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Home My WebLink About20160419 SStormwater Report - Stormwater Report - 2302 TURNPIKE STREET 11/4/2015 Applicant: Project No. NAND-0033 Earth Works,Inc. 23 Ash Street North Andover,MA 01845 Stor-m- -w. . 1 Report & Mitigative Drainage for Proposed Commercial Development #2302 TURNPIKE STREET (ROUTE 114) NORTH ANDOVER, MASSACHUSETTS November 4, 2015 WILLLA MS GE SPARAS crc�a� nN,�s�wanocs T J 189 North Main Street,Suite 101 Middleton,MA 01949 978-539-8088 Ph 978-539-8200 Fax www.wsengineers.com Stormwater Report Table Of Contents 1. USGS Locus Map 2. Checklist for Stormwater Report 3. Long Term Pollution Prevention Plan (LTPPP) 4. Construction Period Pollution Prevention Plan & Erosion and Sedimentation Control (CPPPP) 5. Mitigative Drainage Analysis 6. Stormwater Report Compliance Calculations 7. Soil Test Logs 8. NRCS Web Soil Survey Information 9. Operation & Maintenance Plan 10. Erosion & Sediment Control Plan 11. Snow Disposal Guidelines 12. Deicing Chemical (Road Salt) Storage WILLIAMS&SP 189 NORTH ARAGES MAIN STREET CIVIL ENGINEERING& �T1 &, WILLIAMS SUITE 101RA LAND SURVEYORS SPAGES MIDDLETON,MA 01949 Rm AWNi7RFET� r ""89NOLot PHONE:(978)539-8088 MIDDLETON.W 01949 SIHOFAX:(9 8)53 539_8088 FAX:(978)53 9-8200 FAX.(9)8)539-B200 KSENGWEERS.CbM { Q f) i4l/ o� t Uri r r �f} 1� c l \ d GOCdl 'on { ` L C7 ��1-; d-. r 4-✓'8�. "�..i .ql'y 4 \ _ I !�, 1�Lar /r r 'V t^ ,y `1�— * � {L`� �4.t ti {��a j 1' f l a`' b ` P v) } Yqy � �h,crrrtttrrr��' �� 1� I t r� �v a r ilt'l �rl 11�{r�•\ , `' -i��. ii -- e'?l ,!V� `, 1i,-` `!; C' - � \\ t ii 7.r '.� 4j \, d C1 ` •�``w,t5!!',`F (f'� } , 4�7 R� l SCAAA_��e1�0 YPr— �\`1 E � !f�`J' ? ��1 aP`1J� _ G� � `:,V r. .fit r�-'\� �S \} 1IT�\..R �t�� r.J� �� ` I aM at'tc{,y } . ��,.�,-,_ 't�°c�l �`� arc �`�/��1y'� � SS ".:�✓C,CIi (J� � `��.�e t \,fr-0�5� �).r$� 1 • 1 � x 1tp r xf f S i j C J ze C 1 -J'\) f-! �'�1�/r �-, .,,{ �`.✓ `'1, l O I.��Q //l'S, t t.' A� f'r,r'q�1! �t-�:vr)1 1✓�n�'+a. t 2 }� f`,- i, � 1 / -+-` �� -t}..15( j � � I _ ice.-✓J..-.? � ��4. 1� t .•, �� '' ��ry �t LOCUS sl _ L t _ (t y \ .1 `� �� l 7 `i , = ! I Srv•,. < MWS C? .�--E C\ !VIJ �r Af- rv) l t 1 J F I J1 cr a`IN �� C' v�r� �t STSTAll t. USGS MAPa'Y .-f SOUTH GROVELAND QUADRANGLE LOCUS MAP READING QUADRANGLE #23 02 TURNPIKE STREET(ROUTE 114) SCALE: 1:24,000(tor CONTOURS) NORTH ANDOVER, MA Massachusetts Department of Environmental Protection Bureau of Resource Protection- Wetlands Program Checklist A. Introduction Important:When A Stormwater Report must be submitted with the Notice of Intent permit application to document filling out forms compliance with the Stormwater Management Standards.The following checklist is NOT a substitute for on the computer,use only the tab the Stormwater Report(which should provide more substantive and detailed information) but is offered key to move your here as a tool to help the applicant organize their Stormwater Management documentation for their cursor-do not Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, use the return the Stormwater Report must contain the engineering computations and supporting information set forth in key. Volume 3 of the Massachusetts Stormwater Handbook.The Stormwater Report must be prepared and certified by a Registered Professional Engineer(RPE) licensed in the Commonwealth. The Stormwater Report must include: �. • The Stormwater Checklist completed and stamped by a Registered Professional Engineer(see page 2)that certifies that the Stormwater Report contains all required submittals.' This Checklist is to be used as the cover for the completed Stormwater Report. • Applicant/Project Name • Project Address • Name of Firm and Registered Professional Engineer that prepared the Report • Long-Term Pollution Prevention Plan required by Standards 4-6 • Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan required by Standard 82 • Operation and Maintenance Plan required by Standard 9 In addition to all plans and supporting information, the Stormwater Report must include a brief narrative describing stormwater management practices, including environmentally sensitive site design and LID techniques, along with a diagram depicting runoff through the proposed BMP treatment train. Plans are required to show existing and proposed conditions, identify all wetland resource areas, NRCS soil types, critical areas, Land Uses with Higher Potential Pollutant Loads (LUHPPL), and any areas on the site where infiltration rate is greater than 2.4 inches per hour. The Plans shall identify the drainage areas for both existing and proposed conditions at a scale that enables verification of supporting calculations. As noted in the Checklist, the Stormwater Management Report shall document compliance with each of the Stormwater Management Standards as provided in the Massachusetts Stormwater Handbook. The soils evaluation and calculations shall be done using the methodologies set forth in Volume 3 of the Massachusetts Stormwater Handbook. To ensure that the Stormwater Report is complete, applicants are required to fill in the Stormwater Report Checklist by checking the box to indicate that the specified information has been included in the Stormwater Report. If any of the information specified in the checklist has not been submitted, the applicant must provide an explanation. The completed Stormwater Report Checklist and Certification must be submitted with the Stormwater Report. 'The Stormwater Report may also include the Illicit Discharge Compliance Statement required by Standard 10. If not included in the Stormwater Report,the Illicit Discharge Compliance Statement must be submitted prior to the discharge of stormwater runoff to the post-construction best management practices. 2 For some complex'projects,it may not be possible to include the Construction Period Erosion and Sedimentation Control Plan in the Stormwater Report. In that event,the issuing authority has the discretion to issue an Order of Conditions that approves the project and includes a condition requiring the proponent to submit the Construction Period Erosion and Sedimentation Control Plan before commencing any land disturbance activity on the site. Drainage_swcheck.doc•04/01/08 Stormwater Report Checklist•Page 1 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report B. Stormwater Checklist and Certification The following checklist is intended to serve as a guide for applicants as to the elements that ordinarily need to be addressed in a complete Stormwater Report.The checklist is also intended to provide conservation commissions and other reviewing authorities with a summary of the components necessary for a comprehensive Stormwater Report that addresses the ten Stormwater Standards. Note: Because stormwater requirements vary from project to project, it is possible that a complete Stormwater Report may not include information on some of the subjects specified in the Checklist. If it is determined that a specific item does not apply to the project under review, please note that the item is not applicable(N.A.)and provide the reasons for that determination. A complete checklist must include the Certification set forth below signed by the Registered Professional Engineer who prepared the Stormwater Report. Registered Professional Engineer's Certification I have reviewed the Stormwater Report, including the soil evaluation, computations, Long-term Pollution Prevention Plan, the Construction Period Erosion and Sedimentation Control Plan (if included), the Long- term Post-Construction Operation and Maintenance Plan, the Illicit Discharge Compliance Statement(if included) and the plans showing the stormwater management system, and have determined that they have been prepared in accordance with the requirements of the Stormwater Management Standards as further elaborated by the Massachusetts Stormwater Handbook.'I have also determined that the information presented in the Stormwater Checklist is accurate and that the information presented in the Stormwater Report accurately reflects conditions at the site as of the date of this permit application. Registered Professional Engineer Block and Signature ,sA OF o MATTHEW E. G MOORE o CIVIL y N0.45885 °• �o9�c/STEM Fss/ONAL Signature and Date Checklist Project Type: Is the application for new development, redevelopment, or a mix of new and redevelopment? ® New development ❑ Redevelopment ❑ Mix of New Development and Redevelopment Drainage_swcheck.doc•04/01/08 Stormwater Report Checklist•Page 2 of 8 Massachusetts Department of Environmental Protection ILI Bureau of Resource Protection - Wetlands Program Checklist Checklist (continued) LID Measures: Stormwater Standards require LID measures to be considered. Document what environmentally sensitive design and LID Techniques were considered during the planning and design of the project: ® No disturbance to any Wetland Resource Areas ❑ Site Design Practices (e.g. clustered development, reduced frontage setbacks) ❑ Reduced Impervious Area (Redevelopment Only) ❑ Minimizing disturbance to existing trees and shrubs ❑ LID Site Design Credit Requested: ❑ Credit 1 ❑ Credit 2 ❑ Credit 3 ❑ Use of"country drainage"versus curb and gutter conveyance and pipe ❑ Bioretention Cells (includes Rain Gardens) ❑ Constructed Stormwater Wetlands (includes Gravel Wetlands designs) ❑ Treebox Filter ❑ Water Quality Swale ❑ Grass Channel ❑ Green Roof ❑ Other(describe): Standard 1: No New Untreated Discharges ® No new untreated discharges ® Outlets have been designed so there is no erosion or scour to wetlands and waters of the Commonwealth ® Supporting calculations specified in Volume 3 of the Massachusetts Stormwater Handbook included. Drainage_swcheck.doc•04/01/08 Stormwater Report Checklist•Page 3 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Checklist (continued) Standard 2: Peak Rate Attenuation ❑ Standard'2 waiver requested because the project is located in land subject to coastal storm flowage and stormwater discharge is to a wetland subject to coastal flooding. ® Evaluation provided to determine whether off-site flooding increases during the 100-year 24-hour storm. ® Calculations provided to show that post-development peak discharge rates do not exceed pre- development rates for the 2-year and 10-year 24-hour storms. If evaluation shows that off-site flooding increases during the 100-year 24-hour storm, calculations are also provided to show that post-development peak discharge rates do not exceed pre-development rates for the 100-year 24- hour storm. Standard 3: Recharge ® Soil Analysis provided. ® Required Recharge Volume calculation provided. ❑ Required Recharge volume reduced through use of the LID site Design Credits. ® Sizing the infiltration, BMPs is based on the following method: Check the method used. ® Static ❑ Simple Dynamic ❑ Dynamic Field ❑ Runoff from all impervious areas at the site discharging to the infiltration BMP. ® Runoff from all impervious areas at the site is not discharging to the infiltration BMP and calculations are provided showing that the drainage area contributing runoff to the infiltration BMPs is sufficient to generate the required recharge volume. ® Recharge BMPs have been sized to infiltrate the Required Recharge Volume. ❑ Recharge BMPs have been sized to infiltrate the Required Recharge Volume only to the maximum extent practicable for the following reason: ❑ Site is comprised solely of C and D soils and/or bedrock at the land surface ❑ M.G.L. c. 21 E sites pursuant to 310 CMR 40.0000 ❑ Solid Waste Landfill pursuant to 310 CMR 19.000 ❑ Project is otherwise subject to Stormwater Management Standards only to the maximum extent practicable. ® Calculations showing that the infiltration BMPs will drain in 72 hours are provided. ❑ Property includes a M.G.L. c. 21 E site or a solid waste landfill and a mounding analysis is included. 80%TSS removal is required prior to discharge to infiltration BMP if Dynamic Field method is used. Drainage_swcheck.doc•04/01/08 Stormwater Report Checklist•Page 4 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist for Stormwater Report Checklist (continued) Standard 3: Recharge (continued) ® The infiltration BMP is used to attenuate peak flows during storms greater than or equal to the 10- year 24-hour storm and separation to seasonal high groundwater is less than 4 feet and a mounding analysis is provided. ❑ Documentation is provided showing that infiltration BMPs do not adversely impact nearby wetland resource areas. Standard 4: Water Quality The Long-Term Pollution Prevention Plan typically includes the following: • Good housekeeping practices; • Provisions for storing materials and waste products inside or under cover; • Vehicle washing controls; • Requirements for routine inspections and maintenance of stormwater BMPs; • Spill prevention and response plans; • Provisions for maintenance of lawns, gardens, and other landscaped areas; • Requirements for storage and use of fertilizers, herbicides, and pesticides; • Pet waste management provisions; • Provisions for operation and management of septic systems; • Provisions for solid waste management; ® Snow disposal and plowing plans relative to Wetland Resource Areas; • Winter Road Salt and/or Sand Use and Storage restrictions; • Street sweeping schedules; • Provisions for prevention of illicit discharges to the stormwater management system; • Documentation that Stormwater BMPs are designed to provide for shutdown and containment in the event of a spill or discharges to or near critical areas or from LUHPPL; • Training for staff or personnel involved with implementing Long-Term Pollution Prevention Plan; • List of Emergency contacts for implementing Long-Term Pollution Prevention Plan. ® A Long-Term Pollution Prevention Plan is attached to Stormwater Report and is included as an attachment to the Wetlands Notice of Intent. ❑ Treatment BMPs subject to the 44%TSS removal pretreatment requirement and the one inch rule for calculating the water quality volume are included, and discharge: ❑ is within the Zone II or Interim Wellhead Protection Area ❑ is near or to other critical areas ❑ is within soils with a rapid infiltration rate(greater than 2.4 inches per hour) ❑ involves runoff from land uses with higher potential pollutant loads. ❑ The Required Water Quality Volume is reduced through use of the LID site Design Credits. ® Calculations documenting that the treatment train meets the 80%TSS removal requirement and, if applicable, the 44%TSS removal pretreatment requirement, are provided. Drainage_swcheck.doc•04/01/08 Stormwater Report Checklist•Page 5 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist Checklist (continued) Standard 4: Water Quality(continued) ® The BMP is sized (and calculations provided) based on: ® The %2" or 1"Water Quality Volume or ❑ The equivalent flow rate associated with the Water Quality Volume and documentation is provided showing that the BMP treats the required water quality volume. ❑ The applicant proposes to use proprietary BMPs, and documentation supporting use of proprietary BMP and proposed TSS removal rate is provided. This documentation may be in the form of the propriety BMP checklist found in Volume 2, Chapter 4 of the Massachusetts Stormwater Handbook and submitting copies of the TARP Report, STEP Report, and/or other third party studies verifying performance of the proprietary BMPs. ❑ A TMDL exists that indicates a need to reduce pollutants other than TSS and documentation showing that the BMPs selected are consistent with the TMDL is provided. Standard 6: Land Uses With Higher Potential Pollutant Loads (LUHPPLs) ❑ The NPDES Multi-Sector General Permit covers the land use and the Stormwater Pollution Prevention Plan (SWPPP) has been included with the Stormwater Report. ❑ The NPDES Multi-Sector General Permit covers the land use and the SWPPP will be submitted prior to the discharge of stormwater to the post-construction stormwater BMPs. ❑ The NPDES Multi-Sector General Permit does not cover the land use. ❑ LUHPPLs are located at the site and industry specific source control and pollution prevention measures have been proposed to reduce or eliminate the exposure of LUHPPLs to rain, snow, snow melt and runoff, and been included in the long term Pollution Prevention Plan. ❑ All exposure has been eliminated. ❑ All exposure has not been eliminated and all BMPs selected are on MassDEP LUHPPL list. ❑ The LUHPPL has the potential to generate runoff with moderate to higher concentrations of oil and grease(e.g. all parking lots with >1000 vehicle trips per day)and the treatment train includes an oil grit separator, a filtering bioretention area, a sand filter or equivalent. Standard 6: Critical Areas ❑ The discharge is near or to a critical area and the treatment train includes only BMPs that MassDEP has approved for stormwater discharges to or near that particular class of critical area. ❑ Critical areas and BMPs are identified in the Stormwater Report. Drainage swcheck.doc•04/01/08 Stormwater Report Checklist•Page 6 of 8 Massachusetts Department of Environmental Protection LlBureau of Resource Protection - Wetlands Program Checklist for Stormwater Checklist (continued) Standard 7: Redevelopments and Other Projects Subject to the Standards only to the maximum extent practicable ❑ The project is subject to the Stormwater Management Standards only to the maximum Extent Practicable as a: ❑ Limited Project ❑ Small Residential Projects: 5-9 single family houses or 5-9 units in a multi-family development provided there is no discharge that may potentially affect a critical area. ❑ Small Residential Projects: 2-4 single family houses or 2-4 units in a multi-family development with a discharge to a critical area El Marina and/or boatyard provided the hull painting, service and maintenance areas are protected from exposure to rain, snow, snow melt and runoff ❑ Bike Path and/or Foot Path ❑ Redevelopment Project ❑ Redevelopment portion of mix of new and redevelopment. ❑ Certain standards are not fully met(Standard No. 1, 8, 9, and 10 must always be fully met) and an explanation of why these standards are not met is contained in the Stormwater Report. ❑ The project involves redevelopment and a description of all measures that have been taken to improve existing conditions is provided in the Stormwater Report. The redevelopment checklist found in Volume 2 Chapter 3 of the Massachusetts Stormwater Handbook may be used to document that the proposed stormwater management system (a)complies with Standards 2, 3 and the pretreatment and structural BMP requirements of Standards 4-6 to the maximum extent practicable and (b) improves existing conditions. Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan must include the following information: • Narrative; • Construction Period Operation and Maintenance Plan; • Names of Persons or Entity Responsible for Plan Compliance; • Construction Period Pollution Prevention Measures; • Erosion and Sedimentation Control Plan Drawings; • Detail drawings and specifications for erosion control BMPs, including sizing calculations; • Vegetation Planning; • Site Development Plan; • Construction Sequencing Plan; • Sequencing of Erosion and Sedimentation Controls; • Operation and Maintenance of Erosion and Sedimentation Controls; • Inspection Schedule; • Maintenance Schedule; • Inspection and Maintenance Log Form. ® A Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan containing the information set forth above has been included in the Stormwater Report. Drainage_swcheck.doc•04/01/08 Stormwater Report Checklist•Page 7 of 8 Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program Checklist Checklist (continued) Standard 8: Construction Period Pollution Prevention and Erosion and Sedimentation Control (continued) ❑ The project is highly complex and information is included in the Stormwater Report that explains why it is not possible to submit the Construction Period Pollution Prevention and Erosion and Sedimentation Control Plan with the application. A Construction Period Pollution Prevention and Erosion and Sedimentation Control has not been included in the Stormwater Report but will be submitted before land disturbance begins. ❑ The project is not covered by a NPDES Construction General Permit. ❑ The project is covered by a NPDES Construction General Permit and a copy of the SWPPP is in the Stormwater Report. ® The project is covered by a NPDES Construction General Permit but no SWPPP been submitted. The SWPPP will be submitted BEFORE land disturbance begins. Standard 9: Operation and Maintenance Plan ® The Post Construction Operation and Maintenance Plan is included in the Stormwater Report and includes the following information: ® Name of the stormwater management system owners; ® Party responsible for operation and maintenance; ® Schedule for implementation of routine and non-routine maintenance tasks; ® Plan showing the location of all stormwater BMPs maintenance access areas; ❑ Description and delineation of public safety features; ❑ Estimated operation and maintenance budget; and ® Operation and Maintenance Log Form. ❑ The responsible party is not the owner of the parcel where the BMP is located and the Stormwater Report includes the following submissions: ❑ A copy of the legal instrument(deed, homeowner's association, utility trust or other legal entity) that establishes the terms of and legal responsibility for the operation and maintenance of the project site stormwater BMPs; ❑ A plan and easement deed that allows site access for the legal entity to operate and maintain BMP functions. Standard 10: Prohibition of Illicit Discharges ❑ The Long-Term Pollution Prevention Plan includes measures to prevent illicit discharges; ® An Illicit Discharge Compliance Statement is attached; ❑ NO Illicit Discharge Compliance Statement is attached but will be submitted prior to the discharge of any stormwater to post-construction BMPs. Drainage_swcheck.doc•04/01/08 Stormwater Report Checklist•Page 8 of 8 LONG TERM POLLUTION PREVENTION PLAN Long Term Pollution Prevention Plan (LTPPP) #2302 Turnpike Street North Andover, MA 01845 November 4, 2015 This Long Term Pollution Prevention Plan has been prepared to comply with the provisions set forth in the Massachusetts Department of Environmental Protection(DEP)Stormwater Management Standards.Structural Best Management Practices (BMPs) require periodic maintenance to ensure proper function and efficiency in pollutant removal from stormwater discharges that would otherwise reach wetland resource areas untreated. Maintenance schedules found below are as recommended in Department of Environmental Protections Massachusetts Stormwater Handbook and as recommended in the manufacturer's specifications. I. Street Sweeping: The parking lots&driveways shall be swept twice a year preferably but at the very least once per year in the spring. II. Ownership and Maintenance Responsibilities: After completion,the property owner(s)will assume full responsibility of continuing the operation and maintenance of the stormwater management system as well as the long term pollution prevention plan outlined below. The exception would be if a legal agreement is made with another party to perform such duties for the owner(s). i III. DEP Standard 4:Water Quality The Long Term Pollution Prevention Plan includes the following: A. Good housekeeping practices; Prevent or reduce pollutant runoff from reaching the wetland resource areas through street sweeping,stabilizing all disturbed areas with vegetative cover,catch basin cleaning and cleaning the proprietary separators i.e. Stormceptor Units or approved equivalent. B. Provisions for storing materials and waste products inside or under cover; All materials on site are to be stored in a neat and orderly fashion in their appropriate containers and,if possible,under a roof or other secure enclosure. All waste products are to be placed in secure receptacles until they are emptied by a solid waste management company licensed in the Commonwealth of Massachusetts. C.Vehicle washing controls; The owner(s) shall encourage tenants to wash their vehicles on lawn or gravel areas so that the ground can filter the water naturally. This will prevent soap, dirt and oil from reaching the storm drains and ultimately wetlands,streams,rivers or marine waters. Encourage tenants to wash their vehicles at commercial car washes which recycle water and use approximately 60% on average of the amount of water used in a home wash. Long Term Pollution Prevention Plan #2302 Turnpike Street, North Andover, MA November 4, 2015 D. Requirements for routine inspections and maintenance of Stormwater BMP's; Follow the procedures outlined in the Operation and Maintenance Plan as well as the provided Long Term Inspection and Maintenance Forms. E. Spill prevention and response plans; Spill Prevention: As mentioned previously,all materials on site are to be stored in a neat and orderly fashion in their appropriate containers and,if possible,under a roof or other secure enclosure. Products shall be kept in their original containers with the original manufacturer's label. Products should not be mixed unless recommended by the manufacturer. The manufacturer's recommendations for proper use and disposal shall be followed at all times and,if possible,all of the product should be used up before proper disposal. Response:The manufacturer's recommended methods for cleanup must be followed and spills cleaned up immediately after discovery. Spills shall be kept well ventilated and personnel must wear appropriate protective gear to prevent injury from contact with hazardous substances. Spills of toxic or hazardous material must be reported to the appropriate local and/or State agencies in accordance with the local and/or Commonwealth of Massachusetts regulations. F. Requirements for storage and use of fertilizers,herbicides and pesticides; Consult the Order of Conditions issued by the Town of Middleton Conservation Commission for any questions regarding these materials. Fertilizers:Fertilizers are to be applied at the minimum amounts recommended by the manufacturer and once applied shall be worked into the soil to limit the possibility of entering the storm drains. Storage procedures are to be followed as previously stated and the contents of any partially used bags should be transferred to a sealable container, either bag or bin to avoid spilling. Herbicides and Pesticides: Storage of these materials are to be as outlined previously and especially out of the reach of pets and children,away from damp areas where their containers may succumb to moisture or rust and should not be stored near food. These materials must not be placed in the trash or washed down the drain. Handle using rubber gloves and use an appropriate mask when using these products for extensive periods of time. G. Provisions for maintenance of lawns,gardens,and other landscaped areas; These activities are to be left up to the owner(s) to schedule and perform. H. Pet waste management provisions; These activities are to be left up to the individual tenants to schedule and perform. 2 Long Term Pollution Prevention Plan #2302 Turnpike Street, North Andover, MA November 4, 2015 I. Provisions for operation and maintenance of septic systems; These activities are to be left up to the owner(s) to schedule and perform. I. Provisions for solid waste management; All waste products are to be placed in secure receptacles until they are emptied by a solid waste management company licensed in the Commonwealth of Massachusetts. J.Snow disposal and plowing plans relative to Wetland Resource Areas; Snow disposal/removal is to be in compliance with the Bureau of Resource Protections (BRP's) Snow Disposal Guidelines effective March 8,2001,Guideline No. BRPG01-01. K.Winter Road Salt and/or Sand Use and Storage restrictions; Road Salt: Storage is to be as mentioned previously and the use must be in compliance with the Guidelines on Deicing Chemical(Road Salt) Storage effective date December 19,1997,Guideline No. DWSG97-1 found in the BRP's Drinking Water Program. Sand Use: Encourage the use of environmentally friendly alternatives such as calcium chloride and/or sand instead of road salt for melting ice whenever possible. L.Street Sweeping schedules; As mentioned previously, street sweeping should be performed by the owner(s) twice per year in the spring and fall;however,at the very least sweeping must occur once a year in the spring in order to minimize the amount of Total Suspended Solids load on the deep-sump catch basins and the other Best Management Practices tributary thereto. M. Provisions for prevention of illicit discharges to the stormwater management systems; There are no proposed illicit discharges to the proposed stormwater management systems as can be seen on the Site Plan. According to Standard 10 in the Massachusetts Stormwater Handbook,Illicit discharges to the stormwater management system are discharges that are not entirely comprised of stormwater. Notwithstanding the foregoing,an illicit discharge does not include discharges from the following activities or facilities: firefighting,water line flushing,landscape irrigation,uncontaminated groundwater,potable water sources,foundation drains,air conditioning condensation;footing drains,individual resident car washing,flows from riparian habitats and wetlands,dechlorinated water from swimming pools,water used for street washing and water used to clean residential buildings without detergents. N. Documentation that Stormwater BMP's are designed to provide for shutdown and containment in the event of a spill or discharges to or near critical areas or from land uses with higher potential pollutant loads (LUHPPL); Not applicable as this project does not meet the criteria for a LUHPPL. 3 Long Term Pollution Prevention Plan #2302 Turnpike Street, North Andover, MA November 4, 2015 O.Training for staff or personnel involved with implementing LTPPP; This responsibility lies with the owner(s)unless a legally-binding agreement is made with another party to perform such duties for the owner(s). P. List of Emergency contacts for implementing Long-Term Pollution Prevention Plan; This responsibility lies with the owner(s) unless a legally-binding agreement is made with another party to perform such duties for the owner(s). 4 LONG TERM INSPECTION AND MAINTENANCE REPORT FORM (LONG TERM POLLUTION PREVENTION PLAN) #2302 TURNPIKE STREET NORTH ANDOVER, MA 01845 TO BE COMPLETED EVERY 7 DAYS DURING CONSTRUCTION TO BE COMPLETED FOUR TIMES A YEAR OR WHENEVER THE DEPTH OF DEPOSITS IS GREATER THAN OR EQUAL TO ONE HALF THE DEPTH FROM THE BOTTOM OF THE INVERT OF THE LOWEST PIPE IN THE BASIN Name of Inspector: Date: Inspector's Company/Affiliation: Days Since Last Rainfall: Amount of Last Rainfall: � � LoctlonHood� lnstall�e�!� Buildup Id�nti�ca4 ton � �� Gondltion xv poor flGCB From Parking yes - no fair good poor h CB2 Nori�erly7�rnre yes - no fair good poor �flGfl83 � 1ear Parl�ftl0 yes - no fair good poor yes no fair good poor yes - no fair ood poor yes - no fair good Maintenance Required: To Be Performed By: On or Before: LONG TERM INSPECTION AND MAINTENANCE REPORT FORM (LONG TERM POLLUTION PREVENTION PLAN) #2302 TURNPIKE STREET NORTH ANDOVER, MA 01845 TO BE COMPLETED AFTER EVERY MAJOR STORM DURING FIRST THREE R AND WHEN MONTHS OF OPERATION AND TWICE A YEAR THE THERE ARE DISCHARGES THROUGH THE HIGH OUTLET ORIRFICE Name of Inspector: Date: Inspector's Company/Affiliation: Days Since Last Rainfall: Amount of Last Rainfall: � �� L�- �� Struct�ral Conit�ols:�Su�face Infiltration 8as�n� � , � �`� � � � � �'x► ' ��f� � o�+r�Mu�ch ��di�e�t Hou+r Much Sed�men�B�lltl- lci-up 1n�13as�n up a��h� Outlet 4e�#� ca�ttory . = a Acculmulat�or {Cr�c1e one) err. minor/ moderate / major -Alx minor/ moderate / major 05 minor/ moderate / major minor/ moderate / major Maintenance Required: To Be Performed By: On or Before: LONG TERM INSPECTION AND MAINTENANCE REPORT FORM (LONG TERM POLLUTION PREVENTION PLAN) #2302 TURNPIKE STREET NORTH ANDOVER, MA 01845 TO BE COMPLETED EVERY MONTH AND AT LEAST FOUR TIMES A YEAR AND AFTER EVERY MAJOR STORM EVENT Name of Inspector: Date: Inspector's Company/Affiliation: Days Since Last Rainfall: Amount of Last Rainfall: S#ructural ion#ro1sM Torbay 9 5." �� 3r �-✓x y ��'ii> r ;,�,�'c'-�r"..��ya ��ys7 � 5�„y`'r'�" r'`,% ' �-�� ,,,' a¢"-y} y Co d�t�o fi �Ho�n► Vluh Sdirnen �y �5tructure y ,� � � � �� Y■y n�� -�yy f�I/y�,�{' �k�� i � � How Much Ry��Img or iwi (°la Yg+etaed) (°IoACcumulat�on M r 2p � minor/ moderate / major N minor/ moderate / major imy ' minor/ moderate / major minor/ moderate / major Maintenance Required: To Be Performed By: On or Before: CONSTRUCTION PERIOD POLLUTION PREVENTION PLAN & EROSION AND SEDIMENTATION CONTROL Construction Period Pollution Prevention Plan and Erosion and Sedimention Control SITE DESCRIPTION Proje- ckName and' #2302 Turnpike Street Applicant Name Earth Works, Inc Location: (latitude, (Route 114) and Address 23 Ash Street Lon tude,or Address North Andover, MA 01845 North Andover, MA 01845 Description: (Purpose, This project involves razing a singly family structure and barn, the construction of a multi and`TypeS ofiSoil story building, proposed access driveways, proposed parking, stormwater management bisturbjhd Activities): system. Soil disturbing activities inlcude: clearing and grubbing; installation of erosion and sediment control device, pavement installation, utility installation, building construction, stormwater management system and preparation for final loaming and seeding. Runoff Coefficient: The final composite runoff coefficient for the site is approximately 0.5 Site Area The site is approximately 3.5 acres of which approximately 2.6 acres will be disturbed by construction activities. Se Bence of Ma'or Activities The order of activities shall be as follows: 1. Install construction entrances 9. Finished grading and slope stabilization 2. Install erosion control devices 10. Finished Paving 3. Clearing, cutting and grubbing 11. Loam and seed all disturbed areas. 4. Rough grading 12. Final cleanup including inspection and 5. Utility Installation cleanout of all stormwater structures. 6. Gravel and pavement base course installation 7. Building site preparation 8. Curbing and sidewalk construction Name'of Receiving The site is tributary to Boston Brook Waters. CONTROLS °E`' iori and;Sediment`Coro ls Stablization'Practices Temporary Stabilization -On sediment producing areas, where the period of exposure is more than two months, but less than 12 months, the following procedure should be followed: a. install needed surface water control measures, b. perform all cultural operations at right angles to the slope, c. establish adapted species from Table 1 below, d. apply seed uniformly to the rate indicated by broadcasting or hydraulic application, and e. cover seed with mulch as needed. Permanent Stabilization -To reduce damages from sediment and runoff to downstream areas, and to avoid erosion on the site itself, a permanent type cover shall be established as soon as possible. Seeding herbaceous cover is usually the most economical and practical way to stabilize'any large area. On this site a permanent cover utilizing standard commercial seed mixes containing species similar to Mixtures#3, #4, and#7 is appropriate. Sod or erosion control blanket infused with one of the aforementioned seed mixtures may be installed as permanent cover on the site at the Owner's discretion (See Table 2). CONTROLS,(Continued) Table 2 MIXTURE NO. 1 -Dry to Very Dry Sites Switchgrass -20 lbs. (Blackwell or Nebraska 28) Redtop-3 lbs; or Annual Ryegrass - 15 lbs. Switchgrass seed requires a chilling period of three (3)weeks or longer at common household refrigerator temperatures, except when seeded in late fall or winter. Regular mowing should not be practiced. Very slow growing the first year. MIXTURE NO. 2 - Dry to Very Dry Sites Weeping Lovegrass -5 lbs. Cape and the Islands only. May be killed by severe winters, and should not be seeded where regular mowing will be practiced. Spring seeding only between April 15 and May 15. Should not be used for sand dune stabilization. MIXTURE NO. 3 -Moderately Moist to Dry Sites Red fescue-30 lbs. Redtop-3 lbs.; or Perennial Ryegrass - 15 lbs. Resistant to foot traffic. Tolerant of shade, Good for lawn type cover. MIXTURE NO.4-Moderately Moist to Very Dry Sites Tall fescue-40 lbs. Redtop-3 lbs.; or Perennial Ryegrass - 15 lbs. Resistant to foot traffic when well established. Tolerant of shade. MIXTURE NO. 5-Very Moist to Dry Sites Reed canarygrass -20 lbs. Redtop -3 lbs.; or Perennial Ryegrass - 15 lbs. On moist and very moist sites, reed canarygrass can be established quicker by planting rootstocks. CONTROLS (Continued);. Table 2 cont'd MIXTURE NO. 6-Moderately Moist to Dry Sites Crown vetch - 15 lbs. Redtop -3 lbs.; or Perennial Ryegrass - 15 lbs. Crown vetch should not be seeded as the basic species where regular mowing will be practiced. Spring seeding is preferred. MIXTURE NO. 7 - Moderately Moist to Dry Sites Standard commercial grass or grass-legume mixtures used for lawns or long-term forage crop production. Mixtures should contain at least 75% perennial grasses or legumes. Annual fertilization should be planned. MIXTURE NO. 8 - Moderately Moist Sites Kentucky Bluegrass -20 lbs. Redtop -2 lbs.; or Perennial Ryegrass - 15 lbs. Only for high-fertility sites, usually four(4") inches or more topsoil. Good for lawn-type cover. MIXTURE NO. 9- Moderately Moist to Very Dry Sites Sericea Lespedeza -20 lbs. Redtop -2 lbs.; or Perennial Ryegrass - 15 lbs. Cape and the Islands only, and seeded only in the spring. Should not be seeded where regular mowing will be practiced. REFERENCE United States Department of Agriculture, Soil Conservation Service, 1977. Guidelines for Soil and Water Conservation in Urbanizing Areas of Massachusetts. U.S.D.A. Soil Conservation Service, Amherst, Massachusetts, 88 pages. CONTROLS (Continued)' Structural Practices VSiI'tencing - shall be installed as shown on the approved NOI Plan to help prevent erosion and entation of the downstream wetland resources identified on the project. he accumulaion of sediments in Catch Basins -shall be fitted with filter fa ericleaned o as specified in the prevent t e Long Term Te Pollut otn Prevention Plan. the catch basin sump. Catch Basin is to b Storriiwater,Mana oment The stormwater runoff shall be managed through the use of several best management practices: 1. Deep Sump Catch Basins w/hood 2. Sediment Forebays 3. Infiltration Ponds 4. Level Spreader OTHERyCpNTRQLS Waste:pispcsal; Waste Materials: All waste materials shall be collected and stored in secure metal dumpsters rented from a licensed solid waste management company in Massachusetts. The dumpsters shall meet all local and state solid waste management regulations as outlined in 110 CM he 9.00. 11 trash and shall be emptied construction n deris e often generated on site shall be disposed of in the dumpsters. necessary during construction and transferred to an approved solid waste facility licensed to accept municipal solid waste and/or construction and demolition debris. No construction waste shall be buried on site. All personnel shall be instructed regarding the correct procedure for waste disposal. Hazardous Waste: All hazardous waste materials shall be disposed of in a manner specified by local or State regulation or by the manufacturecol ect personnel from portable units,as needed, by a liceed in these nsed septage hauler Sanitary Waste: All sanitary shall be in Massachusetts, in accordance with the requirements of the local Board of Health. OTHER CONTROLS (continued) Mite Vehicle Tracking: Construction entrances and exits shall be via Sharpners Pond Road - Tim EW OF CONTROLS/MEASURES As indicated in the Sequence of Major Activities, the installation of erosion and sediment control devices shall be in place prior to earth excavating activities. ::CERT#FICATION OF COMPLIANCE WITH 1=E�ERAI:,STATE,AND LOCAL REGULATIONS The stormwater pollution prevention plan reflects the requirements of the Massachusetts Wetlands Protection Act(MGL c.131, section 40). There is no wetland filling associated with this project. It is strictly a buffer zone project. Note that there are no other applicable State or Federal requirements for sediment and erosion control plans(or permits), or stormwater management plans (or permits)required for this project to the best of our knowledge. VAiNTENANCE/'INSPECTION PROCEDURES Erosion and Sediment Control Inspection and;Maintenance'Ptactices. The following items represent the inspection and maintenance practices that will be used to maintain sediment and erosion control for#2302 Turnpike Street. 1. All control measures shall be inspected at least once every fourteen (14)days and following any storm event of 0.5 inches or greater. 2. All measures shall be maintained in good working order; if a repair is necessary, it shall be initiated within 24 hours of the report. 3. Built up sediment shall be removed from silt fencing when it has reached one-third the height of the fence. 4. Silt fence shall be inspected for depth of sediment, tears, to see if the fabric is securely attached to the fence posts, and to see that the fence posts are firmly set in the ground. 6. The catch basin grates shall.be inspected for grate elevation relative to current surface condition; condition of filter fabric, and degree to which sediment has accumulated on the grate and in the sump of the catch basin. ;MAINTENANCEhINSPECTION PROCEDURES (Con lnu4W)' ,_ Erosion.and Sediment Control Inspection and Maintenance Practices Continued 7. Temporary and permanent seeding and any plantings shall be inspected for bare spots, washouts, and healthy growth. 8. A maintenance inspection report shall be prepared following each inspection. A copy of the report form to be completed by the inspector is attached to the CPPP. 9. Earth Works, Inc. shall select three individuals who will be responsible for inspections, maintenance and repair activities as well as who shall be responsible for filling out the inspection and maintenance report. 10. Personnel selected for inspection and maintenance responsibilities shall receive training from Earth Works, Inc. or their designated representative. They will be trained in all the inspection and maintenance practices necessary for keeping the erosion and sediment control devices used on site in good working order. Non-StormwaterDischar es It is expected that the following non-stormwater discharges will occur from the site during the construction period: 1. Water from water line flushing. 2. Pavement wash waters. All non-stormwater discharges shall be directed to the proposed site BMPs prior to discharge. INVENTORY FOR POLLUTION PREVENTION PLAN The materials or substances listed below are expected to be present on site during construction: x Concrete x Fertilizers x Wood x Petroleum Based Products x Structural Steel x Cleaning Solvents x Masonry Block x Paints (enamel and latex) x Othe Building Materials x Tar x Fiber Glass Insulation x Waterproofing Materials SPILL, PRiEVENT.ION 7777 Material Mana ement Practices ' The following are the material management practices that shall be used to reduce the risk of spills or other accidental exposure of materials and substances to stormwater runoff. Good Hauseiceepin `: The following good housekeeping practices will be followed on site during the construction project. 1. A concerted effort shall be made to store only enough product required to complete a particular task. 2. All materials stored on site shall be stored in a neat and orderly fashion in their appropriate containers and, if possible, under a roof or other secure enclosure. 3. Products shall be kept in their original containers with the original manufacturer's label. 4. Substances shall not be mixed with one another unless recommended by the manufacturer. 5. Whenever possible, all of a product shall be used up before disposing of the container. 6. Manufacturer's recommendations for proper use and disposal shall be followed. 7. The site superintendent shall inspect daily to ensure proper use and disposal of materials on site. Hazardous Praducts: The following practices are intended to reduce the risks associated with hazardous materials. 1. Products shall be kept in original containers unless they are not resealable. 2. Where feasible, the original labels and material safety data shall be retained, whereas they contain important product information. 3. If surplus product must be disposed, follow manufacturer's or local and State recommended methods for proper disposal. SPILL.PREVENTION(Continued) Product Specific.Practices' The following product specific practices shall be followed on site: Petroleum'Products: All on site vehicles shall be monitored for leaks and receive regular preventative maintenance t reduce the risk of leakage. Petroleum products shall be stored in tightly sealed containers which are clearly labeled. Any bituminous concrete or asphalt substances used on site shall be applied according to the manufacturer's recommendations. Fertilizers Fertilizers shall be applied in the minimum amounts recommended by the manufacturer. Once applied, fertilizers shall be worked into the soil to� it bags of fertlizers to tshal1l beer.transfea transferred to age l be in a sealable plastic bag o shed r trailer. The contents of any partially use g to avoid spills. Paints, All containers shall be tightly sealed and stored when not required for use. gEexcess paint shall not be discharged be any properly rroperl catch disposed of iaccordingl to or any recommendations or State and local regulations.,paint shall p P Y P Concrete.TrucKs: Concrete trucks shall not be allowed to wash out or discharge surplus concrete or drum wash water on site. S ill Control Practices In addition to the good housekeeping and material management practices discussed in the previous sections of this plan, the following practices shall be followed for spill prevention and cleanup: 1. Manufacturer's recommended methods for or cleanupand the location iif the inform tt the on site trailer and site personnel shall be made aware of the procedures n. 2. Materials and equipment necessary for spill cleanup shall be kept in the material storage area on site.Equipment and materials shall include, but not be limited to brooms,dust pans, mops, rags, gloves, goggles, kitty litter, sand, sawdust, and plastic and metal trash containers specifically for this purpose. 3. All spills shall be cleaned up immediately after discovery. 4. The spill area shall be kept well ventilated and personnel shall wear appropriate protective clothing to prevent injury from contact with a hazardous substance. 5. Spills of toxic or hazardous material shall be reported to the appropriate State and/or local authority.in accordance with local and/or State regulations. 6. The spill prevention plan shall be adjusted to include measures to prevent a particular type of spill from reoccurring and how to clean up the spill if there is another occurrence. A description of the spill,what caused it, and the clean up measures shall also be included. on and 7. Earth Works, Inc.their assas three others to personne designee shall be the iliwho will be cleanup ro be trained n the spill cont . Earth at least practices Works, Inc. shall designate at l identified above. POLLUTION PREVENTION PLAN CERTIFICATION certify under penalty of law that this document and all its attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. Signed: Danny Gill, Manager Earth Works, Inc. Date: #2302 TURNPIKE STREET CONSTRUCTION PERIOD POLLUTION PREVENTION PLAN INSPECTION AND MAINTENANCE REPORT FORM TO BE COMPLETED EVERY 14 DAYS AND WITHIN 24 HOURS OF A RAINFALL EVENT OF 0.5 INCHES OR GREATER Inspector:, Date: Inspector's Title: Days Since Last Rainfall: Amount of Last Rainfall: Structural Controls: Silt Fencing Average Are Fence Depth of Tears Posts Secure? Overall From To Sediment (yes/no) (yes/no) Condition poor yes - no yes - no fair good poor yes - no yes - no fair good poor yes - no yes - no fair good poor yes - no yes - no fair good poor yes - no yes - no fair good Maintenance Required: To Be Performed By: On or Before: #2302 TURNPIKE STREET CONSTRUCTION PERIOD POLLUTION PREVENTION PLAN INSPECTION AND MAINTENANCE REPORT FORM TO BE COMPLETED EVERY 14 DAYS AND WITHIN 24 HOURS OF A RAINFALL EVENT OF 0.5 INCHES OR GREATER Inspector: Date: Inspector's Title: Days Since Last Rainfall: Amount of Last Rainfall: Structural Controls: Existing Catch Basins and Grates Is Catch Basin Is Filter Fabric Sediment Buildup Sediment Buildup Grate to Grade in Place on Grate and Fabric in CB Sump Location es or no es or no (minor/moderate/major) 0 - 100% es -- no yes -- no (minor/moderate/major) es -- no ves -- no (minor/moderate/major) es -- no ves -- no (minor/moderate/major) es -- no yes --__no (minor/moderate/major) es -- no ves -- no (minor/moderate/major) es -- no yes -- no (minor/moderate/major) es -- no yes -- no (minor/moderate/major) yes -- no I yes -- no (minor/moderate/major) Maintenance Required: To Be Performed By: On or Before: #2302 TURNPIKE STREET CONSTRUCTION PERIOD POLLUTION PREVENTION PLAN INSPECTION AND MAINTENANCE REPORT FORM TO BE COMPLETED EVERY 14 DAYS AND WITHIN 24 HOURS OF A RAINFALL EVENT OF 0.5 INCHES OR GREATER Inspector: Date: Inspector's Title: Days Since Last Rainfall: Amount of Last Rainfall Sediment Forebay Condition of Condition of How Much Forebay Forebay Sediment Buildup Description Side Slopes Spillway Circle one minor/ moderate / major minor/ moderate / major minor/ moderate / major minor/ moderate/ major minor/ moderate / major Maintenance Required: To Be Performed By: On or Before: #2302 TURNPIKE STREET CONSTRUCTION PERIOD POLLUTION PREVENTION PLAN (CPPPP) INSPECTION AND MAINTENANCE REPORT FORM CHANGES REQUIRED TO THE POLLUTION PREVENTION PLAN: REASONS FOR CHANGES: certify under penalty of law that the above changes to the document and all its attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. SIGNATURE DATE MITIGATIVE DRAINAGE ANALYSIS A1,H OF Al p� MATTHEW E. yG Mitigative Drainage Analysis X MOORE m Proposed Commercial Development No..45` 5 #2302 Turnpike Street /sT North Andover, Massachusetts BONA U 1 , November 4,2015 Purpose: The purpose of this analysis is to compare the existing watershed condition to the proposed watershed condition or the post-development condition for the project located at#2302 Turnpike Street,North Andover,MA by analyzing the surface runoff rates to the limit of the watershed analysis shown on the accompanying watershed maps. The results of this analysis are presented in the summary table that follows. Introduction: The project is bounded to the east by Sharpners Pond Road,to the south by Turnpike Street(Route 114),to the west by residential properties located off Turnpike Street and to the north by property owned by the town of North Andover (CYR Yard Waste Facility) located off of Sharpners Pond Road. The property is currently occupied by a one story residential structure and barn. Access to the property is from a gravel drive off of Sharpners Pond Road. The property is mostly wooded with areas of grass and a mixture of brush and weeds. The site varies in elevation from approximately 160 feet at the high point in the roadway of Turnpike Street to an elevation of 119 feet at the existing bordering vegetated wetlands located at the northerly portion of the site. The proposal is to redevelop the site by razing the existing structure and construct a new two story (in the front),building,paved driveways,paved parking,landscaping,walkways,and a new drainage system for treatment of stormwater runoff. It should be noted that this is strictly a buffer zone project and there are no proposed disturbances to any wetlands. However,since the Applicant is proposing work within the 100'buffer zone from the edge of bordering vegetated wetlands a Notice of Intent(NOI) filing will be required with the North Andover Conservation Commission. Existing Condition Soils Analysis: In order to model the excess runoff for both the existing and proposed watershed condition,the parent soils on site were mapped using the Web Soil Survey (WSS) made available on the United States Department of Agriculture (USDA)National Resources Conservation Service (NRCS)website. The WSS provides vital soil data and information such as Hydrologic Soil Group (HSG) which is then input into a mathematical model to generate runoff curve numbers. Mitigative Drainage Analysis #2302 Turnpike Street, North Andover, MA November 4, 2015 The user inputs the soil cover type as well as the hydrologic soil group to generate a weighted curve number (CN) and also uses the topography of the land to generate a time of concentration (Tc) from which the stormwater runoff rate as well as volume may be calculated for a certain watershed for comparison. The soils present on site are comprised of Paxton,Freetown Muck,Charlton-Rock Outcrop-Hollis Complex and Urban Land. Paxton soils have a HSG rating of C and Urban Land which does not have a rating with the NRCS is assumed to have a HSG rating of C for the purposes of analysis. The Charlton-Rock Outcrop-Hollis Complex has a HSG rating of A and Freetown Much has a HSG rating of D.The soil boundary of the Freetown Muck is adjusted to coincide with the edge of the flagged bordering vegetated wetlands. Stormwater Modeling Methodology: The mathematical model used in this analysis was provided using the HydroCAD 10.00 Version developed by HydroCAD Software Solutions LLC. HydroCAD is a program used to model the hydrology and hydraulics of stormwater runoff and is based largely on programs and techniques developed by the NRCS,specifically TR-20 and TR-55 as well as other hydraulic calculation methods. HydroCAD allows the user,for a given rainfall event,to generate runoff hydrographs for single or multiple watersheds and is used to determine if a given drainage system is adequate under the desired conditions as well as to predict flooding or other impacts at specified locations such as erosion. Five design storm events were analyzed and the results presented in the Total Peak Rate of Runoff Comparison Table table that follows for the one (1),two (2),ten(10),twenty five (25) and the one- hundred (100) year storm events for comparison. Existing Condition Watershed: The selected edge of comparison is the edge of the flagged bordering vegetated wetlands for comparison with the proposed condition.The area tributary to this selected edge of comparison is 185,489 ft2. All the stormwater runoff from within the limit of watershed analysis flows to this selected edge of comparison. Using the methods described in the stormwater modeling methodology above,runoff curve numbers and times of concentration were generated for each watershed for the existing condition to be used for comparison with the proposed condition described below. A schematic of the mathematical model as well as the results of the calculations for the 1 year,2 year,10 year,25 year and 100 year,Type III,24-hour storm events are included in this report. Proposed Condition Watershed: Similar to the existing condition watershed,the selected edge of comparison is the edge of the flagged bordering vegetated wetlands for comparison with the existing condition.The area tributary 2 Mitigative Drainage Analysis #2302 Turnpike Street, North Andover, MA November 4, 2015 to this selected edge of comparison is 185,489 ft2. All the stormwater runoff from within the limit of watershed analysis flows to this selected edge of comparison. The proposed development requires the construction of a surface infiltration pond which will provide peak rate of runoff mitigation,water quality as well as groundwater recharge opportunity in the volume provided below the pond outlets. Runoff will be collected using deep-sump catch basins with hoods from the paved surfaces or collected through downspouts from roof areas and piped directly into the proposed infiltration basin, see plan for locations. Using the methods described in the stormwater modeling methodology above,runoff curve numbers and times of concentration were generated for each watershed for the proposed condition to be used for comparison with the existing condition. A schematic of the mathematical model as well as the results of the calculations for the 1 year,2 year,10 year,25 year and 100 year,Type III,24- hour storm events are included in this report. Compliance with DEP Stormwater Management Standards: Standard 1• No new stormwater conveyances (e.g. outfalls)may discharge untreated stormzoater directly to or cause erosion in wetlands or waters of the Commonwealth. All new stormwater runoff requiring treatment will be treated prior to being discharged towards the edge of the flagged bordering vegetated wetlands. Standard 2: Stormwater management systems shall be designed so that post-development peak discharge rates do not exceed pre-development peak discharge rates. This Standard may be waived for discharges to land subject to coastal storm flowage as defined in 310 CMR 10.04. See the summary table that follows which demonstrates that the post-development peak discharge rates are less than the existing peak discharge rates. Standard 3: Loss of annual recharge to groundwater shall be eliminated or minimized through the use of infiltration measures including environmentally sensitive site design, low impact development techniques, stormwater best management practices,and good operation and maintenance. At a minimum, the annual recharge from the post-development site shall approximate the annual recharge from the pre-development conditions based on soil type. This Standard is met when the stormwater management system is designed to infiltrate the required recharge volume as determined in accordance with the Massachusetts Stormwater Handbook. The project site has a Hydrologic Soil Group rating primarily of C and a small portion with a rating of A. Groundwater recharge is provided through the use of an infiltration basin which does not he 3 Mitigative Drainage Analysis #2302 Turnpike Street, North Andover, MA November 4, 2015 within an area of rapid infiltration as determined from a soil textural analaysis performed by Williams&Sparages,LLC.See attached calculations which demonstrate the project meets this standard. Standard 4: Stormwater management systems shall be designed to remove 80% of the average annual post-construction load of Total Suspended Solids (TSS). This Standard is met when; a. Suitable practices for source control and pollution prevention are identified in a long-term pollution prevention plan,and thereafter are implemented and maintained; b. Structural stormwater best management practices are sized to capture the required water quality volume determined in accordance with the Massachusetts Stormwater Handbook;and c. Pretreatment is provided in accordance with the Massachusetts Stormwater Handbook The proposed project will utilize deep-sump hooded catch basins and a sediment forebay to collect and pre-treat the stormwater runoff before discharging to an infiltration pond. It should be noted that runoff from certain types of roof areas are considered"clean' by DEP and therefore,do not require treatment. We have assumed that the roof types that are to be installed for this project will satisfy DEP's criteria. Portions of the project site are within an area of rapid infiltration rate as determined from a soil textural analaysis performed by Williams &Sparages,LLC,therefore the water quality volume is based on a runoff of one inch. Standard 5: For land uses with higher potential pollutant loads, source control and pollution prevention shall be implemented in accordance with the Massachusetts Stormwater Handbook to eliminate or reduce the discharge Of Stormwater runoff from such land uses to the maximum extent practicable. If through source control and/or pollution prevention all land uses with higher potential pollutant loads cannot be completely protected from exposure to rain, snow melt,and stormwater runoff, the proponent shall use specific structural stormwater BMPs determined by the Department to be suitable for such uses as provided in the Massachusetts Stormwater Handbook. Stormwater discharges from land uses with higher potential pollutant loads shall also comply with the requirements of the Massachusetts Clean Waters Act,M.G.L. c. 21, §§26-53 and the regulations promulgated there under at 314 CMR 3.00,314 CMR 4.00 and 314 CMR 5.00. This project is not being considered as a LUHPPL. Standard 6• Stormwater discharges within the Zone II or Interim Wellhead Protection Area of a public water supply,and stormwater discharges near or to any other critical area, require the use of the specific source control and pollution prevention measures and the specific structural Stormwater best management practices determined by the Department to be suitable for managing discharges to such areas,as provided in the Massachusetts Stormwater Handbook. A discharge is near a critical area if there is a strong likelihood of a significant impact occurring to said area, taking into account site-specific factors. Stormwater discharges to Outstanding 4 Mitigative Drainage Analysis #2302 Turnpike Street, North Andover, MA November 4, 2015 Resource Waters and Special Resource Waters shall be removed and set back from the receiving water or wetland and receive the highest and best practical method of treatment. A "storm water discharge"as defined in 314 CMR 3.04(2) (a) (1 or(b) to an Outstanding Resource Water or Special Resource Water shall comply with 314 CMR 3.00 and 314 CMR 4.00. Stormwater discharges to a Zone I or Zone A are prohibited unless essential to the operation of public water supply. The stormwater discharge from this property is not within an Interim Wellhead Protection Area of a public water supply nor within a Zone II. Standard 7: A redevelopment project is required to meet the follozving Stormwater Management Standards only to the maximum extent practicable: Standard 2, Standard 3,and the pretreatment and structural best management practice requirements of Standards 4,5,and 6. Existing stormwater discharges shall comply with Standard 1 only to the maximum extent practicable. A redevelopment project shall also comply with all other requirements of the Stormwater Management Standards and improve existing conditions. This project is not being considered as a redevelopment. Standard 8: A plan to control construction-related impacts including erosion, sedimentation and other pollutant sources during construction and land disturbance activities (construction period erosion,sedimentation,and pollution prevention plan)shall be developed and implemented. A Stormwater Pollution Prevention Plan(SWPPP) will be provided. Standard 9• A long-term operation and maintenance plan shall be developed and implemented to ensure that stormwater management systems function as designed. A Long Term Operation and Maintenance Plan(O&M)will be provided. Standard 10: All illicit discharges to the stormwater management system are prohibited. There are no proposed illicit discharges into the Stormwater Management Systems to be constructed as shown on the site plan. Conclusion: As can be seen by examining the following summary&performance tables,the proposed stormwater management system is effective for mitigating the peak flow rates of runoff from the limit of the watershed analysis for the 1,2,10,25&100 year storm events. 5 Mitigative Drainage Analysis #2302 Turnpike Street, North Andover, MA November 4, 2015 Total Peak Rate of Runoff Comparison Table Existing Condition Proposed Condition 24 hour Type III Description Storm Event Peak Rate of Volume of Peak Rate of Volume of (year) Runoff Runoff Runoff Runoff Q (cfs) (ac-ft) Q (cfs) Q (cfs) 1 (2.5 inch) 1.5 0.15 1.3 0.21 e 2(3.2 inch) 3.4 0,28 3.1 0.38 Flow to edge 10 (4.8 inch) 8.7 0.64 8.4 0.83 of BVW 25 (6.0 inch) 13.2, 0.96 12.2 1.19 100 (8.6 inch) 23.8 1.73 19.8 2.02 Proposed Stormwater Management Area #1 HydroCAD Pond 1P Top of Berm=132.3 Bottom of basin=128.0 6'L Stone Spillway=131.8 (Discharges into level spreader) 18" HDPE Culvert out=128.07 (Discharges into level spreader) Peak Rate of Runoff Out 24 hour Type III Peak Rate of (Q) cfs Peak Water Storm Event Runoff In Level (ft) (year) Q(cfs) *Exfiltration 6'L 18" Total Stone (Discarded) Spillway Culvert Outflow 1 4.1 0.1 0.0 0.8 0.9 129.92 2 5.6 0.1 0.0 1.9 2.0 130.21 10 9.0 0.1 0.0 4.5 4.6 130.77 25 11.6 0.1 0.0 6.2 6.3 131.08 100 17.2 0.2 0.0 1 8.5 8.7 j 131.65 *Calculated infiltration rate and peak water levels are based upon a rate of 1.02 inches per hour for Sandy Loams as found on Table 2-1 of the Hydrology Handbook of Conservation Commissioners, March 2002 using Rawls,Brakensiek and Saxton,1982. 6 MAWk Trib , Routing Diagram for Existing Subcat Reach on, Link Prepared by{enter your company name here}, Printed 11/12/2015 \LLJHydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Existing Prepared by (enter your company name here) Printed 11/12/2015 HydroCAD®10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 1 Area Listing (all nodes) Area CN Description (sq-ft) (subcatchment-numbers) 25,048 65 Brush, Good, HSG C (1S) 2,807 96 Gravel surface, HSG C (1S) 17,686 98 Paved roads w/curbs &sewers, HSG C (1S) 2,072 98 Roofs, HSG C (1S) 17,751 30 Woods, Good, HSG A (1S) 120,125 70 Woods, Good, HSG C (1S) 185,489 69 TOTAL AREA Existing Prepared by (enter your company name here} Printed 11/12/2015 HydroCADO 10 00-15 s/n 06611 22015 HydroCAD Software Solutions LLC Pane 2 Soil Listing (all nodes) Area Soil Subcatchment (sq-ft) Group Numbers 17,751 HSG A 1S 0 HSG B 167,738 HSG C 1S 0 HSG D 0 Other 185,489 TOTAL AREA Existing Printed 11/12/2015 Prepared by {enter your company name here} Pa e 3 HydroCAD® 10 00 15 s/n 06611 ©2015 HydroCAD Software Solutions LLC a Ground Covers (all nodes) HSG-A HSG-B HSG-C HSG-D Other Total Ground (sq-ft) (sq-ft) (sq-ft) (sq-ft) (sq-ft) (sq-ft) Cover 0 0 25,048 0 0 25,048 Brush, Good 0 0 2,807 0 0 2,807 Gravel surface 0 0 17,686 0 0 17,686 Paved roads w/curbs & sewers 0 0 2,072 0 0 2,072 Roofs 17,751 0 120,125 0 0 137,876 Woods, Good 17,751 0 167,738 0 0 185,489 TOTAL AREA Existing Type 1/124-hr 2 yr Rainfall=3.20" Printed 11/12/2015 Prepared by{enter your company name here} Page 4 H droCAD®10.00-15 s/n 06611 ©2015 H droCAD Software Solutions LLC Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Subcatchment 1S: Trib. to Wetlands Runoff Area=185,489 sf 10.65% Impervious Runoff Depth=0.78" Flow Length=496' Tc=6.0 min CN=69 Runoff=3.37 cfs 12,050 cf Total Runoff Area= 185,489 sf Runoff Volume = 12,050 cf Average Runoff Depth = 0.78" 89.35% Pervious= 165,731 sf 10.65%Impervious = 19,758 sf Existing Type 111 24-hr 2 yr Rainfall=3.20" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD® 10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 5 Summary for Subcatchment IS: Trib. to Wetlands Runoff = 3.37 cfs @ 12.11 hrs, Volume= 12,050 cf, Depth= 0.78" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.20" Area sf CN Description 2,807 96 Gravel surface, HSG C 2,072 98 Roofs, HSG C 17,686 98 Paved roads w/curbs & sewers, HSG C 25,048 65 Brush, Good, HSG C 120,125 70 Woods, Good, HSG C 17,751 30 Woods, Good, HSG A 185,489 69 Weighted Average 165,731 89.35% Pervious Area 19,758 10.65% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 0.6 50 0.0280 1.37 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.20" 1.6 446 0.0800 4.55 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.2 496 Total, Increased to minimum Tc = 6.0 min Type /I/ 24-hr 1 yr Rainfall=2.50" Existing Printed 11/12/2015 Prepared by {enter your company name here} Pa a e 1 H droCAD®10.00-15 s/n 06611 ©2015 H droCAD Software Solutions LLC Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS-nd method-20 method, routing by Stord-Ind Reach routing by Stor t Subcatchment 1 S: Trib. to Wetlands Runoff Area=185,489 sf 10.65% i e io unous fRf=1 52 noff cfsDepth 6,05 cf Flow Length 496' Tc 6 0 min Total Runoff Area= 185,489 sf Runoff Volume= 6,505 cf 10 Average Renopery off uDs pt19,758 sf 89.35% Pervious 165,731 sf Existing Type Ill 24-hr 10 yr Rainfall=4.80" Prepared by {enter your company name here} Printed 11/12/2015 HydroCADO 10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 2 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Subcatchment 1S: Trib.to Wetlands Runoff Area=185,489 sf 10.65% Impervious Runoff Depth=1.81" Flow Length=496' Tc=6.0 min CN=69 Runoff=8.66 cfs 28,029 cf Total Runoff Area= 185,489 sf Runoff Volume=28,029 cf Average Runoff Depth = 1.81" 89.35% Pervious = 165,731 sf 10.65% Impervious = 19,758 sf Existing Type /// 24-hr 25 yr Rainfall=6.00" Printed 11/12/2015 Prepared by {enter your company name here} Paq e 3 �droCAD® 10 00 15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Subcatchment 1S: Trib.to Wetlands Runoff Area=185,489 sf 10.65% Impervious Runoff Depth=2.71" Flow Length=496, Tc=6.0 min CN=69 Runoff=13.19 cfs 41,929 cf Total Runoff Area = 185,489 sf Runoff Volume =41,929 cf Average Runoff Depth =2.71" 89.35% Pervious = 165,731 sf 10.65% Impervious= 19,758 sf Existing Type 111 24-hr 100 yr Rainfall=8.60" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD®10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Pane 5 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Stor-Ind method - Pond routing by Stor-Ind method Subcatchment 1S: Trib.to Wetlands Runoff Area=185,489 sf 10.65% Impervious Runoff Depth=4.86" Flow Length=496' Tc=6.0 min CN=69 Runoff=23.80 cfs 75,185 cf Total Runoff Area= 185,489 sf Runoff Volume=75,185 cf Average Runoff Depth =4.86" 89.35% Pervious = 165,731 sf 10.65% Impervious = 19,758 sf CB- �; ca Trib to CB2 DGCB1 5 DMH1 D H2 Bldg Roof Trib. 0 1P Trib to ttlands 65 — 8P 7� ce ca 3S Trib.to CB3 C132 7P;..,. -� DMH4 DMH3 Forebay Infiltration Basin Storage Roof Trib.to 2P DGCB3 Culvert Trib.to Wetlands Routing Diagram for Proposed Subcat Reach on Link Prepared by{enter your company name here), Printed 11/12/2015 HydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Proposed Printed 11/12/2015 Prepared by {enter your company name here} Page 2 H dro3ADO 10.00-15 s/n 06611 ©2015 H droCAD Software Solutions LLC Area Listing (all nodes) Area CN Description (sq-ft) (subcatchment-numbers) 4,240 39 >75% Grass cover, Good, HSG A (2S, 7S, 8S) 36,660 74 >75% Grass cover, Good, HSG C (1S, 2S, 4S, 6S, 7S, 8S) 1,815 98 Paved parking, HSG A (4S, 6S) 42,993 98 Paved parking, HSG C (1S, 4S, 6S) 17,683 98 Paved roads w/curbs &sewers, HSG C (1 S, 2S, 6S, 7S) 20,326 98 Roofs, HSG C (3S, 5S) 4,036 98 Water Surface, HSG A (8S) 3,301 98 Water Surface, HSG C (8S) 7,796 30 Woods, Good, HSG A (2S) 46,639 70 Woods, Good, HSG C (2S, 7S) 185,489 82 TOTAL AREA Proposed Printed 11/12/2015 Prepared by{enter your company name here} Page 3 HydroCAD®10 00 15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Soil Listing (all nodes) Area Soil Subcatchment (sq-ft) Group Numbers 17,887 HSG A 2S, 4S, 6S, 7S, 8S 0 HSG B 167,602 HSG C 1 S, 2S, 3S, 4S, 5S, 6S, 7S, 8S 0 HSG D 0 Other 185,489 TOTAL AREA Proposed Prepared by {enter your-company name here} Printed 11/12/2015 HydroCAD®10 00 15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 4 .Ground Covers (all nodes) HSG-A HSG-B HSG-C HSG-D Other Total Ground (sq-ft) (sq-ft) (sq-ft) (sq-ft) (sq-ft) (sq-ft) Cover 4,240 0 36,660 0 0 40,900 >75% Grass cover, Good 1,815 0 42,993 0 0 44,808 Paved parking 0 0 17,683 0 0 17,683 Paved roads w/curbs & sewers 0 0 20,326 0 0 20,326 Roofs 4,036 0 3,301 0 0 7,337 Water Surface 7,796 0 46,639 0 0 54,435 Woods, Good 17,887 0 167,602 0 0 185,489 TOTAL AREA Proposed Prepared by {enter your company name here} Printed 11/12/2015 HydroCAD® 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 5 Pipe Listing (all nodes) Line# Node In-Invert Out-Invert Length Slope n Diam/Width Height Inside-Fill Number (feet) (feet) (feet) (ft/ft) (inches) (inches) (inches) 1 1 P 128.07 128.00 7.0 0.0100 0.013 18.0 0.0 0.0 2 3P 143.52 142.24 64.0 0.0200 0.013 12.0 0.0 0.0 3 4P 142.24 140.00 164.0 0.0137 0.013 12.0 0.0 0.0 4 5P 138.71 134.03 67.0 0.0699 0.013 12.0 0.0 0.0 5 6P 130.36 130.00 36.0 0.0100 0.013 24.0 0.0 0.0 6 7P 131.29 130.61 29.0 0.0234 0.013 18.0 0.0 0.0 7 8P 134.33 134.27 6.0 0.0100 0.013 12.0 0.0 0.0 8 9P 132.59 131.54 105.0 0.0100 0.013 15.0 0.0 0.0 9 10P 137.00 133.00 56.0 0.0714 0.013 12.0 0.0 0.0 Proposed Type/1/24-hr 2 yr Rainfall=3.20" Prepared by {enter your company name here} Printed 11/12/2015 HydroCAD010 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 6 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points x 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 1S: Trib to CB2 Runoff Area=19,291 sf 59.99% Impervious Runoff Depth=2.00" Flow Length=496' Tc=6.0 min CN=88 Runoff=1.01 cfs 3,210 cf Subcatchment 2S: Trib to Wetlands Runoff Area=68,288 sf 15.45% Impervious Runoff Depth=0.83" Tc=6.0 min CN=70 Runoff=1.34 cfs 4,712 cf Subcatchment 3S: Storage Roof Runoff Area=4,410 sf 100.00% Impervious Runoff Depth=2.97" Tc=6.0 min CN=98 Runoff=0.31 cfs 1,091 cf Subcatchment 4S: Trib.to 2P Runoff Area=31,626 sf 79.57% Impervious Runoff Depth=2.45" Tc=6.0 min CN=93 Runoff=1.97 cfs 6,446 cf Subcatchment 5S: Bldg Roof Runoff Area=15,916 sf 100.00% Impervious Runoff Depth=2.97" Tc=6.0 min CN=98 Runoff=1.11 cfs 3,936 cf Subcatchment 6S: Trib. to CB3 Runoff Area=16,132 sf 83.46% Impervious Runoff Depth=2.54" Tc=6.0 min CN=94 Runoff=1.03 cfs 3,420 cf Subcatchment 7S: Trib.to Wetlands Runoff Area=18,357 sf 9.48% Impervious Runoff Depth=0.98" Tc=6.0 min CN=73 Runoff=0.45 cfs 1,503 cf Subcatchment 8S: Trib. to 1P Runoff Area=11,469 sf 63.97% Impervious Runoff Depth=1.61" Tc=6.0 min CN=83 Runoff=0.49 cfs 1,538 cf Pond 1P: Infiltration Basin Peak EIev=130.19' Storage=7,124 cf Inflow=5.59 cfs 18,111 cf Discarded=0.12 cfs 6,575 cf Primary=2.00 cfs 9,447 cf Outflow=2.11 cfs 16,021 cf Pond 213: Forebay Peak EIev=130.19' Storage=440 cf Inflow=4.02 cfs 13,076 cf Outflow=4.00 cfs 12,637 cf Pond 3P: DGCB1 Peak EIev=144.04' Inflow=1.01 cfs 3,210 cf 12.0" Round Culvert n=0.013 L=64.0' S=0.0200'/' Outflow=1.01 cfs 3,210 cf Pond 4P: DMH1 Peak EIev=142.76' Inflow=1.01 cfs 3,210 cf 12.0" Round Culvert n=0.013 L=164.0' S=0.0137'/' Outflow=1.01 cfs 3,210 cf Pond 5P: DMH2 Peak EIev=139.23' Inflow=1.01 cfs 3,210 cf 12.0" Round Culvert n=0.013 L=67.0' S=0.0699'/' Outflow=1.01 cfs 3,210 cf Pond 613: DMFI3 Peak EIev=131.28' Inflow=4.02 cfs 13,076 cf 24.0" Round Culvert n=0.013 L=36.0' S=0.0100'/' Outflow=4.02 cfs 13,076 cf Pond 7P: DMH4 Peak EIev=132.10' Inflow=3.00 cfs 9,866 cf 18.0" Round Culvert n=0.013 L=29.0' S=0.0234'/' Outflow=3.00 cfs 9,866 cf Pond 8P: CB2 Peak EIev=134.95' Inflow=1.03 cfs 3,420.cf 12.0" Round Culvert n=0.013 L=6.0' S=0.0100'/' Outflow=1.03 cfs 3,420 cf Proposed Type 111 24-hr 2 yr Rainfall=3.20" Prepared by {enter your company name here} Printed 11/12/2015 HydroCAD®10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 7 Pond 9P: DGCB3 Peak Elev=133.28' Inflow=1.97 cfs 6,446 cf 15.0" Round Culvert n=0.013 L=105.0' S=0.0100 '/' Outflow=1.97 cfs 6,446 cf Pond 10P: Culvert Peak Elev=137.33' Inflow=0.45 cfs 1,503 cf 12.0" Round Culvert n=0.013 L=56.0' S=0.0714'/' Outflow=0.45 cfs 1,503 cf Link 1L: Inflow=3.25 cfs 16,753 cf Primary=3.25 cfs 16,753 cf Total Runoff Area= 185,489 sf Runoff Volume=25,856 cf Average Runoff Depth = 1.67" 51.40% Pervious =95,335 sf 48.60% Impervious =90,154 sf Proposed Type/1/24-hr 2 yr Rainfall=3.20" Prepared by{enter your company name here} Printed 11/12/2015 HydroCADO 10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 8 Summary for Subcatchment 1S: Trib to CB2 Runoff = 1.01 cfs @ 12.09 hrs, Volume= 3,210 cf, Depth= 2.00" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.20" Area (sf) CN Description 4,562 98 Paved roads w/curbs & sewers, HSG G 7,010 98 Paved parking, HSG C 7,719 74 >75% Grass cover, Good, HSG C 19,291 88 Weighted Average 7,719 40.01% Pervious Area 11,572 59.99% Impervious Area Tc Length Slope Velocity Capacity Description , (min) (feet) (ft/ft) (ft/sec) (cfs) 0.6 50 0.0280 1.37 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.20" 1.6 446 0.0800 4.55 Shallow Concentrated Flow, Unpaved Kv= 16.1 fps 2.2 496 Total, Increased to minimum Tc = 6.0 min Summary for Subcatchment 2S: Trib to Wetlands Runoff = 1.34 cfs @ 12.10 hrs, Volume= 4,712 cf, Depth= 0.83" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.20" Area (sf) CN Description 10,551 98 Paved roads w/curbs & sewers, HSG C 12,924 74 >75% Grass cover, Good, HSG C 2,040 39 >75% Grass cover, Good, HSG A 34,977 70 Woods, Good, HSG C 7,796 30 Woods, Good, HSG A 68,288 70 Weighted Average 57,737 84.55% Pervious Area 10,551 15.45% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec)' (cfs) 6.0 Direct Entry, Proposed Type/1/24-hr 2 yr Rainfall=3.20" Prepared by {enter your company name here) Printed 11/12/2015 HydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 9 Summary for Subcatchment 3S: Storage Roof Runoff = 0.31 cfs @ 12.09 hrs, Volume= 1,091 cf, Depth= 2.97" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.20" Area (sf) CN Description 4,410 98 Roofs, HSG C 4,410 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment 4S: Trib. to 2P Runoff = 1.97 cfs @ 12.09 hrs, Volume= 6,446 cf, Depth= 2.45" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.20" Area (sf) CN Description 6,462 74 >75% Grass cover, Good, HSG C 24,844 98 Paved parking, HSG C 320 98 Paved parking, HSG A 31,626 93 Weighted Average 6,462 20.43% Pervious Area 25,164 79.57% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment 5S: Bldg Roof Runoff = 1.11 cfs @ 12.09 hrs, Volume= 3,936 cf, Depth= 2.97" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.20" Area (sf) CN Description 15,916 98 Roofs, HSG C 15,916 100.00% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Proposed Type/1/24-hr 2 yr Rainfall=3.20" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 10 Summary for Subcatchment 6S: Trib. to C133 Runoff = 1.03 cfs @ 12.09 hrs, Volume= 3,420 cf, Depth= 2.54" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.20" Area (sf) CN Description 1,495 98 Paved parking, HSG A 2,668 74 >75% Grass cover, Good, HSG C 11,139 98 Paved parking, HSG C 830 98 Paved roads w/curbs & sewers, HSG C 16,132 94 Weighted Average 2,668 16.54% Pervious Area 13,464 83.46% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment 7S: Trib. to Wetlands Runoff = 0.45 cfs @ 12.10 hrs, Volume= 1,503 cf, Depth= 0.98" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.20" Area (sf) CN Description 236 39 >75% Grass cover, Good, HSG A 4,719 74 >75% Grass cover, Good, HSG C 1,740 98 Paved roads w/curbs &sewers, HSG C 11,662 70 Woods, Good, HSG C 18,357 73 Weighted Average 16,617 90.52% Pervious Area 1,740 9.48% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Subcatchment 8S: Trib. to 1 P Runoff = 0.49 cfs @ 12.09 hrs, Volume= 1,538 cf, Depth= 1.61" Runoff by SCS TR-20 method, UH=SCS, Weighted-CN, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Type III 24-hr 2 yr Rainfall=3.20" Proposed Type/1/24-hr 2 yr Rainfall=3.20" Prepared by {enter your company name here} Printed 11/12/2015 HydroCAD®10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 11 Area sf CN Description 4,036 98 Water Surface, HSG A 1,964 39 >75% Grass cover, Good, HSG A 3,301 98 Water Surface, HSG C 2,168 74 >75% Grass cover, Good, HSG C 11,469 83 Weighted Average 4,132 36.03% Pervious Area 7,337 63.97% Impervious Area Tc Length Slope Velocity Capacity Description (min) (feet) (ft/ft) (ft/sec) (cfs) 6.0 Direct Entry, Summary for Pond 1 P: Infiltration Basin Inflow Area = 94,434 sf, 77.78% Impervious, Inflow Depth = 2.30" for 2 yr event Inflow = 5.59 cfs @ 12.09 hrs, Volume= 18,111 cf Outflow = 2.11 cfs @ 12.35 hrs, Volume= 16,021 cf, Atten= 62%, Lag= 15.4 min Discarded = 0.12 cfs @ 12.35 hrs, Volume= 6,575 cf Primary = 2.00 cfs @ 12.35 hrs, Volume= 9,447 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/2 Peak Elev= 130.19' @ 12.35 hrs Surf.Area= 4,884 sf Storage= 7,124 cf Flood Elev= 132.30' Surf.Area= 7,805 sf Storage= 20,458 cf Plug-Flow detention time= (not calculated: outflow precedes inflow) Center-of-Mass det. time= 142.5 min ( 941.5 - 799.0 ) Volume Invert Avail Storage Storage Description #1 128.00' 20,458 cf Custom Stage Data(Prismatic) Listed below(Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 128.00 1,957 0 0 129.00 2,943 2,450 2,450 130.00 4,640 3,792 6,242 131.00 5,957 5,299 11,540 132.00 7,337 6,647 18,187 132.30 7,805 2,271 20,458 Device Routing Invert Outlet Devices #1 Device 3 129.40' 12.0"Vert. Orifice/Grate C= 0.600 #2 Device 3 130.25' 12.0"Vert. Orifice/Grate C= 0.600 #3 Primary 128.07' 18.0" Round Culvert L= 7.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 128.07'/ 128.00' S= 0.0100 T Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf #4 Discarded 128.00' 1.020 in/hr Exfiltration over Surface area #5 Primary 131.80' 6.0' long x 7.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 Proposed Type Ill 24-hr 2 yr Rainfall=3.20" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD010.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 12 Coef. (English) 2.40 2.52 2.70 2.68 2.68 2.67 2.66 2.65 2.65 2.65 2.66 2.65 2.66 2.68 2.70 2.73 2.78 Discarded OutFlow Max=0.12 cfs @ 12.35 hrs HW=130.18' (Free Discharge) t-4=ExflItration (Exfiltration Controls 0.12 cfs) Primary OutFlow Max=1.99 cfs @ 12.35 hrs HW=130.18' TW=0.00' (Dynamic Tailwater) 3=Culvert (Passes 1.99 cfs of 9.20 cfs potential flow) LI=Orifice/Grate (Orifice Controls 1.99 cfs @ 3.02 fps) 2=Orifice/Grate ( Controls 0.00 cfs) =B road-C rested Rectangular Weir ( Controls 0.00 cfs) Summary for Pond 2P: Forebay Inflow Area = 67,049 sf, 74.87% Impervious, Inflow Depth = 2.34" for 2 yr event Inflow = 4.02 cfs @ 12.09 hrs, Volume= 13,076 cf Outflow = 4.00 cfs @ 12.09 hrs, Volume= 12,637 cf, Atten= 0%, Lag= 0.0 min Primary = 4.00 cfs @ 12.09 hrs, Volume= 12,637 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs /2 Peak Elev= 130.19' @ 12.34 hrs Surf.Area= 448 sf Storage= 440 cf Plug-Flow detention time= 30.7 min calculated for 12,616 cf(96% of inflow) Center-of-Mass det. time= 11.5 min ( 808.2- 796.7 ) Volume Invert Avail.Storage Storage Description #1 128.00' 440 cf Custom Stage Data(Prismatic) Listed below(Recalc) Elevation Surf.Area Inc.Store Cum.Store (feet) (sq-ft) (cubic-feet) (cubic-feet) 128.00 151 0 0 129.00 336 244 244 129.50 448 196 440 Device Routing Invert Outlet Devices #1 Primary 129.50' 9.0' long x 2.0' breadth Broad-Crested Rectangular Weir Head (feet) 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00 2.50 3.00 3.50 Coef. (English) 2.54 2.61 2.61 2.60 2.66 2.70 2.77 2.89 2.88 2.85 3.07 3.20 3.32 Primary OutFlow Max=4.04 cfs @ 12.09 hrs HW=129.93' TW=129.85' (Dynamic Tailwater) L1=Broad-Crested Rectangular Weir (Weir Controls 4.04 cfs @ 1.04 fps) Summary for Pond 3P: DGCB1 Inflow Area = 19,291 sf, 59.99% Impervious, Inflow Depth = 2.00" for 2 yr event Inflow = 1.01 cfs @ 12.09 hrs, Volume= 3,210 cf Outflow = 1.01 cfs @ 12.09 hrs, Volume= 3,210 cf, Atten= 0%, Lag= 0.0 min Primary = 1.01 cfs @ 12.09 hrs, Volume= 3,210 cf Proposed Type ///24-hr 2 yr Rainfall=3.20" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD® 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 13 Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs /2 Peak Elev= 144.04' @ 12.09 hrs Flood Elev= 147.52' Device Routing Invert Outlet Devices #1 Primary 143.52' 12.0" Round Culvert L= 64.0' CPP, square edge headwall, Ke= 0.500 Inlet/ Outlet Invert= 143.52'/ 142.24' S= 0.0200 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.79 sf Primary OutFlow Max=0.99 cfs @ 12.09 hrs HW=144.03' TW=142.75' (Dynamic Tailwater) L1=Culvert (Inlet Controls 0.99 cfs @ 2.44 fps) Summary for Pond 4P: DMH1 Inflow Area = 19,291 sf, 59.99% Impervious, Inflow Depth = 2.00" for 2 yr event Inflow = 1.01 cfs @ 12.09 hrs, Volume= 3,210 cf Outflow = 1.01 cfs @ 12.09 hrs, Volume= 3,210 cf, Atten= 0%, Lag= 0.0 min Primary = 1.01 cfs @ 12.09 hrs, Volume= 3,210 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/2 Peak Elev= 142.76' @ 12.09 hrs Flood Elev= 148.50' Device Routing Invert Outlet Devices #1 Primary 142.24' 12.0" Round Culvert L= 164.0' CPP, square edge headwall, Ke= 0.500 Inlet/ Outlet Invert= 142.24'/ 140.00' S= 0.0137 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.79 sf Primary OutFlow Max=0.99 cfs @ 12.09 hrs HW=142.75' TW=139.22' (Dynamic Tailwater) L1=Culvert (Inlet Controls 0.99 cfs @ 2.44 fps) Summary for Pond 5P: DMH2 Inflow Area = 19,291 sf, 59.99% Impervious, Inflow Depth = 2.00" for 2 yr event Inflow = 1.01 cfs @ 12.09 hrs, Volume= 3,210 cf Outflow = 1.01 cfs @ 12.09 hrs, Volume= 3,210 cf, Atten= 0%, Lag= 0.0 min Primary = 1.01 cfs @ 12.09 hrs, Volume= 3,210 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs /2 Peak Elev= 139.23' @ 12.09 hrs Flood Elev= 144.00' Device Routing Invert Outlet Devices #1 Primary 138.71' 12.0" Round Culvert L= 67.0' CPP, square edge headwall, Ke= 0.500 Inlet/ Outlet Invert= 138.71'/ 134.03' S= 0.0699 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.79 sf Proposed Type Ill 24-hr 2 yr Rainfall=3.20" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD010.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 14 Primary OutFlow Max=0.99 cfs @ 12.09 hrs HW=139.22' TW=131.26' (Dynamic Tailwater) L1=Culvert (Inlet Controls 0.99 cfs @ 2.44 fps) Summary for Pond 6P: DMH3 Inflow Area = 67,049 sf, 74.87% Impervious, Inflow Depth = 2.34" for 2 yr event Inflow = 4.02 cfs @ 12.09 hrs, Volume= 13,076 cf Outflow = 4.02 cfs @ 12.09 hrs, Volume= 13,076 cf, Atten= 0%, Lag= 0.0 min Primary = 4.02 cfs @ 12.09 hrs, Volume= 13,076 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/2 Peak Elev= 131.28' @ 12.09 hrs Flood Elev= 139.53' Device Routing Invert Outlet Devices #1 Primary 130.36' 24.0" Round Culvert L= 36.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 130.36'/ 130.00' S= 0.0100 T Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 3.14 sf Primary OutFlow Max=3.92 cfs @ 12.09 hrs HW=131.26' TW=129.94' (Dynamic Tailwater) 'L1=Culvert (Barrel Controls 3.92 cfs @ 4.19 fps) Summary for Pond 7P: DMH4 Inflow Area = 47,758 sf, 80.88% Impervious, Inflow Depth = 2.48" for 2 yr event Inflow = 3.00 cfs @ 12.09 hrs, Volume= 9,866 cf Outflow = 3.00 cfs @ 12.09 hrs, Volume= 9,866 cf, Atten= 0%, Lag= 0.0 min Primary = 3.00 cfs @ 12.09 hrs, Volume= 9,866 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/2 Peak Elev= 132.10' @ 12.09 hrs Flood Elev= 147.96' Device Routing Invert Outlet Devices #1 Primary 131.29' 18.0" Round Culvert L= 29.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 131.29'/ 130.61' S= 0.0234 7' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.77 sf Primary OutFlow Max=2.93 cfs @ 12.09 hrs HW=132.09' TW=131.26' (Dynamic Tailwater) L1=Culvert (Inlet Controls 2.93 cfs @ 3.05 fps) Summary for Pond 8P: CB2 Inflow Area = 16,132 sf, 83.46% Impervious, Inflow Depth = 2.54" for 2 yr event Inflow = 1.03 cfs @ 12.09 hrs, Volume= 3,420 cf Outflow = 1.03 cfs @ 12.09 hrs, Volume= 3,420 cf, Atten= 0%, Lag= 0.0 min Primary = 1.03 cfs @ 12.09 hrs, Volume= 3,420 cf Proposed Type 111 24-hr 2 yr Rainfall=3.20" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD® 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 15 Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs /2 Peak Elev= 134.95' @ 12.09 hrs Flood Elev= 138.33' Device Routing Invert Outlet Devices #1 Primary 134.33' 12.0" Round Culvert L= 6.0' CPP, square edge headwall, Ke= 0.500 Inlet/ Outlet Invert= 134.33'/ 134.27' S= 0.0100 7' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.79 sf Primary OutFlow Max=1.01 cfs @ 12.09 hrs HW=134.95' TW=132.09' (Dynamic Tailwater) L1=Culvert (Barrel Controls 1.01 cfs @ 2.84 fps) Summary for Pond 9P: DGCB3 Inflow Area = 31,626 sf, 79.57% Impervious, Inflow Depth = 2.45" for 2 yr event Inflow = 1.97 cfs @ 12.09 hrs, Volume= 6,446 cf Outflow = 1.97 cfs @ 12.09 hrs, Volume= 6,446 cf, Atten= 0%, Lag= 0.0 min Primary = 1.97 cfs @ 12.09 hrs, Volume= 6,446 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/2 Peak Elev= 133.28' @ 12.09 hrs Flood Elev= 135.75' Device Routing Invert Outlet Devices #1 ' Primary 132.59' 15.0" Round Culvert L= 105.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 132.59'/ 131.54' S= 0.0100 '/' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 1.23 sf Primary OutFlow Max=1.92 cfs @ 12.09 hrs HW=133.27' TW=132.09' (Dynamic Tailwater) L1=Culvert (Inlet Controls 1.92 cfs @ 2.81 fps) Summary for Pond 10P: Culvert Inflow Area = 18,357 sf, 9.48% Impervious, Inflow Depth = 0.98" for 2 yr event Inflow = 0.45 cfs @ 12.10 hrs, Volume= 1,503 cf Outflow = 0.45 cfs @ 12.10 hrs, Volume= 1,503 cf, Atten= 0%, Lag= 0.0 min Primary = 0.45 cfs @ 12.10 hrs, Volume= 1,503 cf Routing by Dyn-Stor-Ind method, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs/2 Peak Elev= 137.33' @ 12.10 hrs Flood Elev= 138.33' Device Routing Invert Outlet Devices #1 Primary 137.00' 12.0" Round Culvert L= 56.0' CPP, square edge headwall, Ke= 0.500 Inlet/Outlet Invert= 137.00'/ 133.00' S= 0.07147' Cc= 0.900 n= 0.013 Corrugated PE, smooth interior, Flow Area= 0.79 sf Proposed Type/1/24-hr 2 yr Rainfall=3.20" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD® 10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 16 Primary OutFlow Max=0.45 cfs @ 12.10 hrs HW=137.33' TW=0.00' (Dynamic Tailwater) t-1=Culvert (Inlet Controls 0.45 cfs @ 1.96 fps) Summary for Link 1 L: Inflow Area = 185,489 sf, 48.60% Impervious, Inflow Depth = 1.08" for 2 yr event Inflow = 3.25 cfs @ 12.16 hrs, Volume= 16,753 cf Primary = 3.25 cfs @ 12.16 hrs, Volume= 16,753 cf, Atten= 0%, Lag= 0.0 min Primary outflow= Inflow, Time Span= 0.00-30.00 hrs, dt= 0.05 hrs Proposed Type/1/24-hr 9 yr Rainfall=2.50" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD®10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Pagel Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points x 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 1 S: Trib to CB2 Runoff Area=19,291 sf 59.99% Impervious Runoff Depth=1.38" Flow Length=496' Tc=6.0 min CN=88 Runoff=0.70 cfs 2,221 cf Subcatchment 2S: Trib to Wetlands Runoff Area=68,288 sf 15.45% Impervious Runoff Depth=0.46" Tc=6.0 min CN=70 Runoff=0.64 cfs 2,591 cf Subcatchment 3S: Storage Roof Runoff Area=4,410 sf 100.00% Impervious Runoff Depth=2.27" Tc=6.0 min CN=98 Runoff=0.24 cfs 834 cf Subcatchment 4S: Trib.to 2P Runoff Area=31,626 sf 79.57% Impervious Runoff Depth=1.78" Tc=6.0 min CN=93 Runoff=1.46 cfs 4,690 cf Subcatchment 5S: Bldg Roof Runoff Area=15,916 sf 100.00% Impervious Runoff Depth=2.27" Tc=6.0 min CN=98 Runoff=0.86 cfs 3,012 cf Subcatchment 6S: Trib.to CB3 Runoff Area=16,132 sf 83.46% Impervious Runoff Depth=1.87" Tc=6.0 min CN=94 Runoff=0.77 cfs 2,513 cf Subcatchment 7S: Trib. to Wetlands Runoff Area=18,357 sf 9.48% Impervious Runoff Depth=0.57" Tc=6.0 min CN=73 Runoff=0.24 cfs 868 cf Subcatchment 8S: Trib. to I Runoff Area=11,469 sf 63.97% Impervious Runoff Depth=1.06" Tc=6.0 min CN=83 Runoff=0.32 cfs 1,009 cf Pond 1P: Infiltration Basin Peak Elev=129.89' Storage=5,731 cf Inflow=4.12 cfs 13,006 cf Discarded=0.11 cfs 6,186 cf Primary=0.90 cfs 4,959 cf Outflow=1.01 cfs 11,145 cf Pond 2P: Forebay Peak Elev=129.89' Storage=440 cf Inflow=2.93 cfs 9,424 cf Outflow=2.95 cfs 8,985 cf Pond 3P: DGCB1 Peak Elev=143.94' Inflow=0.70 cfs 2,221 cf 12.0" Round Culvert n=0.013 L=64.0' S=0.0200'/' Outflow=0.70 cfs 2,221 cf Pond 4P: DMH1 Peak Elev=142.66' Inflow=0.70 cfs 2,221 cf 12.0" Round Culvert n=0.013 L=164.0' S=0.0137'/' Outflow=0.70 cfs 2,221 cf Pond 5P: DMH2 Peak Elev=139.13' Inflow=0.70 cfs 2,221 cf 12.0" Round Culvert n=0.013 L=67.0' S=0.0699 /' Outflow=0.70 cfs 2,221 cf Pond 6P: DMH3 Peak Elev=131.12' Inflow=2.93 cfs 9,424 cf 24.0" Round Culvert' n=0.013 L=36.0' S=0.0100'/' Outflow=2.93 cfs 9,424 cf Pond 7P: DMH4 Peak Elev=131.98' Inflow=2.23 cfs 7,203 cf 18.0" Round Culvert n=0.013 L=29.0' S=0.0234'/' Outflow=2.23 cfs 7,203 cf Pond 8P: CB2 Peak Elev=134.86' Inflow=0.77 cfs 2,513 cf 12.0" Round Culvert n=0.013 L=6.0' S=0.0100'/' Outflow=0.77 cfs 2,513 cf Proposed Type 111 24-hr I yr Rainfall=2.50" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD®10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 2 Pond 9P: DGCB3 Peak Elev=133.17' Inflow=1.46 cfs 4,690 cf 15.0" Round Culvert n=0.013 L=105.0' S=0.0100 '/' Outflow=1.46 cfs 4,690 cf Pond 10P: Culvert Peak Elev=137.24' Inflow=0.24 cfs 868 cf 12.0" Round Culvert n=0.013 L=56.0' S=0.0714 '/' Outflow=0.24 cfs 868 cf Link 1 L: Inflow=1.38 cfs 9,253 cf Primary=1.38 cfs 9,253 cf Total Runoff Area= 185,489 sf Runoff Volume = 17,738 cf Average Runoff Depth = 1.15" 51.40% Pervious=95,335 sf 48.60% Impervious =90,154 sf Proposed Type 111 24-hr 10 yr Rainfall=4.80" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD® 10.00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 3 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points x 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 1S: Trib to C132 Runoff Area=19,291 sf 59.99% Impervious Runoff Depth=3.48" Flow Length=496' Tc=6.0 min CN=88 Runoff=1.73 cfs 5,593 cf Subcatchment 2S: Trib to Wetlands Runoff Area=68,288 sf 15.45% Impervious Runoff Depth=1.89" Tc=6.0 min CN=70 Runoff=3.34 cfs 10,751 cf Subcatchment 3S: Storage Roof Runoff Area=4,410 sf 100.00% Impervious Runoff Depth=4.56" Tc=6.0 min CN=98 Runoff=0.46 cfs 1,677 cf Subcatchment 4S: Trib. to 2P Runoff Area=31,626 sf 79.57% Impervious Runoff Depth=4.00" Tc=6.0 min CN=93 Runoff=3.14 cfs 10,546 cf Subcatchment 5S: Bldg Roof Runoff Area=15,916 sf 100.00% Impervious Runoff Depth=4.56" Tc=6.0 min CN=98 Runoff=1.67 cfs 6,053 cf Subcatchment 6S: Trib. to C133 Runoff Area=16,132 sf 83.46% Impervious Runoff Depth=4.11" Tc=6.0 min CN=94 Runoff=1.63 cfs 5,526 cf Subcatchment 7S: Trib. to Wetlands Runoff Area=18,357 sf 9.48% Impervious Runoff Depth=2.12" Tc=6.0 min CN=73 Runoff=1.02 cfs 3,250 cf Subcatchment 8S: Trib. to 1P Runoff Area=11,469 sf 63.97% Impervious Runoff Depth=2.99" Tc=6.0 min CN=83 Runoff=0.90 cfs 2,861 cf Pond 1P: Infiltration Basin Peak EIev=130.75' Storage=10,096 cf Inflow=9.04 cfs 30,141 cf Discarded=0.13 cfs 7,265 cf Primary=4.44 cfs 20,567 cf Outflow=4.57 cfs 27,833 cf Pond 2P: Forebay Peak EIev=130.75' Storage=440 cf Inflow=6.49 cfs 21,666 cf Outflow=6.46 cfs 21,227 cf Pond 3P: DGCB1 Peak EIev=144.24' Inflow=1.73 cfs 5,593 cf 12.0" Round Culvert n=0.013 L=64.0' S=0.0200 T Outflow=1.73 cfs 5,593 cf Pond 4P: DMH1 Peak EIev=142.96' Inflow=1.73 cfs 5,593 cf 12.0" Round Culvert n=0.013 L=164.0' S=0.0137 /' Outflow=1.73 cfs 5,593 cf Pond 5P: DMH2 Peak EIev=139.43' Inflow=1.73 cfs 5,593 cf 12.0" Round Culvert n=0.013 L=67.0' S=0.0699 T Outflow=1.73 cfs 5,593 cf Pond 6P: DMH3 Peak EIev=131.58' Inflow=6.49 cfs 21,666 cf 24.0" Round Culvert n=0.013 L=36.0' S=0.0100 T Outflow=6.49 cfs 21,666 cf Pond 7P: DMH4 Peak EIev=132.36' Inflow=4:76 cfs 16,073 cf 18.0" Round Culvert n=0.013 L=29.0' S=0.0234'/' Outflow=4.76 cfs 16,073 cf Pond 8P: CB2 Peak EIev=135.15' Inflow=1.63 cfs 5,526 cf 12.0" Round Culvert n=0.013 L=6.0' S=0.0100 '/' Outflow=1.63 cfs 5,526 cf Proposed Type 111 24-hr 10 yr Rainfall=4.80" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD® 10 00-15 s/n 06611 02015 HydroCAD Software Solutions LLC Page 4 Pond 9P: DGCB3 Peak Elev=133.52' Inflow=3.14 cfs 10,546 cf 15.0" Round Culvert n=0.013 L=105.0' S=0.0100'/' Outflow=3.14 cfs 10,546 cf Pond 10P: Culvert Peak Elev=137.52' Inflow=1.02 cfs 3,250 cf 12.0" Round Culvert n=0.013 L=56.0' S=0.0714'/' Outflow=1.02 cfs 3,250 cf Link 1 L: Inflow=8.33 cfs 36,246 cf Primary=8.33 cfs 36,246 cf Total Runoff Area= 185,489 sf Runoff Volume=46,259 cf Average Runoff Depth =2.99" 51.40% Pervious=95,335 sf 48.60% Impervious =90,154 sf Proposed Type 11124-hr 25 yr Rainfall=6.00" Printed 11/12/2015 Prepared by{enter your company name here} Paae 5 HydroCADO 10 00 15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points x 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 1S: Trib to CB2 Runoff Area=19,291 sf 59.99% Impervious Runoff Depth=4.63" Flow Length=496' Tc=6.0 min CN=88 Runoff=2.27 cfs 7,436 cf Subcatchment 2S: Trib to Wetlands Runoff Area=68,288 sf 15.45% Impervious Runoff Depth=2.81" Tc=6.0 min CN=70 Runoff=5.03 cfs 15,963 cf Subcatchment 3S: Storage Roof Runoff Area=4,410 sf 100.00% Impervious Runoff Depth=5.76" Tc=6.0 min CN=98 Runoff=0.58 cfs 2,117 cf Subcatchment 4S: Trib. to 2P Runoff Area=31,626 sf 79.57% Impervious Runoff Depth=5.18" Tc=6.0 min CN=93 Runoff=4.00 cfs 13,659 cf Subcatchment 5S: Bldg Roof Runoff Area=15,916 sf 100.00% Impervious Runoff Depth=5.76" Tc=6.0 min CN=98 Runoff=2.10 cfs 7,642 cf Subcatchment 6S: Trib.to CB3 Runoff Area=16,132 sf 83.46% Impervious Runoff Depth=5.30" Tc=6.0 min CN=94 Runoff=2.06 cfs 7,120 cf Subcatchment 7S: Trib.to Wetlands Runoff Area=18,357 sf 9.48% Impervious Runoff Depth=3.09" Tc=6.0 min CN=73 Runoff=1.50 cfs 4,725 cf Subcatchment 8S: Trib.to 1P Runoff Area=11,469 sf 63.97% Impervious Runoff Depth=4.09" Tc=6.0 min CN=83 Runoff=1.22 cfs 3,910 cf Pond 1P: Infiltration Basin Peak EIev=131.05' Storage=11,845 cf Inflow=11.64 cfs 39,329 cf Discarded=0.14 cfs 7,689 cf Primary=6.11 cfs 29,260 cf Outflow=6.25 cfs 36,949 cf Pond 2P: Forebay Peak EIev=131.05' Storage=440 cf Inflow=8.33 cfs 28,216 cf Outflow=8.32 cfs 27,777 cf Pond 3P: DGCB1 Peak EIev=144.38' Inflow=2.27 cfs 7,436 cf 12.0" Round Culvert n=0.013 L=64.0' S=0.0200'/' Outflow=2.27 cfs 7,436 cf Pond 4P: DMH1 Peak EIev=143.10' Inflow=2.27 cfs 7,436 cf 12.0" Round Culvert n=0.013 L=164.0' S=0.0137'/' Outflow=2.27 cfs 7,436 cf Pond 5P: DMH2 Peak EIev=139.57' Inflow=2.27 cfs 7,436 cf 12.0" Round Culvert n=0.013 L=67.0' S=0.0699 '/' Outflow=2.27 cfs 7,436 cf Pond 6P: DMH3 Peak EIev=131,78' Inflow=8.33 cfs 28,216 cf 24.0" Round Culvert n=0.013 L=36.0' S=0.0100 '/' Outflow=8.33 cfs 28,216 cf Pond 713: DMH4 Peak EIev=132.57' Inflow=6.07 cfs 20,779 cf 18.0" Round Culvert n=0.013 L=29.0' S=0.0234'/' Outflow=6.07 cfs 20,779 cf Pond 8P: CB2 Peak EIev=135.29' Inflow=2.06 cfs 7,120 cf 12.0" Round Culvert n=0.013 L=6.0' S=0.0100'/' Outflow=2.06 cfs 7,120 cf Proposed Type /// 24-hr 25 yr Rainfall=6.00" Printed 11/12/2015 Prepared by{enter your company name here} Pane 6 H droCADO 10.00-15 s/n 06611 ©2015 H droCAD Software Solutions LLC Pond 9P: DGC133 Peak EIev=133.70' Inflow=4.00 cfs 13,659 cf 15.0" Round Culvert n=0.013 L=105.0' S=0.0100 '/' Outflow=4.00 cfs 13,659 cf Pond 10P: Culvert Peak EIev=137.65' Inflow=1.50 cfs 4,725 cf 12.0" Round Culvert n=0.013 L=56.0' S=0.0714'/' Outflow=1.50 cfs 4,725 cf Inflow=12.12 cfs 52,065 cf Link 1 L: Primary=12.12 cfs 52,065 cf Total Runoff Area= 185,489 sf Runoff Volume=62,574 cf Average Runoff Depth =4.05" 51.40/o Pervious=95,335 sf 48.60% Impervious =90,154 sf Proposed Type 111 24-hr 100 yr Rainfall=8.60" Prepared by {enter your company name here} Printed 11/12/2015 HydroCAD® 10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 7 Time span=0.00-30.00 hrs, dt=0.05 hrs, 601 points x 2 Runoff by SCS TR-20 method, UH=SCS, Weighted-CN Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method Subcatchment 1 S: Trib to CB2 Runoff Area=19,291 sf 59.99% Impervious Runoff Depth=7.16" Flow Length=496' Tc=6.0 min CN=88 Runoff=3.42 cfs 11,503 cf Subcatchment 2S: Trib to Wetlands Runoff Area=68,288 sf 15.45% Impervious Runoff Depth=4.98" Tc=6.0 min CN=70 Runoff=8.97 cfs 28,363 cf Subcatchment 3S: Storage Roof Runoff Area=4,410 sf 100.00% Impervious Runoff Depth=8.36" Tc=6.0 min CN=98 Runoff=0.83 cfs 3,072 cf Subcatchment 4S: Trib. to 2P Runoff Area=31,626 sf 79.57% Impervious Runoff Depth=7.76" Tc=6.0 min CN=93 Runoff=5.86 cfs 20,447 cf Subcatchment 5S: Bldg Roof Runoff Area=15,916 sf 100,00% Impervious Runoff Depth=8.36" Tc=6.0 min CN=98 Runoff=3.01 cfs 11,088 cf Subcatchment 6S: Trib. to CB3 Runoff Area=16,132 sf 83.46% Impervious Runoff Depth=7.88" Tc=6.0 min CN=94 Runoff=3.01 cfs 10,592 cf Subcatchment 7S: Trib. to Wetlands Runoff Area=18,357 sf 9.48% Impervious Runoff Depth=5.35" Tc=6.0 min CN=73 Runoff=2.58 cfs 8,177 cf Subcatchment 8S: Trib. to 1P Runoff Area=11,469 sf 63.97% Impervious Runoff Depth=6.55" Tc=6.0 min CN=83 Runoff=1.92 cfs 6,262 cf Pond 1 P: Infiltration Basin Peak Elev=131.63' Storage=15,555 cf Inflow=17.16 cfs 59,453 cf Discarded=0.16 cfs 8,430 cf Primary=8.52 cfs 48,556 cf Outflow=8.68 cfs 56,985 cf Pond 2P: Forebay Peak Elev=131.63' Storage=440 cf Inflow=12.29 cfs 42,542 cf Outflow=12.23 cfs 42,103 cf Pond 3P: DGCB1 Peak Elev=144.84' Inflow=3.42 cfs 11,503 cf 12.0" Round Culvert n=0.013 L=64.0' S=0.0200 T Outflow=3.42 cfs 11,503 cf Pond 4P: DMH1 Peak Elev=143.56' Inflow=3.42 cfs 11,503 cf 12.0" Round Culvert n=0.013 L=164.0' S=0.0137'/' Outflow=3.42 cfs 11,503 cf Pond 5P: DMH2 Peak EIev=140.03' Inflow=3.42 cfs 11,503 cf 12.0" Round Culvert n=0.013 L=67.0' S=0.0699 T Outflow=3.42 cfs 11,503 cf Pond 6P: DMH3 Peak EIev=132.19' Inflow=12.29 cfs 42,542 cf 24.0" Round Culvert n=0.013 L=36.0' S=0.0100 T Outflow=12.29 cfs 42,542 cf Pond 7P: DMH4 Peak EIev=133.26' Inflow=8.86 cfs 31,039 cf 18.0" Round Culvert n=0.013 L=29.0' S=0.0234 T Outflow=8.86 cfs 31,039 cf Pond 8P: CB2 Peak EIev=135.62' Inflow=3.01 cfs 10,592 cf 12.0" Round Culvert n=0.013 L=6.0' S=0.0100 '/' Outflow=3.01 cfs 10,592 cf Proposed Type 11124-hr 100 yr Rainfall=8.60" Prepared by{enter your company name here} Printed 11/12/2015 HydroCAD® 10 00-15 s/n 06611 ©2015 HydroCAD Software Solutions LLC Page 8 Pond 9P: DGCB3 Peak Elev=134.54' Inflow=5.86 cfs 20,447 cf 15.0" Round Culvert n=0.013 L=105.0' S=0.0100 '/' Outflow=5.86 cfs 20,447 cf Pond 10P: Culvert Peak Elev=137.96' Inflow=2.58 cfs 8,177 cf 12.0" Round Culvert n=0.013 L=56.0' S=0.0714 '/' Outflow=2.58 cfs 8,177 cf Link 1L: Inflow=19.76 cfs 88,168 cf Primary=19.76 cfs 88,168 cf Total Runoff Area= 185,489 sf Runoff Volume =99,504 cf Average Runoff Depth = 6.44" 51.40% Pervious = 95,335 sf 48.60% Impervious =90,154 sf STORMWATER REPORT COMPLIANCE CALCULATIONS Stormwater Report Compliance Calculations #2302 Turnpike Street North Andover, Massachusetts November 4,2015 Standard 1• No Untreated Discharges Or Erosion To Wetlands Untreated Discharges: To document compliance that new discharges are adequately treated refer to calculations for Standards 4 through 6. Erosion To Wetlands: Flow exiting the infiltration pond discharges to a level spreader. For minimum stone size of level spreader based on a Qioo=8.5 cfs, see the following graphical solution to the Isbash Curve. 0.9 ft. recommended,1.0 ft. provided. Flow exiting the level spreader for Qio=4.5 cfs Weir Equation: Q=CLH3/2 Continuity Equation: Q=VA Length of level spreader=8 ft Q=4.5 = (3.3)(8 ft.)(H3/z) H=0.3ft. A= (0.3)(8) =2.4 ft2 V=Q/A=4.5/2.4=1.9 ft/s (< 2 ft/s per Stormwater Management Handbook) Velocity per foot of level spreader=0.24 ft/s 1 Tecludeal Supplement 14C Stone Sizing Criteria Part 654 National Engineering Handbook Figure TS14C-6 Graphical solution for Isbash technique (a) 1,000 U 800 1135- 45 205 600 -_t , (.- j/{ j ( 185 + i .. r" _ /Li i i i 165 4 — t r- 4 155 400 185 { +� 300 High turbulence t t; - 135 (stilling basins) 200135 145 I j 100 __ 1 165 a Low turbulence _ _ _ _ 165 (river closures) L 60 40 d --i-- a — _ � ___- 30 20 IT r 10 5 6 7 8 9 10 14 18 22 04 0.5 0.6 0.7 0.8 0.9 1.0 1.2 1.6 2.0 2.4 Average velocity(ft/s) Spherical diameter,D60(ft) Basic equations: where: V = Velocity,ft/s Stone stability i Y = Specific stone weight,lb/ft3 velocity vs.stone a i 5 Y 'YS-'�W 11 = Specific weight of water,62.51b/ft3 diameter V=C�2g IJ (Dsp)2 W Yw W = Weight of stone,subscript denotes Hydraulic design f Percent of total weight of material chart 712-1 1 containing stone of less weight (Sheet 1 of 2) D _ 8W5o/3 D60 = Spherical diameter of stone having 61 the same weight as W, 5 C = Isbash constant(0.86 for high turbulence level flow and 1.20 for low turbulence level flow) g = Acceleration of gravity,ft/92 TS14C-4 (210-VI-NEH,August 2007) Standard 2:Peak Rate Attenuation Refer to Total Peak Rate of Runoff Comparison Table below(see Mitigative Drainage Study) Total Peak Rate of Runoff Comparison Table Existing Condition Proposed Condition 24 hour Type III Description Storm Event Peak Rate of Volume of Peak Rate of Volume of (year) Runoff Runoff Runoff Runoff Q (cfs) (ac-ft) Q (cfs) Q (cfs) 1 (2.5 inch) 1.5 0.15 1.3 0.21 2 (3.2 inch) 3.4 0. 3. 0.38 Flow to edge 10 (4.8 inch) of BVW 25 (6.0 inch) 8.7 0.64 8.4 0.83 13.2 0.96 12.2 1.19 100 (8.6 23.8 1.73 19.8 2.02 inch) Standard 3: Stormwater Recharge Recharge Volume: R„required=F x Impervious Area Site consists of Hydrologic Soils Group C and A: FA=0.6in. Fc=0.25 in. Impervious Areas: Ainp A=1815 ft2(excludes existing pavement,see Mitigative Drainage Study) AiI„p c=63319 ft2 (excludes existing pavement, see Mitigative Drainage Study) R,.required= (1815)(0.6) + (63319)(0.25) =1410 ft3 Capture Area Adjustment: Total site impervious area: 65135 ft2(see Mitigative Drainage Study) Site impervious area draining to recharge facility: 60724 ft2(see Mitigative Drainage Study) Ratio of total site impervious area to site impervious area draining to recharge facility= (65134) / (60724) =1.07 Adjusted minimum required recharge volume = (1410)(1.07) =1512 ft3 Rv provided=3763 ft3(provided below lowest hydraulic outlet device) 2 Drawdown Within 72 Hours: Tdrawdown=R,,/ (K)(Bottom Area) R„=3763 ft3 (volume below lowest hydraulic outlet device) K=1.02 in/hr (Rawls Rate,see soil test logs) Bottom Area=1957 ft2(see Mitigative Drainage Study) Tdrawdown=3763 / (1.02)(1957) =22.6 hours < 72 hours For drawdown of entire infiltration basin: Tdrawdown= (time to drain from 100 yr water level to lowest outlet device + time to drain from lowest outlet device to basin bottom) Tdrawdown= (13.1 hrs +22.6 hrs) =35.7 hours <72 hours Standard 4:Water Quality Water Quality: VWQ required= (DwQ)(Aicup) DwQ=1 in. (Rapid infiltration rate,Rawls Rate 2.41 in/hr,see soil test logs TH-2) Aimp =44808 ft2(excludes existing pavement,see Mitigative Drainage Study) VWQ required= (1)(44808) =3734 ft3 VWQ provided=3763 ft3(provided below lowest hydraulic outlet device) TSS Removal: See TSS removal calculation worksheets below. Pretreatment Chain=44% Surface Infiltration Pond=80% Standard 5• Land Uses With Higher Potential Pollutant Loading This project is not being considered as a LUHPPL. Standard 6: Critical Areas The stormwater discharge from this property is not within an Interim Wellhead Protection Area of a public water supply nor within a Zone II. Standard 7: Redevelopment This project is not being considered as a redevelopment. 3 Standard 8: Construction Period Controls A Stormwater Pollution Prevention Plan(SWPPP)will be provided. Standard 9. Operation And Maintenance Plan See Long Term Operation and Maintenance Plan (O&M)below. Standard 10• Illicit Discharges To Drainage System There are no proposed illicit discharges into the Stormwater Management Systems to be constructed as shown on the site plan. 4 V Location: PietreatmentChain B C D E F TSS Removal Starting TSS Amount Remaining BMP' Rate' Load` Removed C*D Load D-E Q -Deep Sump and Hooded, :Catch�Basm 0.25 1.00 0.250.75 L 0.19 0.56 O O Sediment�orebay, . 0.25 0.75 4) _ ® 0.00 0.56 0.00 0.56 0.00 0.56 0.00 0.56 C� t� V 0.00 0.56 0.00 0.56 Separate Form Needs to be Completed for Each Total TSS Removal = 44% outlet or BMP Train Project: NAND-06033- MEIN Prepared By: *Equals remaining load from previous BMP (E) Date: 4-Nov-15 which enters the BMP Non-automated TSS Calculation Sheet must be used if Proprietary BMP Proposed Mass.Dept.of Environmental Protection 1.From MassDEP Stormwater Handbook Vol.1 V Location: Suffice l6filtrabon Pond B C D E F TSS Removal Starting TSS Amount Remaining BMP' Rate' Load* Removed C*D Load D-E SInfiltration Basin 0.80 1.00 0.80 0.20 > L ® ® 0.00 0.20 0.00 0.20 E ® 0.00 0.20 0.00 0.20 0.00 0.20 0.00 0.20 V tQ V 0.00 0.20 0.00 0.20 Separate Form Needs to be Completed for Each TSS 1 SS Removal 80% Outlet or BMP Train Project: NAND-0033 Prepared By: MEM *Equals remaining load from previous BMP(E) Date: 4-Nov-15 which enters the BMP Non-automated TSS Calculation Sheet must be used if Proprietary BMP Proposed 1.From MassDEP Stormwater Handbook Vol.1 Mass.Dept.of Environmental Protection SOIL TEST LOGS PF., v"iCT truly BEP\ Commonwealth of Massachusetts N.4,WP-00 33 City/Town of l o/za�i5 m P _ Form 11 - Soil Suitability Assessment for On-Site Sewage Disposal C. On-Site Review (continued) Deep Observation Hole Number: I �— Redoximorphic Features Coarse Fragments Depth(in.) Soil Horizon/Soil Matrix:Color- Soil Texture %by Volume Soil Layer Moist(Munsell) (USDA Soil Structure Consistence Other Depth Color Percent Gravel Cobbles Stones (Moist) 8� 0-- 5 0 7 - ZI Ouf Z( -53 ) 0 % M Ort 36 Z5% 51 15 5 Q armT PIq Additional Notes: t5form11 •rev.8/15 Form 11—Soil Suitability Assessment for On-Site Sewage Disposal •Page 3 of 8 PROJECT NUMBER (L\ Commonwealth of Massachusetts MAID- 0033 City/Town of fO�Za\15 /�P Form 11 - Soil Suitability Assessment for On-Site Sewage Disposal C. On-Site Review (continued) Deep Observation Hole Number: Redoximorphic Features Coarse Fragments Depth(in.) Soil Horizon/Soil Matrix:Color- Soil Texture %by Volume Soil Layer Moist(Munsell) (USDA) Soil Structure Consistence Other Depth Color Percent Gravel Cobbles (Moist) &Stones D-39 1 F1 3Q- 3(0-% Po W -FS 5 °�� M 10- 51 C 1 l s 10 510 rv� F; Cd -73 1 i�ha Additional Notes: t5form11 •rev.8/15 Form 11 —Soil Suitability Assessment for On-Site Sewage Disposal •Page 3 of 8 PkvjcCT ivulvlB&i Commonwealth of Massachusetts N,490 ®D 33 City/Town of 10 A4� _ Form 11 - Soil Suitability Assessment for On-Site Sewage Disposal C. On-Site Review (continued) Deep Observation Hole Number: Redoximorphic Features Coarse Fragments Depth(in.) Soil Horizon/Soil Matrix:Color- Soil Texture %by Volume Soil Layer Moist(Munsell) (USDA) Soil Structure Consistence Other Depth Color Percent Gravel Cobbles (Moist) 8�Stones f5I M ZZ_�� 30�Q S 5 firm i�p1a 0o C � hard Additional Notes: t5form11 •rev.8/15 Form 11—Soil Suitability Assessment for On-Site Sewage Disposal •Page 3 of 8 NRCS WEB SOIL SURVEY Soil Information for All. Uses Soil Properties and Qualities The Soil Properties and Qualities section includes various soil properties and qualities displayed as thematic maps with a summary table for the soil map units in the selected area of interest.A single value or rating for each map unit is generated by aggregating the interpretive ratings of individual map unit components. This aggregation process is defined for each property or quality. Soil Qualities and Features Soil qualities are behavior and performance attributes that are not directly measured, but are inferred from observations of dynamic conditions and from soil properties. Example soil qualities include natural drainage, and frost action. Soil features are attributes that are not directly part of the soil. Example soil features include slope and depth to restrictive layer.These features can greatly impact the use and management of the soil. Hydrologic Soil Group Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long- duration storms. The soils in the United States are assigned to four groups (A, B, C, and D)and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential)when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands.These soils have a high rate of water transmission. Group B.Soils having a moderate infiltration rate when thoroughly wet.These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. 18 Custom Soil Resource Report Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential)when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material.These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas.Only the soils that in their natural condition are in group D are assigned to dual classes. 19 Custom Soil Resource Report 3 Map—Hydrologic Soil Group 3 a; 331060 331120 331180 331240 331300 331360 42°37 40'N 42°37 40'N o .y oti Sid f' a v 0 a a A i P d 'r O M n v a 0 -a a 420 3724'N - 42°3T 24'N 331060 331120 331180 331240 331300 331360 3 3 Map Scale:1:2,340 if printed on A portrait(8.5"x 11")sheet Meters N ° 0 30 60 120 180 Feet 0 100 200 400 600 Map projedion:Web Mercator Comerwordinabes:WGS84 Edge tics:UTM Zone 19N WGS84 20 Custom Soil Resource Report MAP LEGEND MAP INFORMATION Area of Interest(AOq M C The soil surveys that comprise your AOI were mapped at 1:15,800. Area of Interest(AOI) C/D Soils D Warning:Soil Map may not be valid at this scale. Soil Rating Polygons EM A ® Not rated or not available Enlargement of maps beyond the scale of mapping can cause Water Features misunderstanding of the detail of mapping and accuracy of soil line EN A/D placement.The maps do not show the small areas of contrasting NM B Streams and Canals soils that could have been shown at a more detailed scale. Transportation B/D l-14 Rails Please rely on the bar scale on each map sheet for map C ,.4r Interstate Highways measurements. C/D a US Routes Source of Map: Natural Resources Conservation Service D Major Roads Web Soil Survey URL: http://websoilsurvey.nres.usda.gov Q Not rated or not available Local Roads Coordinate System: Web Mercator(EPSG:3857) Soil Rating Lines Background Maps from the Web Soil Survey are based on the Web Mercator res A Aerial Photography projection,which preserves direction and shape but distorts AID distance and area.A projection that preserves area,such as the Albers equal-area conic projection,should be used if more accurate r+r B calculations of distance or area are required. •ram B/D This product is generated from the USDA-NRCS certified data as of +" C the version date(s)listed below. .,.a C/D Soil Survey Area: Essex County,Massachusetts,Northern Part D Survey Area Data: Version 10,Sep 19,2014 . r Not rated or not available Soil Rating Points Soil map units are labeled(as space allows)for map scales 1:50,000 A or larger. AID Date(s)aerial images were photographed: Aug 29,2014—Sep B 19,2014 B/D The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps.As a result,some minor shifting 21 Custom Soil Resource Report Table—Hydrologic Soil Group Hydrologic Soil Group—Summary by Map Unit-Essex County,Massachusetts,Northern Part(MA605) Map unit symbol' Map unit name Rating Acres in AOI Percent of AOI 52A Freetown muck,0 to 1 A/D 3.1 23.0% percent slopes 306B Paxton fine sandy loam,3 C 3.2 24.0% to 8 percent slopes, very stony 306D Paxton fine sandy loam, C 4.6 34.7% 15 to 25 percent slopes,very stony 421 B Canton fine sandy loam,3 A 0.0 0.0% to 8 percent slopes, very stony 602 Urban land 0.6 4.5% 711 C Charlton-Rock outcrop- A 1.8 13.8% Hollis complex,8 to 15 percent slopes Totals for Area of Interest 13.3 100.0% Rating Options—Hydrologic Soil Group Aggregation Method: Dominant Condition Component Percent Cutoff.- None Specified Tie-break Rule: Higher 22 OPERATION AND MAINTENANCE PLAN Operation & Maintenance Plan #2302 Turnpike Street North Andover, Massachusetts November 4,2015 This Operation&Maintenance Plan has been prepared to comply with the provisions set forth in the Massachusetts Department of Environmental Protection(DEP)Stormwater Management Standards. Structural Best Management Practices (BMPs) require periodic maintenance to ensure ch wetland resource proper function d efficiency in pollutant removal from stormwater discharges that would otherwise areas untreated. Maintenance schedules found below are as recommended in recommended in theDmpanu acturer's specifarent of ications. ental Protections Massachusetts Stormwater Handbook and as The following BMPs shall be utilized for pollutant removal from stormwater discharge as well providing additional groundwater recharge on site: • Deep-Sump Catch Basin w/hood • Sediment Forebay • Surface Infiltration Pond(1P) Deep Sump Catch Basins w/Hood: • Inspect or clean at least four times per year with special consideration given to the end of foliage and snow removal seasons. • Sediments must also be removed four times per year or whenever the depth of deposits is greater than the bottom of the sump or one half the depth of the invert of the or equal to one half the depth from outlet pipe. • Clamshell buckets and/or vacuum trucks are typically used to remove sediment in Massachusetts. • Cleanings may be taken to a landfill or other facility permitted by MassDEP to accept solid waste, without any prior approval by MassDEP. However, some � MassDEP reandfills euirtch basin cleanings to be ement pertaining to the tested before they are accepted. For information on all o q disposal of catch basin cleanings go to www. ass.gov/dep/recycle/laws/cafacts.doc Sediment Forebay: • Inspect the forebays monthly with special consideration given to the end of foliage and snow removal seasons and clean them out at least four times per year. • Frequently removing accumulated sediments will make resuspension less likely. • Stabilize the floor and sidewalls before making it operational to avoid excess amounts of suspended sediments. Operation & Maintenance Plan #2302 Turnpike Street, North Andover, MA November 4, 2015 • Keep the grass in the sediment forebay no lower than three (3) to four (4) inches but no higher than six (6) inches. • Inspect the sediment forebay for signs of rilling and gullying and repair as necessary. • Replace any vegetation damaged during the clean-out by either reseeding or resodding. • If reseeding,utilize practices such as hydroseeding with a tackifier,blanket,or similar practice to ensure that no scour occurs in the forebay and allow the seeds to germinate and develop roots. Surface Infiltration Ponds (1P): • Infiltration basins are prone to clogging and failure so it is imperative to develop and implement aggressive maintenance plans and schedules. Installing the required pretreatment BMPs,e.g. deep- sump catch basins and sediment forebays,will significantly reduce the maintenance requirements for the basin. • Inspections and preventative maintenance shall be performed at least twice a year,and after every time drainage discharges through the high outlet orifice or a major storm event which is defined as a storm that is equal to or greater than the 2-year,24-hour storm(3.1 inches in a 24 hour storm) • After the basin is on line,inspect it after every major storm for the first few months to ensure that it is stabilized and functioning properly. Take corrective action if necessary. • Note the time that water remains standing in the basin after a storm event. Standing water within the basin 48 to 72 hours after a storm indicates that the infiltration capacity of the basin may have been overestimated or the bottom has been clogged. • If the reason is clogging,determine the cause,e.g. erosion,excessive compaction,or low spots and take the necessary corrective action. Thereafter,inspect the infiltration basin at least twice per year. • Important items to check during the inspections include: Signs of differential settlement, Cracking, Erosion, Leakage in the embankments, Tree growth on the embankments, Condition of riprap, Sediment accumulation and, Health of the turf. • At least twice a year the buffer area,side slopes,and basin bottom shall be mowed. Remove the grass clippings and accumulated organic matter to prevent an impervious organic mat from forming. Remove trash and debris at this time as well as using deep tilling to break up any clogged surfaces, revegetate immediately. 2 Operation & Maintenance Plan #2302 Turnpike Street, North Andover, MA November 4, 2015 • Remove sediment from the basin as necessary only when the floor of the basin is completely dry. Use light equipment to remove the top layer to prevent compacting the underlying soil. Deep till the remaining soil and revegetate as soon as possible. The following BMPs shall be utilized to minimize impacts to wetland resource areas: Grassed Drainage Channel: • Inspect the grass channel semi-annually the first year and at least once a year thereafter. • Frequently removing accumulated sediments will make resuspension less likely. Sediment build-up in the grass channel reduces the capacity to treat and convey the water quality event,2-year and 10-year 24-hour storm. • Stabilize the floor and sidewals before making it operational to avoid excess amounts of suspended sediments. Check on a yearly basis and clean as needed. Use hand methods when cleaning to minimize disturbance to vegetation and underlying soils. • Keep the grass no lower than three (3) to four (4) inches but no higher than six (6) inches. Remove accumulated trash and debris prior to mowing. • Inspect for signs of rilling and gullying and repair as necessary. • Replace any vegetation damaged during the clean-out by either reseeding or resodding. If grass grown is impaired by winter road salt or other deicer use,re-establish grass in the spring. • If reseeding,utilize practices such as hydroseeding with a tackifier,blanket,or similar practice to ensure that no scour occurs in the forebay and allow the seeds to germinate and develop roots. Parking Lot Street Sweeping: • Street sweeping will be conducted four times annually within the parking lot area. Special attention will be given to the spring(March or April) and late fall (November or December). Snow Removal: • Snow will be removed from the parking area and sidewalks during snow events. The snow will be stockpiled in the designated"Proposed Snow Storage Areas"shown on the property. • Provisions will be made to remove snow from the site when the designated areas have reached their capacity. 3 EROSION & SEDIMENT CONTROL PLAN Erosion & Sediment Control Plan #2302 Turnpike Street North Andover, Massachusetts November 4, 2015 In order to limit the amount of erosion and sedimentation that takes place during and after construction,it is important to implement a management plan,which will protect and limit the amount of land area that is devoid of vegetation at any given time. Prior to Construction: Prior to start of construction activities,the owner,builder,and site contractor shall clearly identify areas that may be affected by the proposed clearing and earth moving activities by reviewing the approved grading plan as part of an initial site visit. During the site visit,the limit of work line shall be reviewed to confirm the type of erosion control measure to be used to protect downstream wetland resources and abutting property. Limits of tree clearing shall be verified during the initial site visit with emphasis on identifying"save areas" for existing trees and vegetation where practicable. Erosion and Sediment Control Device: Siltfence is proposed as the primary erosion control device for this project(see construction detail provided on the subdivision plan set). It is important for the owner,builder,and/or site contractor to have access to a supply of haybales should the need arise for additional erosion and sediment control measures. Haybales can be used along a slope and/or together with siltfence to protect against concentrated stormwater runoff over exposed surfaces (see attached construction detail for haybale installation). The erosion and sediment control devices shall be inspected every 7 days or within 24-hours of a 1/2-inch(or greater) rainfall event to ensure that they are operating properly. If sediment levels begin to build up on the erosion control devices,it may be necessary to remove the accumulated sediment to ensure that the erosion control devices continue to operate as designed. Sediment shall be removed if it builds up more than 12-inches above the ground surface at the erosion control device. Earth-moving Activities: After trees and other vegetation are cleared,earth-moving(or grading)activities can begin. The approved grading plan shall be used to help guide the site contractor during regrading activities. Often times it is helpful to have a land surveyor establish benchmark elevations and/or lines of grade to aid the site contractor during regrading activities. This is the time during which the site is most vulnerable to erosion. Therefore,it is important for the site contractor to finalize grading activities as soon as practicable following land clearing. Areas than remain exposed longer than 30 working days in an interim condition shall be stabilized in a temporary fashion. Once final grades have been established,permanent vegetation can be established. Temporary Seeding: During construction it may be necessary to temporarily stabilize areas that will not be brought to final grade for a period longer than 30 working days. Temporary seeding is accomplished using fast-growing grass seed species such as ryegrass. Seeding shall be performed in accordance with the guidelines set forth in the attached Temporary Seeding Guidance,which is an excerpt from a publication entitled,"Massachusetts Erosion &Sediment Control #2302 Turnpike Street, North Andover, MA November 4, 2015 Erosion and Sediment Control Guidelines for Urban and Suburban Areas,May 2003,prepared by Franklin, Hampden, and Hampshire Conservation Districts." Permanent Seeding&Plantipys. Once final grades have been established and the weather permits,every effort shall be made to establish permanent vegetation on disturbed and exposed areas. In addition to grass seed,tree and shrub plantings shall be an integral part of the permanent stabilization plan. Care shall be taken by the owner,builder,and/or site contractor to select trees,shrubs,and seed mixes that are best suited to the soil conditions on the site. Soil moisture, depth to seasonal groundwater,and exposure to sunlight shall be carefully considered when selecting species. In recent years,the emphasis on using plant species native to Massachusetts has grown. Information on the use of non-native and native species can be found on the web and in many local nursery catalogs. Permanent seeding shall be performed in accordance with the guidelines set forth in the attached Permanent Seeding Guidance,which is an excerpt from a publication entitled,"Massachusetts Erosion and Sediment Control Guidelines for Urban and Suburban Areas,May 2003,prepared by Franklin,Hampden, and Hampshire Conservation Districts." 2 Erosion and Sediment Control Practices 157 Seeding, ' 'r anent The establishment of perennial { vegetative cover on disturbed areas. r Purpose _ NANO se ANG Permanent seeding of grass r '` and planting trees and shrubs provides stabilization to the soil by t. holding soil particles in place. Vegetation reduces sediments and runoff to sTAxaP.iDM-01MG downstream areas by slowing the velocity of runoff and permitting greater infiltration of the runoff. Vegetation also filters sediments, helps the soil absorb water, improves wildlife habitats, and enhances the aesthetics of a site. Where Practice Applies Permanent seeding and planting is appropriate for any graded or cleared area where long-lived plant cover is needed to stabilize the soil. Areas which will not be brought to final grade for a year or more. Some areas where permanent seeding is especially important are filter strips, buffer areas, vegetated swales, steep slopes, and stream banks. This practice is effective on areas where soils are unstable because of their texture or structure, high water table, winds, or steep slope. Advantages Advantages of seeding over other means of establishing plants include the small initial establishment cost,the wide variety of grasses and legumes available,low labor requirement,and ease of establishment in difficult areas. Seeding is usually the most economical way to stabilize large areas. Well established grass and ground covers can give an aesthetically pleasing,finished look to a development. Once established,the vegetation will serve to prevent erosion and retard the velocity of runoff. Disadvantages/Problems Disadvantages which must be dealt with are the potential for erosion during the establishment stage,a need to reseed areas that fail to establish, limited periods during the year suitable for seeding,and a need for water and appropriate climatic conditions during germination.Vegetation and mulch cannot prevent soil slippage and erosion if soil is not inherently stable. 158 Erosion and Sediment Control Practices Coarse,high grasses that are not mowed can create a fire hazard in some locales.Very short mowed grass,however,provides less stability and sediment filtering capacity. Grass planted to the edge of a watercourse may encourage fertilizing and mowing near the water's edge and increase nutrient and pesticide contamination. Depends initially on climate and weather for success. May require regular irrigation to establish and maintain. Planning considerations Selection of the right plant materials for the site, good seedbed preparation, timing,and conscientious maintenance are important. Whenever possible, native species of plants should be used for landscaping. These plants are already adapted to the locale and survivability should be higher than with "introduced" species. Native species are also less likely to require irrigation,which can be a large maintenance burden and is neither cost-effective nor ecologically sound. If non-native plant species are used, they should be tolerant of a large range of growing conditions, as low-maintenance as possible, and not invasive. Consider the microclimate within the development area. Low areas may be frost pockets and require hardier vegetation since cold air tends to sink and flow towards low spots. South-facing slopes may be more difficult to re-vegetate because they tend to be sunnier and drier. Divert as much surface water as possible from the area to be planted. Remove seepage water that would continue to have adverse effects on soil stability or the protecting vegetation. Subsurface drainage or other engineering practices may be needed. In this situation, a permit may be needed from the local Conservation Commission: check ahead of time to avoid construction delays. Provide protection from equipment,trampling and other destructive agents. Vegetation cannot be expected to supply an erosion control cover and prevent slippage on a soil that is not stable due to its texture, structure, water movement, or excessive slope. Erosion and Sediment Control Practices 159 Seeding Grasses and Legumes Install needed surface runoff control measures such as gradient terraces, berms, dikes, level spreaders, waterways, and sediment basins prior to seeding or planting. Seedbed Preparation If infertile or coarse-textured subsoil will be exposed during land shaping, it is best to stockpile topsoil and respread it over the finished slope at a minimum 2-to 6-inch depth and roll it to provide a firm seedbed. If construction fill operations have left soil exposed with a loose, rough, or irregular surface, smooth with blade and roll. Loosen the soil to a depth of 3-5 inches with suitable agricultural or construction equipment. Areas not to receive top soil shall be treated to firm the seedbed after incorporation of the lime and fertilizer so that it is depressed no more than 'ri- 1 inch when stepped on with a shoe. Areas to receive topsoil shall not be firmed until after topsoiling and lime and fertilizer is . applied and incorporated, at which time it shall be treated to firm the seedbed as described above. This can be done by rolling or cultipacking. Cool Season Grasses Cool Season Grasses grow rapidly in the cool weather of spring and fall, and set seed in June and July. Cool season grasses become dormant when summer temperatures persist above 85 degrees and moisture is scarce. Lime and Fertilizer Apply lime and fertilizer according to soil test and current Extension Service recommendations. In absence of a soil test, apply lime (a pH of 5.5-6.0 is desired) at a rate of 2.5 tons per acre and 10-20-20 analysis fertilizer at a rate of 500 pounds per acre (40 % of N to be in an organic or slow release form). Incorporate lime and fertilizer into the top 2-3 inches of soil. Seeding Dates Seeding operations should be performed within one of the following periods: April 1 -May 31, August 1 -September 10, November 1 -December 15 as a dormant seeding(seeding rates shall be increased by 50% for dormant seedings). Seeding Methods Seeding should be performed by one of the following methods. Seed should be planted to a depth of %4 to �a inches. Drill seedings, Broadcast and rolled, cultipacked or tracked with a small track piece of construction equipment, Hydroseeding, with subsequent tracking. 160 Erosion and Sediment Control Practices Mulch Mulch the seedings with straw applied at the rate of �tons per acre. Anchor the mulch with erosion control netting or fabric on sloping areas. Warm Season Grasses Warm Season Grasses begin growth slowly in the spring, grow rapidly in the hot summer months and set seed in the fall. Many warm season grasses are sensitive to frost in the fall, and the top growth may die back. Growth begins from the plant base the following spring. .Lime and Fertilizer Lime to attain a pH of at least 5.5. Apply a 0-10-10 analysis fertilizer at the rate of 600 lbs./acre. Incorporate both into the top 2-3 inches of soil. (30 lbs. of slow release nitrogen should be applied after emergence of grass in the late spring.) Seeding Dates Seeding operations should be performed as an early spring seeding (April 1-May 15) with the use of cold treated seed. A late fall early winter dormant seeding(November 1 -December 15) can also be made, however the seeding rate will need to be increased by 50%. Seeding Methods Seeding should be performed by one of the following methods: Drill seedings (de-awned or de-bearded seed should be used unless the drill is equipped with special features to accept awned seed). Broadcast seeding with subsequent rolling, cultipacking or tracking the seeding with small track construction equipment. Tracking should be oriented up and down the slope. Hydroseeding with subsequent tracking. If wood fiber mulch is used, it should be applied as a separate operation after seeding and tracking to assure good seed to soil contact. Mulch Mulch the seedings with straw applied at the rate of %a tons per acre. Anchor the mulch with erosion control netting or fabric on sloping areas. Seed Mixtures for Permanent Cover Recommended mixtures for permanent seeding are provided on the following pages. Select plant species which are suited to the site conditions and planned use.Soil moisture conditions,often the major limiting site factor,are usually classified as follows: Dry-Sands and gravels to sandy loams.No effective moisture supply from seepage or a high water table. Moist-Well drained to moderately well drained sandy loams,loams,and finer; or coarser textured material with moderate influence on root zone from seepage or a high water table. Wet-All textures with a water table at or very near the soil surface,or with enduring seepage. When other factors strongly influence site conditions,the plants selected must also be tolerant of these conditions. Erosion and Sediment Control Practices 161 Permanent Seeding Mixtures Seed, Pounds per; Mix Site Seed Mixture Acre 1,000 sf Remarks 1 Dry Little Bluestem *Use Warm Season planting procedure. or Broomsedge 10 0.25 *Roadsides Tumble Lovegrass* 1 0.10 *Sand and Gravel Stabilization Switchgrass 10 0.25 *Clover requires inoculation with nitrogen- fixing bacteria , Bush Clover* 2 0.10 Red Top 1 0.10 *Rates for this mix are for PLS. s 2 Dry Deertongue 15 0.35 *Use Warm Season planting procedures. Broomsedge 10 0.25 *Acid sites/Mine spoil 4`. Bush Clover's 2 0.10 *Clover requires inoculation with nitrogen- fixing bacteria. i Red Top 1 0.10 *Rates for this mix are for PLS. 3 Dry Big Bluestem 10 0.25 *Use Warm Season planting procedures. I Indian Grass 10 0.25 *Eastern Prairie appearance Switchgrass 10 0:25 *Sand and Gravel pits. Little Bluestem 10 0.25 *Golf Course Wild Areas Red Top or 1 0.10 *Sanitary Landfill Cover seeding -. Perennial Ryegrass 10 0.25 *Wildlife Areas *OK to substitute Poverty Dropseed in place of RedTop/Ryegrass: *Rates for this mix are for PLS. 4 Dry Flat Pea 25 0.60 *Use Cool Season planting procedures Red Top or 2 0.10 *Utility Rights-of-Ways(tends to suppress Perennial Ryegrass 15 0.35 woody growth) 5 Dry Little Bluestein 5 0.10 *Use Warm Season planting procedures. ' Switchgrass 10 0.25 *Coastal sites' Beach Pea* 20 0.45 *Rates for Bluestein and Switchgrass are for '. Perennial Ryegrass 10 0.25 PLS. .6 Dry- Red Fescue 10 0.25 *Use Cool Season planting procedure. Moist Canada Bluegrass 10 0.25 *Provides quick cover but is non-aggressive, Perennial Ryegrass 10 0.25 will tend to allow indigenous plant colonization.' Red Top 1 0.10 *General erosion control on variety of sites, '•. including forest roads,skid trails and I, landings. 7 Moist- Switchgrass 10 0.25 Use Warm Season planting procedure. E Wet Virginia Wild Rye 5 0.10 *Coastal plain/flood plain *Rates for Bluestem and Switchgrass are for Big Bluestem 15 0.35 Red Top 1 0.10 PLS. i,' 162 Erosion and Sediment Control Practices Permanent Seeding Mixtures Seed, Pounds per: f Mix Site Seed Mixture Acre 1,000 sf Remarks '18 Moist Creeping Bentgrass 5 0.10 *Use Cool Season planting procedures. Wet Fringed Bromegrass 5 0.10 *Pond Banks Fowl Meadowgrass 5 0.10 *Waterways/ditch banks t Bluejoint Reedgrass L° or Rice Cutgrass 2 0.10 �r Perennial Ryegrass 10 0.25 S 9 Moist Red Fescue 5 0.10 *Salt Tolerant h Wet Creeping Bentgrass 2 0,10 *Fescue and Bentgrass provide low growing appearance,while Switchgrass provides tall cover for wildlife. f: Switchgrass 8 0.20 f . Perennial Ryegrass 10 0.25 'i0 Moist Red Fescue 5 0.10 *Use Cool Season planting procedure. Wet Creeping Bentgrass 5 0.10 *Trefoil requires inoculation with nitrogen fixing bacteria. ` Virginia Wild Rye 8 0.20 Wood Reed Grass* 1 0.10 *Suitable for forest access roads,skid Showy Tick Trefoil* 1 0.10 trails and other partial shade ' situations. 11 Moist Creeping Bentgrass 5 0.10 *Use Cool Season planting procedure. w. Wet Bluejoint Reed Grass 1 0.10 *Suitable for waterways,pond or ditch banks. Virginia Wild Rye 3 0.10 *Trefoil requires inoculation with nitrogen fixing bacteria. Fowl Meadow Grass 10 0.25 Showy Tick Trefoil* 1 0.10 Red Top 1 0.10 Wet; Blue Joint Reed Grass 1 0.10 *`Use Cool Season planting procedure. Canada Manna Grass 1. 0.10" *'OK to seed in saturated soil conditions,but not in standing water. Rice Cut Grass 1 0.10 Creeping Bent Grass 5 0.10 *Suitable as stabilization seeding for . created:wetland. ' Fowl Meadow Grass 5 0.10 *All species in this mix are native to Massachusetts. ;13 Dry- American Beachgrass 18" 18' *Vegetative planting with dormant culms,3-5 culms per planting f' Moist centers centers Y. ' 14 Inter- Smooth Cordgrass 12-18" 12-18 *Vegetative planting with transplants. Y Tidal Saltmeadow Cordgrass centers centers 163 Erosion and Sediment Control Practices Notes: * Species such as Tumble Lovegrass,Fringed Bromegrass,Wood Reedgrass, Bush Clover and Beach Pea,while known to be commercially available from specific seed suppliers, may not always be available from your particular seed suppliers.The local Natural Resources Conservation Service office may be able to help with a source of supply. In the event a particular species listed in a mix can not be obtained, however, it may be possible to substitute another species. Seed mixtures by courtesy of Natural Resources Conservation Service,Amherst,MA. (PLS) Pure Live Seed Warm Season grass seed is sold and planted on the basis of pure live seed.An adjustment is made to the bulk rate of the seed to compensate for inert material and non-viable seed. Percent of pure live seed is calculated by multiplying the percent purity by the percent germination; C/ purity)x(/' germination) =percent PLS. For example, if the seeding rate calls for 10 lbs./acre PLS and the seed lot has a purity of 70% and germination of 75%, the PLS factor is: (.70 x .75) =.53 10 lbs. divided by.53 = approx. 19 lbs. Therefore, 19 lbs of seed from the particular lot will need to be applied to obtain 10 lbs. of pure live seed. Special Note Tall Fescue, Reed Canary Grass, Crownvetch and Birdsfoot Trefoil are no longer recommended for general erosion control use in Massachusetts due to the invasive characteristics of each. If these species are used, it is recommended that the ecosystem of the site be analyzed for the effects species invasiveness may impose. The mixes listed in the above mixtures include either species native to' Massachusetts or non-native species that are not perceived to be invasive, as per the Massachusetts Native Plant Advisory Committee. 164 Erosion and Sediment Control Practices Wetlands Seed Mixtures For newly created wetlands, a wetlands specialist should design plantings to provide the best chance of success. Do not use introduced, invasive plants like reed canarygrass (Phalaris arundinacea) or purple loosestrife (Lythrum salicaria). Using plants such as these will cause many more problems than they will solve. The following grasses all thrive in wetland situations: c93 Fresh Water Cordgrass (Spartina pectinata) c!s Marsh/Creeping Bentgrass (Agrostis stolonifera, var. Palustric) cs Broomsedge (Andropogon virginicus) C3 Fringed Bromegrass (Bromus ciliatus) C,s Blue Joint Reed Grass (Calamagrostis cavedensis) cis Fowl Meadow Grass (Glyceria striata) cis Riverbank Wild Rye (Elymus riparius) cos Rice Cutgrass (Leersia oryzoides) Cr3 Stout Wood Reed (Cinna arundinacea) Cr3 Canada Manna Grass (Glyceria canadensis) A sample wetlands seed mix developed by The New England Environmental Wetland Plant Nursery is shown on the following page. Wetland Seed Mixture The New England Environmental Wetland Plant Nursery has developed a seed mixture which is specifically designed to be used in wetland replication projects and stormwater detention basins.It is composed of seeds from a variety of indigenous wetland species. Establishing a native wetland plant understory in these areas provides quick erosion control, wildlife food and cover, and helps to reduce the establishment of undesirable invasive species such as Phragmites and purple loosestrife(Lythrum salicaria). The species have been selected to represent varying degrees of drought tolerance, and will establish themselves based upon microtopography and the resulting variation in soil moisture. Erosion and Sediment Control Practices 165 ' Common Name x (5ctent�fic 1Vame / n'-Mlk CO mends �.urid Side 30 A low ground cover that toleratesmesic sites (Carex lurch) in addition to saturated areas,prolific seeder r � II-se 0 grOWang SeaSOIi Fo�v1 lVie4dow Grass 25 Prolific seed producer that is a va#cable �Ghycerrcr cznad t04,) _ wildli#e food souurce. `ringed Sedge 10 A medium toarge}sedge that tolerates Carexrrria) saturated areas good seed producer Jo`e-P ye Need l 0 �'l9 r�er�r��nl tk�at�s�ahua e for w�tiiX�#e ( trpatvrccelprs maculalus) eove� Grows to feet Bro�►k Sedge 10 'aleates a wide atge ohydrologie aare " Pvae group potditoris x J WooerjwTolerates#luPA ttati�ng b�rdr©logy E C[ 4 rprrs peaz 3 T �1ne3ert yal�able#or w�ldl�#e o di xate s Aq a d ex Qpor feet��y used an d t m� � i # xt s w + b r re�� x +e ise c� � r be txestiltsY Xale fiiu P�� o�� r�;t��.� d�� ' �a�� xe�imtne�►�:ed��r�� li �n��ate� 166 Erosion and Sediment Control Practices Maintenance Inspect seeded areas for failure and make necessary repairs and reseed immediately. Conduct or follow-up survey after one year and replace failed plants where necessary. If vegetative cover is inadequate to prevent rill erosion, overseed and fertilize in accordance with soil test results. If a stand has less than 40% cover, reevaluate choice of plant materials and quantities of lime and fertilizer. Re-establish the stand following seedbed preparation and seeding recommendations, omitting lime and fertilizer in the absence of soil test results. If the season prevents resowing, mulch or jute netting is an effective temporary cover. Seeded areas should be fertilized during the second growing season. Lime and fertilize thereafter at periodic intervals, as needed. References North Carolina Department of Environment, Health, and Natural Resources, Erosion and Sediment Control Field Manual, Raleigh, NC, February 1991. Personal communication,Richard J. DeVergilio, USDA, Natural Resources Conservation Service,Amherst, MA. U.S. Environmental Protection Agency,Storm Water Management For Construction Activities, EPA-832-R-92-005,Washington, DC, September, 1992. Washington State Department of Ecology, StormwaterManagement Manual for the Puget Sound Basin, Olympia, WA, February, 1992. HYDRO-SEEDING Erosion and Sediment Control Practices 167 Seeding, eri3orary Planting rapid-growing annual grasses, small grains, or legumes to provide initial, temporary cover for erosion control on disturbed areas. f101��:ken„. Purpose wwat To temporarily stabilize areas that will not be brought to final grade foray„ period of more than 30 working days. T¢rF To stabilize disturbed areas before final grading or in a season not suitable for in-'tMt aawWPO-1. permanent seeding. art's M w t OU Temporary seeding controls runoff and erosion until permanent vegetation or other erosion control measures can be established. Root systems hold down the soils so that they are less apt to be carried offsite by storm water runoff or wind. Temporary seeding also reduces the problems associated with mud and dust from bare soil surfaces during construction. Where Practice Applies On any cleared, unvegetated, or sparsely vegetated soil surface where vegetative cover is needed for less than one year.Applications of this practice include diversions, dams,temporary sediment basins, temporary road banks, and topsoil stockpiles. Where permanent structures are to be installed or extensive re- grading of the area will occur prior to the establishment of permanent vegetation. Areas which will not be subjected to heavy wear by construction traffic. Areas sloping up to 10% for 100 feet or less, where temporary seeding is the only practice used. Advantages This is a relatively inexpensive form of erosion control but should only be used on sites awaiting permanent planting or grading. Those sites should have permanent measures used. Vegetation will not only prevent erosion from occurring, but will also trap sediment in runoff from other parts of the site. Temporary seeding offers fairly rapid protection to exposed areas. 168 Erosion and Sediment Control Practices Disadvantages/Problems Temporary seeding is only viable when there is a sufficient window in time for plants to grow and establish cover. It depends heavily on the season and rainfall rate for success. If sown on subsoil, growth will be poor unless heavily fertilized and limed. Because overfertilization can cause pollution of stormwater runoff, other practices such as mulching alone may be more appropriate. The potential for over-fertilization is an even worse problem in or near aquatic systems. Once seeded, areas should not be travelled over. Irrigation may be needed for successful growth. Regular irrigation is not encouraged because of the expense and the potential for erosion in areas that are not regularly inspected. Planning Considerations Temporary seedings provide protective cover for less than one year. Areas must be reseeded annual or planted with perennial vegetation. Temporary seeding is used to protect earthen sediment control practices and to stabilize denuded areas that will not be brought'into final grade for several weeks or months. Temporary seeding can provide a nurse crop for permanent vegetation, provide residue for soil protection and seedbed preparation, and help prevent dust production during construction. Use low-maintenance native species wherever possible. Planting should be timed to minimize the need for irrigation. Sheet erosion, caused by the impact of rain on bare soil, is the source of most fine particles in sediment. To reduce this sediment load in runoff, the soil surface itself should be protected. The most efficient and economical means of controlling sheet and rill erosion is to establish vegetative cover. Annual plants which sprout rapidly and survive for only one growing season are suitable for establishing temporary vegetative cover. Temporary seeding is effective when combined with construction phasing so bare areas of the site are minimized at all times. Temporary seeding may prevent costly maintenance operations on other erosion control systems. For example, sediment basin clean-outs will be reduced if the drainage area of the basin is seeded where grading and construction are not taking place. Perimeter dikes will be more effective if not choked with sediment. Proper seedbed preparation and the use of quality seed are important in this practice just as in permanent seeding. Failure to carefully follow sound agronomic recommendations will often result in an inadequate stand of vegetation that provides little or no erosion control. Soil that has been compacted by heavy traffic or machinery may need to be loosened. Successful growth usually requires that the soil be tilled before the seed is applied. Topsoiling is not necessary for temporary seeding; however, it may improve the chances of establishing temporary vegetation in an area. Erosion and Sediment Control Practices 169 Planting Procedures Time of Planting Planting should preferably be done between April 1 and June 30, and September 1 through September 30. If planting is done in the months of July and August, irrigation may be required. If planting is done between October 1 and March 31, mulching should be applied immediately after planting. If seeding is done during the summer months, irrigation of some sort will probably be necessary. Site Preparation Before seeding, install needed surface runoff control measures such as gradient terraces, interceptor dike/swales, level spreaders, and sediment basins. Seedbed Preparation The seedbed should be firm with a fairly fine surface. Perform all cultural operations across or at right angles to the slope. See Topsoiling and Surface Roughening for more information on seedbed preparation.A minimum of 2 to 4 inches of tilled topsoil is required. Liming and Fertilization Apply uniformly 2 tons of ground limestone per acre(1001bs. per 1,000 Sq. Ft.) or according to soil test. Apply uniformly 10-10-10 analysis fertilizer at the rate of 400 lbs. per acre(14 lbs. per 1,000 Sq. Ft.) or as indicated by soil test. Forty percent of the nitrogen should be in organic form. Work in lime and fertilizer to a depth of 4 inches using any suitable equipment. ►p � ► �� ib �tecombieWd rr11.t June l � J'oi ;ll� 0A" Matey to Jrpe U 51 Rl "�►�I1rst ICJ0ept 1 { 170 Erosion and Sediment Control Practices Seeding Select adapted species from the accompanying table: Apply seed uniformly according to the rate indicated in the table by broadcasting, drilling or hydraulic application. Cover seeds with suitable equipment as follows: .Rye grass '/a inch Millet '!,i to 3/ inch pOats 1 to 1-1/2 inches Winter rye 1 to 1-1/2 inches. Mulch Use an effective mulch, such as clean grain straw; tacked and/or tied down with netting to protect seedbed and encourage plant growth. Common Trouble Points Lime and fertilizer not incorporated to at least 4 inches May be lost to runoff or remain concentrated near the surface where they may inhibit germination. Mulch rate inadequate or straw mulch not tacked down Results in poor germination or failure, and erosion damage. Repair damaged areas, reseed and mulch. Annual ryegrass used for temporary seeding Ryegrass reseeds itself and makes it difficult to establish a good cover of permanent vegetation. Seed not broadcast evenly or rate too low Results in patchy growth and erosion. Maintenance Inspect within 6 weeks of planting to see if stands are adequate. Check for damage after heavy rains. Stands should be uniform and dense. Fertilize, reseed, and mulch damaged and sparse areas immediately. Tack or tie down mulch as necessary. Seeds should be supplied with adequate moisture. Furnish water as needed, especially in abnormally hot or dry weather or on adverse sites. Water application rates should be controlled to prevent runoff. Erosion and Sediment Control Practices 171 References Massachusetts Department of Environmental Protection, Office of Watershed Management, Nonpoint Source Program, Massachusetts Nonpoint Source Management Manual,Boston, Massachusetts, June, 1993. North Carolina Department of Environment, Health, and Natural Resources, Erosion and Sediment Control Field Manual,Raleigh, NC, February 1991. U.S. Environmental Protection Agency,Storm Water Management For Construction Activities, EPA-832-R-92-005,Washington, DC, September, 1992. Washington State Department of Ecology, Stormwater Mana ement Manual for the Puget Sound Basin, Olympia, WA, February, 1992. A temporary sediment barrier installed parallel to the bank of a stream or lake. Used to contain the sediment produced by construction operations on the bank of a stream or lake and allow for its removal. -` Where Practice ,' e Applies , The silt curtain is used along the banks of streams or lakes where sediment could '4 pollute or degrade the - - stream or lake. Planning Considerations A silt curtain is useful where construction is on the bank of a stream or lake and coarse sediment is a major concern.A silt curtain will not keep the water from being muddy during construction operations, but it will contain the coarse sediment to the construction area. The curtain should obstruct the flow as little as possible to reduce the chance of failure. SNOW DISPOSAL GUIDELINES Snow Disposal #2302 Turnpike Street North Andover, Massachusetts November 4, 2015 The snow disposal guidelines below offer information on the proper steps to take when locating sites and coming up with options for disposing of snow. Finding a place to dispose of collected snow poses a challenge to municipalities and businesses as they clear roads, parking lots, bridges, and sidewalks. Public safety is of the utmost importance. However, care must be taken to ensure that collected snow, which may be contaminated with road salt, sand, litter, and automotive pollutants such as oil, is disposed of in a manner that will minimize threats to nearby waterbodies. This guidance describes appropriate measures to be taken, including in cases of emergency when,other options are not available. If you have questions on MassDEP's snow disposal guidance, you may contact one of MassDEP's Regional Offices: Northeast Regional Office, Wilmington, 978-694-3249 Southeast Regional Office, Lakeville, 508-946-2714 Central Regional Office, Worcester, 508-767-2722 Western Regional Office, Springfield, 413-784-1100. Effective Date: March 8, 2001 Guideline No. BRPG01-01 Applicability: Applies to all federal, state, regional and local agencies, as well as to private businesses. Supersedes: BRP Snow Disposal Guideline BRPG97-1 issued 12/19/97, and all previous snow disposal guidance Approved by: Glenn Haas, Assistant Commissioner for Resource Protection PURPOSE: To provide guidelines to all government agencies and private businesses regarding snow disposal site selection, site preparation and maintenance, and emergency snow disposal options that are acceptable to the Department of Environmental Protection, Bureau of Resource Protection. APPLICABILITY: These Guidelines are issued by the Bureau of Resource Protection on behalf of all Bureau Programs (including Drinking Water Supply, Wetlands and Waterways,Wastewater Management, and Watershed Planning and Permitting). They apply to public agencies and private businesses disposing of snow in the Commonwealth of Massachusetts. INTRODUCTION Finding a place to dispose of collected snow poses a challenge to municipalities and businesses as they clear roads, parking lots, bridges, and sidewalks.While we are all aware of the threats to public safety caused by snow, collected snow that is contaminated with road salt, sand, litter, and automotive pollutants such as oil also threatens public health and the environment. Snow Disposal #2302 Turnpike Street, North Andover, MA November 4, 2015 As snow melts, road salt, sand, litter, and other pollutants are transported into surface water or through the soil where they may eventually reach the groundwater. Road salt and other pollutants can contaminate water supplies and are toxic to aquatic life at certain levels. Sand washed into waterbodies can create sand bars or fill in wetlands and ponds, impacting aquatic life, causing flooding, and affecting our use of these resources. There are several steps that communities can take to minimize the impacts of snow disposal on public health and the environment. These steps will help communities avoid the costs of a contaminated water supply, degraded waterbodies, and flooding. Everything we do on the land has the potential to impact our water resources. Given the authority of local government over the use of the land, municipal officials and staff have a critically important role to play in protecting our water resources. The purpose of these guidelines is to help municipalities and businesses select, prepare, and maintain appropriate snow disposal sites before the snow begins to accumulate through the winter. RECOMMENDED GUIDELINES These snow disposal guidelines address: (1)site selection; (2) site preparation and maintenance; and (3)emergency snow disposal. 1. SITE SELECTION The key to selecting effective snow disposal sites is to locate them adjacent to or on pervious surfaces in upland areas away from water resources and wells. At these locations, the snow meltwater can filter in to the soil, leaving behind sand and debris which can be removed in the springtime. The following areas should be avoided: • Avoid dumping of snow into any waterbody, including rivers, the ocean, reservoirs, ponds, or wetlands. In addition to water quality impacts and flooding, snow disposed of in open water can cause navigational hazards when it freezes into ice blocks. • Do not dump snow within a Zone II or Interim Wellhead Protection Area (IWPA)of a public water supply well or within 75 feet of a private well, where road salt may contaminate water supplies. • Avoid dumping snow on MassDEP-designated high and medium-yield aquifers where it may contaminate groundwater(see the next page for information on ordering maps from MassGIS showing the locations of aquifers, Zone II's, and IWPAs in your community). • Avoid dumping snow in sanitary landfills and gravel pits. Snow meltwater will create more contaminated leachate in landfills posing a greater risk to groundwater, and in gravel pits, there is little opportunity for pollutants to be filtered out of the meltwater because groundwater is close to the land surface. • Avoid disposing of snow on top of storm drain catch basins or in stormwater drainage swales or ditches. Snow combined with sand and debris may block a storm drainage system, causing localized flooding. A high volume of sand, sediment, and litter released from melting snow also may be quickly transported through the system into surface water. 2 Snow Disposal #2302 Turnpike Street, North Andover, MA November 4, 2015 Site Selection Procedures a) It is important that the municipal Department of Public Works or Highway Department, Conservation Commission, and Board of Health work together to select appropriate snow disposal sites. The following steps should be taken: b) Estimate how much snow disposal capacity is needed for the season so that an adequate number of disposal sites can be selected and prepared. c) Identify sites that could potentially be used for snow disposal such as municipal open space (e.g., parking lots or parks). d) Sites located in upland locations that are not likely to impact sensitive environmental resources should be selected first. e) If more storage space is still needed, prioritize the sites with the least environmental impact(using the site selection criteria, and local or MassGIS maps as a guide). MassGIS Maps of Open Space and Water Resources If local maps do not show the information you need to select appropriate snow disposal sites, you may order maps from MassGIS (Massachusetts Geographic Information System)which show publicly owned open spaces and approximate locations of sensitive environmental resources (locations should be field-verified where possible). Different coverages or map themes depicting sensitive environmental resources are available from MassGIS on the map you order. At a minimum, you should order the Priority Resources Map. The Priority Resources Map includes aquifers, public water supplies, MassDEP-approved Zone II's, Interim Wellhead Protection Areas, Wetlands, Open Space, Areas of Critical Environmental Concern, NHESP Wetlands Habitats, MassDEP Permitted Solid Waste facilities, Surface Water Protection areas (Zone A's)and base map features.The cost of this map is $25.00. Other coverages or map themes you may consider, depending on the location of your city or town, include Outstanding Resource Waters and MassDEP Eelgrass Resources. These are available at$25.00 each, with each map theme being depicted on a separate map. Maps should be ordered from MassGIS . Maps may also be ordered by fax at 617-626-1249(order form available from the MassGIS web site) or mail. For further information, contact MassGIS at 617-626-1189. 2. SITE PREPARATION AND MAINTENANCE In addition to carefully selecting disposal sites before the winter begins, it is important to prepare and maintain these sites to maximize their effectiveness. The following maintenance measures should be undertaken for all snow disposal sites: • A silt fence or equivalent barrier should be placed securely on the downgradient side of the snow disposal site. • To filter pollutants out of the meltwater, a 50-foot vegetative buffer strip should be maintained during the growth season between the disposal site and adjacent waterbodies. • Debris should be cleared from the site prior to using the site for snow disposal. 3 Snow Disposal #2302 Turnpike Street, North Andover, MA November 4, 2015 • Debris should be cleared from the site and properly disposed of at the end of the snow season and no later than May 15. 3. EMERGENCY SNOW DISPOSAL As mentioned earlier, it is important to estimate the amount of snow disposal capacity you will need so that an adequate number of upland disposal sites can be selected and prepared. If despite your planning, upland disposal sites have been exhausted, snow may be disposed of near waterbodies. A vegetated buffer of at least 50 feet should still be maintained between the site and the waterbody in these situations. Furthermore, it is essential that the other guidelines for preparing and maintaining snow disposal sites be followed to minimize the threat to adjacent waterbodies. Under extraordinary conditions, when all land-based snow disposal options are exhausted, disposal of snow that is not obviously contaminated with road salt, sand, and other pollutants may be allowed in certain waterbodies under certain conditions. In these dire situations, notify your Conservation Commission and the appropriate MassDEP Regional Service Center before disposing of snow in a waterbody. Use the following guidelines in these emergency situations: • Dispose of snow in open water with adequate flow and mixing to prevent ice dams from forming. • Do not dispose of snow in saltmarshes, vegetated wetlands, certified vernal pools, she beds, mudflats, drinking water reservoirs and their tributaries, Zone Its or IWPAs of public water supply wells, Outstanding Resource Waters, or Areas of Critical Environmental Concern. • Do not dispose of snow where trucks may cause shoreline damage or erosion. • Consult with the municipal Conservation Commission to ensure that snow disposal in open water complies with local ordinances and bylaws. FOR MORE INFORMATION If you have questions on MassDEP's snow disposal guidance, you may contact one of MassDEP's Regional Offices: Northeast Regional Office,Wilmington, 978-694-3249 Southeast Regional Office, Lakeville, 508-946-2714 Central Regional Office, Worcester, 508-767-2722 Western Regional Office, Springfield, 413-784-1100. 4 DEICING CHEMICAL (ROAD SALT) STORAGE Deicing Chemical (Road Salt) Storage #2302 Turnpike Street North Andover, Massachusetts November 4, 2015 Effective Date: December 19, 1997 Guideline No. DWSG97-1 Applicability:Applies to all parties storing road salt or other chemical deicing agents. Supersedes: Fact Sheet: DEICING CHEMICAL (ROAD SALT)STORAGE (January 1996) Approved by: Arleen O'Donnell, Asst. Commissioner for Resource Protection PURPOSE: To summarize salt storage prohibition standards around drinking water supplies and current salt storage practices. APPLICABILITY: These guidelines are issued on behalf of the Bureau of Resource Protection's Drinking Water Program. They apply to all parties storing road salt or other chemical deicing agents. I. The Road Salt Problem: Historically, there have been incidents in Massachusetts where improperly stored road salt has polluted public and private drinking water supplies. Recognizing the problem, state and local governments have taken steps in recent years to remediate impacted water supplies and to protect water supplies from future contamination. As a result of properly designing storage sheds, new incidents are uncommon. These guidelines summarize salt storage prohibition standards around drinking water supplies and current salt storage practices. II. Salt Pile Restrictions in Water Supply Protection Areas: Uncovered storage of salt is forbidden by Massachusetts General Law Chapter 85, section 7A in areas that would threaten water supplies.The Drinking Water Regulations, 310 CMR 22.21(2)(b), also restrict deicing chemical storage within wellhead protection areas (Zone I and Zone II)for public water supply wells, as follows: "storage of sodium chloride, chemically treated abrasives or other chemicals used for the removal of ice and snow on roads [are prohibited], unless such storage is within a structure designed to prevent the generation and escape of contaminated runoff or leachate." For drinking water reservoirs, 310 CMR 22.20C prohibits, through local bylaw, uncovered or uncontained storage of road or parking lot de-icing and sanding materials within Zone A at new reservoirs and at those reservoirs increasing their withdrawals under MGL Chapter 21 G, the Water Management Act. For people on a low-sodium diet, 20 mg/L of sodium in drinking water is consistent with the bottled water regulations' meaning of"sodium free."At 20 mg/L, sodium contributes 10% or less to the sodium level in people on a sodium- . restricted diet. For more information contact: Catherine Sarafinas at 617-556-1070 or catherine.sarafinas(a),state.ma.us. III. Salt Storage Best Management Practices (BMP): Components of an "environment-friendly"roadway deicing salt storage facility include: 0 the right site =a flat site; Deicing Chemical (Road Salt)Storage #2302 Turnpike Street, North Andover, MA November 4, 2015 • adequate space for salt piles; • storage on a pad (impervious/paved area); • storage under a roof; and • runoff collection/containment. For more information, see The Salt Storage Handbook, 6th ed. Virginia: Salt Institute, 2006 (phone 703-549-4648 orhttp://www.saltinstitute.org/publication/safe-and-sustainable-snowfighting/). IV. Salt Storage Practices of the Massachusetts Highway Department: The Massachusetts Highway Department(MHD) has 216 permanent salt storage sheds at 109 locations in the state. On leased land and state land under arteries and ramps, where the MHD cannot build sheds, salt piles are stored under impermeable material. This accounts for an additional 15 sites.The MHD also administers a program to assist municipalities with the construction of salt storage sheds. Of 351 communities, 201 municipalities have used state funds for salt storage facilities. For more information about MHD's salt storage facilities, contact Paul Brown at the Massachusetts Highway Department, 10 Park Plaza, Boston, MA 02116 (phone 617-973-7792). 2