutants occurs when sediment collection systems are cleaned, therefore regular maintenance is required. The more frequent the removal of accumulated sediments,the less likely sediments will be resuspended and adversely affect the downstream drainage systems or downstream receiving waters. Inspection ports are provided at each end of the sediment collection system for visual checks of the system. At a minimum the sediment collection systems shall be cleaned four times a year and inspected monthly. Monthly inspection reports can be furnished to the Town upon request. - 15 - V UNDERGROUND DETENTION SYSTEMS There are five underground detention systems proposed for the site. Pretreatment through the use of deepsump hooded catch basins and sediment collection systems and the proper maintenance of these pretreatment systems as described above will eliminate sediment and litter accumulation within the proposed underground detention systems. Inspection and maintenance requirements are outlined by the manufacturer and should be used as the minimum requirements for this site. It is essential to any subsurface system to detail and perform proper inspection and maintenance program. The inspection and maintenance of these systems will be performed by the site maintenance company that is employed by the owner of the property. The manufacturer specified for these proposed systems is "Infiltrator Systems Inc.", 123 Elm Street, Suite 12, Old Saybrook, Connecticut 06475, (203) 388-6639. Each infiltrator chamber is provide with a"knockout"in the center of the unit. This may be used to provide an inspection port at grade level. A 6"PVC pipe is placed through the access port as a riser to grade and then capped with a cast iron cover in the paved areas as needed. Inspections shall be conducted following major storm events (25 year storm or greater) so that potential sediment levels and draw down times can be determined. Sediment removal will be accommodated through the use of the deepsump and sediment collection systems. Should the pretreatment structures be not completely effective in silt removal and sediment enters the chamber system, then the Infiltrator chamber may be maintained through the access ports, which are supplied on the proposed systems. For removal of sediment from the underground systems, the outlet pipe from the chamber system can be plugged at the downstream manhole and water injected into the system which will put the fine sediments into suspension. The water and suspended sediment can then be pumped out and removed from the site. This method can also be used for sediment removal in the collection systems. Various types of equipment are available commercially for clean out of drainage systems. The most commonly used equipment and techniques used for cleaning systems are vacuum pump and water jet spray. Both systems are generally mounted on a self contained vehicle and can effectively remove stones, leaves and sediment deposits from sumps and chambers. The underground detention systems shall be inspected monthly or after a heavy rainfall and cleaned as needed, depending on the amount of sediment accumulation in the systems. The underground systems to be used for roof drainage infiltration shall have monitoring wells installed in the system with an at grade access cap. These monitoring wells shall be inspected after a major storm event (25 year storm or greater) and then 72 hours thereafter to ensure the proper operation of these systems. In addition to the monitoring wells, several access ports are located within the underground systems to check various areas of the system. - 16 - VI. WATER QUALITYSWALE Water quality swales should be inspected at least semi-annually, and maintenance and repairs made as necessary. Additional inspections should be made during the first few months after construction to make sure that the vegetation has been adequately established. Repairs and reseeding should be done as required. Water quality swales should be mowed once a year and grass clippings be removed. Grass must not be cut shorter than 4 inches and excessive mowing is discouraged. Sediment and debris removal should be done manually, at least once a year. The seed mix for the water quality swale is a specified below and is also shown on the design plans. WATER 0UALITYSW4LE PLANTING SPECIFICATIONS Tall fescue 20 lbs/acre or 0.45 1bs/10,000 sf Creeping red fescue 20 lbs/acre or 0.451bs/10,000 sf Birdsfoot trefoil 81bs/acre or 0.201bs/10,000 sf Lime and fertilizer should be applied prior to or at time of seeding and incorporated into the soil. The following rates are recommended: Agricultural limestone 2 tons/acre or 100 lbs/1,000 sf Nitrogen(N) 50 lbs/acre or 1.1 lbs/10,000 sf Phosphate(P205) 100 lbs/acre or 2.2 lbs/10,000 sf Potash (K20) 100 lbs/acre or 2.2 lbs/10,000 sf (This is equivalent to 500 lbs/acre of 10-20-20 fertilizer or 1,000 lbs/acre of 5-10-10). Attached to this report is a revised Operation and Maintenance Schedule which has been included as part of the Stormwater Management Form under the Stormwater Management Policy. - 17 - OPERATION AND MAINTENANCE SCHED ULE FOR PROPOSED RETAIL FACILITY Maintenance Item Proposed Schedule 1. Sweeping of parking lots Monthly(March-June) Monthly(September-November) 2. On site litter pickup Weekly 3. Catch basin cleaning Every 2 months or after a major storm event.* 4. Sediment collection systems inspection Monthly or after a major storm event Sediment collection systems cleaning Four times a year 5. Underground detention system inspection Monthly or after a major storm event Underground detention system cleaning As needed depending on results of inspections Underground roof infiltrator systems Inspect monitoring wells after a major storm event 6. Water quality Swale inspection Semi-annually Inspection of outlet protection Yearly or after a major storm event apron and level spreader * A major storm event is definded for purposes of this report as a 25 year storm or greater. - 18 - E. Stormwater Management Policy Standards Attached to this section is a description of the standards prescribed under the Stormwater Management Policy and the methods and calculations by which this project complies with those standards. - 19 - Stormwater Management Form This form is intended to ensure that proposed stormwater control designs meet the stormwater management standards described in the Department of Environmental Protection's Stormwater Management Policy (November 1996). The Depart- ment of Environmental Protection (DEP) recommends that applicants submit this form with the Notice of Intent, as well as supporting documentation and plans, to provide stormwater information for conservation commission review. If a particu- lar stormwater management standard cannot be met, information should be provided to demonstrate how adequate water quality and water quantity protection will be provided bY the project. DEP encourages engineers to use this form to certifi- that the project meets the stormwater management standards as well as acceptable engineering standards. This form should be completed by checking the appropriate boxes for each standard and by signing and stamping the back of this form. Project Location: /Z,-J; /V,-uz7 W�uv ❑ The proposed projecto is not(circle one)exempt from one or more of the stormwater management standards. If project is exempt, explain whv: NO 7-14,C4-_, t—z) /Nt Stormwater runoff volumes to be treated for water quality are based on the following calculations: (check one that applies) ❑ 1 inch of runoff x total impervious area of post-development site for critical areas (e.g. Outstanding Resource /`Waters and shellfish growing areas) Lam' 0.5 inches of runoff x total impervious area of post-development site for other resource areas Stan rd #1: Untreated stormwater (See plan The project is designed so that new stormwater conveyances (outfalls/discharges) do not discharge untreate, stormwater into. or cause erosion to, wetlands or waters. Standard #2: Post-development peak discharge rates (See plan 3 E? Post-development peak discharge rates do not exceed pre-development rates on the site either at the point of discharge or downgradient property boundan. ❑ N/A: project site contains waters subject to tidal action. so standard is not applicable. �41he­'pnroject's owater controls have been designed for the 2-year and I0-year, 2-1-hour storms. stormwater desisn will not increase flooding impacts offsite from the 100-year, 2Y-hour storm. Stan and #3: Recharge to groundwater (See plan The annual groundwater recharge for the post-development site approximates annual recharge from existing site conditions. ❑ Soil types have been identified according to either the U.S. Natural Resources Conservation Service (NRCS)County Soils Survey or onsite soil evaluation.Calculations on stormwater flow are based on a soil hydrologic group Of C , and total impervious area of 1"91 fe ¢ (square feet). Soil types at each planned point of stormwater runoff infiltration include: 2 Infiltration Best Management Practices(BMPs)used for this project include: Stan rd #4: 80% TSS removal (See plan The proposed stormwater management systems will remove 80% of the post-development site's average annual load of Total Suspended Solids (TSS). l!�'�The BMPs selected for this project include(list BMPs with TSS removal rates): P12� SUht/J �J��J ��� .�(�"7//L✓ Z 5 fig �J�J//lam-7""�.�d'�-G���'°`=��✓u 5'a�t"�l�I /�,�,5 % ,� -�'�f7� �fi�/�l'���•-7`� �GIJi��� C.GV� °"°' �/o (11196) 13� Sta0ard #5: Higher potential pollutant loads (See plan ) The project sit oes does not (circle one) contain Land Uses with Higher Potential Pollly4ant Loads. If site contains such land uses, describe: � �' 1G ��L" f�� / 414.ZIiuz.- 21"If applicable, BMPs selected for controlling stormwater in these areas are designed to prevent infiltration of untreated stormwater and include: /Voy (j C 40,x'" ° Standard #6: Protection of critical areas (See plan ❑ The project site does does no (circle one) contain critical areas with sensitive resources. If site contains critical areas, describe: ❑ If applicable, BMPs selected for stormwater discharges in these areas include: /1111-1/4' Standard #7: Redevelopment projects (See plan ❑ The proposed activity is/' 'not one) a redevelopment project. Note: Components of redevelopment projects which plan to develop previously undeveloped sites do not fall wider the scope of Standard 7. ❑ If the project is a redevelopment project. the following stormwater management standards have been met: ❑ The standards which have not been met include: ❑ The proposed project will reduce the annual pollutant load on the site with new or expanded stormwater controls. Sta Vdard #8: Erosion/sediment control (See plan A YS Erosion and sediment controls are incorporated into the prole: design to prevent erosion. control sediment movement. and stabilize exposed soils. Sta and #9: Operation/maintenance plan (See plan ( An operation and maintenance plan for both construction and post-development stormwater controls has been developed. The plan includes BMP owner(s):parties responsible for operation and maintenance; schedule for inspection and maintenance: routine and non-routine maintenance tasks; and provision.for appropriate access and maintenance easements surrounding control(s)and extending to public right-of-iva.y. I attest under the penalties of perjury that I have personally examined and am familiar with the information contained in this submittal,including any and all documents, accompanying this certification statement; and that I ���gN OF am fully authorized to make this attestation on behalf of the project FRANK e. �N applicant. o MONTEIRO CIVIL No.36341 ,o�oF�9EC 1� C. 1�DlJ �lt �8 q� Print Name Date S p/ tgnature) 138 manklmommemomm AN ® PROJECT NAME: MHF Design Consultants, Inc. CALL. BY: CHECKED BY: DATE: SHEET No. OF_� ... _ .. . I_ ---------- ell 10 : : ... Ila AN MENMW ® PROJECT NAME: Ammome P Ammon soon anowmaumm� MHF Design C®nsulf®nfs, Inc. CALL. BY:/K CKED BY: DATE: SHEET No. 6r OF PS -- --- wig' Afl: =" -- - - -- . _�._......... •— 1a -- -- . - -. =-�= ------�--�- - -- -- •- -- .-- .:.ice-=- - ..- ...__ .. -- - -- --- -- - - - _ ... ............._ -- --- - -- ... . ---------------- -.. --- cr. ... _ .._ � .� � �,� tip= � _ - - --• Ta Table 4.2: TSS Removal Rates (adapted from Schueler, 1996 & EPA, 1993) Range of General BMP List Average TSS Brief Design Requirements 9 �. Removal Rates [Extended] 45-60% Sediment forebay; see design guidelines Detention Pond and references in 4.A. Wet Pond (a) 60-80% Sediment forebay; see design guidelines _} and references in 4.B. t Constructed 65-80% Sediment forebay; see design guidelines Wetland (b) and references in 4.C. Water Quality 60-80%.. Designed to infiltrate or retain; see design Swale - guidelines and references in 4.D. - Infiltration Trench 75-80% Pretreatment critical; see design (predicted) guidelines and references in 4.E. yz° Infiltration Basin_ 75-80% Pretreatment critical; see design (predicted) guidelines and references in 4.17. z Dry Well 80% (predicted) Rooftop runoff (uncontaminated) only; see design guidelines and references in 4.G. : Sand Filter (c) 80% Pretreatment; see design guidelines and references in 4.H. Organic Filter (d) 80% + Pretreatment; see design guidelines and {t references in 4.H. Water Quality Inlet 15-35% w/ Off-line only; 0.1" minimum Water Quality cleanout Volume (WQV) storage; see 4.1. ;l Sediment Trap 25% w/ cleanout Storm flows for 2 year event (Qp) must [Forebay] not cause erosion; 0.1" minimum WQV storage; see 4.J. Drainage Channel 25% Check dams; non-erosive 2 yr. Qp; see 4.K. Deep Sump Catch , o w/ cleanout Sump = 4.0" pipe diameter; see 4.1. Basin 4 /a ' NOTES: rj (a) Includes wet extended detention ponds, wet ponds, multiple pond designs. (b) Includes shallow marsh, extended detention wetland, pocket wetland, and pond/wetland designs. { (c) Includes surface, underground, pocket and perimeter designs. (d) Includes compost, peat/sand, and StormTreat designs. s ® Performance Standards and Guidelines for Stormwater Management Page 4-5 1.m fo -01 M NOW ® PROJECT NAME: OF Design C®nsult®nfs, Inc. CALC. BY:��HECKED BY: DATE: SHEET No. OF_� _ -`-� j D' .dY G:7 C ... . . . . . . . . . . . . _ ._ : _.. _ _ ._ ..:... ..:... ............ - .,. , _4 - 10, 7171....... .__..._.._......_ --- .— .. -- -- -- ... __............... _ _ _... __ ... --............ ...._. ........ _......._......._......J. _. _ _... __ , Q ... _ ...... ...:.. . . .. €� .. .. ......... _ ... - - _ .. _ . ... ........ _ _ _. . ... _ .. .. v ,i0 Ow i - - _ - - - -- ... _ --- _..... .- .. --- ............... . ..,� _o.. w V6 AN -. —.r MEOW .i .� ® PROJECT NAME: It,- IV Mum mn= mmmmwmwm� OF Design Consultants, Inc. CALC. BY: C.�CHECKED BY: DATE: T /9 47 SHEET No. 1�OF JL _:.. �.. 0° r� -- ;. r .. .. .... ..........-- ........ ..-_.............. __..._........_-.._.. __._- ....... VO F 'R4 ... _ _ .... ..... ... ... --- ... .. ... __ ... _._ .. _ _._ ... _ --- ........ ...._.. ..._. .................. - - — —. c _ %...:. ..; ..�- ................. _. --- ----- - - - _...�___ lev— ... _.. _ ». _ ... - _ /� J^ E---E .......... ............. PROJECT NAME: A.)freWl MHF Design Consulfanfs, Inc. CALC. BY. A/4-THECKED BY: DATE: 0 14 SHEET No. 2er—oi 47V" 56 44 5 . . . . . . . . . . . ............... .`.. - -............. ........... ................ . . . . . . . . . . . . . . . ........_.................................................... .........V.,.............. ......... ....... ........ ........ ........... ...... -Kl!!:)Z4-,5 1 . ........ ..... ... ................ ......................... ....-......... ........................ ........ W. ............... . . . . . . . . . . . . . . Al W- , 6-41H ........... ................ . . . . .... ... . . . . . . . ... . .. ...... ....... ....... ....... ... ............... .............. .............. .............. ...... ........................... ................ ......... ........ ... .......... . . . .......... ... ........ t5 ............... .............. ....... ... -- ............... .... ..." , . .. .... r I2D 3 /:?15 14-(61 /z s� = lzlCv SF ��I j A PROJECT NAME: A� OF Design Consultants, Inc. cALC. BY: P-- CHECKED BY: DATE: SHEET No. 9F %rUU i AM 0F 14 114: Ao .......... �7- -/- .......... .......... ........... ........... ........... kAl ............... ........ ........... . . . . . . . . . . . . . ............... ...... ............ ................................ ........ ........................... ....... . . . . . . . . . . . . . . . . . . . . . ......... ........ ........ -------L—L- .................................... ............... ...... .............. ........ ........ ..... ............ ............... ......... ................ .................... ............... ........ ................ ........ . . . . . . . .............. ...... .......... .. . . . . . . . . . . . . . . ................... .............. ................ ............... ................ ....... ........ ..... ............ ............ ............. WA� AN NNW A PROJECT NAME: OF Design Consultants, Inc. CALC. BY: kt—,CHECKED BY: \-- -DATE: SHEET No. 0 F SW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7! .......... .......... .. ............. . . . . . . . . . . . . . . . . . . . ............ . ........................... .......................... ............... .......... : ?........... ........... ........ .......................... ............................... ....... ................ .............. ...... ........... 6A ---—--------- r; ........... ............ ................ ............... ....... ........ '/V .... ......... ................................. .............. . . . .......... ......... 4P .......... ..................... ....... LA C, ............... ....... ....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............... ...... *k O� .. ........ ... ....... . . . . . . . . . . . W e, ............. -T .........--­­­-,­--- 3� 7 .......... 4� doe F . . . . . . . . . . . AIR mw A PROJECT NA-ME: r MHF Design Consultants, Inc. C,C- BY. CHECKED BY: --- DATE: SHEET No. __6_OF . . . . . . . . . . eir-46 ... ------- .......... V- Z ............_------ err r. . . . . . . . . . . . . . . . . . ............ .............. ................ :Ak -—----------- . ........ e. ..................—----- ............ ................ ............... ............ ....... .................................................... .............................. -4j UA-ore7 - - -------------------- ..................................... ............... ........... ............. . . . . . . . . . . . . . . . . . . . . ............. ..............r . . . .......... . . . . . . . . . . . APPENDIX A PRE/POST DEVELOPMENT CONDITIONS NO DETENTION 2, 101 100 YEAR DESIGN STORM m I 0 4 O Q. I IL 0 co UL I n LL: ry 1 tD I 1 ° I 0 Of :3 CL 0Q rn D 0 -C o `n tY J m .• 2 r d a N CL CL O a *� a a- 0- O 0 o O o F- F- F- F- =o 0 0 0 0 0 t` a a m a m a 0- a r r CC) E d M � �°� E cc N� i cv c � o E x > m a, G yv0 N (O r + + + c= N IT LL p Q.T N N N N N N N N rQ V ry Q d U > :a O O O O O O O O LL O gd"C p LO Lf) O P CL CL � >_ ca E mow � Ea= rn N - O M N N (V 1t N C0 C / 0 w w L LJ Q. a o 0 0 `o o w w E E to c = ai (D C) co U) co U v O L r Q) rn CL J N Q CL CL 0 a- rna (9 > (9 > > w o 0 w o cn o n o v I- w w O O O O O=a x n_ o_ a o_ a o_ a a O r i r (Y) i E m L7 m U) ms LL w d oa + + + cL I i LD IT LL O E9- Y,o � 0 0 0 0 0 0 0 0 c a C� a' d U 0 N 00 O O O O O O O O LL c L E a ' ' Q � a 0)L _ CO 0) co 0) 0) _ N a n o r O CL o o O o 0 a � a O E cn w E E LO v U v I O L :,_ =Z r CL J J N Q CL a a O a a O o'a cn w w w cn cn o 0 =o � x w O O O O O CL a (L a a m a a r I = t (� C y y �D LL 7 O E= m a I r IT LL D 8 8 8 8 8 8 8 8 ice^ � O ` 2 O d U u 8 O � N 8 ai o ;°. o 0 0 0 0 — > LL L O CD wE P P O H a` Q E >E E a �- (d oi a r 0 a 4, S > > d 01.�� Q 27 O., L L O ai cUn U U APPENDIX B POST DEVELOPMENT CONDITIONS WITH DETENTION 2, 10, 100 YEAR DESIGN STORM r rn a) M O O cn t CL t6 L O LL L r ',. 0 V LL U 0 � C7 a i m N C 6 w Q `o -0 C � =s O � p LO a> °� c 4- ■ �• ^L LL P IL 0 Q C CL O f0.� Q > O Q 0_ Q LL 0 MM O Q _L co LL (n O (n a- <n D (f) cn U) O O r i M O E �, Un XLp I m I j 0) i I M ! r I j o Qj y i (D i (O i I LO L i � N C E7 O m I 0$ c00o I o ` Ci (�D I co N N (D N I I ` N i O Q) i W I m i 0 i co O co r oco (D + + +co CL P i N `t r I I m N N L.L. 0 c L•D�� w C >' N N N N N N N N N N N N N N N N N a Q ` m U E V W -M Cl) O O M N N N N 00 00 O O N M M O O O O O O P P O �7 O O P P N M M N o .�.. O O O O O O O O O O O O O O O O O LL �t N V (O N V (D Lo V N V r (D (D M L N (6•- N M N N V N N V N M N M N V' V M FE aE r r r r r r r r r r r r r r r r r W E ?c P P P P P P P P P P P P P P P P E ED O r 'd• V r U) IT 00 (D M N r O (D N N N a N N v/ N t o 0 0 0 0 o O Q. G c c c c c c L m e � c c c c � o c c c o d rn CL-5 w g w g ; g Z n Z n Z O LO L `a o U aNi U o o to E voi to U U o E w E E w a� U o a) U U U o (1) o o (1) d" > cn (n U (n U X cn (n (n (Y- U U U O L Er- >1 S Z P N M V LO (D r W O - - .r-- MP - N N N i rn rn C) 4 0 Q. crto L 0 LO L .Y U- 0 V U ai LL cl CL U �r 0 0 O LY D ry O o c -� to U U c ai v �� - r m a Q C O a o ' 0 Ma p O a a w O ai v=i a 0 r d i E a, O E m (0 N.V.. _ N _ 2 co ~ c C D Ec 7 p Xj N ON i i N 11 , , f0 ''... eQ d 0) i 1 C-4 LO co LL cl 3 V1 P7 co O iV E O� ap O O O O O O O O O O O O O O O Q IL d� V� r �"' �"' �"' r r r r r r r r r r r m CL �j �g 7 7 Cf) N N N LO QJ. O O O O O O O O O O O O O O O O 4-- LL fl O ',.. 0 EcE H N ' ' //O�� 1L W E >s_ ~_E Ri E d ° � _ O O r O O r O tV cv N N in iD i CL y d C 7 D W D 7 C O D j m [�-) 9 d Z Z Z U ai U o ai U o ai Cam} a0i o U ai a ai LO VJ = cn 1Y V) U W- CA U ir (n W U to x U i L c� th �i in co r� ao rn ° ch ui CL r a� a� R (L _ D Q O Q O O- co a�a Q Q O Q D a W o �- a E- i- O i _I �- Cn In U {h (q LL U7 �- >,y IIU'l I— LL ID < W m tp m U) < U Q x a > > > w (7 C7 0 w m cn O cn a. Z) u> > cn a cn r i = Ec � � O p X j t4 co r N Lo co LL 0 8 8 8 8 8 8 8 8 8 8 8 8 8 u- w CL CD pp �p �p _ t¢.� O U m m O N ON N N N N A 'V' V' O :S O O O O 0 O O d O O O d d O O LL O c Q M _ � }"c E G. (O r O 0 O O I- N M O M M N (i (h (11 f7 i0 +b aD CLQ. a O p p Q i d C 7 •O 7 Z p Z lY 7 p Z � C Z Q CL 6T i L a U N U O a U Q N U co O U N O N O APPENDIX C UNDERGROUND DETENTION SYSTEM DESIGN 21 10, 100 YEAR DESIGN STORM Stage / Storage 1 . 5 1 . 0 tage (ft) 0 . 5 0 . 0 0 200 400 600 800 1000 Storage (cuft) r rn O o o L- O O O LO O � " OMOOMf� 000d OOMI� O O (M r Z V aN- 000 M "t00 0 (O ^ O O O m O O O LA O U y u O O M r Z ^ O O C) m N Q O Cl O N O O i i I i i i i i I i i O O M r Z p O II II 11 II 11 11 N c 0 ++ a=i o Q crl y J W 0 L ,}, Uwe? 3 U N '`- c = in U U W H i i i , I i i i i i U m 9 V i i i i i i i i I i i U o o M O U o 0 0 0 o r (o 0 L., do o 0 0 0 °. o Z Q y O0wcor- mw14- wCOI,- 7 - 000r NOMqrLOLn (0 (0 u 0 0 0 0 0 0 0 0 0 0 0 U r, o o M O 0 0 O O O � (q O m O o 0 0 0 0 0. o Z v M r M (0 00 r M (O 00 r M m 0 LO (p 1- 00 0 r N Co Lo (D N yo' (D > 0 0 0 0 0 0 0 0 0 0 0 co rrrrrrrrrrc- 0 r co c S W Q Q O O 0 O Ln Ln Ln r r Ln O O O i II II II II Jl 11 11 lI 11 �' � U R ■� Z 4� � � t�0 7 r M (0 0Ln0000 (000 (00N r > O ++ 0 M (000 (00NOrM •4 � O h � 0) � � � OrNMtn (0I� 0rrr ^+ LL. 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O > O - 7 m aa+ � ^ Or- M V: Lq (00000 -7 M U cn z 5 J f� z O m z to � $ OOOOOOOO - � � 4-I 4 H 0 V N CD N j N � 2 Ln $4 N 1 � � $a F' r-I N Lc) O ,n O LO O M N N I r1 O O i U1 H 0 LH 0 CV N �4 N to x I~ O H I-Ln O I N N a C) N �n o Ln o Ln o N N N rl c-i o 0 a 4- H o V N O LO LO NCD Ln C.A I N o � �4 CD 41) L4I 14 L O a) -L ' 0) i o � m l0 Ln (Y N ,--I O i 44 H p U v H N O Ln N J o N H O '-+ _� � H o a Ln a� a O y Ln lQ Ln ct fn N r-1 O r-i a n cn ) 4-I H O ko OD N I N i o x o -- o H H rl 0 LO Q N N CD co Qo N o M � i a � to -P U H o V, W LO N U (J( O fN 'H LO O � I , $4 •r-1 14 LO a (D a � O CO l9 1C) LO lJ a � PEAK OUTFLOW HYDR0GRAPHS DETENTION SYSTEM 2 YEAR DESIGN STORM -u t/3 O U � tY) Ln 11 o 14 14 p N x f � ri Ln O - m a i o CO l0 (V O N 0 0 0 0 0 a 4 i t!} + O U l0 LO i II $4 '-1 ^ N x rl LO O - a I i i p m Q N o a i UI + O 0 r- LO ti 1 a N N x 1 � N rl H LO 0 0 t!I 0 a 1 O Co O 00 O O O O O CY 44 o O r-I -LO II j i � o r N x •0 n ` �I m a i o Ln o o p r-1 o 0 PEAK OUTFLOW HYDR0GRAPHS DETENTION SYSTEM 10 YEAR DESIGN STORM i i N if LO 11 a � I � o x 0 Q1 a o in a N o a 44 ko ,-a li � I o x � P 14 j N I C4 CD Ln o In o lo i o OD o cq o ,--� 14 O LO (1) CD a O CD rl I O O 4+ H s U 00 .-I o Ln N �C 1 T� �-i >4 U) N CD Ln D x I � O N N a a o CD D N N 1 c-I O O H a PEAK OUTFLOW HYDR0GRAPHS DETENTION SYSTEM 100 YEAR DESIGN STORM i 44 H O LO U LO 7771 -CD II i k O O x o-� 1 � H O N N P4 CD L o Ln o 0 N N o 0 Ol 44 H O OD ca CD N it i o CD x LO 0 m N o o Ln o Lr) o 11) N a i 44 H U .--i o N II �n o � o � o � H p � 1 ► o 0 l � N 4-) 14 �l U � � o LO \ rn CD CV j I 1 Ln 0 O � o 4CC M EI O W (D CD a 1 o Ol APPENDIX D SCS DA TA/RAINFALL MAPS Z, 101 100 YEAR DESIGN STORM Wi 'S. _. 7 -:r,3 ) T f�. y,,E+��' , r l.rt,. 1...•�Y a S. t kk+ - 't t A� Y L fs �• b :W. 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'•E�i +��� 1�R�;, Y',� ;tfi Crja�t^'G ��{�fiG��G�'f s ��"`�,�'i�.�µ�- 1 r�`GJ;,Y .r�..-tr �, ry ry ;: �_ �/ lw�'� i WJ r fdf 7�.t Cf� �i''++ s 1• n f y � '+T �V� � Tr���• �. G I 7-•� rr,}' i { .'f'' r '� C}! ti� n i �i-(�Y°3��T1 `� Y. „t ,.�f j t,�. r y '�, •• • — • • (Joins sheet 23) ESSEX COUNTY, MASSACHUSETT: 'J.S.DEPARTMENT OF AGRICULTURE >OILCONSERVATION SERVICE ESSEX COUNTY, MASSACHUSETTS, I SOIL LEGEND The publication symbol consists of letters.The first letter,alwa I of the soil name.The second letter is a capital if the mapping u, '.. it is a small letter.The third letter,always a capital A,B,C,D,c symbols without a slope letter are those of nearly level soils,hr have considerable range of slope but have similar use interpre' '.. r SYMBOL NAME SYMBOL NAME AgA Agawam fine sandy loam,0 to 3 percent slopes IW Ipswich and Westbrook mucky peats '.. AgB Agawam fine sandy loam,3 to 8 percent slopes AgC Agawam fine sandy loam,8 to 15 percent slopes LeA Leicester fine sandy loam,0 to 3 percent AmA Amostown fine sandy loam,0 to 3 percent slopes LeB Leicester fine sandy loam,3 to 8 percent s AmB Amostown fine sandy loam,3 to 8 percent slopes Lr Limerick and Rum ney soils Ela Beaches Ma Maybid silt loam BeA Belgrade very fine sandy loam,0 to 3 percent slopes MC Medisaprists,deep BeB Belgrade very fine sandy loam,3 to 8 percent slopes MD Medisaprists,shallow BeC Belgrade very fine sandy loam,8 to 15 percent slopes MeB Melrose fine sandy loam,3 to 8 percent si Br Birdsall sill loam MmA Merrimac fine sandy loam,0 to 3 percen. BuA Buxton silt loam,0 to 3 percent slopes MmB Merrimac fine sandy loam,3 to 8 percent '.. BUB Buxton silt loam,3 to 8 percent slopes MmC Merrimac fine sandy loam,8 to 15 percen '.. BuC Buxton silt loam,8 to 15 percent slopes MmD Merrimac fine sandy loam,15 to 25 perce BxB Buxton-Rock outcrop complex,3 to 8 percent slopes MoB Montauk fine sandy loam,3 to 8 percent s BxC Buxton-Rock outcrop complex,8 to 15 percent slopes MoC Montauk fine sandy loam,8 to 15 percent MoD Montauk-fine sandy loam,15 to 25 percer CaA Canton fine sandy loam,0 to 3 percent slopes MsB Montauk very stony fine sandy loam,3 to, CaB Canton fine sandy loam,3 to 8 percent slopes MsC Montauk very stony fine sandy loam,8 to CaC Canton fine sandy loam,8 to 15 percent slopes MsD Montauk very stony fine sandy loam,15 tc CaD Canton fine sandy loam,15 to 25 percent slopes MxC Montauk extremely stony fine sandy loam CbB Canton very stony fine sandy loam,3 to 8 percent slopes CbC Canton very stony fine sandy loam,8 to 15 percent slopes NnA Ninigret fine sandy loam,0 to 3 percent sl CbD Canton very stony fine sandy loam,15 to 25 percent slopes NnB Ninigret fine sandy loam,3 to 8 percent si CcB Canton extremely stony fine sandy loam,3 to 8 percent slopes CcC Canton extremely stony fine sandy loam,8 to 15 percent slopes PaB Paxton fine sandy loam,3 to 8 percent slo CcD Canton extremely stony fine sandy loam,15 to 25 percent slopes PaC Paxton fine sandy loam,8 to 15 percent sl '.. CDE Canton and Charlton extremely stony fine sandy foams,steep PaD Paxton fine sandy loam,15 to 25 percent '.. CeA Carver loamy coarse sand,0 to 3 percent slopes PbB Paxton very stony fine sandy loam,3 to 8 CeB Carver loamy coarse sand,3 to 8 percent slopes PbC Paxton very stony fine sandy loam,8 to 1? Cm El Charlton fine sandy loam,3 to 8 percent slopes PbD Paxton very stony fine sandy loam,15 to CmC Charlton fine sandy loam,8 to 15 percent slopes PcC Paxton extremely stony fine sandy loam,E '.... CmD Charlton fine sandy loam,15 to 25 percent slopes PcD Paxton extremely stony fine sandy loam,3 '.. CoB Charlton very stony fine sandy loam,3 to 8 percent slopes PcE Paxton extremely stony fine sandy loam, CoC Charlton very stony fine sandy loam,8 to 15 percent slopes Pe Pipestone loamy sand CoD Charlton very stony fine sandy loam,15 to 25 percent slopes Pg Pits,gravel '.. CrB Charlton-Rock outcrop-Hollis complex,3 to 8 percent slopes '.... CrC Charlton-Rock outcrop-Hollis complex,8 to 15 percent slopes Qu Quarries C r D Charlton-Rock outcrop-Hollis complex,15 to 25 percent slopes Ra Raynham silt loam De Deerfield loamy fine sand RdA Ridgebury fine sandy loam,0 to 3 percen '.. Du Dumps RdB Ridgebury fine sandy loam,3 to 8 percen I RIA Ridgebury and Leicester extremely stony EIA Elmwood fine sandy loam,0 to 3 percent slopes RIB Ridgebury and Leicester extremely stony E1B Elmwood fine sandy loam,3 to 8 percent slopes RnC Rock outcrop-Buxton complex,3 to 15 pe RnD Rock outcrop-Buxton complex,15 to 25 p '.. Ha Hadley very fine sandy loam RoC Rock outcrop-Charlton-Hollis complex,3 I HfA Hinckley loamy sand,0 to 3 percent slopes RoD Rock outcrop-Charlton-Hollis complex,1` '..., HfB Hinckley loamy sand,3 to 8 percent slopes Rx Rock outcrop-Hollis complex HfC Hinckley loamy sand,8 to 15 percent slopes HfD Hinckley loamy sand,15 to 25 percent slopes HWE Hinckley and Windsor loamy sands,steep I I I < I t4 i ACHUSETTS, NORTHERN PART MASSACHUSETTS AGRICULTURAL EXPERIMENT STATION �4 >011 'EGEND a rs.The first letter,always a capital,is the initial letter `{ capital if the mapping unit is broadly defined;otherwise, ys a vital A.B.C,D,or E, indicates the slope. Most f: of r. ly level soils,however,some are for units that 7 ive s,,,.,lar use interpretations. ME SYMBOL NAME - ;1 `3Y'3 orook mucky peals Sa Saco Variant sift loamsi '.. ScA Scantic silt loam,0 to 3 percent slopes dy Ic--.0 to 3 percent slopes ScB Scantic silt foam,3 to 8 percent slopes .3 dy Ic .3 to 8 percent slopes Se Scarboro muck fine sandy loam _ iney Is SgB Scituate fine sandy loam,3 to 8 percent slopes '.. SgC Scituate fine sandy loam,8 to 15 percent slopes - =� ShB Scituate very stony fine sandy loam,3 to 8 percent slopes -, k7 P ShC Scituate very stony fine sandy loam.8 to 15 percent slopes Now SrA Sudbury fine sandy loam,0 to 3 percent slopes *'{ T-� y IN 3 to 8 percent slopes SrB Sudbury fine sandy loam,3 to 8 percent slopes j idy icam,0 to 3 percenLelopes SsB Suffield silt loam,3 to 8 percent slopes - iei!oam,3 to 8 percent slopes SsC Suffield silt loam,8 to 15 percent slopes idy'--­i,8 to 15 percent slopes StA Sutton fine sandy loam,0 to 3 percent slopes idy, 1,15 to 25 percent slopes SIB Sutton fine sandy loam,3 to 8 percent slopes - dy:a. .3 to 8 percent slopes SIC Sutton fine sandy loam,B to 15 percent slopes dy loam,8 to 15 percent slopes SUB Sutton very stony fine sandy loam,3 to 8 percent slopes dy!cam,15 to 25 percent slopes SuC Sutton very stony fine sandy loam,8 to 15 percent slopes €; ny F---,andy loam,3 to 8 percent slopes SwA Swanton fine sandy loam,0 to 3 percent slopes ny fi sandy loam,8 to 15 percent slopes SW B Swanton fine sandy loam,3 to 8 percent slopes ny fi sandy loam,15 to 25 percent slopes ,ly stony fine sandy loam,5 to 20 percent slopes UAC Udipsamments,rolling '.. U Udorthents,smoothed - iy Ic 0 to 3 percent slopes UnA Unadilla very fine sandy loam,0 to 3 percent slopes iy!0 3 to 8 percent slopes Un8 Unadilla very fine sandy loam,3 to 8 percent slopes UnC Unadilla very fine sandy loam,8 to 15 percent slopes loam,3 to 8 percent slopes Ur Urban land _ r loam.8 to 15 percent slopes r loa.. l5 to 25 percent slopes WaA Walpole fine sandy loam,0 to 3 percent slopes P fini ndy loam,3 to 8 percent slopes WaB Walpole fine sandy loam.3 to 8 percent slopes '... r f nt ndy loam,8 to 15 percent slopes Wb Walpole Variant fine sandy loam r fine sandy loam,15 to 25 percent slopes WeA Wareham loamy sand.0 to 3 percent slopes stony fine sandy loam,8 to 15 percent slopes WeB Wareham loamy sand.3 to 8 percent slopes 'stor 'ne sandy loam,15 to 25 percent slopes Wf Whately Variant fine sandy loam '.. stoi. 'me sandy loam,25 to 45 percent slopes Wg Whitman loam sang Wh Whitman extremely stony loam WnA Windsor loamy sand,0 to 3 percent slopes '..... WnB Windsor loamy sand.3 to 8 percent slopes WnC Windsor loamy sand,8 to 15 percent slopes WnD Windsor loamy sand,15 to 25 percent slopes m WoC Windsor-Rock outcrop complex,3 to 15 percent slopes '.. andy loam,0 to 3 percent slopes WoD Windsor-Rock outcrop complex,15 to 25 percent slopes andy loam,3 to 8 percent slopes WP Winooski very fine sandy loam '.. eice-'--extremely stony fine sandy loamy,0 to 3 percent slopes WrA Woodbridge fine sandy loam,0 to 3 percent slopes eice extremely stony fine sandy foams,3 to 8 percent slopes WrB Woodbridge fine sandy loam,3 to 8 percent slopes xton nplex,3 to 15 percent slopes WrC Woodbridge fine sandy loam,8 to 15 percent slopes xton complex,15 to 25 percent slopes WsB Woodbridge very stony fine sandy loam,0 to 8 percent slopes arlton-Hollis complex,3 to 15 percent slopes - WsC Woodbridge very stony fine sandy loam,8 to 15 percent slopes arltr-`iollis complex,15 to 35 percent slopes WsD Woodbridge very stony fine sandy loam,15 to 25 percent slopes Ili$( plex WtB Woodbridge extremely stony fine sandy loam,3 to 8 percent slopes WtC Woodbridge extremely stony fine sandy loam,8 to 15 percent slopes i m .. a 0 tl O N PP PP P P O pN O P Pw co cc C ' L 3 v _ 7 � pp fr1 p.t. L c U �f�ac1 CO o, o7PPN v•- P W07COO P v0••L P Pao COP PP b 45 Y ✓ c uc UL 0 14 y m �O�n P CO&A co AN co t�•I�n�O� of vg- �C m L� co b � µ21 ��ppNN tll 7.0 vi .y� P 01 t, W co a7 .Oh V7 V7.t O ✓ > C b L L L ; > �' °' Y > N C U O Q v y m c v E U Y L 0 ',.. v L 7 L pp U m 0 0 = Y- N L y CI - L u WM11 O V1 N to CC O V1 0 N 'pm C N L G7 W(� •O M M N N.- 4 m O Y't7 L Y .U 0 m L 4 C C ` m < u u L L p1 Y p v o c uv L � ►, U L v m v u m 0co• ��T ✓ L 00, m ^1 U m L q 0 O L Y W L O L Y✓L ✓ yv, O O d 7 7 .o.. € OLLtXV) > � o a °Y U� Zi 7c� w U E a, . � L. Y v L r a p U C3 7 U y.. 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O e4 o p L. a E ° a+ v N O N O 'j L L •r•{ > L L U L L rd F U O v v L\ U ' N U Im 7 O v cd O W L a+ 111 ° p L V M U V m �(f O O L T w cz D' QlL IM U L 6 O V L w0: L L u 0:Ix UU O O m U'° d' J N L T u 7 1'w 7 u Cw _ W m O W '^ O UU O •d ua u Idd Vy1�\O U .> L J V a 3G m -4•d a+ a+ •d ca "• C+• L . 0 4 L p L C das [NN H ��F Ff-►-• FF- M O U 'O O: O L C K d' O O.3-4-8 Q'1'1 K eii ad ea as It S' pa ed [ L O ypC O M u u NV) N V)UUUUUUUU 0V7N VIUUUU UUUU NNUUUU O U �� O r•{ y. J a+a O a. ` •0 =� O L ' H N o LVLM� C/1 C.7 CVi O L U N L V > in C �p 0\ O ++�i J uj O V O m+• m U ! U U L O O O � y 16 L L J v u �.: N U U O 6-20 A b � b U b o m c Q! m 0 a W � . ~ �f M M K1 v M v M M. v Fn?n LM Id cr Z 14 � C " C a Gov u L U " U co L W L v L u u U V cu. ,1 c V {54 t M Q L — c L a+ LA CD 0 O L L H E O m r at+ V~ 0 tj a i U D U V,*. L O N tq L oam 0 LL N J 2 N O C QJ � o 1 Kw U LL L q 1. N 'p 0 O Q O L C q U U U a " °' U C _ Q Soo 0 H 41 ° w 95 o 0 o V1 o u _ •"• g-CD � w 7 9L U 0 6-21 01 ........... .................. ----------- E L: >7 4 - ---------- --- F r R-6 (210-VI-TR-55, Second Ed., June 1986) Ui < -K C>a cc k—_a cr 0 K 0 eq k W TT L ------------- ----------- (210-VI-TR-55, Second Ed., June 1986) B-9 '+ " lei .. y°• � -.p-�: — V✓: '' � ',. v� ice' << LL �� __ _ _ �-ti. -t-tea ��,•� O N W � y._y i _ , f- I , L rte' r^tom-•- � Cj I — f C - 13-4 (210-VI-TR-55, Second Ed., June 1986) PROJECT NAME: MHF Design Consultanfs, Inc. CALC. BY-,Z ,?—Cl-lECKED BY: DATE: -41141'97 SHEET No. OF- . . . . . . . . . . . . . . . . . . . . . . . . . . . ............ ...... . . . . . . . . . . ........................ ........ k Z�lc ........... ........... z� -1-0-............... ................. ........ ............ &......... .................... . . . . . . .......................... ..................... ........ ........................ 2 .... ........... ......................... . . . . . . . . . . . . ................... ........ ........ ......... ZJ- . . .... ........ ......... ............. . .......... ........ ................... ...._ ... ........... ............... -_-- A i ....................... ev V4 ............................... .............. ........ 7,f ito r. . . . . . . . . . . . . . . . . ... . ..... ...... j 4F 4e, . . . . ....... M7 . . . . . . ..... .........4-e...... . . ......._4 . . . . . . . . . . . . ...... ...... ........ ....... .............. .U......___._........._._........ .................... ------------ ................................. An Now A PROJECT NAME: IV • MHF Design Consultants, Inc. CALC. BY: 4,;-�ECKED BY: -DATE: �¢4 SHEET No. OF Z KL Alt FT i........... .._ -_ ...__. _ .._._. ..__._.... _.....-----------_............................ _..........._—_....:....._�_........ _._.. .........._..............:...._-:... : ...-..,_..._..,........,. --: ----- �_._:._... _ ... _ _:..__.._i._.._. ._—:�»....�._.....__....:._.:.._......�...._..i..._._:_._.....:__...:.........i_.. _.:.................i.._...._.........:..__.. _........ .?._.-_° _........... ___....i......{""""""""_i...... •J--....:_...._...__-E..........-'- ............ .............. ....................... ...... ........ ........ . . . . . . . . . . . . TIME OF CONCENTRATION (TC) OR TRAVEL TIME (Tt) WORKSHEET 6®2 Project r--(V %✓!r>��if�ls�-�Ls� 1 �J By Date 3//3/ Location �_ Checked Date Circle one: resent Developed Circle one: QTICD Tt through subarea NOTES: 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 T only)y) Segment ID 1. Surface description (Table 6-6) ---------------- 2. Manning's roughness coeff., n (Table 6-6) ------ Im 3. Flow length, L total L <g � ( 300 feet) ft 4. Two-yr 24-hour rainfall, P2 ____________________ in 5. Land slope, s ---------------------------------- 0.007 (nL)0.8 ft/ft 6. Tt P2 0.55p;y — Compute Tt ----------- hr Shallow concentrated flow Segment ID 1+1 3 7. Surface description (paved or upaved) ----__Flow length, L -------------------------- ft 90 9. Watercourse slope, s --------------------------- ft/ft O/7 10. Average velocity, V (Figure 6-14) ..............11. Tt = C 3600V ompute Tt ----------- hr Channel e_ l flow Segment ID 12. Cross sectional flow area, a ------------------- ft, 13. Wetted perimeter, pw --------------------- a ------ ft 14. Hydraulic radius, r = — Compute r 15. Channel slope, Pw ft/ft 16. Manning's pyghy72s coeff., n -------- 1.49 r s ---------- 17. V = n Compute V --------------- ft/s 18. Flow length, L -------------------- L ------------- ft 19. Tt = 3600 V Compute Tt _.'""'-----... hr _ 20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, and 19) 6-40 TIME OF CONCENTRATION (TO OR TRAVEL TIME (Tt) WORKSHEET 6®2 Project /fJ- Y � as- ri%r 6y Date 3 / Location _ 2/�l> G i�G//.�i`L,r�� / 4 4 Checked - Z,_ Date Circle one: Pr_e ens t� Developed Circle one: / D Tt through subarea NOTES: 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 T onl C Y) Segment ID I. Surface description (Table 6-6) ---------------- I+H 2, Manning's roughness coeff., n (Table 6-6) ------ 3. Flow length, L (total L 5 300 feet) ------------ ft 4. Two-yr 24-hour rainfall, P2 ____________________ in 5. Land slope, s - ------------------------------- ft/ft 0.007 (nl)0.8 6. -,T =t P2 0.5— s 0y Comte Tt ----------- hr Shallow concentrated flow / Segment ID 7. Surface description (paved or upaved) ---------- 8. Flow length, L 'ft 9. Watercourse slope, s ___________________________ ft/ft DZ7 10. Average velocity, V (Figure 6-14) ______________ 11. T L ft/s 2, (= t 3600V Compute T � t ----------- hr , p s - + Channel flow Segment ID 12. Cross sectional flow area, a ___________________ ft, 13. Wetted perimeter, pw --------- a--------------------------- ft 14. Hydraulic radius, r = — Compute r ........... ft 15. Channel slope, Pw ----------- ft/ft 16. Manning's mghT72s coeff., n ------------------ 1.49 r s 17, V = n Compute V --------------- ft/s 18. Flow length, L ------------------- L -------------- ft 19, Tt = Compute 7t -------------- hr _ 3600 V + _ 20. Watershed or subarea Tc or Tt (add Tt in steps 6, 11, and 19) ---------- hr f 3,yM�N 6-40 I TIME OF CONCENTRATION (TC) OR TRAVEL TIME (Tt) WORKSHEET 6®g Project 1 By ?fie Date location / , G!" ? �5 , .. ° # E° Checked Date Circle one: PresentDeveloped F° Circle one: 6C Tt through subarea DOTES: 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 I 1. Surface description (Table 6-6) ---------------- 2. Manning's roughness coeff., n (Table 6-6) ------ p`� 3. Flow length, L (total L 5 300 feet) ------------ ft �d-O 4. Two-yr 24-hour rainfall, p2 ____________________ in 5. Land slope, s ---------------------------------- 0.007 (nL)0.8 ft/ft t -- P2 s 0.55 4 — Comte 7t ----------- hr 0 v 0'L + Shallow concentrated flow Segment ID / ,?/ 3 7. Surface description (paved or upaved) __________ 8. Flow length, L --------------------------------- ft 9. Watercourse slope, s -------------------------- - ft/ft � O/,S �03Z 10. Average velocity, V (Figure 6-14) -------------- L ft/s 2�2 f(O 2 ¢- 11. Tt = Compute T 3600V t hr 0.07, + O.D� Qr0! Channel f-l-ow Segment ID 12. Cross sectional flow area, a ------------------- ft_ 13. Wetted perimeter, pw - - --------------- - a ------ ft 14. Hydraulic radius, r = — Compute r ----------- ft 15. Channel slope, pw --------- ft/ft 16. Manning's mghy7p coeff., n __________________ 1.49 r s 17. V = n Compute V --------------- ft/s 18. Flow length, L --------------------------------- ft 19. T = Tt Compute 7t -------------- hr _ 3600 V + _ 20. Watershed or subarea T or Tt (add Tt in steps 6, 11, and 19) 6-40 TIME OF CONCENTRATION (TC) OR TRAVEL TIME (Tt) WORKSHEET 6®2 Project—//, �� 8y Date Location Checked Date Circle one: Preseneveloped Circle one: Tc Tt through subarea NOTES: 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 6-6) ---------------- UNF�1) low 2. Manning's roughness coeff., n (Table 6-6) ------ 3. Flow length, L (total L 5 300 feet) ------------ D/ ft ohm 4. Two-yr 24-hour rainfall, P2 -------------------- in 5. Land slope, s ---------------------------------- 0.007 OL)0.8 ft/ft 6.' T = t P2 0.5— s0.4 — Comte Tt ---- hr Shallow concentrated flow Segment ID / 7. Surface description (paved or upaved) ---------- N 8. Flow length, L --------------------------------- g ft qo 9. Watercourse slope, s --------------------------- ft/ft OZ 7 10. Average velocity, V (Figure 6-14) -------------- L ft/s (p _ 11. Tt 3600V Compute Tt ------ hr r D S` + Channel flow Segment ID 12. Cross sectional flow area, a ------------------- ft= 13. Wetted perimeter, pw --------------------------- a ft 14. Hydraulic radius, r = — Compute r 15. Channel slope, s Pw ft/ft 16. Manning's inghT72s coeff., n ------------------ 1.49 r s 17. V = ----------- Compute V --------------- ft/s 18. Flow length, L ----------------------- L ft 19. Tt = Compute T t -- _....- 3600 V hr 20. Watershed or subarea T. or Tt (add Tt in steps 6, 11, and 19) -------- -- hr 6-40 APPENDIX E MISCELLANEOUS PIPE_CHARTS/NOMOGRAPHS/CHARTS c rn a c c zs > > 'D O .-1 W CL o� a �-' � al Q)i c 4: v: c m A G' G3 O• cn w w w x H A > n - v o ci b ®b v CHART 35 oft o , � �Iyye, i ' b D h LL °9- 4� ,e 0 CC v o 4 ob °� b °°� At IAJ 0 00 h y 00 01 9 O O w 1 ° W 00 m o t g 1 °pp b J. n 1 p o U 8o i d o a 1 0 h t•• � 1 0 0 1 S/O• a U SdJ -A -Al10073A ! h N ® ti b h 7 �•f N � � O ® fi b h � h N O 0 ►� b h Q � f.'0'+U 9-45 . 50 - -� i .20 - i , .10 4 a; n- .06 - 0 v� (U L .04 - 0 CU IF IF U 3 IF _ .02 - a IF a17Y .01 - fl .005 - 1 1 2 4 6 10 20 Average velocity, ft/sec Figure 3-1.—Average velocities fo`r estimating travel time for shallow concentrated flow. 3-2 (210-VI-TR-55, Second Ed., June 1986) �4 �4 �A >1 �4 �4 I I I O L(� O O N Ln r-I N Ln c-I a 0 0 H o U) Ln 0 0 a) CD M U U H O W N A O H O O 00 lfl O H H APPENDIX F BMP DESIGN -OUTLET PROTECTION DESIGN -LEVEL SPREADER DEsMN -TREATMENT SWALE DESIGN - ROOF INFIL TRA TION DESIGN - CUL VERT ANAL YSIS- 12"INLET low PROJECT No. 9g(r� ® — ® PROJECT NAME: A— MHF Design Consultants, Inc. CALC. BY: yYIlvl—EHECKED BY:- "�- DATE: Z 9' SHEET No. / OF _ : _ L__..___..-= -_...................__..._.._._.._......... _. _..... _ _ ... _ ... ... -- - ... _ ..._.. ...........__........._. __ _ .-....... — —-- -- -- _ ........... ... — -- _ _ ... ._ ._ - - --. —_._._:___...._._._.... __. ........ _ ._...............--- – – - -- ... ... ... _ _ ... ... .. ._.._.. ..._...__._....__. ...---.-_ _--..._........... .-. i _....... ......._:.._.__..........._i.._...:........:........:............. ..._.._...T_....__. __._.-____...._..... .�....._....................... .__ .. _... : :. . : _. �? E -- _ ..__.__..........a....`--. _'......... _ .._..... — — .......--.........................._ ............... ' _` ......... . = :... .. _... ... ... .- -- _ _ ... ... ... _ ......... . ____...._--._...............:.._........._: - - --- -- - --- - - .:... ...:... ....... ...... ....... ....... ....... ....... ... , ,_ _.. v ,cr% 1.._.. ..........................P..�... ..`..... ... -..... . .......... ................._.................. ........:.........:.�_..... ....t.......... _... ......�...... _ ... .................:.........:._._..:......... :.�... _.. ...:........___...........__.._..___.._. _-----:.........................- .._ --- - ................. _. .....__.:.........__.:....._.__-.........:.........:................: ... ................. _.._ _.. -- -- ... € .. ... ... ...... � ,x..•.2..1 r�z ; �_.__.......:................_.........,... ... . .._�a ....................._... -- - ... .. ... _ ... ................ ...:... ...:... ....... ....... ....... ...:... _.:__. : :_.....:........__...:_._._:.._.......... ... ... _. ... _.... .�. .:... ........ . ...__.._...................... _.. _..........._......._..........--•---......._ - -. -- - ._ _ -- - _- -- -- ..._ .. ... ... . ......`..._.._......... ...... mmv PROJECT No. AN MW A mb(0 PROJECT NAME: r MHF Design Consultants, Inc. CALC. BY:_AA_-rfMCKED BY: �--C�DATE: SHEET No. OF . . . . . . . . . . . . . . . . . . ........... ........... . . . . . . . . . . . A,) o ......... L ... ................ ........ ......... ............ ............................... ................. ......... ....................................................... ................. .................... ...... ....... ....... .. ......... .......... ................ ...... .................. .......... ......... . . . . . . . . . . . . . . . ,r 0 .�.......... .................... ..................... .............. ......... ............................ ---------------......... ......... ............ ......... ........................... ................................................... .......... .................. . ........... ..... ......... ..................... ................. ............ -------- ---------- ......... .......... ...... ........------ ... .................. .................................. .. ................ ............................ ................. ......... . ............................... ........................ ....... ......... ......... ......... ....... ........ ........ ........ .......... ............... ......... .............. ............................------------ ............... ............................. ........ ................................................... ... ........ ................. ................. ................ ........... .......................................... ................ ................ ............ ........ .............................................. ................. ................. .......... .................. ......... ....... ............ ....... ........ .............. ............. ............................. UNEW � PROJECT No. mmmmv* d MMUF MEN mm�wmm= PROJECT NAME: MHF Design Consultants, Inc. CALC. BY-A4t----(tMECKED BY: --'— DATE:.)/6/?/' SHEET No. —OF -- - ................. ..................... ...... ............... ............... .... ................. ....... ......... ..... ............................ .................. ..................... .......... **""'*T................. 7----–---------------------- .................. .................... ........................... A_ .................. ....................................... .......... ....... .... .. ......... . .... ......... . ........................... ........ ------------- ............. 0'/Z m N�^ o.00 po 0 8 0.8/ ° CHART 17 0Y/ O'S/ 1 ° I 0 S/k. 0 / , o g 0'Z/ 0'0/- 0'0/ N I ° 09-/, ° � ovb 00 8 ov 8 001L ��0 00Z 0019 00'9 00'9 0°0 0 -00Y ; °.v Q WV NL o S Q °. I R U 00'2 2c, W 00'0 08'/ o o I y o9Y oo°0 0 oz OSY 0 0 O OZ'/ C° ° —� OZy h 001/ I W 00'/ 06'0 b c°i 06'0 08'O i 06'0 OL'0 U OL•O 0910 0 - ` N 09'0 OS'0 05 10 S4'0 I- W sPo oq•o %>)I o yw 59 06,0- °y-0£o 92.0 I moo- > T � cz ��. Sz'v 02.0 U 02'0 s,o i h s,'o z/of o z/'o 0/'0- �I v 0/'0 PO I ct m 90.0 90'0 I 90 0 ti C \ Q I \ Q Q 'S d y ,U10073A I I 1 I I I I I I I I 1 1 1 1 I I I I I I I 37COS u^ o h o 0 0 D o h N p a t� L h tr m ti N h o o0o p o CHANNEL CHAR' 2 :1 b - 4 FT. 25 A PROJECT NAME: M� AMM M� MHF Design Consultanfs, Inc. CALL. BY: M-el-,CHECKED BY: # Zr—DATE: s SHEET No. OF . . . . . . . . . . . . . . ............. .J........... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... ........... .. .......... ....... ....... ......................... ;J/ L ............... ...... rf7 ................. 4-A -.5* ;7 Jj ........ ............ 4 A /0 (--,v .............. VL ....... . . . . ......... ................. ?K ef 4 . . . . . . . . . . . 171 /A) ... ....... 97 9F � 37.50' (6 UNITS) • • RD ROOF INFILTRATOR 50.94' SYSTEM 111 (18 UNITS BED BOTTOM-196.75 RD 17 HOPP HEADER FIF 6' PVC INSPECTION 4! HDPP (TYP.) . PORT (TYP) • PROPOSED ROOF DR.Uh (SEE PLAN) OT 8' HDPP OVERFLOW PIPE 2 RD HIGHEST EXISTING ELEVATION BELOW INFILTRATOR-194.508 TIMATED GROUND WATER ELEVATION (BASED ON 7' DEPTH)-193.92 _ RD ROOF INFILTRATOR SYSTEM #1 BOTTOM ELEVAMN=196.75 PLAN :PARATION DISTANCE-2.83' R001' INFILTRATOR . SYSTEMS.#I. FIGURE 1 mmmomr NEW , AN NEW A PROJECT NAME: edO OF Design Consultants, Inc. CHECKED BY- 6--DATF,:--,c q-7 SHEET No. OF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.6 Wk . . . . . . . . . . . TO, T 7 e . . . . . . . . . . ................ . . . . . . . . . . . AM Alk Mi .* -7 . . . . . . . . . . . . . . ......... ....... . . . . . . . . . . . . .... .. ......... ww .......... . . . . . . . . . . . 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ROOF INFILTRATOR o • SYSTEM (1UNIITS) 12' HDPP HEADER PIPE BED BOTTOM-193.75 RD 67.92' (24 NITS) • PROPOSED ROOF DRAIN (SEE PLAN) RD • 6' PVC INSPECTION PORT (TYP) �725.00' 4 UNITS 2 PLAN NOTES: HIGHEST EXISTING ELEVATION BELOW INFILTRATOR-191.88 ESTIMATED GROUND WATER ELEVATION (BASED ON 7' DEPTH)-191.30 ROOF INFILTRATOR SYSTEM 12 BOTTOM ELEVATION-193.75 SEPARATION DISTANCE-2.45' ROOF INFILTRATOR SYSTEM ,2 FIGURE 2 NNW An Now A PROJECT NAME: )A✓ OF Design Consultants, Inc. CALL. BY- NECKED BY- DATE:.. l 4/1 SHEET No. ALOF el p .................... Zk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......... . . . . . . . . . . . . . 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ElEiEEEEEEEElEEEE ! lEEEE U .Q Ln 1- O N Ln fl- O N Ln I— a N Ln t— O N Ln 1- O N to 1l_ 0 N N l- O ('M CMNtrh Ntll� LnLnLnLn CQ CC! ggpl-: I� I� I� cqqRqOC gO (AO (Q W V N OvR= I-- N00 � OtnrI- N00VM0 1*- NMV0M 0 N W '-t M0 MCn � O (OrI� N00MOd O (Orf� N00MOLnO (OrI� N00 MM ,;tLnN(fl (Q rI . oc CACt :::t MMd V! CC) U) Nti �+ N N N N N rrrrrrrrrr � � NCANNCA NN (NNN N LL y � d 8 - (p (p (q 1� I� 00 00 00 00 00ggqq9OOOrrrrNNNM w (n co - 000000000 CDo0000rrrrrrrrrrrr -�fno 1\ C-E ECHNIC E ICES C. 4 Geotechnical Engineering — Environmental Studies _j Materials Testing _-j Construction Monitoring April 30, 1997 Mr. Mark Gross, P.E. ADVANCE COPYBYFAX MHF Design Consultants 10 Manor Parkway Salem, New Hampshire 03079 RE: Renee's Florist Andover, MA Project No. 97154 Dear Mr. Gross: This report presents the results of permeability testing for the referenced project in accordance with your verbal request. The permeability testing was required from which to design an infiltration basin for roof drain and/or stormwater run-off. GSI initially attempted to perform insitu permeability testing with a Guelph permeameter but the shallow groundwater conditions at the site precluded the use of the equipment. Three samples of the subsurface parent soils were collected and tested for grain size analysis. The proposed drainage strata soil was also tested for permeability in accordance with procedures detailed in USCOE Manual EM 1110-2-1906 for constant head permeability testing. The specimen was prepared by compacting the soil in a 4 inch standard proctor mold with 25 blows of a hammer in five separate lifts. The test results indicate that the grain size distribution are indicative of a fine to medium sand and silt. The constant head permeability test on the proposed drainage strata had a rate of 9.48x10^ cm/sec at an estimated 95% of max. dry density. This would correspond to 1.34 inches/hour. The supporting test data is attached to this letter report. We trust that the contents of this report meets with your satisfactions. Should you have any questions with respect to the contents herein, please do not hesitate to contact us. We thank you for this opportunity to have been of service to you and look forward to working with you in the future. Very truly yours, GEOTECHNICAL S VICES, INC. Harry K. Wetherbee, P.E. Principal Engineer Enclosures -A 12 Rogers Road, Haverhill, MA 01835 a 508/374/7744 FAX 508/374/7799 — 18 Cote Avenue, Unit #11, Goffstown, NH 03045 -4 603/624/2722 - FAX 603/624/3733 i t GEOTECHNICAL SERVICES, INC. ® Geotechnical Engineering -.A Environmental Studies _A Material Testing : Construction Monitoring a— PROJECT: Renee's Florist "ROJECT No.: 97154 SAMPLED BY: W. Shedd DATE SAMPLED: 4/22/97 4MPLE No.: L-225-97 TESTED BY: K. Sanborn DATE TESTED: 4/24/97 ELEVATION: 8"to 15" PLOTTED BY: W. Shedd DATE PLOTTED: 4/28/97 CATION: Test Location#1 CHECKED BY: H. Wetherbee _3URCE: In-situ soils SOIL DESCRIPTION: Olive Gray fine to medium SAND and Silt MARKS: "B"Soil PARTICLE-SIZE ANALYSIS -COARSE SOIL ASTM D 422 GRAIN SIZE DISTRIBUTION CURVE BOULDERS&COBBLES UKAVLL SAND SILT&CLAY COARS FINE COARSE MEDIUM FINE i 100 \'60 0 CL z 40 a - 20 0 1.0E+03 1.0E+02 1.0E+01 1.0E+00 1.0E-01 1.0E-02 GRAIN SIZE (MM) I GEOTECHNICAL SERVICES, INC. ® Geotechnical Engineering Environmental Studies Material Testing d Construction Monitoring _A PROJECT: Renee's Florist "ROJECT No.: 97154 SAMPLED BY: W. Shedd DATE SAMPLED: 4/22/97 ;AMPLE No.: L-225-97 TESTED BY: K. Sanborn DATE TESTED: 4/24/97 ELEVATION: 8"to 15" PLOTTED BY: W. Shedd DATE PLOTTED: 4/28/97 .00ATION: Test Location#1 CHECKED BY: H. Wetherbee SOURCE: In-situ soils SOIL DESCRIPTION: Olive Gray fine to medium SAND and Silt :EMARKS: "B" Soil PARTICLE-SIZE ANALYSIS -COARSE SOIL ASTM D 422 COARSE SIEVE TEST SIEVE CUMULATIVE PERCENT PERCENT I� MESH WEIGHT RETAIN RETAINED FINER (Lbs.) (%) (%) 6 0.0 100.0 3 0.0 100.0 2 0.0 100.0 1 0.0 100.0 3/4 0.0 100.0 1/2 0.0 100.0 3/8 0.0 100.0 4 0.0 100.0 WEIGHT OF SOIL= 431.4 Grams FINE SIEVE TEST SIEVE CUMULATIVE PERCENT PERCENT PERCENT MESH WEIGHT RETAIN RETAINED FINER FINER PASSING (9m) (%) (%) #4 SIEVE (%) 8 36.00 8.3 91.7 91.7 10 42.70 9.9 90.1 90.1 16 62.10 14.4 85.6 85.6 40 113.90 26.4 73.6 73.6 50 137.60 31.9 68.1 68.1 100 193.50 44.9 55.1 55.1 200 263.70 61.1 38.9 38.9 WEIGHT OF SOIL= 431.4 grams WAS cAGSI-LAB\SIEVE\225.XLS GE E IC SERVICES, � Geotechnical Engineering ® Environmental Studies ® Material Testing .A Construction Monitoring © � PROJECT: Renee's Florist ''ROJECT No.: 97154 SAMPLED BY: W. Shedd DATE SAMPLED: 4/22/97 SAMPLE No.: L-226-97 TESTED BY: K. Sanborn DATE TESTED: 4/24/97 ELEVATION: 8"to 18" PLOTTED BY: W. Shedd DATE PLOTTED: 4/28/97 OCATION: Test Location#2 CHECKED BY: H. Wetherbee SOURCE: In-situ soils SOIL DESCRIPTION: Brown fine to coarse SAND; some Silt 'REMARKS: "B" Soil PARTICLE-SIZE ANALYSIS - COARSE SOIL ASTM D 422 GRAIN SIZE DISTRIBUTION CURVE BOULDERS&COBBLES SAND SILT&CLAY I COARS FINE I COARSE MEDIUM FINE i 100 l I `60 Z a. z ; . w v w 40 Io 20 0 1.0E+03 1.0E+02 1.0E+01 1.0E+00 1.0E-01 1.0E-02 GRAIN SIZE (MM) GEOTECHNTICAL SERVICES, INC. ® Geotechnical Engineering _� Environmental Studies Material Testing ® Construction Monitoring v PROJECT: Renee's Florist 20JECT No.: 97154 SAMPLED BY: W. Shedd DATE SAMPLED: 4/22/97 \MPLE No.: L-226-97 TESTED BY: K. Sanborn DATE TESTED: 4/24/97 ELEVATION: 8"to 18" PLOTTED BY: W. Shedd DATE PLOTTED: 4/28/97 )CATION: Test Location#2 CHECKED BY: H. Wetherbee QJURCE: In-situ soils SOIL DESCRIPTION: Brown fine to coarse SAND; some Silt MARKS: "B"Soil PARTICLE-SIZE ANALYSIS -COARSE SOIL ASTM D 422 COARSE SIEVE TEST SIEVE CUMULATIVE PERCENT PERCENT MESH WEIGHT RETAIN RETAINED FINER (Lbs.) (%) (%) 6 0.0 100.0 3 0.0 100.0 2 0.0 100.0 1 0.0 100.0 3/4 0.0 100.0 1/2 0.0 100.0 3/8 0.0 100.0 [7EIG0.0 100.0 HT4 OF SOIL= 298.7 Grams FINE SIEVE TEST SIEVE CUMULATIVE PERCENT PERCENT PERCENT MESH WEIGHT RETAIN RETAINED FINER FINER PASSING (9m) N (%) #4 SIEVE (%) 8 75.70 25.3 74.7 74.7 10 87.20 29.2 70.8 70.8 _ 16 115.80 38.8 61.2 61.2 40 157.00 52.6 47.4 47.4 50 171.40 57.4 42.6 42.6 100 201.80 67.6 32.4 32.4 200 241.30 80.8 19.2 19.2 iNEIGHT OF SOIL= 298.7 grams WAS cAGSI-LAB\SIEVE1226.XLS GEOTECHNICAL SERVICES, INC. ® Geotechnical Engineering � Environmental Studies a Material Testing Co Construction Monitoring PROJECT: Renee's Florist "ROJECT No.: 97154 SAMPLED BY: W. Shedd DATE SAMPLED: 4/22/97 AMPLE No.: L-227-97 TESTED BY: K. Sanbom DATE TESTED: 4/24/97 ELEVATION: 1811+ PLOTTED BY: W. Shedd DATE PLOTTED: 4/28/97 OCATION: Test Location#2 CHECKED BY: H. Wetherbee —OURCE: In-situ soils SOIL DESCRIPTION: Brown fine to coarse SAND; some Silt EMARKS: "C"Soil PARTICLE-SIZE ANALYSIS -COARSE SOIL ASTM D 422 GRAIN SIZE DISTRIBUTION CURVE BOULDERS&COBBLES SAND SILT&CLAY I COARS FINE I COARSE MEDIUM FINE i 100 d H z 1 1 WO a 20 0 1.0E+03 1.0E+02 1.0E+01 1.0E+00 1.0E-01 1.0E-02 GRAIN SIZE (MM) WAS c: - GEOTECHNICAL SERVICES, INC. -4a Geotechnical Engineering a Environmental Studies Material Testing -A Construction Monitoring PROJECT: Renee's Florist PROJECT No.: 97154 SAMPLED BY: W. Shedd DATE SAMPLED: 4/22/97 ;AMPLE No.: L-227-97 TESTED BY: K. Sanborn DATE TESTED: 4/24/97 ELEVATION: 18"+ PLOTTED BY: W. Shedd DATE PLOTTED: 4/28/97 .00ATION: Test Location#2 CHECKED BY: H. Wetherbee .;OURCE: In-situ soils SOIL DESCRIPTION: Brown fine to coarse SAND; some Silt ZEMARKS: "C" Soil PARTICLE-SIZE ANALYSIS - COARSE SOIL ASTM D 422 COARSE SIEVE TEST SIEVE CUMULATIVE PERCENT PERCENT II MESH WEIGHT RETAIN RETAINED FINER (Lbs.) N N 6 0.0 100.0 3 0.0 100.0 2 0.0 100.0 1 0.0 100.0 314 0.0 100.0 1/2 0.0 100.0 3/8 0.0 100.0 4 0.0 100.0 WEIGHT OF SOIL= 354.7 Grams FINE SIEVE TEST SIEVE CUMULATIVE PERCENT PERCENT PERCENT MESH WEIGHT RETAIN RETAINED FINER FINER PASSING (9m) N N #4 SIEVE (%) 8 69.50 19.6 80.4 80.4 10 77.40 21.8 78.2 78.2 16 97.30 27.4 72.6 72.6 40 140.50 39.6 60.4 60.4 50 159.90 45.1 54.9 54.9 100 207.70 58.6 41.4 41.4 200 259.30 73.1 26.9 26.9 I WEIGHT OF SOIL= 354.7 grams WAS c:\GSI-LAB\SIEVE\227.XLS GEOTECHNICAL SERVICES, INC. ® Geotechnical Engineering � Environmental Studies ® Material Testing � Construction Monitoring CONSTANT HEAD PERMEABILITY TEST DATA SUMMARY ZOJECT: Renee's Florist PROJECT No.: 97154 SAMPLED BY: W. Shedd DATE SAMPLED: 4/22/97 'AMPLE No.: L-227-97 TESTED BY: W. Shedd DATE TESTED: 4/28/97 _EVATION: 18"+ PLOTTED BY: W. Shedd DATE PLOTTED: 4/28/97 LOCATION: Test Location#2 CHECKED BY: H. Wetherbee SOURCE: In-situ soils AIL DESCRIPTION: Brown fine to coarse SAND; some Silt SST METHOD ASTM D 2434 REMARKS: "C"Soil ;AMPLE DIAMETER: 10.16 cm SAMPLE LENGTH: 11.65 cm SAMPLE AREA: 81.0 cm2 VOLUME: 944.0 CM 111ASS OF WET SOIL: 1818.2 gm ORIG. MOISTURE: 10.4% DRY DENSITY: 108.8 pcf HEAD: 16.65 cm MAX DRY DENSITY: pcf % OF MAX. DRY DENSITY: N/A PECIMEN NOTES: Laboratory prepared specimen TEST No. Q (cm') TIME (s) TEMP. (°C) 1 50.0 489 18 2 50.0 485 18 3 50.0 490 18 4 50.0 1 487 18 5 6 AVERAGE 50.0 487.8 18.0 0.00107 CORRECTION FACTOR= a= TIT/TI20 = 1.07 COEFFICIENT OF PERMEABILITY= KT= QL = 8.86E-04 cm/s Aht CORRECTED COEFFICIENT= K20= a KT = 9.48E-04 cm/s LAB-10 CON-PERM/227ALS a ESSEX COUNTY, MASSACHUSETTS, NORTHERN PART 189 TABLE 15.--PHYSICAL AND CHEMICAL PROPERTIES OF SOILS--Continued t Soil name and ; Depth ; Permeabilit ' Erosion map symbol ; Y Available Soil reaction ; Shrink-swell water cao-city ; factors _ ! potential ; -n -n r In/in p K ; T UnA, UnB, UnC---- 0-9 ; 0.6-2.0 ; 0. 18-3.21 Unadilla 9-60 i 0.6-2.0 Low------------ . - .2 0.49 _ 3 . . !Low------------ 0.6a Ur* ; Urban land Waal ole---------! 0-10 ! 2.0-6.0 ! 0. 10-0.2< ! p 10-24 2.0-6.o - 4.5-6.0 ;Low------------1 0.2D ! 24-60 ! >6.0 0.07-0.13 i 4.5-6.0 ;Low------------1 0.29 3 ! 0.01-0.13 4.5-6.0 lLow------- -----' Wb-------------t-1 0-8 ! 2.0-6.0 0. 15-0.23 0.17 Walpole Variant , 8-25 1 2.0-6.0 ' 4.5-6.0 !Low------------ 1 25-60 ; 0.2-0.6 0. 14-D.25 5. 1-6.5 ;Low------------' 0.49 ; 3 WeA, WeB---------' ' Wareham 0-10 6.0-20 0.06-0. 15 i 3.6-5.5 :Low------------' 1 10-32 1 6.0-20 0.03-0.11 3.6-5.5 0.17 5 ! 32-60 : 6.0-20 i � ,Low------------! 0.17 0.01-D.13 3.6-5.5 !Low----------- 0. 17 df---------------i 0-8 i o.6-6.o i 0. 12-0.1% Whately Variant 1 8-23 1 2.0-6.0 5.6-6.5 ;Low------------ 0.28 3 23-60 1 <0.2 0.07-D.13 5.6-6.5 lLow------------' 0. 10-3. 18 � 0.17 6. 1-7.3 iModerate------- ; 0.24 Wg--------------- ! 0-9 ! 0.6-6.0 ! Whitman 1 4.5-7.3 0. 13-0.23 ! 20-60 0.6-6.0 0.10-3.17 4.5-6.5 ;Low------------' 0.24 3 <0.2 0.02-].03 ; 4.5-6.5 !Low------------! 0.24 Wh--------------- 0-9 1 o.6-6.o 0. 15-D.23 ! i Whitman ! 9-20 ! 0.6-6.0 1 4.5-6.5 !Low------------ 0.24 ! 20-60 ! .6-6 0.10-0.17 i 4.5-6.5 !Low------------! 0.24 3 1 i 0.02-0.03 4.5-6.5 ;Low------------! 0.24 1 WnA, WnB, 'WnC, ; WnD-------------' ' 1 ! Windsor ; 10-16 6.0->20 ; 0.08-0.12 ! 4.5-5.5 lLow------------' ! 16-60 1 6.0->20 1 0.02-D. 1? ! 4.5-5.5 :Low------------ ' 0.17 5 1 i 6.0->20 0.01-0.00 ; 4.5-5.5 !Low------------ 0.17 WoC* WoD*: Windsor---------1 0-3 ! 6.0->20 3-16 ! 6.0->20 ! 0.02-0.12 4.5-5.5 Low------------! 0. 17 ! 5 4.5-5.5 :Low------------' 16-60 , 6.0->20 ; 0.01-0.08 1 4.5-5.5 !Low------------ 0.17 1 Rock outcrop. 1 ; ! 0.17 0-8 1 ! - 'Winooski ! : 8-60 ! 0.6-6.0 i 0.15-0.25 1 4.5-7.3 !Low------------; 0.49 ; 3 3 4.5-7.3 0.49 ! WWoodbriry---- dge i 9-26 o.6-6.0 ! 0.08-0.23 ! 4.5-6.0 Mow------------' ' : 26-60 o.6-6.0 , 0.06-0.23 ! 4.5-6.0 ;Low------------' 0.24 ; 3 j <0.2 1 0.05-0.12 ; 4.5-6.0 Mow------------1 0.17 Ws B, Ws C, WsD----! 0-6 ! 0.6-6.0 ! 0.08-0.23 1 Woodbridge ; 6-25 ! 0.6-b.0 i 4.5-6.0 !Low------------ ; 0.24 ! .6- 0.06-3.23 4.5-6.0 3 25-60 : 0.05-0.12 ! 4.5-6.0 Low------------1 0.43 ; ! :Low------------: 0.17 ; nWoodbridge------1 0-4 -25 i 0.6-6.0 i 0.08-0.23 ! 4.5-6.0 lLow---------__-' ! ! 25-60 0.6-6.0 0.06-0.23 ! 4.5-6.0 ;Low----°- i 0.24 ; 3 1 <0.2 : 0.05-0.12 : 4.5-6.0 °-----! 0.43 1 !Low------------! 0.17 ; * See description of the map unit for composition and behavior characteristics of the map unit. I APPENDIX G "INFILTRATOR CHAMBER" SYSTEM DATA STORMWATER DESIGN MANUAL INFILTRATOR SYSTEMS INC. JUNE 1992 STORMWATER DESIGN MANUAL 'INFILTRATOR°"CHAMBERS Written by:Judd P. Efinger Prepared by: Infiltrator Systems Inc. 123 Elm Street Old Saybrook, CT 06475 (203)388-6639 Copyrighted April, 1991 'INFILTRATOR" is a trademark of Infiltrator Systems Inc. TABLE OF CONTENTS Page 9 I. INTRODUCTION 1. General ...................................................................................................................... 1 2. Conventional Methods ................................................................................................ 1 3. Environmental Impacts ............................................................................................... 2 II. SITE EVALUATION 1. Preliminary Site Inspection.......................................................................................... 2 2. Soil Investigation ..............................................::...................................................:.... 2 111. HYDROLOGY 1. General ...................................................................................................................... 3 2. Rational Method ......................................................................................................... 4 3.Technical Release 55 ................................................................................................. 4 IV. DESIGN 1. Design Goals .............................................................................................................. 4 a. First Flush ...................................................................................................... 4 b. Zero Net Runoff ............................................................................................. 5 c. Retention........................................................................................................ 5 d. Detention ....................................................................................................... 5 2. System Sizing............................................................................................................. 5 a. General .......................................................................................................... 5 b. Exfiltration Credit............................................................................................ 6 3. Inlet and Interface Design ........................................................................................... 6 a. General .........................................................................................................6,7 b. Inlet Designs .................................................................................................. 8 1. Pipe Header Design ................................................................................. 8 2. Catch Basin Sump ................................................................................... 9 3. Swale/Median Design ............................................................................. 10 4. Distribution/Infiltration Design.................................................................. 11 7. Porous Pavement ................................................................................... 11 8. French Drains ......................................................................................... 11 4. Pretreatment/Siltation ................................................................................................ 12 a. General......................................................................................................... 12 1. System Decentralization ......................................................................... 12 2. Serial Distribution .................................................................................... 13 3. Upstream Prevention .............................................................................. 13 b. Parking Lot Perimeter........................................................ c. Water Quality Inlet......................................................................................... 15 d. Detention System.......................................................................................... 16 V. INFILTRATOR'"ADVANTAGE 1. General ..................................................................................................................... 17 2. Cost Savings ............................................................................................................. 17 3. Environmental Impacts .............................................................................................. 17 4. Siltation ..................................................................................................................... 17 5. Exfiltration ................................................................................................................. 17 6. Design Flexibility..........................................................................:............................. 18 7. Material ..................................................................................................................... 18 VI. INSTALLATION 1. General ....................................................................................................................... 18 2. Stone or Gravel Specification....................................................................................... 18 3. Geo-textile Specification .............................................................................................. 19 4. Cover Material Specification ........................................................................................ 19 5. Vibratory Roller Specification ....................................................................................... 19 6. Installation Instructions ................................................................................................ 20,21 VII. INSPECTION AND MAINTENANCE................................................................................... 22 1. General .....................................................................................:............................... 22 2. Operation .................................................................................................................. 22 3. Maintenance.............................................................................................................. 22 VIII. DOWNSPOUT DRAINAGE ................................................................................................ 23 IX. SUMMARY........................................................................................................................ 23 REFERENCES APPENDIX A. Sizing Calculation Example B. Cost Comparison C. Specification Standard D. Standard Details I. INTRODUCTION 1. General The rapid growth of urban areas over the past few decades created the need for construction of expensive storm drainage facilities. In years past, it has been customary to handle this increase in runoff with the installation of large storm sewer systems and/or surface detention basins. Over the years, however, it has become apparent that a reliance on these type of systems has created a series of problems. Among the most critical of these are the following: 1) Storm sewer capacities have reached their limit in most urban areas; 2) Water tables have been drastically lowered in some areas; 3) Streams and lakes have become more susceptible to erosion and pollution due to increase in storm sewer discharge; 4) Urban land has become much more scarce and expensive, not allowing for large surface deten- tion basins to be cost effective. Nature intended for rain water to soak back into the soil and recharge the water table, but by continually creating increased amounts of impervious surface area, many water table levels are being stressed. It is becoming obvious to more design professionals that a practical solution when designing storm drainage systems is to facilitate nature's process, and allow storm water to infiltrate directly back into the soil through the use of subsurface infiltration systems. The major advantages of using a subsurface infiltration system for handling storm water runoff, include: 1) the replenishment of ground water supplies, 2) the removal of pollutants by infiltration through the soil, 3) and an economical means of storing runoff because it saves valuable surface land. 2. Conventional Methods Typically, infiltration systems have consisted of either a stone filled trench, large diameter perfo- rated pipe with stone, or deep vertical wells, but inherent limitations are associated with all these sys- tems. The traditional stone filled trench uses large volumes of stone which is expensive. More seri- ously, stone occupies 60 to 66% of a trench's total void area or volume. This relatively small total void ratio makes stone more susceptible to silt clogging. Stone also restricts the lateral flow of water through- out the trench or bed. The combination of these two processes will clog the inlet of the system and seal off the remaining storage volume. Hence, it is better engineering practice to provide internal distribution to alleviate this problem. Large diameter perforated pipe has been used to increase the storage volume filled by stone and allow for distribution throughout the trench or bed. Large diameter perforated pipe may be very expen- sive and labor intensive to install. Also the relatively small perforations or slots in the pipe can be partially blocked by stone, leaving the pipe-susceptible to silt clogging. (deep vertical wells filled with stone have also been traditionally used but are limited to sites with deep groundwater reservoirs. Wells are also susceptible to discharging stormwater pollutants directly into the groundwater without any soil treatment. 1 q. Environmental Impacts Recently, the environmental impacts of stormwater runoff have received increased scrutiny from the engineering and regulatory communities. The U.S. Environmental Protection Agency has outlined new stormwater quality requirements which restrict industrial and municipal stormwater runoffs. These regulations are a first step in a massive movement to clean up depleting groundwater resources Rapid urbanization over the past decade has increased stormwater runoff which has caused the quality of water to be degraded. While some runoff from rainfall is a natural occurrence, the volume and rate of runoff and the associated pollutant loads drastically increase as the amount of paved, impervious surfaces increases. As stormwater flows over roofs, streets, parking lots, lawns, and commercial sites, it transports many pollutants into surface and groundwater. Stormwater pollutants may include sediments, heavy metals, hydrocarbons, salts, benzene, pesticides and fertilizers. The natural renovation capabilities of soil can remove many of these pollutants. The Metropolitan Washington Council of Governments recommends the use of infiltration trenches to remove pollutants and has accumulated data which indicates levels of removal with various pollutants. T�D Qt_._U.t f is - Poflu,ant ;R.,mgvaf., �te Lim try rag Sea menr �:�Trac�eat p Cisrpatmsr`Of T c�l P os�holus K-- r ra izdd _ganic..r v�FNrrbga _ c�-ru Lea ;moos�ful� n,t�a at T=aC° fJle,cl5 Caw I?cl7peCf EII�1IEitc3ic'il?rit .: tScCTe[13 C"3�0�-Stlaf�"nG'. :Scu�ce Ccr trolling Urban Runorf .A°�aCC 1 Mph=al f6 Panning ano Desig*t:ria Urban B�rIP's DeY' t c v � n;tg C�un I bf CQ ents, �V nr� o , Research has shown that a very large percentage of pollutants can be removed by the natural renovation abilities of soil. Simply pus - the creaser the oeparaLon distance from the system to the ground wafer- the greater the pollutant removal. H. SITE EVALUATION t. Preliminary Site Inspection Essential to the design of a stormwater management system is a oreliminary site evaluation. ? areal deal can be learned about a site from the initial site inspection and other source information. Macs ano repor,s detailing soil and geologic conditions are readiiy available from the Soil Conservation Service - U.S. Dept. of Aariculture and from the U.S. Geological Survey. This preliminary evaluation can be accomplished at little cost and can often provide enough insight of the site's conditions to prepare a plan for final design. 2. Soil Investigation A key element in designing a subsurface storm water system is an analysis of a site's soils and related infiltration capacities. An extensive subsurface exploration can detail soil types, locate the water tabie and bedrock elevations and expose any additional limiting layers that may effect a soil's ability to transmit water. Soil explorations can be implemented in various ways, such as drill rig borings, test pits, or auger hoies. Test pits are often the best method of soil exp;cration because it exposes soil and water conditions at an economical price. The infiltration capacity of a soil at any time is the maximum rate at which water will enter the soil_ This process is a key element when considering the effectiveness of an underground storage facility. Infiltration rates can be determined from field investigation, permeability testing, percolation testing or empirically from tables, one of which is reproduced on the following page: f. HYDROLOia7CSOILF'ROPtR-TlE GEASS1FlEI3fYSO[L EirXZURA" Sit >:irn Erfec.tva. :o>: itatta n u -�f- L .f V.a r.- at y..ro `n :::3nch� ranch Lches ue�:hoet� -Sal-G ot�p a xtFlre-;Ctass:..: l? _ __::=> <:::<>>: ;<:: :> e . ::•.:::San ..::. . ::.:?::, 2- A:.. <S 4 v_::.,.:.::.:'.;..,_..:...:: "Try'':::.'i'::v'iv':vr:"hii:::j'.':'i:.-y ::iii•:'..;i.'::v': - Sa :... 52 ::.LIB:>Loazt� .D. : :Z f C Panay C[ q Loam D 1 1 7 G Cray E.oarrr D�a 09 Slity Clayoarrt B 1 05 l Sandy Gray O f3� Q� SIEty Ciao i?� Clay 02 'Scisrce Rtris, Vet i B,�tenslek, O>_ ar�d ScX.Cri, K E "mss#rmai�on of Sc�i ...:rope. las 3 Tr�ns�ctlo�,s �: .of•tti�F,rner�n Soc�e� nt Ao��ul�ur�l tno'n�prs,�tol 25,�,a :1 o-o X33 Er i a20, �032 Permeability tests are generally accepted as the standard for best simulating a saturated soil condition. Permeability is the volume rate of water flow through a given unit area of soil, and is typicaiiy expressed In feet/day. Permeability tests are usually performed in a laboratory using either the constant or fallina head methods. Because soii conditions can be more readiiy controlled, permeability tests are generaily considered the preferred method of measuring a soii's infiltration abl'tliV. Percolation tests are widely accepted as a means of determining the infiltration rate of a soii and when done properly, can provide a 'quick and easy' method from simulated en site soil conditions. Percolation is the movement of water through soil and typically is measured in minutes per inch. A percolation rate may be converted to infiltration rate, in inches/hour as follows: Infiltration Rate (in/hr) = 60 perc rate (mints) III. HYDROLOGY 1. General Once a site's soils have been determined suitable, the next step in the design process is to analyze the site hydrology. The hydrologic input required for the design of any infiltration drainage system is the total time-related runoff that enters and is stored by that system. Accurate estimation of the hydrological changes due to land development involves evaluation of site specific variables such as soil type, slcoe, watershed area, and on-site storage capacity. Typically, the two methods used most often for estimating runoff are the Rational Method and U.S. Dept. of Agriculture, Soil Conservation Service's Revised Technical Release 55 (TR-55). I J 2. Rational Method The rational method is the preferred approach for pavement drainage calculations needed for roads, industrial or commercial sites with paved areas, and where drainage is towards a design point. It is a simplistic method which makes it easy to use, but it also works as a disadvantage because its simplicity does not factor in specific site characteristics such as soil conditions, surface routing, and storage. The Rational Method Equation: Q=C i A where Q =design flow runoff, in cubic feet per second C =coefficient of runoff i= average rainfall intensity, in inches per hour for a given frequency and duration A= drainage area, in acres The rational method is best when estimating runoff on sites less than 3 acres in area, and where there are no wetlands or ponds located on-site. 3. Technical Release 55 (TR-55) USDA Soils Conservation Service's TR-55 contains methods for calculating runoff, volume, peak discharge rates and flood storage capacities. It accounts for many site specific variables and is appli- cable to all land development watersheds greater than an acre and less than 200 acres. TR-55 contains data comparing runoff records in past years and is preferred for calculating runoff on large sites because it accounts for site specific conditions. IV. DESIGN 1. Design Goals Assuming all the preliminary site constraints have been addressed and the designer has decided to use a subsurface infiltration system with INFILTRATOR`chambers, the next step is system sizing. System design should depend on local and state requirements, design goals, and sound engineering practice. It is not the intent of this manual to detail design processes but rather to provide a minimum outline to aid in design. The first step in system design is determining the design goals. In some regula- tory communities the design goal may be to store a percent volume of a given storm frequency typically between a 2 and 100 year storm. In other areas the coal may be to store a given volume of runoff calculated by totaling a pre-determined depth of rainfall over the entire impervious area. Four design techniques typically used with subsurface infiltration systems are first flush, zero net runoff, retention, and detention. a. First Flush A typical regulatory design goal for many designers is maintaining groundwater quality. The term 'First Flush' has been established to represent a given storage volume which collects the first part of a storm's runoff for exfiltration into the soil. Typically, the first flush of runoff carries a large percentage of a given storm's pollutants, so it is critical for that first volume of water to be allowed to use the natural renovation abilities of the surrounding soil. The first flush volume has been variously defined as either one-half inch of rainfall per impervious acre, or the volume of runoff produced by a one inch storm. Water quality infiltration systems are sized to handle the first flush volume while the remaining volume of runoff is routed to a normal outfall. 4 b. Zero Net Runoff The term 'zero net runoff' has been outlined by many regulatory communities to provide a standard for sites with proposed development. Just as the title states, the proposed development can not have any increase in the total stormwater runoff from the historical conditions. Essentially, this design goal has allowed municipalities to keep their overtaxed storm sewers functional, while making developers engineer proper on-site detention and retention systems. c. Retention In a retention system the complete runoff volume is stored and eAltrated into the underlying soil. The system must be sized to accommodate the entire anticipated design runoff volume, less any volume lost via exfiltration during the storm event. It may not alwayste prudent to rely completely on eAltration because the long term permeability may be reduced due to the clogging of the infiltrative surface by sediment. Careful consideration must be taken to design up-stream sediment traps to handle siltation before it enters the system. Retention systems typically do not have any positive pipe outlets from the system, but it is recommended that some kind of overflow structure be provided to handle storm events greater than the design storm and period. d. Detention Detention systems are similar to retention systems except that the stormwater is held for later release through a normal outfall such as a storm sewer. By providing.an outlet structure the risks of total exfiltration are eliminated. The goal of a detention system is to store runoff during peak storm conditions and slowly meter the outflow into an existing drainage system. Most regulatory communities have out- lined a 'zero net increase" philosophy with respect to proposed development runoff. Detention systems fit this outline by providing enough storage, and residence time to reduce any increase in post-develop- ment runoff. 2. System Sizing a. General The INFILTRATOR'- chamber can be utilized as a storm wafer system in either a trench or bed configuration depending on the design requirements. Infiltrator Systems Inc. recommends, whenever possible, to design chamber systems in a single layer to take advantage of soil depth to groundwater and increased soil interface area for exfiltration. On sites where it is necessary to maximize storage, INFIL- TRATOR"" chambers may be placed two or three layers deep with stone or gravel between the layers. Illustrations of some typical design examples can be seen in Appendix D. INFILTRATOR"chambers are available with an AASHTO rating of either H-10 or H-20. The H-10 unit is typically installed in non-traffic areas and can support H-10 loads (16,000 Ibs/axle)with 12' of cover. The high strength H-20 unit (32,000 Ibs per axle) allows for shallow installation under paved traffic areas with only 18' of cover. Appendix D. has standard details of single and double layer beds with H-10 and H-20 installations. The length of the trench required or the bed area needed can be easily calculated when given the proper storage volumes for INFILTRATOR" chambers. The following chart indicates the storage volume for INFILTRATOR" leaching chambers. NOTE: The Standard INFILTRATOR'"chamber is primarily designed for septic system leachfields. 5 STORAGE VOLUME TYPa � SOME= t3lunri a€lunEt ,..f,.. F i r- .Sfar� J hfFi C.TRATC?� R �i h•. age 3 F[t�► . .T 1 t� RA Examples of typical calculations for bed systems combining stone and INFILTRATOR'"'cham- bers are shown in the attached Appendix A. The first step in sizing an INFILTRATOR"chamber system is determining a total volume of storage needed to handle the design flow. The design flow must be determined using proper hydrologic ta-chniaues and following local guidelines and regulations. Once the designer has calculated the total runoff volume, the site must be analyzed and a layer depth must be determined. The following chart is taken from Appendix B. and breaks down the various storage volumes for each layered system. STORAG VOLUNsE WITH STON �H ign C�pac t�� ft3l;t� a ::: Nom?� Ca>cn:.a?�o� s arm bas=g o-�3 stone vfl�r�tic of 3.,o A ouick and easy way to get the total number of INFILTRATORt-- units needed is to divide the total storage volume required (ft�) by 22 ft-2 oer unit with stone. b. Ex-filtration Credit As with any subsurface stormwater system careiui consideration should be made to the capability of the underlying soil to transmit water from the system. An INFILTRATOR""chamber has a marked advantage over most conventional systems because it provides a large open bottom area which maxi- mizss the soil's interface area and exfiltration abiiity. On sites with sandy or permeable soils (type 'A' or 'B' see table on pace 3) exfiltration during the storm event will take place, and regulators should give storage credit for that water leaving the system. The ability of a site to accept stormwater into the ground is very site specific and depends on the principles of Darcy's Law. A detailed site evaluation is needed to determine the site's; hydraulic gradient, hydrauiic conductivity, and cross sectional area available to L.ansmit water away from the system. However, if the proper soil and site conditions show sufficient exfiitration, then careful consideration should be taken in storage reduction. 3. Inlet And Interface Design a. General A subsurface system which utilizes INFILTRATOR'-chambers has the real advantage of design flexibility. The molded polymer chambers are light, very strong, easy to work with and unlike concrete and metals, are impervious to the chemicals in storm water. 6 INFILTRATOR" stormwater beds or trenches are typically accessed through the closed end plate. The closed end plate is a solid plate which is guide. Thetplatepmay beneasi y adapted to accept a pipe secured with screws and is provided with a hole gu p as large as 12' in diameter, by either cutting the plastic with a drill hole saw or saber saw. The closed end plate may also be used as a solid plate at the ends of a closed system. The following is an illustra- tion of a closed end plate. �Q Closed End Plate-Can be easily converted to accept any pipe size from ® 2'-12'diameter. A drill- ing guide is provided as ® ® an aid when using a drill hole saw. A standard O '�� saber saw may also be rl © ® used to cut plastic. With a stone and chamber system, there is no need ot es ide e either intemal di trib ambers. The access into every row of a bed because of the large op av stormwater should be inletted every several rows. This Will minimize the amount of pipe and connections. Tne water will free flow between the stones and nli tooh utilize a multi-tier design typically are inletted through the upper only, and to the lower layer. Large volume systems requiring pipe sizes larger than 12' in ia eter will umprequire some kind of design structure to interface with the bed. Typical precast catch basin and chambers may be converted to act a interface to casein place m custom anifolds. Onlsyseems which ruit lizPced concrete pipe can be a cost effective alternative pipes larder than 112' and have relatively low flows, Infiltrator Systems Inc. recommends that an inlet sump be created at the end of the unit and backfum with other cost t provide'effective alternative d aisoto run allow the water to rise into the unit through the stone sump. Another perforated or slotted large diameter pipe through the center of the stone bed and in between the rows of chambers. As shown below, t5' Dia. Pipe INFILTRATOR'" F Geotextile � r—Stone � T r Units 12'-18' _ 3' min. Suitable Base 7 b. Inlet Designs INFILTRATOR"chamber trenches and beds should be installed with appropriate up-stream inlet designs that will reduce the amount of sediment that will enter the system. The following is a Partial list of various inlet designs that may be utilized with an INFILTRATOR"'chamber system. Each design is accompanied with an appropriate schematic depiction. 1. Pipe Header Design A typical means of inletting an INFILTRATOR-chamber bed is through the use of a pipe header. In designs with relatively low flows a pipe header system may be installed and directly inletted into the chambers. Chamber end plates may be cut to form to any pipe sized from 4' to 12'. The pipe header may also be sized large enough to provide additional storage for the settling of silt. The large diameter pipe can then be provided with manhole access ports for inspection and maintenance. FILTER FABRIC PAVEty ENT tall i „ SUBG�ADE ISTONE OR GRAVEL/ Iol �f �� I Io �� x 1 101 1 u I 5i ei INFILTRATORS"" I u , F n � Pipe Size W-12'dia.) PLAN VIEW 15'-72'Diameter Pipe �— Fabricated end plate or overflow outfall rn CROSS SECTION Overflow detcil NOTES: 1. Precast knock-outs may be provided for laterals by consulting local concrete company prior to fabrication. 2. Pipe headers may be used to detain the water when used with an overflow or, to retain the water when used with a solid end plate. 8 2. Catch Basin Sump A common means for inletting any stormwater system is the use of a grated catch basin. Each catch basin should be provided with a sump to settle out sediment and other associated solids. Unfortu- nately, most sumps can not be sized large enough to provide the appropriate settling time. However, if a decentralized philosophy (page 12) is implemented then each basin should be receiving less water and hence additional settling time. It is also imperative to outline and enforce a strict inspection/mainte- nance program so that the sediment can be removed and the sump's volume can be restored. FlLTER FABRIC PAVEMENT M. SUBG�P;DE U, l STONE OR GRAVEL � I of I : Ifi [Cl fi NINI IOI I P. ti I� I INFILTRATORS' I - ;� ki . Pipe Sizes (4'-12'dla.) Overflow - outicJ Catch Bcsn -E---- Sump =� PLAN VIEW Pipe Sizes (15'-�6'ciaJ �y CROSS SECTION Catch Basin M • NOTES: 1. Precast catch basins may be used to detain the water when provided with an overflow outfall. 2. Catch basins should be provided with the maximum sump depth possible. o 3. Swale/Median Strip Design A simple means for inletting an INFILTRATOR'n chamber system, while providing excellent sediment removal, is the use of a grass or stone swale. Low flow runoff can be treated by passing through the swale and trickling down into an INFILTRATOR'm trench or bed. Side slopes of the swale should be provided with a grass buffer for sediment removal and the center of the swale with filter cloth to keep fines out of the stone and chambers. This cloth can then be easily removed when clogged with sediment and replaced, leaving the underground system in working order. The major design requirement is to maintain the longitudinal slope of the trench main as level as possible to maximize infiltration. The median strip is similiar to a swale design and is commonly used in parking lot islands or medians between two parking areas. Sheet flow enters the system from both sides through a sloped grass buffer strip. The slope should be shallow and uniform•to allow for sediment removal. Either design may be modified to utilize a trench or a bed configuration. An overflow should be provided when pos- sible. RL'noff Grass buffer-5%max.slope • 1.1 Ir 1, a rr,.11 '. .. r Washed stcne or pao gravel . Rae(faodc r..✓ Clean washed stone INFILTRATOR n Q. Chamber, SWALE DESIGN (side view) Slotted curo Pavement Grass buffer Runot \ Wash edroneorpea6ravel Filter fabric INFILTRATOR .o. tQ Clean'washecl Vcne Chomoe; MEDIAN STRIP DESIGN (side view) Modified from:Controlling Urban Runoff:A Practical Manual for planning and Designing Urban BMP's-Dept.of Environmental Programs-Metropolitan Washington Council of Governments, 1987. 10 4. DistributionAnfiltration Design A cost effective design which may be used is to replace costly pipe connections between catch basins with runs of INFILTRATOR'"chambers. The INFILTRATOR'chambers can then be used for both infiltration and distribution. Til 47 INFILTRATOR' - CHAMBERS e - ------ ------. , - ,----------- C c UR (typical) -----_;_'---=��®�1=------------•-��®' ISLAND - CATCH --------------, ,-®,`--_-- - ------.�,�, BASIN '®^=-------------=^._ ^=---------------`` _ ' �` DISTRIBUTION/INFILTRATION DESIGN 5. Porous Pavement INFILTRATOR'" leaching chambers may also be a cost effective alternative to stone when used with porous pavement. When designed, installed and maintained properly, porous pavement is an effective system for pollutant removal and groundwater recharge. It is typically designed with a stone reservoir beneath a course of porous pavement which allows runoff to filter directly into the ground. H-20 INFIL T RATOR'm chambers with their large void area can be used effectively as a storage medium while being less susceptible to silt and fines clogging. 6. French Drain INFILTRATOR' chambers may also be designed and installed as a french drain for the collection of water. In this type of application, the INFILTRATOR'"'chambers may be placed in a stone trench or bed and used to collect the surrounding groundwater and discharge it to a given outfall. When placed at the proper elevation, the end plate may be provided with a discharge pipe to carry the unwanted water to a location downstream. The major advantage of using an INFILTRATOR'm chamber rather than a perforated pipe is that a chamber provides a much larger void area for collection and is less susceptible to clogging. INFILTRATOR'"chambers also provide the advantage of being relatively shallow which allows the designer to place the outlet structure at the highest elevation possible. INFILTRATOR' chambers also provide the engineer with design flexibility and the contractor with installation savings. 11 i 4. PRETREATMENT/SILTATION DESIGNS a. General As with any subsurface stormwater system, careful consideration should be made to handle sediment and gross solids. The longevity of a system's life is directly dependent on the ability of the designer to keep sediment out of the system and the ability of the user to routinely maintain the system. Siltation of a system will severely influence infiltration rates and ultimately lead to system failure. The following design approaches are suggestions which may reduce the likelihood of siltation: 1.) System decentralization - large central systems should be avoided by breaking the watershed into many smaller systems. Reducing flows and volumes will make the catch basin sumps and stilling tanks more effective in silt settlement. For example: if a parking lot has 10 catch basins, instead of interconnecting the basins to one central infiltration bed, it would be ideal to provide a smaller individual bed for each basin (see below). TYPICAL PARKING LOT DETAIL (PLAN VIEW) 1 r 1 CJR9 GroI � CroI I.li yam: Z jN it ! I.••1 I I•.I F M-11 j 7iI I I C5 I �Ii 1 II 1_;1 i 7� 7C CENTRALIZED �;_C--lc,Scsn SL�o DE-CENTRALIZED --- ,- INFILTRATOR-oed L --- 12 2.) Serial distribution - the first run of a bed system can be separated from the other sections through serial or overflow distribution. The first section can be utilized as a settling chamber for silt removal. This will leave the rest of the system in working order. It is better to maintain or replace one section than a whole system, particularly if the settlement section can be placed outside a paved area. Infiltrator Systems Inc. suggests that the settlement section be sized at a minimum of 10% of the total runoff volume to be effective at silt removal. The following design is an example of serial distribution using a catch basin type inlet structure. However, this example also works well with all types of inlet design. Ilgh Level Overflow Plpe - ® �—f--Catch Bcsln sump(typ.) Dlstrlbutlon Plpe i Seine enr Sec on Manhde ISLAND Sump INRLTRATOechamber Bed 3.) Upstream prevention -the key to lowering the amount of silt in any subsurface stormwater system is handling the problem before it enters the main storage facility. Upstream prevention should include proper sedimentaion and erosion control devices such as silt fences and ground stabilization in addition to the appropriate inlet structure which will aid in silt removal. The use of the above design approaches, coupled with the implementation of the previously listed inlet structures, should reduce the effects of siltation. 13 b. Parking Lot Perimeter Design This design is very similiar to the median strip design, except that sheet flow enters the system from the lower end of a sloped parking lot. Once again stormwater is filtered over a grass buffer strip to remove sediment. Slotted curb spacers may be used to protect the buffer strip. A separate filtration section is designed to provide additional settling time for the removal of sediment. The filtration section should be sized at a minimum of 10% of the total runoff volume. Protective filter fabric should be placed within 6" of the stone surface to trap sediment and ease in routine maintenance. FlLTER FABPJC PAVEMENT SUBdRADE STONE OR GRAVEL H 1 pl 1 i hl 101 1 .9 y o ti 11 101 0 H 1 ' INRLTRATORS'1— - I I 1 fl I PLAN VIEW 1 1 I I I M H I I I I M M M I I I I " M I I I 1��� I 11 1 ; 1111 H H, 111 III H 1 M F M. iol I H. fi 1 101 1 y I H 1 101 1 H I Q1 I M 1 101 1 Ml 101 I M . H I I I IFJ I f I a tM H I I I I M I ; HI I I t I I I .z '' Possiote Insoection MCI.1 a —Pipe to man storage Inspection Port Possible overtowpipe - I 10 0 I O -I O 1 EM CROSS SECTION Sorted cubs act = as a level s„reader .. - TrenCl 1 . T 14 c. Water Quality Inlet This design collects parking lot runoff before it enters the infiltration system. It may also be referred to as an oil/grit separator because it is primarily designed to remove heavy solids and hydrocar- bons from the runoff. The water quality tank must be properly sized so that it is not by-passed during peak flows. However, because of the limiting size of these facilities, typically only moderate removal abilities can be expected because of the short residence time of the stormwater. These inlets must also be frequently inspected and maintained. Outlet to Curb Inlet to f� Stormdrain System Top View First Chamber I I Curb I I II I i I Trash ri.16 Inch <'"I I _� �\ Rack Orifices I I I 1 Road it O 1 1 1 Weep Holes 1 1 I 1 1 ----\5- --- -��--j --- - t_,--�- -1 I Inlet Manholes Side View Road Surface Inverted Elbow Sediment Chamber Oil Chamber Trash Rack Stormdrain Weep Holes Outlet Weep Hole •Qc 0 o: .o or;•� oh�o '_. .:•._.o. �.J.o �.::I ' :.. Gravel Layer Soil Modified from:Controlling Urban Runoff:A Practical Manual for planning and Designing Urban BMP's-Dept.of Environmental Programs-Metropolitan Washington Council of Governments, 1987. 15 d. Detention System Design On site's where discharge to the underlying soil is not desired because of soil type or water quality, the INFILTRATOR-chambers may be designed as a sealed detention system. The stone and chamber bed may be wrapped with a PVC or polyethylene liner. Prefabricated pipe seals and chemically fused seams should be used at all connections and joints, the design must include an outlet which can meter the discharge flow and properly drain the system. Filter fabric may be used on either side of the membrane liner to provide puncture resistance for the liner. This may be a cost effective altemative because the membrane thickness can be reduced. DETENTION SYSTEM DESIGN ? &)emically fused seam 12'-18 fill/cover/sub base membrane liner' P-2'stone High Capacity INFILTRATOR�'°chambers 3'-6'ston —optional geotextife Sol (external layeo 'Note: WATERSAVER CO., INC. P.O. Box 16466, Dever, CO 80216 (303) 289-1818 or approved equal. 16 V. INFILTRATOR°n ADVANTAGE 1. General The INFILTRATOR" leaching chamber is the ideal unit for subsurface storm water infiltration systems. Each hollow, open bottomed, arched high capacity chamber is molded of high density polyeth- ylene and is 76" long x 34' wide and 16' deep while weighing only 30 lbs. The INFILTRATOR"chamber is designed to maximize storage volume and infiltrative surface area while occupying a shallow cross sectional area. Each unit can store 16.3 cubic feet of water(2.60 ft3/ft)while providing 23 square feet of infiltrative area in a trench (3.7 W/ft), and 18 square feet in a bed configuration (2.83 W/ft). The INFIL- TRATOR" chamber has been structurally tested and is warranted to meet either AASHTO H-10 (16,000 Ibs/axle) or H-20 (32,000 Ibs/axle) loadings with a required 12' and 18' of cover respectively for each type of unit. 2. Cost Savings INFILTRATOR"chambers can replace any type of conventional subsurface structure utilized for stormwater management. The INFILTRATOR"chamber provides a large void area at an attractive cost compared to other systems. One of the largest savings that can be found by using INFILTRATOR"" chambers is in installation costs. The plastic chambers are lightweight and easy to install, eliminating the need for costly, heavy machinery that is needed to install most large diameter pipe and concrete galler- ies. The following chart indicates a relative cost comparison of some typical systems. Additional cost savings can be obtained by using a single layer INFILTRATOR"chamber system because of its shallow cross section. A single layer H-20, High-capacity INFILTRATOR'chamber system typically has only a three foot cross-section, and because of this shallowness the system can be excavated using either a bulldozer or a front-end loader for a considerable cost savings. A detailed cost comparison can be found in Appendix B which clearly outlines the installation costs of a typical INFIL- TRATOR"' system relative to large diameter pipes, and concrete galleries. 3. Environmental INFILTRATOR leaching chambers provide a shallow cross section with a large infiltrative area which maximizes soil treatment. Unlike most infiltration systems, the INFILTRATOR chamber gives the designer a cost effective means of storing storm water while providing maximum pollutant removal capabilities. To maximize the renovation capabilities of leaching chambers, Infiltrator Systems Inc. recom- mends that a single layer system be utilized where ever possible. In addition, it is recommended that a water quality inlet structure be provided to remove additional pollutants such as oils, road debris and sediment. 4. Siltation The effects of siltation on any infiltration system can not be over stressed, although the open chambered INFILTRATOR"' unit is certainly less susceptible to complete clogging than a stone trench or a large diameter perforated pipe. The INFILTRATOR"'chamber provides a larger void ratio, and an increased infiltrative surface area which can minimize the effects of siltation. The INFILTRATOR" chamber is also provided with a 4' knock-out which can be used with a 4' pipe as a riser to grade for inspection and/or maintenance. 5. Exfiltration The shallow cross section, and large bottom area of the INFILTRATOR"" chamber allows the designer the ability to desion a subsurface infiltration system which maximizes the exfiltration capabilities of the natural soil. An INFILTRATOR"'system can be designed to occupy a shallow cross section with a large plan area which allows for increased soil interface and ultimately leads to increased exiiltration. 17 Because of this fact, many regulatory communities have allowed for total system volume reduction to account for this increased exfiltration. However, in many cases this total volume reduction may not actually be a reduction in soil interface area, so the effectiveness of the system is maintained. 6. Design Flexibility INFILTRATOR" chambers combine the wisdom of chamber technology with the modem material technology of polyethylene. This simplistic design allows for tremendous design flexibility to the engineer- ing and regulatory communities. INFILTRATOR' chambers may be easily interlocked to form trenches, or laid side-by-side to form large beds. In areas where land area is restricted, multiple INFILTRATOR'" chambers may be used. The tiers must be laid perpendicular to each other. In all cases, INFILTRA- TOR-chambers can provide a technically sound cost effective alternative to conventional stormwater management systems. 7. Material INFILTRATOR'" chambers are molded from a high density polyethylene polymer which enables the product to be incredibly strong while still being relatively lightweight. This combination allows INFIL- TRATOR"chambers to be installed at a significant cost savings over other more bulky and costly materials. Polyethylene is also a very chemically resistant material and is completely inert to most of the chemicals found in stormwater runoff. VI. INSTALLATION 1. General A subsurface stormwater facility which utilizes INFILTRATOR"chambers will provide time, labor, and ultimately money savings over other conventional systems. Each durable, lightweight unit is easily handled by one man for a quick and easy installation. There is no need for any additional heavy equip- ment to lay the units. INFILTRATOR" units snap together with interlocking joints to form trenches. Trench runs may be laid side by side to form beds. In most all storm,water applications, the use of stone for stabilization, and geo-textile fabric to prevent fines intrusion, is required and detailed in the following sections. 2. Stone-or-Gravel Specification The benefits of an aggregate material-in an INFILTRATOR""chamber system is fourfold: it stabilizes the base material, provides energy dissipation to stop erosion, provides free flow between the chambers, and provides additional void storage volume. However, also critical to the use of aggregate is that it must not adversely effect the structural integrity of the chambers. As stone is placed in the sys- tem, it inherently has the ability to move before it se ties. Infiltrator Systems Inc. recommends that each lift of stone be compacted with a light vibratory plate or roller(see VI 5). This will reduce the ability of the stone to move during construction and provide increased structural stability. Through extensive testing and increased field experience, Infiltrator Systems Inc. requires the following stone specifications: 1. crushed stone - 1.5 inch to 2.5 inch 2. rounded gravel - 2 inch to 2.5 inch or: American Society for Testing and Materials ASTM D - 448, size number ,1"72 18 3. Geo-textile or Filter Fabric The use of geo-textiles as a filtering medium has revolutionized the stormwater industry over the last decade. Infiltrator Systems Inc. recommends a minimum weight of 4 oz. filter fabric be used to wrap the sides and top of the stone surrounding the chambers to prevent fines intrusion and maintain void area between the stones. The following chart is a partial list of acceptable geo-textiles that may be used in an INFILTRATOR"chamber system. .)=P- "GE-O-TEX L ,A CC T r.� N=CH aR a F L-1--f-3 A y.. L ..J %J<.. <: > AM BE ..4 .4 t s 1 !:f•. r,: t d. " � m ..,. LY�L. 0 sy% - �AN Or U :.8 .-A Za 4. Cover Material and Backfill The backfill material for H-20 applications should be a well-graded sandy material ranging from silt to gravel. A well-graded soil contains an even distribution of grain sizes, ranging from silt through sand to gravel. A maximum of 10%should pass the no.200 sieve and 90% should pass the 3" sieve. The material should at minimum meet the applicable state's Department of Transportation specifications for sub-grade material 5. Vibratory Roller Specification TYPE: A. Maximum gross vehicle weight of 8,000 lbs. Maximum dynamic force of 10,000 lbs. B. Maximum gross vehicle weight of 12,000 lbs. Maximum dynamic force of 20,000 lbs. C. Maximum gross vehicle weight of 20,000 lbs. Maximum dynamic force of 40,000 lbs. Use: A, B or C (preferrably C) on 6' base layer of stone A ONLY on 6' of stone over INFILTRATOR"' units A or B on 6' of stone plus 6' of compacted soil cover over INFILTRATOR'" A, B, or C (preferrably C) on 6' of stone plus 12' of compacted soil cover over INFILTRATOR'"' r PAVEMENT INFILTRATORS RTER FABRIC '.... C�ale"ea A d 8 � � CCtAPACTED FILL 11• SIN. '.,,... . 16• KIN. '... YL 7 1B• UIN. '.. SUITABLE BASE GRAVEL OR CRUSHED STONE 19 6. Installation Instructions An installation instruction brochure is available upon request and outlines general guidelines which should be followed when installing an INFILTRATOR"chamber system. It should be noted however that most jobs are site specific and may require additional guidelines. Detailed installation instructions are listed below and should be used as a minimum standard when installing an INFILTRA- TOR"chamber bed. 1. Before the site is disturbed by excavation, the area planned for the INFILTRATOR"bed should be roped off to prevent heavy equipment from compacting the underlying soils. 2. Silt fence should be placed around the perimeter of the bed before construction begins to keep sediment out of system area. Actual construction of the bed should not begin until the site is completely stabilized. 3. Excavate bed area using either a bulldozer,front-end loader, or an excavator. (Note. A shallow INFILTRATOR" system may be excavated using a dozer or loader for a significant cost sav- ings.)The bed bottom should be leveled to the specified depth. a. Labor and construction costs can be reduced on larger systems by using "Dig and Lay Process' approach, rather than by doing the entire system in individual steps. 4. Analyze basal material for soil type and texture; if the soil is a loose, well- sorted sand, then the base may be lightly compacted with a vibratory plate or roller. However, if the soil is a firm to dense, well-graded material, then careful consideration should be taken to not further compact and reduce the soil's permeability. 5. Line perimeter of excavation (sidewall)with specified geo-textile. Infiltrator Systems Inc. does not recommend geotextile beneath the bed. 6. Place specified stone in bed and level to form 3' to 6' base layer. The base layer of stone should be compacted to a minimum level of 950X0 using a vibratory roller (see VI, 5 c.) 7. Place first INFILTRATOR'm units in the inlet end of excavation with interlocks facing downstream. 8. Siip INFILTRATOR' units together, fully encaoing interlocks to form desired bed length. Place rows of chambers side by side to achieve desired bed width. a.To keep joints from coming apart during construction,joints may be screwed together. b. Bed laterals may be kept from shifting by tying bottom flanges of INFILTRATOR"' units together using plastic wire ties through molded holes at random locations along rows. c. System grade can be checked with a level or surveying equipment. 9. Construct inlet structure as specified in appropriate design requirements. Run distribution pipe to rows of INFILTRATOR" chambers as per design. NOTE: There is no need to inlet every row of chambers- several inlet points per bed is sufficient. 10. Cut appropriate size hole in closed end plate for distribution pipe. Screw end plate into both inlet and outlet ends of each row. a. End plates are stepped to fit either end of chambers. Upper step fits into inlet end and lower step in downstream end (with interlocks). b. A cordless drill and self drilling screws work well for all connections. 20 11. Run distribution pipe through inlet opening in end plate. NOTE: Pipe does not run the length of the system. The water will enter at inlet and rise level throughout the stone and chamber bed. 12. Fill stone in between and 6' (when specified) over of the INFILTRATOR'"chambers. In long, narrow trenches and beds the stone may be ladled on to the bed, flush with top of units, from an excavator, avoiding vehicular traffic on the chambers. For larger rectangular beds, where this is not possible, the stone should be spread carefully to a minimum depth of 6' with a track mounted machine with a gross vehicle weight no greater than 16,000 lbs. An equivalent low ground pressure machine with greater gross weight may be used. When spreading the stone, a 6' minimum layer of stone MUST be kept beneath the tracks of the vehicle at all times. In addition, the tracks must be kept perpendicular to the chamber rows at all times with a minimal amount of abrupt track turning. A vibratory roller meeting specification 5.a., shall be used to compact the first 6' lift. 13. The backfill material should be laid in 6'to 12' lifts to the required H-20 AASHTO rating of 32,000 Ibs/axle with 18' of backfill cover. A minimum of 6' lifts may be used when backfilling with a machine less than or equal to 16,000 Ibs gross weight. When using a machine greater than 16,000 Ibs then the backfill material should be spread with a minimum of 12' of soil always beneath the tracks of the machine. The gross vehicle weight of the track mounted machine should not exceed 30,000 Ibs. and should always operate perpendicular to the chamber rows. Once the backfill material has been properly placed in the lifts, then the soil should be com- pacted. The compaction may be performed with a vibratory plate or roller. The compaction levels and sub-base preparation should at a minimum, meet the applicable State's Department of Transportation specification for asphalt or pavement sub-base. NOTE: DO NOT USE WHEELED VEHICLES ON THE BED DURING CONSTRUCTION. Infiltrator Systems Inc. recommends using a well-graded soil for backfill to maximize load carrying capabil- ity. 14. Rope off immediate bed area when construction is completed to avoid any unnecessary wheeled vehicle traffic. After proper depth of cover is compacted and settled, INFILTRATOR'"chambers will support H-10 and H-20 loads as marked, and final surface grade may be constructed. NOTE: A full paving truck will in most situations be the greatest loads that the system will encounter, so careful consideration should be taken during this construction phase to avoid any increased dynamic loading through abrupt movement. 15. Engineering designs may require a multi-layer system. Follow previous instructions, adding additional tiers of INFILTRATOR`'units, separated by a 6' minimum stone layer. In a multi-layer system, it is particulady critical to compact the intermediate layer of stone with a light vibratory plate or roller(spec. 5.a.) to ensure proper settle ment for structural support. Tiers MUST be perpendicular to each other and must be constructed using H-20 units. a. Run distribution to the top tier only, with gravity distribution to the lower tiers. b. Distribution need only be run to rows indicated by engineering design, and not to every row. NOTE: Single-layer systems maximize exfiitration area and minimize construction costs. 21 V11. INSPECTION AND MAINTENANCE 1. General It is essential to any subsurface stormwater system to detail and perform a proper inspection and maintenance program because poor maintenance can soon render a system useless. Many communi- ties set forth a legally binding maintenane agreement which is outlined in the property deeds. This agreement should detail maintenance tasks and schedules, and grant access for regular inspections to enable the town to perform the maintenance and sen the bill to the owner if the system has been ne- glected. 2. Operation Each INFILTRATOR' chamber is provided with a'knock out' in the center of the unit. This may be used to provide an inspection port at grade level. A 2' -6' pvc or cast iron pipe can be placed through the access port as a riser to grade. This riser can be capped with various cast iron covers in paved areas as needed. Inspection should be conducted following major storm events so that potential sediment levels and draw down times can be determined. This routine inspection will allow for a maintenance schedule to be determined prior to system malfunction. 3. Maintenance The following maintenance schedule is to be used as a minimum requirement for systems utilizing INFILTRATOR'"chambers. Site specific designs may deviate from these general requirements. TYPE OF ,STRUCTURE REMOVAL MINIMUM SCHEDULE PRIMARY catch basin sump heavy solids, quarterly or when routine debris, sediment inspection shows need SECONDARY oil & grit seperation hydrocarbons, bi-annually or when routine tank, oversized fine sediment inspection shows need manifold or header pipe PRIMARY/ parking lot heavy solid quarterly or when routine SECONDARY perimeter fine sediment inspection shows need filter strip hydrocarbons Sediment removal should take place prior to entering any subsurface infiltration system - chambers included. However, because of their large open areas, chambers are less susceptible to silt clogging than pipe and stone designs. If the pretreatment structures are not completely effective in silt removal and it enters the chamber system, then INFILTRATOR'"chambers may be maintained through the access port. Water may be injected into the system which should put the fine sediments back into suspention where it can be pumped out and removed. Various types of equipment are available commercially for the clean out of systems. The most commonly used equipment and techniques used for cleaning subsurface systems are vacuum pump and water jet spray. Both systems are generally mounted on a self-contained vehicle and can effectively remove stones, leaves, litter and sediment deposits from sumps and chambers. 22 VIII. DOWNSPOUT DRAINAGE INFILTRATOR"chambers are commonly used to store and exfiltrate runoff water from roof downspouts. The impervious area created from roof-top development can often cause flooding of residential and commercial lawns, driveways, basements, and parking areas. This runoff is usually handled by the installation of roof gutters and drains which typically flow into down spouts which dis- charge waters directly to the ground surface. INFILTRATOR"chambers are perfect units forosW ex avat onnl�Itrator light Syst m slnc. recom� are easy to install and typically only require a very shall mends that each system be installed with a 3' stone bed beneath the units for energy dissipation. Al- though,when installed in coarse sand or gravel soils which have little erosion characteristics, the stone may not be required. A typical design example is shown below. The sizing of each downspout system should meet all state and local regulations; but where local regulations do not apply, Infiltrator Systems Inc. recommends sizing each downspout drain on the first inch of any given storm event.This sizing will allow for the handling of the majority of storms while occupying the limited area of most residential developments. It should also be noted that the actual storage capacity of the system may be much greater due to the volume of water that is leaving the chamber during the storm event through exfiltration. The following is a sizing formula for downspout drainage. DESIGN EXAMPLE ROOF AREA(FT-) X 1 INCH =VOLUME(FT-) NO. OF DOWNSPOUTS 12 VOLUME(FP) _ NO. OF INFILTRATORTM UNITS 16.3 F—P/INFILTRATOR REQUIRED PER DOWNSPOUT Id ' - L •:r 1 r •'1 .:rt•. Imo..-.c--•t-- r...-a _ .•. ;::,.'`r''� .r :;:-r: �i'. 23 IX. SUMMARY The INFILTRATOR'" is a complete stormwater system that provides the engineering community tremendous design freedom to effectively handle the drainage needs on most sites. INFILTRATOR" chambers may be combined with stone to provide a maximum storage void ratio in either trench or bed configurations to satisfy both retention or detention design goals. The shallow INFILTRATOR""chamber can be designed in a single layer bed providing a tremendous infiltrative surface area for maximum exfiltration while allowing for an increased soil separation to groundwater which maximizes pollutant treatment and fits perfectly into the environmental protection issues of the'90's. INFILTRATOR'"'cham- bers may also be designed in multi-tier configurations to maximize storage volume on sites with limited area and increased depths to groundwater. These systems MUST be installed using H-20 units with layers perpendicular to each other. INFILTRATOR"chambers are impervious to mosf of the chemicals found in stormwater. They have been structurally tested by a Registered Professional Engineer and are available with an AASHTO rating of H-10 (16,000 lbs/axle with 12' of compacted cover) or H-20 (32,000 Ibs/axle with 18" of com- pacted cover). INFILTRATOR'" units have been specified and installed in hundreds of systems, and are pre- ferred by many engineers and regulators because they provide a technically superior and environmentally sound stormwater system at a significant cost savings over traditional systems. Infiltrator Systems Inc. is an engineering oriented company led and staffed by civil, sanitary and mechanical engineers. If we can help you with your design, please call us for assistance. 24 REFERENCES 1. Chow, U. T., Editor-in-Chief, Handbook of Applied Hydrology, McGraw-Hill Book Co., New York, 1964. 2. Gburek, W. J. & Urban, J. B. 1980. Stormwater Detention and Groundwater Recharge Using Porous Asphalt in International Symposium on Urban Storm Runoff. University of Kentucky, Lexington, KY. 3. Hannon, J.B., "Underground Disposal of Storm Water Runoff, Design Guidelines Manual", prepared by the California Department of Transportation in cooperation with the Federal Highway Administration, Washington, D.C., February, 1980. 4. Maryland Water Resources Administration (MD WRA), 1984. Standards and Specifications for Infiltra- tion Practices. Maryland Department of Natural Resources, Annapolis, MD. 5. Schueler, T.R., Department of Environmental Programs Metropolitan Washington Council of Govern- ments, Controlling Urban Runoff: A Practical Manual for Planning and Designing Urban BMP's., Washing- ton, D.C., July, 1987. 6. South Florida Water Management District, Management and Storage of Surface Waters, Volume IV, West Palm Beach, FL., June 1987. 7. South West Florida Water Management District, Management and Storage of Surface Waters, Volume I, Brooksville, FL, March 1988. 8. United States Department of Agriculture, Soil Conservation Services, Engineering Division, Technical Release 55, Urban Hydrology for Small Watersheds., Washington, D.C., June 1986. 9. United States Environmental Protection Agency, Federal Register, National Pollutant Discharge Elimination System Permit Application Regulations for Stormwater Discharges, Final Rule, November 16, 1990. APPENDIX A. SIZINQ CALCULATION (based on figures A-C of Appendix B) Given: 1.Total storage volume 2. Depth of groundwater from finish grade 3.'Total land area available for INFILTRATOR bed Find: 1. Number of INFILTRATOR°"chambers required 2. Amount of stone required 3. Number of INFILTRATOR°"tiers (single, double,triple) 4. Area of INFILTRATOR'bed required 5. Total runoff volume stored Assume: 1. 16.3 ft'of storage per High Capacity INFILTRATOR' unit 2. 17.7 ft'of bed area per INFILTRATOR'"unit 3. INFILTRATOR°" chamber dimensions of 2.83 ft wide x 6.25 ft long x 1.33 tall. 4.Average stone void ratio=35% 5. System void ratio : 75% in INFILTRATOR'm chamber 25°10 in stone void Note: Different depths of stone will change % 6. Total storage volume per ftz of bed area Single layer = 1.24 W/ftz Double layer=2.47 ft'/ft' Triple layer =3.72 ft'/ft' 1 EXAMPLE Given: 1. 40,000 ft'of storage required 2. 4 ft. depth to groundwater 3. 35,000 ft2 of land area available Find: 1. Number of INFILTRATOR' chambers required _. 40,000 ft'x .75 (vol. %) = 30,000 ft' 30;000 ft'—16.3 ft'/unit = 1,840 units 2.Amount of stone required 40,000 ft'x .25 (vol. %) = 10,000 ft' 10;000 ft'—35 (% void) = 28,571 ft' 28;571 ft'—27 yd'/ft' = 1,058 yd' 1,058 yd3 x 1.30 tons/yd' = 1,375 tons 3. Number of INFILTRATOR- layers only 4 ft to groundwater = single layer Note: Infiltrator Systems Inc. recommends using single layer systems whenever possible to maximize soil interface and depth to groundwater for increased treatment. 4. Area of INFILTRATOR-bed required 40,000 ft3- 1.24 ft3/ft2 = 32,258 ft2 required 1,840.units x 17.7 ft2/unit $2,568 ft2 provided Note: Actual bed dimensions should be divisible by 2:83 wide and 6.25 long. Multi-layer systems must be divisible by 6.25 both ways because layers are laid perpendicular to one another. Multi- layer systems should be designed as close to square as possible to minimize number of end plates. 5. Total storage volume provided 32,568 ft2 x 1.24 ft'/ft 2 = 40,$84 ft? 2 APPENDIX B. VOLUME COMPARISON A. INFILTRATOR'^—'Chambers Single Layer CRUSHED STONE s GRAVEL OR - 18" MIN. o 16" o 3° MIN. 12" \\//\\/. Unit Cross Section x 1 Ft. Thick Storage Volume: Total Volume 2.83 ft x 1.83 ft x 1 ft = 5.18 ft3 Less Infiltrator Volume 2.60 ft'/ft = 2.60 ft3 Stone Volume = 2.58 ft' Stone Void 0.35 (2.58 ft3) _ .90 ft3 Unit Section Void 2.60 ft3+ .90 ft3 = 3.50 ft' (stone void) (Infiltrator void) Stone Required 2.58 ft3/unit section = 0.096 yd'/LF Total Storage 3.50 ft'/L.F.-2.83 wide = 1.24 ft3/ft2 of bed surface area 1 B. INFILTRATOR"—"Chambers in 2 Layers e e e e 18" MIN. e e e e i 1 6" I - i 0 O O O 6" o 1 t 1 1 i 1 1 1 1 1 1 ! 1 1- -1 1 1 1 1 1 1 1 t 1 1 ! 1 7 1 1 f 1 7 1 1 1 1 j UO O O 3" _MIN. Ft 12 7 l 3 6 --T Unit Cross Section x 1 ft. thick Storage Volume: Total Volume 2.83 ft x 3.5 ft x 1 ft = 9.90 ft' Less Infiltrator Volume 2 x 2.35 ft'/ft = 4.70 ft' Stone Volume = 5.20 ft' Stone Void 0.35 (5.20 ft)' = 1.82 ft' Unit Section Void 1.82 ft'+4.70 ft' = 6.52 ft' (stone void) (Infiltrator void) Stone Required 5.20 ft'/unit section = 0.193 yd'/LF Total Storage 6•.52 ft'/L.F. -2.83 ft wide = 2.30 ft'/ftz - of bed surface area 2 C. INFILTRATOR"—"chambers in 3 Lavers 1 18" MIN. i 1 6" -- T v ° 6" o i 16 0 oUoUo 6„ 116„ o T 12 36" —� Unit Cross Section x 1 ft. thick Storage Volume: Total Volume 2.83 ft x 5.50 ft x 1 ft = 15.57 ft' Less Infiltrator Volume 3 x 2.6 ft'/ft = 7.80 ft' Stone Volume = 7.77 ft' Stone Void 0.35 (7.77 ft = 2.72ft' Unit Section Void 2.72 ft' +7.80ft' = 10.52 ft (stone void) (Infiltrator void) Stone Required 7.77 ft'/un it's ection = 0.288 yd'/LF Total Storage 10.52 ft'/L.F. - 2.83 ft. wide 3.72 ftgff of bed surface area 3 D. COST COMPARISON CHART A B C D E F G H I MATERIAL System Storage Stone Excavated Material Material Excavate& Average Average Width Volume Required Material cost Placement Backfill Cost Storage w/stone Cost Cost Cost Fr. F-PA-F. YD'/L.F. YD'A-F. S/LF. S/LF. I SN[)3 S(L-F. VFP 1 LAYER 2.83 3.50 .096 .31 6 .15 4 9.80 2.80 INFILTRATOR" ------------------------------------------ 2LAYER 6.25 7.00 .191 .55 12 .30 6 20.40 1 2.90 INFILTRATOR" ------------------------------------------ 3 LAYER 6.25 10.5 288 .70 18 .45 7 30.60 2.95 INFILTRATOR" 1� -------------------------------------- --- 4x4 CONCRETE 6.0 16.86 .395 1.33 22 9 7 50.30 3.00 GALLEY I 24'CMP 3.0 5.72 .273 .50 10 8 6 27.85 1 4.85 ------------------------------------ - 24'ACCMP, 3.0 5.72 .273 .50 12 8 6 29.85 5.20 ALUMINUM 24' PLASTIC 30 5.72 .273 .50 13 6 6 28.85 5.05 PIPE 24' RCP 3.0 5.72 .273 .50 18 10 6 37.85 6.60 --- I- - - ---------------------------- I---- 36'CMP 4.5 11.68 .488 .92 18 10 7 43.65 I 3.75 ----------------------------- 36-ACCMP, 4.5 11.68 .488 .92 18 10 7 46.65 4.00 ALUMINUM ------------------------------------ 36* PLASTIC 4.5 11.68 .488 .92 22 8 7 48.65 4.15 rPIPE --- -------------------------- I'--- 48'CMP 6-0 19.71 .757 1.45 28 20 7 71.10 3.60 -------------- 48-ACCMP, 6-0 19.71 .757 1.45 28• 20 7 77.10 3.95 LALUMINUM ----- -------------------------- 60'CMP 8.0 30.96 1.200 2.22 45 30 8 122.75 3.95 ------ ---------------------------- 60-ACCMP, 8.0 30.96 1.200 2.22 50 30 8 127.75 4.10 ALUMINUM ---------------------------------------------------------------------- - - 72'CMP 10.0 4-4.63 1.731 3.15 55 40 8 163.45 3.65 ------------------------- -------- 72'ACCMP, 10.0 44.63 1.731 3.15 65 40 8 173.45 3.90 ALUMINUM 4 COST COMPARISON EXAMPLE Step 1: Calculate total storage volume required for given design storm in cubic feet (fig) as required by local regulations. 'Step 2: Divide total storage volume by figure in column B to find total linear feet (L.F.) of system required. Step 3: Calculate total cubic yards of stone required by multiplying total L.F. required (found in step 2) by the figure in column C. Step 4: Calculate total cubic yards of material to be excavated by multiplying total L.F. required by the figure in step D. Step 5: Calculate material cost by multiplying total L.F. required with the figure in column E. Step 6: Calculate material placement cost by multiplying figure in step 2 with the figure in column F. Step 7: Calculate stone cost by multiplying figure in column C by$25/yd'placed (may be adjusted to meet regional cost). Step 8: Calculate total excavation and backfill costs by multiplying figure in column G with total step 4. Step 9: Calculate total cost of stormwater system by adding steps 5-8. Notes: 1. Abbreviations: CMP =Corrugated Metal Pipe ACCMP =Asphalt Coated Corrugated Metal Pipe RCP = Reinforced Concrete Pipe 2. Total costs do not include filter fabric material &placement cost. 3. All pipe costs are for perforated, slotted or pervious pipe and may be adjusted for regional pricing. 4. Material and labor costs were taken from "Means Construction Cost Data" 1991, 49th Annual Edition R.S. Means Co. Inc. and may be adjusted to meet regional or site specific conditions. 5. Call or write, Infiltrator Systems Inc., 123 Elm Street, Suite 12, Old Saybrook, CT 06475 (203) 388- 6639 or(800) 221-4436. 5 APPENDIX C. INFILTRATOR SYSTEMS INCORPORATED SPECIFICATION STANDARD 1.0 GENERAL INFILTRATOR"chambers are manufactured plastic units designed to control stormwater runoff. An INFILTRATOR'"chamber system may be designed to retain the water and infiltrate the water back into the soil, or detain the water and store it for a metered flow to an outfall. 2.0 TYPES AND FITTINGS 2.1 High Capacity units shall be plastic arch shaped, open-bottomed chamber with side wall openings. The nominal unit dimensions shall be 16' high x 34' wide x 75" Iona with a minimum distance of 10' below the invert. 2.2 H-10 units (American Association of State Highway and Transportation Officials AASHTO) shall have a load rating of 16,000 Ibs/axle with 12" of backfill cover. 2.3 H-20 units (American Association of State Highway and Transportation Officials AASHTO) shall have a load rating of 32,000 Ibs/axle with 18' of backfill cover. 2.4 Open End Plates shall be plastic plates which conform and attach to the end of a cham ber unit. The inlet access hole shall be able to receive a 4' diameter pipe. 2.5 Closed End Plates shall be plastic plates which conform and attach to the end of a chamber unit. Solid plates shall be used to restrict soil and stone intrusion into the chamber. They shall also be utilized to accept larger diameter inlet pipes through a custom cut access port. 3.0 MANUFACTURING PROCESS Each high density polyethylene unit shall be processed by an injection molding process. 4.0 PRODUCT PARAMETERS _ 4.1 Each unit shall have a nominal wall thickness of 1/8'. 4.2 Each unit shall have a bearing footprint of 2.0 square feet to prevent sinking and to minimize soil masking. 4.3 Each unit shall have a minimum nominal sidewall height of 10'. Side openings shall extend to the top of each sidewall. 4.4 Each unit shall have a minimum of.30 square feet of sidewall openings per linear foot or 1.9 square foot per unit. Side openings shall be .020'wide and have ribs above and below to maximize infiltration and minimize fines intrusion. Ribs shall be a minimum of .25' high and the bottom of the openings shall slope upward at approximately 200 to prevent fines intrusion. Use of filter fabric or geotextile shall be prohibited, except at interface of soil and stone. 4.5 Each unit shall have interlocking joints for the latching of units. A minimum of 1-1/4' overlap of each joint shall be provided. 4.6 Each chamber shall have a knockout access port sized to receive a 4' diameter pipe, and centered on top of each unit. .. 1 5.0 MATERIALS 5.1 Plastic leaching chambers shall be manufactured from high density polyethylene. 5.2 The density of polyethylene raw material shall be a minimum of.0950 g/cm' - ASTM D1248, D1505. 5.3 The unit shall be color coded so to clearly identify H-10 and H-20 units. 6.0 TESTING REQUIREMENT 6.1 In ground structural tests shall have been performed by a registered Professional Engi neer and meet an AASHTO rating H-10 (16,000 Ibs/axle)with 12' of cover and H-20 (32,000 Ibs/axle)with 18' of cover. 6.2 Drop weight impact testing shall have been performed at a minimum of 1 unit per 60, and shall conform to manufacturers specifications. The minimum standard shall require a 6 lb. weight with a 1/4` diameter rounded head dropped from a height of 20 inches onto a panel of the product which rests on a 2' diameter support ring. 7.0 GENERAL REQUIREMENT 7.1 Installation shall be in accordance with manufacturers recommendations and conform to all applicable state, county and local regulations. 2 t , ;_;, rQ �/ai ' �✓ \YI�} ' t� rrylry``ar1�1 t'll!+' } v . c Hi-Q narrows the performance gap that exists between what traditional drainage products can provide and what engineers demand. For stormwater drainage, Hancor Hi-Q provides superior hydraulics, unsurpassed durability, proven structural integrity, and ease of installation, all in one economical product. EVALUATION OF STORM DRAINAGE PRODUCTS x ` The table below compares the performance of traditional drainage products and Hancor HI-0 to what engineers demand for storm drainage. "Desired performance"for each criteria is given a value of 10. Using 18 inch i I pipe, each pipe material is rated by how well it compares to the desired performance. ! �, Class III Corrugated Polyvinyl Corrugated ' Reinforced Corrugated Aluminum Chloride Polyethylene HIGH STRENGTH Performance Desired Concrete Pipe Steel Pipe Pipe Pipe Pipe Criteria Performance HI•Q (RCP) (CSP) (CAP) (PVC) (CPeP) Structural Integrity High fill heiahts 10 10 6 10 10 10 7 Minimum fill heights 10 10 10 10 10 10 10 Installation Light weight 10 6 1 �- 3 10 4 8 — Long lengths 10 10 4 10 10 7 10 Ease of connecting 10 10 3 3 4 5 10 FAST INSTALLATION Hydraulic Caoacity 10 9 7 7 7 10 5 Durability Corrosion resistant' 10 10 3 2 10 10 10 Abrasion resistant 10 10 3 3 1 10 10 � Value— 20 18 11 14 16 16 15 HIGHER FLOW RATES Total Performance 100 93 48 62 78 82 85 � t doom Total Performance Value Analysis a a" 60 Z r t 20r DURABILITY E` ....... ...... ....... ...... K•O cPeP p%C ,y, RCP Conditions used to qualify the corrosion "Value mc}udes material costs. eauioment and - resistance were off of 5.0 and soi)resistivity of laoor reouirements. and installation rates. I1000 onm-cm. Manufacturers of concrete otoe Excavation and backfill are eauai in eacn stronoly urae that additional protection tior case and are.inerefore.not considered. examoie: coatinosi be used in sucr environments to provide a reasonable desion life. - VALUE MIMI- �.�,. APPENDIX NDIX D• S114GLE LAYER (H-10 LOAD RATING) _If-IFILTP.A(ORS FILTER FABRIC i > / ' COMPACTED FILL ' ' ' 12 MIN. I h� 16, \\`\\`\\`\` \`\`\\`\/�`` // /i /i/ ixii�/i�/ice/i SUIr-ELE BASE �/ GRAVEL OR CRUSHED STCNE SINGLE LAYER (H-20 LOAD RATING) _ PAVEmENT -INFILTRATORS �FILTER FABRIC COMPACTED FILL 18' MIN. 16' < i _ O�O O O LAIN. \/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\/\\ /\\j\\/\\j I \//\//\//\//\//\//\// //\/ \\jxi\\` SUITABLE OAS: ORJ C.'.USHEO STGrIE .. 1 DOUBLE LAYER (H-20 LOAD RATING) /-PAVEMENT COMPACTED FILL A-INFILTRATORS FILTER FABRIC 18" MIN. I1r (no � 10 1 i 1diN. ,�\//\\��\\/\//\/\// \%\\\/\\//\\/\\//\\//\\//\/\\\//\\//\\//\\/� SUIT°'-E BASE GRAVEL OR CRUSHED STONE TRIPLE LAYER (H-20 LOAD RATING) -.EIMENT C0).t?ACTED FILL INFILTRATORS r-FIDE.'. F-EF.IC . /. i 18 611N. 1 I 10 1 a. IE' L_ MIN. \//\\// I SUIT:.BLE BASE GRAVEL OR CRUSHED STONE CAD disks are available upon request 2 w MATCH UNE MATCH UNE H � ,�,.M el,�e p.y,.n 4prrx,rinnrc .p �1so Nm4r 6 o Tai Maaw 20 b acre or 0.45 b/10,000 SF °�0N :,� O �„, � �a Creeping red feaeue 20 bfien or 0.45 Ibe/10,000 SF Bbdefoot l,afo8 a IW/acre or 0.20 IbA/10A00 SF 0 Urre and tertRw tlauW be appfl pr(or to or at Wss• G p � ya, t1 m &f wadaq and Irmrpomtod irdo th0 d1. The foeowkq rate,am rowmmonded: :r Agt,ouitural 3mestona 2 ton./acre or too 3,a/1,o00 SF R�11-,e4.9 L 50 b/acre or 1.1 b 10,000 SF \ \ ® i \ MV.UI.1825. / Oa Qa� n (N) / 4 V 125 j f 1�1 -•� I ,\ i,1 , 4 , OW-182 kq / // 'Se //H i"L�.,OJ.4tV. \ 13't PPo )��) 100�aoro a R2 1410,000 SF �� S.TT�. pU(�2 -1- = N.GUi.I UPC4L 3' m"b puNai«,t to 500 ibs/aero of,o-2P-2o fatl6ser or II�\ alnr•, 's,,!/ J� �� , Er''ie5r184.� �Bx a�+ 2:1 1,000 ft/ocre of 5-10-10). y -184.,5 SLOPE qr -192- j\� / e tl♦ 133 41.' \ X 8 � j ' \ i 'J f ` ♦.. \\'(R 3�s. -- \ I \\ 89 Im or L aF1�fq.12 'a er 4 !1/T' ` 9 ` NEVI Iscm �'zr H". `•� ' SUBC#9A NOTES: uan,lc['■ �. w - C. 1.FOR GENERAL NOTES,SEE SHEET NO. 5 l I 87 A k, eEO BOna11 L 1 - A-0.20 A RCN=98.0 ` WOvr ^ ' 2.SEE O DRAIN�.#2EROSION CONTROL NOTES AND DETAILS aa.' ,5 r„ , , :, R3r° \• a, tc=5.0 MIN. a1°iia,cn u 3.ALL DRAINAGE PIPE FOR THE ON-STTE DRAINAGE SMALL BE to y ■ 101N ° ROiJa®Da[1100+t 1.4Y DESIGNATED AS HIGH DENSITY POLYETHYLENE PIPE(HDPP) s ..am ANDDSSHN1 DESIGNATED AS DOUBLE WALLED SMD07H . ( a % ionou 4 t°p.E �A µ I.1 la� �° 8 i 11100 ae *m NO.12 wymn IF 190 aM L a BLANKET n6. / - J• � R�` J\ \ 'Too LF R/FT Ad VAROVArin aw1e�� • 1 X ,? b\ a \\ \ \ 1�TO 1:0 11NL 1 ----•l• ,?H>PP g - )9� NO '-�0p,w001�0 r kx \ \ - A=0.41 Ac. RCN=93.0 NOW / •^°` �1 \\ `a� �•i ••�...r < ""Ow11n'ao ` % 0 tc=5.0 MN _ � V,.Oa WIN i of I 4 s5 I , 1 64-05 a,i,n' -r / \ aauenow aramr k a a1ar1M 93 t. y.0.0�t fT4v 7\` \ / xri 1 tn.ss i� a Ig10 1�■a uals 1dwa \ a i4ip$GA N/F NeN HERITAGE TRUST' w �� ;•,. •,t effEfZ110TFNT \, \om BOTTOM rnae io v 1? bV 3.1 IBM s.aat R/rt \-� ioou°a\ SLOPE p W. talna \ I�IL In" Ise V IN IN r � \ ,o e.aeMe,.Ea' � � t� aM ouraia�a o'er 11.°1CPt 30 V \ l-a00eJf/rT ` ,l3c+�/ SUBC#8A \ \ w ou~,amaaoo 19, A=0.18 Ac. SUBC#5 X91 ; A=1.65 AC. . \ o""'�oc"M'.�: ,ao► a �+ ' ,aolnna, \ \\ 2, oRAD�G RCN=98.0 �a.area. "' tc=5.0 MIN. RCN=72.7 z� tc=13.9 HN. \ \ 9\ mi 'r a -1 mVINNOD AvouE 10-00015 F 19, we mm SUBC#5A 10 Gxnc scn A=0.16 Ac. -- a a a ' \\ �� A=0.10 Ac. -202 RCN=93.0 , ♦ IL m \ \ t RCN=98.0 tc=5.0 MIN. ;` \\ tc=5.0 M. 1�-m�1t. RED \\ ' iT MAC l}R � � �. > \� � e REVISE RFLTRATO1tS 4 97 n •'i \ S _-_-- REVISE PER TOWN OOYLENTS 3 4 07 .. TRUSTEES OF/,RESERVATIONS 'D0J0 r(Ag \ SUBC#3A J � o rR4 I 4 REVISE PER TOWN OOYLE,tT" 1 1 07 l \ ,:1p/ee IF A=0.24 Ac. home h , 3 ADD sflBAa(s 12/1e/9e # rRNlE �a x.00 RCN=98.0 2 REM WETLANDS A=0.16 Ac. 1� + fin 1 our,� fi mt 5.0 MIN. No EIJYIES AY ,DATE IT%t zx � RCN=93.0 UP IN ?�" _ ,�` 1.0-m G 510 „� 10110 \ REVISIONS? VT%nY1aa tc=5.0 MIlJ. E<20 \\ a oo SUBCATCII�N'�' MAP o a,a,r.rasa ■ WM7a7E mm rood a Poll uwo1E -- 'T"`- _--' - �_:•. -- --- -- ---- -202- asau ear�c a - - - - - 71D1►N #48 • 1aaAao area rouo m 001,r/aolc Pan of la,E e ono M Elallo m ,aot1ae 10r•att ---- ' -- _ - -------- -- �- cs er corn.:-_- q' •e'' ,c sc4.n wr= __ 1'-. _ •+ec ert. .6? __ ( s IILL YAP�d LOTS 36 n p'eCl�R1f10 ROAD ANDOVER, UA. f7,iaaM IUM09 WWI n am Y/N �}- -----_ DOOaE"a Mun Lot -'- amt u[ �°2- s,a �R-� 4 DISTRICT -_ c c -- -_ ° ` ,4w NORM ABED ��:s:__ - -- - --^� riESlooxE - - ,o„"^=- �� .-W- if CONSTRUCTION CO., INC. o u my 0100 1wr y 100 auE �-3 3 D6TPoC1'-j �� .�r Mx a 20 IF - an1 1E na 1AOnarr �' a J 1,-0006 n/'T .«. n.n I HAS MASSACHUSETTS 3 000uuanl nt -� er vuE -�, a. � ci ��T OM55 rm wr - w 1x i' ulna yawn mow J p aaACUlew mr -'- laaoMeaAO tna,o[ta[ F ( WDE- WAn y e®a0110Y faaao I 12-�Move mMm Yalu P m r + 31a1.n,� KE-01Z0 03070 1 x w aga[,�,p�9 it C p uTq WM n-wt-� �� --os- 1Me1011a11a 6t11EC pyt RN MINA - - °a»w ntt a,¢_san4:s fml omer_wi rur. ,9.sm,•n 31tlK32tt•3NAINIOt3•SUR MON ,t ma.sror moon aallwo 1N< 2- - - -' ( waE - - - - -'- - - - - NHF Dai n Can i Ina oaccolR"na mu maw For. w /F ° R9) SCALE 1••30 DATE OCTOBER 7,loge ®-x Tim ror aawaoa nta.n:1o,a H/F \ ARCIDZIND N/F � SHEET N0. �_ �.a==0.5,401011 TRUSTEES OF RtSE,NATIONS CM"/F f� (xC MSC 450e 1 ew'3BMT D MATCH LINE MATCH UNE 72-9 o \I ;�` ' e°yA sa.• L2 5211.440 E 9.29 wluul 1 ' i _-smeS l.3 552'08 W F9 9 - .8. L4 N00 E 299 ow §\ _ v' 4. SUE 4� 1ffi X192- 110 1-0 133 II I \ I I I/ ,1� `.v 4X•. :\\ \L'S/, ®° /8e \ \\ 784 ,u cow N/F NEW HER*GE TRl\ s° \ 0ai m xxq 1 y = \r®k A ' ;\�. / ♦ 188 '.'.. • \ \\ I i ; ' i 1 1 ♦�S 9'C, \ .`}\; \s$ � / t\ ®\ ' \' \ "\ ♦\ \ ,z.:� 1)TOWN MAP 48 LOTS 35 h 48: TOTAL AREA(COMBINED) - �52 Sq. FL (PER PLAN REFERENCE/1) / , + \ \ ` ` /\ 8 \b_ ms's \, \\\ ♦p=\ \ ej 2)LOCATION OF UIIDERCROUND UTILITIES IS APPROMATE ONLY. ''........... ADDITIONAL SHOWN MAY BE UNDERGROUND UTILITIES OTHER THAN THOSE / \1 \\ •�\`'' \ 1♦\ ,r / t1 \ R \\' P' \ �, `) \ \\,LS \ 3)ZONE: B-1 AND R-4 DISTRICTS. 4)EXISTING BOUNDARY AND TOPOGRAPHIC INFORMATION AS 1 90 \ esss SHOWN WAS TA(M FROM PLAN RUERFNCES/1 4#2 _' ' ,,•, :,u:� AND IS NOT THE RESULT OF A FIELD SURVEY BY THIS OFnM 7rl FL ' ` \ S VDC#2 s3 8\ ; t\:\ (k \ \ \ ,reee 5)WEMND DELINEATION SHOW WAS PERFORMED BY \ \ \\ , \ . a s CONE ENVROWENTAL SERVICES. INC. / 9TtTRMmtNxr srR \ \ \A=2.63 AC. 1 DETERMINATION COMMISSION THE MAID DELINEATON sNLOrrN \ , , \ S V DC#Jj 1� / \ _\ N/F NEW HERITAGE TRUST ;>\ \ � e \ m TT' 8)OH DECEMEIE'Ft 10. 1998,THE NORTH ANDONEt =—5.2 \ \ ; —A—"3 Ac. \ 'B9 WNSERVATIO THEW LAND A POSITIVE tclf 13.9 M \,�a A;R \ RCN— 0 \ \ ♦ Ns,u ON THIS PLAx 29 tc=18.0 192 _* �� ♦ PLAN REFERENCES: ` \ 1 A94— / , v\ �;y 1)'PLAN OF LAND IN NORTH ANDOVER MASS.- PREPARED FOR CAROL RYM' ? EfCADNNEEF" 14 1998;SCALE. 1'-80':BY j\ ��o ♦ \ 19\l�_ 1 '�' ; y L 196 \ , =q /yJ 2)'ww&PERMIT AND SITE PION FOR OLD TOWN vuAGE PREPARED FOR SCOTT CONSTRUCTION CO., It .•DATED ° APRIL 19, 1990.REVISED 8/21//98 SCALE r�40:BY \ ,,° \ ( / \• \ '�/ yes MERRUNCK ENGNEERINO SF�YIl S. 1 -FRC I n I ��\�� �-�--• �d ,d'o�° ' X198� \ ''',. 2 STORY \ •\ \ 4` \ WOOD EAAV 1 _ ) ' ! \ ♦ usac 198 SHED ' 21 ft TRUST OF TRUSTEES RESERVATIONS .E cRErxrrovs , \\\ ♦ \\ \ , c- o r e spa REVISE PER COMMENTS MSIi 3 14/97 TBM: A.� ('dRAgE ,Rrrs p ` e'H,a:oueux d" ` _ NAIL 1'UP IN lT \'G- h`P ° \ D-01:28'37• ID. DESCRIPTION ETY DATE U.POLEI5218 \\ \, , \-POO y t� ♦ L-i9.98' RENSpNg L 205 R�Z0.00' O na1 loco u�m rai —�s— P ♦ s P=EV=PIMNT CONDITIONS HYDROLOGY h ■ Fm m %m law a [1W1 IY1wli , '° \ auss k �� '� \ ♦ 210 36 ALL • ualao e,a Two a oa rYtcic � , t�° '. K SEnfR w2 S'ro'dC ?�£K S]fR Y mulat,aw a, TnAFHWwmHmx . ------s------- -- -- - ----- -------- -- Mk � - f 1N7V JfIP 13 L015 36 d' -s ---s -- ' " CVCSFw+wm s s 200p#CI07i1NOR0AD - - - Od*M SCM VM ❑ om WM sA ` '� r�r::=ate 6"s c c c c c y--d O —G a us uw NORTH ANDOVER,: _ J PREPARED FOR: WALE KW MW.ac s 5 .vo11 K �-4 RESIDENT t� ok m Il�m la � m m m ■� � 1��I&Vii°` il";{�i � x SCOTT CON,STRUM RO. CO., INC. _ R-3 RESIDENCE 3 otsTRrci CHICIO!'RING ROAD ROUTE ljgsoz� R-3 RESNOENCNA�° n HAVERHIL°01MASSACHUSETTS a 1X nc 1rnMwr oaelwal —°a or wx w (80'WOE-PUBLIC WAY) . ' . . of Ilf W tN[ O FECO1AO1a1 IM a oomMuD lnvm [Il[ 12-I Meelaf►07410/ n^"� 7ss[ enn.o t- ��� = �U_— aIFRSM nr•t NFL SeZ[JFE(,1P) 6HWVIL FSEL k lFl SE,i.%E _ i'sai -�� —\ MHF Dal n ConsMHa Ino. oH91NmLS.nAHlloLS.wHtvc117Is —�- era .nlno ui N/F • \ H� COBBLFSTOIE CROSSING ° • � SCIIE Y�30' MTE:AUq)5F 30. 1998 .iil TRUSTEES OF RESERVKWl A<tgDLAroNO REALTY TRUST SHEET NCL DJP CCC MSG 45998 E HBR A MATCH LINE MATCH LINE 10 1 t � / f' � I I tt V / ® �z i ® \\ \ A=1.10 Ac. x% �° iOwv,as,l�t ® _ \ RCN=83.8 � ,m - ..�\\�.;• � \ SLOPE k � 114 133 or p \t cam Ilo tt (a1 w■aN11 \\ `/ . ��1.Ip�001J1L110X fY Ip*y \ f 8 M r 1a 1kv o tn '.. / I I I ♦k \, a �yNyM�11 c .� \ .N .0..0 NOTy1IQQ I� ,,° ' \ I (i I av( I �♦ \ 7g-jt- 1 11.FOR GENERAL NOTES,SEE SHEET NO. S ) k 1 1 ,-- t7f■R 1 V q 2.FOR DRAINAGE k EROSION CONTROL NOTES AND DETAILS ' I ( , � @ O ; M0.000 R \x s SEE SHEET NO. 12. \J y 9_ to t a tOfq 6 ° ` \I _ smm am WN P Law a DESIGNATED AS HIGH DENSITY PO.YETIMENE PIPE__(HDPP)E .. 51100TH \<% AND SHALL EIE DESNRY7TED AS DOUEttE YUU.ED 6' 1lYC. JIM \ II■01C.AY till fJ10■011 COM1110L � ior,al a 1°�iu � \±�t tn. �,� \`\ , s � .oc a° INTERIOR PIPE. 111Yw1II .790 V' µ tr as FT \ 1, 5• „1KYi1 �� I k\ ♦ ' \ ,.O.OR.R,R vAmLqycRm Wf NOW \ H!.1>3 2 GRADING I , }•� `I , a' 7fA _ � P `- '1A00.R ly�p�• ! 9_ � ►� /Ip 2-J j■I00180�'10f v IN IIIIAme law jW- uC-AXW1.46 Ac. 1r tlem ••1sglatloaT.1 \ w 1'%IYlJ �eB �'mu aw 1�RdCN=95.5 I , \ IN '•• A w: m i9Jaur 1n / \ rmm p \ a " ` 1a►w LW w, ♦un r aaa�l>m1o1 H \ // \ , \ \ �°►°sl Ihp p a� \ r ex esas umioillm Inn 1°M°No t J i,>\ 1 INTFRAQTIE]!T \\ \lo tNflf m f a 0 1xls \ - s d N, N6YYl HERTEAGE TRUST t�.0110■H1Jt. V 3:1 9 3 - ' �1 L797 s -X89 10 V M •� \ -- \V \ 9 \ SLOPE 'to `MC l µota(tw�,,\ \ IS• •-OO!R/R 798 —� — \ 3�ooulOCtanomm p 0uT 1s" "tt \ tl a ltuo f0 0.Ma31ffi 1y`p I7 \iD 10If0Y fns �� .w dR 1.110 g~'�V \ k� \0 \\ 1 ' ,O i 191 d+° ��..°,�MIDI ♦ ®i__um lmeld Iaa I k �t 4°l°R°h \ \ 21 GRADING -IM BID I 1 .N N 1 79\ tiT►-0 •. d� \ .IrN1 t.IR.O{R � s ' \ 1 1woo>d a/n I ♦* ` a \ o ( t■Y nwai t� SUBC 5 \ \ 94 # { ® _ y� . 1� Ti7 WAIl71� A=1.65 Ac. t► �-- a • � \ ♦9 —2oz RCN=72.7 Q \ ou U.f 1 \ c tc-13.9 MIN. .w our 1 — 0 GRAPHIC SCALE zn� 798 e \ x .rt HFD \ tQ or QVAG/Bi0<AT llff \ x I Imb-So fL TRUSTEES OF RESERVATIONS e REVISE PER TOWN COMMENTS MS0 3/114/97 zro- `\ , .w our 1 'c"•_/` I \ \ I 4 REVISE PER TOWN COMMENTS 1/21/97 \ / \ 1Y 110P►A V \ 3 ADD sETEtWf2C3 1 2/ie f)e J� ` .w stn. Law�irr aap 2 REVISE WETLANDS iY 0 Tr?iA: �� • - _ E1IMINTE DRIVEWAY 1 96 NAIL 1'/ -414'2e•3Y ND. DESCRIPTION 11Y DATE I U.POLE u Z056D16 ,t�IMa a l01■ \ ; 7 a9 -mm, ReASKM umm pow EL ■ Dane.mum Fain s w.e IYI#= —zez— - ---- =-- - - B'VICWPMl4IQ'P CONDITIONS HYDROLOGY wU10,0 w.a IOU• s as Inaat .[t 1tl \� lbe7/IGP id L075 StT&'48 CHICKERM a POSTD ROIAGY • ott.tn.Iol.o lawn■rr..a. __ _ � 'n - - on.o•tw�tto ❑ oaww.l orr�errca=----6)- - '--- 4 dSTRICT510f -- ,c- - ••wcm. 9 vcsnW --'--- - -}� - \c.csnmwm cuswx �� 000a20 m I■tm ta[ —•— mm u■ _ RS2 a ° o _ _�� —_d c s---a----s-- PREPARED FOR: INN fiao tw.tx t floe Mo♦ -3�3 D ,�.a a mow.is RES� m nu xo.>a 11� -- x r SCOTT CONSTRUCTION VER1ilL MASSI41USETI3 O.1 INC. - ■•I 1z mm"~ _ B s 0.0.00.n/R w.la,.s a.tlwaal lei —A as wx �, s .e �m , c, m m m m' 01635 71m R — w I.■ F v 60'WDE WAIF 'Ittlt o.malt Um 1�M.ee.►wt••r o r.naA,otl,m —•— utmnlotwlaslncu■ � 1 .m1,ol,a,tit•o M M'rl^\ llm.■ —.�— 1.•p■n110 6L'71Rt •� v r r S q M1W WJI r d �♦•TIM •�� .F al.r.■ol an.w =m IK �— — . — . uPOCC — . °FM �usar: — . —. _IW OUr 1—.— ort»r o¢cn a to scmxc(rte —\ 1 11 — 1y gvaviq¢cc.k ra sw.xq CIOI�tt 3tAYLYOIf —t9o- cm o0.01R ab"m M� 11m II♦•4Y fsasv xasx u+ql ff-- { - MHF Dell n Coft Irlo. ®—x IMO►,wol■11ta1 nla►.ly Iwla WF r W4CON0 N/F / mp, SCALP: i'-30 DATE OCTOBER 7. 1096 �_ .oa.a■■� TRUSTEES OF RESERVATIONS ARO COE6LES-TOEIE CROSSHG WAWN OT GHEC SHEET N0. REVTY TRUST CCC MSTN 45996 warn 9