three county fairgrounds stormwater drainage report 11-03-2010

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Storm water Drainage Report

City of Northampton Stormwater Permit Application For:

Prepared by:

~~~The ~ Berkshire Design Group, Inc.

4 Allen Place, Northampton, Massachusetts 0 I 060

Three County Fairgrounds Phase 1 Redevelopment Plan

Northampton, MA

October 1, 2010 Revised October 25,2010 Revised November 1,2010 Revised November 3,2010

Prepared for: Three County Fairgrounds

59 Fair Street Northampton, MA 01060

STORM WATER MANAGEMENT PERMIT

Fcc: Paid

Dale: Paid

Pc:mulll

City ofNortta.mpton DCplrlmenl of Public: Work.~

APPLICA TION Approved By' _____ _

Appro .. ·aJ Dati: =---,,=_~,-( For IJPW 1J.Je only)

1. Project I Site Information

ProjectlSiteName: :r1yV'« rM'l\~ ~NJ\.lMS -?L..'&.i.12Lrtle\6(~~ Project Street I Location: S1' ~J~+ Assessor's Map: -- 2ff~ Parcel(s): ""2.6"(

Estimated Area to be Disturbed (rr): _--7\--'-'-D-'>LJJ-I.O;.."1B-""-'-\'L/-=-_________ _

Total Area ofimpervious Surfaces:

(paved, parking, decks, roofs, etc.) (rr)

Existing

i30,9'2-Proposed

•

Project Type (check one)

CJ Residential Site (I unit and 1-5 Acres Disturbed)

CJ Residential Site (I unit and greater than 5 Acres Disturbed)

CJ Minor Residential Subdivision (I lot and disturbing I to 5 acres ofland)

CJ Residential Subdivision and Other Residential such as Townhouse or Retirement Development (2 or more units in B

common plan of development) CJ Commercial Subdivision

I 'j9..commerciaJ or Industrial Site ~c::: CJ Land Disturbance Only (No change in site use or buildings.

May include reconstruction of parking lots, roads, and driveways ' utility work; and lawn and landscaping work.)

2. Applicant Information

Name: ~.jc.e.. ;\v.\\c [r)'3;7:

Address: 0/1 ~ lJ 50llih ?t-.-eef-Telephone: lfB- S8Y- '1030 E-Mail: rna; Ie h4¥bo.rj~dl~ F~: __________________________ __

4. Certification

53D. "\:} I

Permit Review and Inspection Fee

5700 51 , 100

5700 or S I per linear foot of roadway or common driveway (which ever is greater)

52000 or 52 per linear foot of roadway or common driveway (which ever is greater)

52000 or 52 per linear foot of roadway or common driveway (which ever is greater)

I- 5700 per acre disturbed (maximum of55,OOO)

5100 per acre disturbed

3. Owner Information (if different from (%;ca.t)

&uce.. 7h4 ~

I herby certify that the information contained herein Including all attachments Is true, accurate and complete to the best of my k.nowledge. Further, l grant the Northampton Department of Public Works and its agents permission to enter the property to review this application and make inspections during and after

cL £v4 /!)8;Uo ) _ Applient;S ~i~alure date

R?v::e~~b~~"~·\ C> ~-"Bt-OLeStJ &ro;-S

~? UJ&t!J4t F

Owner's sig;.ature . Date

5. Application Requirements

The application to the Northampton Department of Public Works (DPW) for a Stormwater Management Permit must include submission of the following:

ill Completed and Signed Stormwater Management Permit Application

o Non-Refundable Permit Review and Inspection Fee \l/A ~Operation, Maintenance, and Inspection Agreement

~hree complete copies of the Stonnwater Management Plan and Erosion and Sediment Control Plan prepared by a professional engineer licensed by the Commonwealth of Massachusetts, and including the minimum documentation listed below (see the Northampton Stonnwater Management Ordinance (Chapter 22, Article V) for more information): :2--?-ofILS

Project Documentation: (Check circles below indicating that you have provided the following minimum infonnation)

A Identity all operators for the project site and the potions over which each operator has control. ci:: All plans submitted have been prepared and stamped by a professional engineer licensed by

the Commonwealth of Massachusetts o The applicant has certified on the drawings that all clearing, grading. drainage, construction,

and development shall be conducted in strict accordance with the plan f:f Locus map ill The existing zoning, and land use at the site ~ The proposed land use C4 The location of existing and proposed easements ® The location of existing and proposed utilities -fQ The site' s existing & proposed topography with contours at 2 foot intervals fQ Soils investigation (by a Certified Soil Evaluator or Certified Professional Soil Scientist)

including borings or test pits, to a depth greater than 4 ft. below estimated seasonal ground water for areas where construction of infiltration practices will occur.

Q Estimated seasonal high groundwater elevation (November to April) in areas to be used for storm water retention, detention, or infiltration (by a Certified Soil Evaluator or Certified Professional Soil Scientist).

~ A description & delineation of existing stonmwater conveyances. impoundments, and wetlands on or adjacent to the site or into which stom] water flows.

!Q A delineation of 100-year flood plains, if applicable. ~ The existing and proposed vegetation and ground surfaces with runoff coefficient for each. S{. A drainage area map showing pre and post construction watershed boundaries, drainage area.

stonm water flow paths, and receiving water. ~ A description and drawings of all components of the proposed drainage system including:

I) tbe structural details for all components of the proposed drainage systems and stonm water management facilities (including size, inverts, and grade);

2) all measures for the detention, retention or infiltration of water; 3) all measures for the protection of water quality; 4) notes on drawings specitying materials to be used, construction specifications, and

typicals; 5) the existing and proposed site hydrology with supporting drainage calculations (including

the 1,2, 10, and 100 year NRCS design stonms);

Northampton Department of Public Works Stonnwater Management Penn it

Page 2

6) proposed improvements including location of buildings or other structures, impervious surfaces. and drainage facilities, if applicable;

7) location, cross sections, and profiles of all potentially impacted brooks, streams, drainage swales and their method of stabilization; and

8) proposed ownership of drainage system structures.

\l- Estimate ofthe total area expected to be disturbed by excavation, grading or other construction activities.

Iii..A description and location of all measures (i.e., Best Management Practices) that will be implemented as part of the construction activity to control pollutants in storm water discharges. A description of when each control measure will be implemented in the construction schedule, which operator is responsible for the implementation of each control measure and a maintenance and inspection schedule for each control measure during construction.

6( A description of construction and waste materials expected to be stored on-site, and a description of controls to reduce pollutants from these materials including storage practices to minimize exposure of the materials to storm water, and spill prevention and response.

P- Timing, schedules, and sequence of development including clearinjl, strippi~g, "m rading,. I construction, final grading, and vegetative stabilization. I _ Ui 1\ tIL. '5>\>'0 M1 ~ \o:>'tT\'\

L-Y l..lWt:~ "5'Wt" P r; o('{ 0

6. Application Submission, Review, and Approval Procedures q)t1"*,,,"d-~ 0<\

1. Application Submittal: The application to the Northampton DPW for a Stormwater Management Permit must be submitted prior to or concurrently with any land use permit application. Submission of an application should be made to the Northampton Department of Public Works, 125 Locust St., Northampton, MA 01060. For more information and copies of the Northampton Storm water Ordinance visit the DPW web site at http://www.northamptonma.gov/dpw/Stormwater/ or contact Doug McDonald at 413-587-1582 x308 or dmcdonaldlalnohodpw.org

2. Administrative Review: The Northampton DPW will have 7 days from the receipt of the application to review the application for administrative completeness. Incomplete applications will be disapproved and returned to the applicant based on the determination that they are admirustratively incomplete.

3. Review: If the application is found to be complete, the Northampton DPW will review the application and supporting documents based on the criteria set forth in the Northampton Stonnwater Management Ordinance (Chapter 22, Article V) and will take final action within 21 days (including the 7 day administrative review period) of the receipt of a complete application unless such time is extended by agreement between the applicant and the DPW.

4. Final Action: The Northampton DPW' s tinal action will be in writing and will be sent to the applicant and the appropriate City Department(s) and Board(s).

Northampton Department of Public Works Stonnwater Management Pennit

Page 3

Three County Fairgrounds • 10/08/09 Stormwater Report Checklist • Page 1 of 8

Massachusetts Department of Environmental Protection Bureau of Resource Protection - Wetlands Program

Checklist for Stormwater Report

A. Introduction

Important: When filling out forms on the computer, use only the tab key to move your cursor - do not use the return key.

A Stormwater Report must be submitted with the Notice of Intent permit application to document compliance with the Stormwater Management Standards. The following checklist is NOT a substitute for the Stormwater Report (which should provide more substantive and detailed information) but is offered here as a tool to help the applicant organize their Stormwater Management documentation for their Report and for the reviewer to assess this information in a consistent format. As noted in the Checklist, the Stormwater Report must contain the engineering computations and supporting information set forth in 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.

1 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 8

2

• 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.

1 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.

I



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 Longterm 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 Repo~71"~¥~~5\-o~i~S ~~~ date of this permit application.

Registered Professional Engineer Block and Si~ature

~ ,. Signature and Date

I oj e/zDl 0 • I

Checklist Project Type: Is the application for new development, redevelopment, or a mix of new and redevelopment?

D New development

[8J Redevelopment

D Mix of New Development and Redevelopment

Three County Fairgrounds· 10/08109 Stormwater Report Checklist· Page 2 of 8




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):

Media filtration system inlets for detention system

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.





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

1

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 (to the maximum extent practicable)

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. 21E 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. As a redevelopment project

Calculations showing that the infiltration BMPs will drain in 72 hours are provided.

Property includes a M.G.L. c. 21E site or a solid waste landfill and a mounding analysis is included.

1 80% TSS removal is required prior to discharge to infiltration BMP if Dynamic Field method is used.





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.





Standard 4: Water Quality (continued)

The BMP is sized (and calculations provided) based on:

The ½” 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. Per STC Sizing

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. Rated 2 on MASTEP

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 5: Land Uses With Higher Potential Pollutant Loads (LUHPPLs) Not Applicable – Proposed project site is not expected to yield high potential pollutant loads.

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 Not Applicable – The project site does not discharge to a critical area.

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.





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

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.





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.

Three County Fairgrounds - Phase 1 October 1, 2010 – Revised 10/25/10 & 11/1/10& 11/3/10

Northampton, Massachusetts Stormwater Drainage Report

The Berkshire Design Group, Inc. Page 1

Table of Contents

Introduction 2

Site Terrain and Soils 3

Existing Conditions 3

Proposed Conditions 5

Calculations and Design 6

MADEP Stormwater Standards 8

Summary 10

Figures

Figure 1 Pre- Development Drainage Area Map

Figure 2 Post Development Drainage Area Map

Figure 3 USDA Soils Map

Appendices

Appendix A Pre- and Post Development Hydrologic Calculations

Appendix B Soil Test Pit Information

Appendix C TSS Removal Summary and Calculations

Appendix D Standard 3 Recharge Calculations

Appendix E Proposed Stormwater Management System Operation &Maintenance

P Plan

Appendix F Long Term Pollution Prevention Plan




I. Introduction

The following report presents an analysis of the stormwater management system

for the proposed Phase 1 redevelopment the Three County Fairgrounds, located

off Route 9 in Northampton, Massachusetts which is located in the SC zoning

district.

Locus Map (site outlined in red)

The proposed project involves the redevelopment of a portion of the site. The 15

existing horse barns and other small buildings will be demolished and 3 new barns

are proposed to be constructed, along with associated roads/walking paths,

landscaping, and stormwater management.

The drainage areas analyzed total 56.80 acres of which approximately 16.30 acres

will be disturbed by construction activities. The impervious area on site will

increase by approximately 1.16 acres due to the new construction. The proposed

stormwater management system will work in conjunction with the existing

system. Mechanisms to reduce runoff and treat water quality include existing

deep sump catch basins, new drains with sumps, subsurface detention systems, an




infiltration trench designed specifically for the phase 1 portion of the project,

stormwater treatment chamber, and 2 existing detention ponds.

Site Terrain and Soils

The project site is comprised of a relatively flat terrain with the exception of the

steep slope adjacent to Route 9. The site surface generally consists of grassed,

gravelly, exposed dirt, and paved areas.

The USDA Soil Survey of Hampshire County, Massachusetts, Central Part report

classifies the site soils as (see Figure 3 for Soil Map):

• (8A) Limerick Silt Loam

Hydrologic Group: C

Depth to Water Table: 0.0’-1.5’

• (96A) Hadley Silt Loam

Hydrologic Group: B


• (98A) Winooski Silt Loam

Hydrologic Group: B


A series of test pits were conducted on site to determine subsurface conditions.

The purpose of the test pits was to evaluate the site for the existence of ledge, the

ability of the site to support stormwater drainage components, and for

groundwater information. In general, the test pits confirmed the USDA Soil

Survey findings for the site as ground water is generally high throughout the site,

and the soils consisted mostly of a silty loam. The test pit logs are attached in

Appendix B.

III. Existing Conditions

The existing site contains 6 drainage areas (E-1 through E-6) and 3 different

control points used for determining peak runoff rates, and the site has an average

curve number of 74. The drainage areas and control points are shown on the Pre-

Development Drainage Area Plan (see Figure 1). The following is a brief

description of each drainage area:




E-1

E-1 is approximately 24.06 acres and contains a large area of the existing track,

horse barns, other miscellaneous buildings, grassed areas, paved areas, and gravel

areas. The area drains to existing catch basins which direct the stormwater to the

existing detention basin at the east end of the site (shown as E-Pond1 on Figure

1). The easterly detention pond has 2 outlets: The first outlet is a 12” CMP

located on the north edge of Fair Street which discharges water across the street to

the property line located at the southeastern area of the site (shown as E-CP1 on

Figure 1). The second outlet is a catch basin located just south of Horse Barn H &

C. When the level of water in the pond exceeds elevation 117’, it overflows out

of the catch basin and spills over Cross Path Road into the adjacent property

(shown as E-CP3 on Figure 1) causing standing water in the spring and summer

and frozen ponding in the winter. Occasionally when a large fairgrounds event is

planned, the detention pond is pumped at 200gpm (0.45cfs) to an existing catch

basin on the west side of the site (shown as E-Pond2 on Figure 1) in order to drain

the adjacent area. It is pertinent to pump the drainage system due to the fact that

the only piped outlet is at elevation 116’ on Cross Path Road. For the sake of

consistency within pre and post calculations, the pump system is assumed to run

full time for the duration of the storm events. This allows a similar comparison

between existing conditions and the proposed site design. The pump is modeled

as a pond with a base flow out of 0.45cfs which discharges to the Williams Street

Brook system (shown as E-CP2 on Figure 1) which is undersized in most storms.

E-2

E-2 is approximately 10.75 acres and contains a portion of the existing track,

buildings, grassed areas, paved areas, and gravel areas. This area sheet flows into

existing catch basins which discharge into the westerly retention basin (E-Pond2).

The detention pond discharges into the Williams Street Brook drainage system

through a 12” pipe (E-CP1).

E-3

E-3 is approximately 10.38 acres and contains adjacent houses, buildings, grassed

areas, paved areas, and gravel areas. This area sheet flows into existing catch

basins which discharge directly into the Williams Street Brook drainage system

(E-CP1).

E-4

E-4 is approximately 7.52 acres and is located south of the main area and contains

a portion of Fair Street, existing buildings, grassed areas, and gravel areas. This

area sheet flows overland to the southern property line (E-CP2).

E-5




E-5 is approximately 3.41 acres and is located north of the main area and contains

a portion of Ferry Road, a basketball court, and grassed areas. This area sheet

flows over Ferry Road where it begins to pond until it enters the existing westerly

detention basin which drains to the Williams Street Brook system (E-CP1).

E-6

E-6 is approximately 0.68 acres and is located north of the main area and contains

a portion of Ferry Road, abutting houses, and grassed areas. This area sheet flows

toward existing catch basins where it is directed to the easterly detention basin

which drains to the south eastern area of the site (E-CP2).

IV. Proposed Conditions

The proposed project does not alter the site significantly and it retains the general

flow patterns of the existing stormwater system. The proposed site contains 6

drainage areas (P-1 through P-6) and 3 different control points used for

determining peak runoff rates. The drainage areas and control points are shown

on the Post-Development Drainage Area Plan (see Figure 2). The following is a

brief description of each drainage area:

P-1

P-1 is approximately 27.48 acres and contains the 3 new horse barns, a new

restroom, new paved road/walk areas, a large area of the existing track, other

miscellaneous buildings, grassed areas, paved areas, a portion of the Morgan

horse rings, and gravel areas. This area of the site will contain 2 large subsurface

stone detention systems which will be hydraulically connected to the easterly

detention basin. Areas that drain directly to the subsurface system are directed to

low spots which allow for the runoff to infiltrate through the specified soil media

prior to entering the system. The area adjacent to the 3 new horse barns will drain

to a new system installed under 2 new concrete pads between the barns. Each pad

contains drain inlets with 2’ sumps. Before horse manure is permitted to be

stockpiled on the pads, the drains inlets are replaced with covers to prohibit

potential contamination of the drainage system and the horse barn roof areas are

piped directly into the drain system to allow for separation of roof runoff which

will increase the water quality entering the detention basin. The outlet from the

new subsurface system will be outfitted with a stormwater treatment chamber

designed to remove a minimum of 80% TSS for the increase in impervious area

on site.

The rest of the area within P-1 drains to existing catch basins or sheet flows to the

existing detention basins on the east side of the site (shown as P-Pond1 on Figure

2). The detention pond has 3 outlets. The first outlet is a 12” CMP located on the

north edge of Fair Street which discharges water across the street to the property

(P-CP2); unlike in existing conditions, the existing low catch basin adjacent to

Cross Path Road is proposed to be removed in this phase and a berm at elevation




117.2’ (second outlet) will be constructed to ensure the water flowing to the east

is less than it was in existing conditions (P-CP3). Occasionally when a large

fairgrounds event is planned, the retention pond is pumped (the site will continue

to utilized the existing pump at 200gpm) to an existing catch basin (P-CP1) on the

west side of the site (shown as P-Pond2 on Figure 2). In order to provide a

consistent timing of pump use for existing and proposed conditions, the pump was

modeled as a base flow of 0.45cfs (200gpm) directed to the Williams Street Brook

drainage infrastructure and was assumed to be running at all times. With the

construction of the new drainage infrastructure, an Operation and Maintenance

plan is proposed that will require the pump system to run after storms to ensure

the drainage system will be drained within 72 hours. It is pertinent to pump the

drainage system due to the fact that the only outlet remains at Cross Path Road.

An infiltration trench has been designed to catch and retain the runoff from a large

part of the main road that is proposed in the middle of the site. The system

consists of a long and shallow stone filled bed which will catch the runoff from a

large amount of the new pavement, and allow the runoff to recharge into the

ground. The system has been designed to be very shallow and has low spot at the

center of the trench which will promote the runoff to infiltrate as well as serve as a

monitoring system for determining the trench’s performance.

P-2

P-2 is approximately 9.27 acres and contains a portion of the existing track,

buildings, grassed areas, paved areas, and gravel areas. This area sheet flows into

existing catch basins which discharge into the westerly retention basin (P-Pond2).

The detention pond discharges into the Williams Street Brook drainage system

through a 12” pipe (P-CP1).

P-3

P-3 is approximately 8.46 acres and contains adjacent houses, buildings, grassed

areas, paved areas, new horse rings, and gravel areas. This area sheet flows into

existing catch basins which discharge directly into the Williams Street Brook

drainage system (P-CP1).

P-4

P-4 is approximately 7.52 acres and is located south of the main area and contains

a portion of Fair Street, existing buildings, grassed areas, and gravel areas. This

area sheet flows overland to the southern property line (P-CP2).

P-5

P-5 is approximately 3.41 acres and is located north of the main area and contains

a portion of Ferry Road, a basketball court, and grassed areas. This area sheet

flows over Ferry Road where it begins to pond until it enters the existing westerly

detention basin which drains to the Williams Street Brook system (P-CP1).




P-6

P-6 is approximately 0.68 acres and is located north of the main area and contains

a portion of Ferry Road, abutting houses, and grassed areas. This area sheet flows

toward existing catch basins where it is directed to the easterly detention basin

which drains to the south eastern area of the site (P-CP2).

V. Calculations and Design

Drainage calculations were performed on Hydrocad Stormwater Modeling System

version 8.0 using Soil Conservation Service (SCS) TR-20 methodology. The SCS

method is based on rainfall observations, which were used to develop the

Intensity-Duration-Frequency relationship, or IDF curve. The mass curve is a

dimensionless distribution of rainfall over time, which indicates the fraction of the

rainfall event that occurs at a given time within a 24-hour precipitation event. This

synthetic distribution develops peak rates for storms of varying duration and

intensities. The SCS distribution provides a cumulative rainfall at any point in

time and allows volume dependent routing runoff calculations to occur. These

calculations are included in the appendices.

The watershed boundaries for calculation purposes are divided according to the

proposed site grading and the natural limits of the drainage areas. The curve

numbers (CNs) and times of concentration for the existing and proposed

subcatchment areas are based on the soil type and the existing and proposed cover

conditions at the site. The soil hydrologic group assumed for the site is noted in

Figure 3. Watershed subcatchment areas, runoff coefficients and watercourse

slopes are based on survey information.

Calculations were performed for the 2-, 10-, and 100-year frequency storms under

existing and proposed conditions. The results of the calculations are presented in

Table 1 below. Appendix A presents the Hydrocad calculations.

Flow Rates & Water Quantity

Table 1 on the following page presents the comparison of flow rates and water

quantity at both existing and proposed control points.




Table 1 Peak Flow and Volume

Summary

*Names in parentheses refer to HydroCad model and calculations.

Note that the volumes are less for proposed conditions during the first 24 hours

after the storm began. This is due to the large increase in storage area within the

proposed detention system. However when the pump system drains the proposed

basin, the volume directed to the Williams Street Brook control point (CP3) will

be greater in proposed conditions.

VI. MADEP Stormwater Standards Compliance

The following section details how the project follows the MADEP Stormwater

Management Policy’s ten stormwater management standards.

Standard 1 - Untreated Stormwater

No new outlets are proposed on the site and the site has added treatment capacity

to the existing site through the use of infiltration trenches, deep sump basins, a

large subsurface detention system with filtration inlet areas, and a stormwater

treatment chamber. The existing stormwater system has been modified to treat the

stormwater prior to discharging it off site.

Condition

& Point of

Analysis

Peak Flow

Rate(cfs)

Volume

(acre-ft)

Peak Flow

Rate(cfs)

Volume

(acre-ft)

Peak Flow

Rate(cfs)

Volume

(acre-ft)

Existing –

Control Pt.

(E-CP1)*

Proposed –

Control Pt.

(P-CP1)*

Existing –

Control Pt.

(E-CP2)*

Proposed –

Control Pt.

(P-CP2)*

Existing –

Control Pt.

(P-CP3)*

Proposed –

Control Pt.

(P-CP3)*

2.779

0.00 0.000 0.00 0.000 35.50 2.620

0.00 0.000 1.52 0.178 35.51

33.17

7.960

7.14 2.582 16.48 4.543 29.19 7.310

7.52 2.696 18.21 4.891

2-Year Storm 10-Year Storm 100-Year Storm

3.00” 4.50” 6.50”

23.43 4.551

4.21 0.474 10.65 2.620 21.42 4.538

4.21 0.879 10.82 3.136




Standard 2 - Post-Development Peak Discharge Rates

The stormwater system is designed so that post-development peak discharge rates

are equal or less than pre-development peak discharge rates leaving the site.

Although the proposed site will have an increase of impervious area, the new

subsurface detention systems will provide significant storage and reduce the peak

flows from existing conditions. During the 24 hour storm the volume of water

discharged to the control points will be less than existing conditions due to the

large storage area proposed. However because the system requires pumping to

drain, the proposed basin is not fully drained after the 24 hour period shown in the

peak flow/volume calculations. The remaining volume left after the storm will be

drained by the pump for the next several hours (which happens in existing

conditions as well). However, the peak flows will be equal to or reduced from

existing conditions in the 2, 10, and 100 year storms which will improve the

functionality of the site. Refer to Table 1 Peak Flow and Volume Summary and

Appendix A for HydroCAD calculations.

Standard 3 - Recharge to Groundwater

The proposed redevelopment has been designed to provide recharge groundwater

to the maximum extent practicable in proposed conditions. In the full build of the

project (a mix of new and redevelopment) a large infiltration basin is proposed at

the south parcel. However the connection under the roadway to this basin was

proposed at this phase and shallow infiltration trench systems are proposed at the

south side of the main roadway and adjacent to 2 of the new barns. These systems

have been sized to accommodate and recharge the increase in impervious area and

are designed to capture approximately 84.8% of the 1.16acres of increased

impervious area. The basin has been designed to be very shallow which will

allow it to drain down in less than 72 hours and will encourage infiltration on the

smaller more common storms.

Note that the infiltration trench was not included in the peak flow calculations to

provide a more conservative proposed peak flow and volume estimate.

Standard 4 – Water Quality

The proposed redevelopment will provide increase water quality treatment of the

site. The proposed detention system has been designed with multiple inlet areas

which allow the runoff to infiltrate through soil media prior to entering the system

which provides treatment for runoff very similar to a rain garden. The new

detention systems will then discharge to a stormwater treatment chamber (STC

900) which has been sized to treat the increase in impervious area with a TSS

removal rate of 81.2% (see appendix for StormCeptor sizing chart). The

treatment chamber then discharges into the existing basin where any remaining

solids have the opportunity to settle on the bottom.




The site will also be implementing an improved manure management system

between the horse barns. Contaminated water will not be able to enter the system

as it will be block until the manure has left the vicinity of the drains

Standard 5 - Higher Potential Pollutant Loads

The proposed project is not expected to yield high potential pollutant loads.

Standard 6 - Protection of Critical Areas

The project site does not discharge to critical areas as defined in MA DEP

Stormwater Policy Handbook.

Standard 7 - Redevelopment Projects

The proposed project is a redevelopment project and will improve the site to the

maximum extent practicable by incorporating recharge and water quality measures

that will function for the phase until the full build out is constructed.

Standard 8 - Erosion/Sediment Control

Erosion and sediment controls will be fully been incorporated into the project

design to prevent erosion, control sediments, and stabilized exposed soils during

construction and land disturbance. This project is covered by a NPDES

Construction General Permit and a SWPPP will be submitted by the contractor

prior to the start of construction.

Standard 9 - Operation/Maintenance Plan

An Operation and Maintenance Plan for the proposed project is included in

Appendix E. It includes general controls for construction and long term

maintenance of the stormwater management system.

Standard 10 – Prohibition of Illicit Discharges

No illicit discharges will occur as a result of this project.

VII. Summary

The impervious area from existing to proposed conditions will increase by

approximately 1.16 acres from the construction of the 3 new barns and new paved

areas. The combination of the improvements to the stormwater system on site will

ensure that the redevelopment will significantly improve the existing site.

Three County Fairgrounds-Phase 1 October 1, 2010 Revised 11/1/10

Northampton, Massachusetts Stormwater Drainage Report Appendix

The Berkshire Design Group, Inc. Figures

Figures

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_The _Berkshire =-oos;gn _ Group, Inc. 4 Allen Place Northampton, MassachuseUs 01060 (413) 582-7000 • FAX (413) 582-7005

Figure Title:

/ . /[§J / n / -= / ~\ I

Pre-Deve/opemen! Drainage Area Map

Three County Fairgrounds

j

NORTHAMPTON MASSACHUSEITS

Revisions:

Date: Scale: 10/01/10 1"=300'

Figure Number

1

I I

_The _Berkshire =-oos;gn _ Group, Inc.

100_........... i '1ft'a,"'F'"\, .. -"

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4 Allen Place Northampton, MassachuseUs 01060 (413) 582·7000 • FAX (413) 582·7005

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Figure Title:

Post-Developement Drainage Area Map

Three County Fairgrounds NORTHAMPTON MASSACHUSETTS

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Revisions: 10125110

Date: Scale: 10/1/10 1"=300'

Figure Number

2

_The _Berkshire =-oos;gn _ Group, Inc. 4 Allen Place Northampton, MassachuseUs 01060 (413) 582-7000 • FAX (413) 582-7005

Figure Title:

Hydrologic Soils Group Map


Revisions:

Date: Scale: 10/1/10 1"=300'

Figure Number

3

Three County Fairgrounds-Phase 1 October 1, 2001 Revised 11/1/10 &11/3/10


The Berkshire Design Group, Inc. Appendix

Appendix A – Pre- and Post Development

Hydrologic Calculations

E-1

Area to Easterly BasinE-2

Area To Westerly Basin

E-3

Direct to Road Drainage Infrastructure

E-4

Southeast Area of Site to South Property Line

E-5

Area north of site (includes basketball

court)

E-6

Northeast of Site (Road and abutting property)

P-1

Area to Easterly Basin

P-2

Area To Westerly Basin

P-3

Direct to Road Drainage Infrastructure

P-4

Southeast Area of Site to South Property Line

P-5

Area north of site (includes basketball

court)

P-6

Northeast of Site (Road and abutting property)

E-CP1

Williams St. Brook Infrastructure

E-CP2

South Property Line

E-CP3

Cross Paths Road

P-CP1

Williams St. Brook Infrastructure

P-CP2

South Property Line

P-CP3

Cross Paths Road

E-Pond1

Existing East Detention Basin

E-Pond2

Existing West Detention Basin

E-Pump

CB

Existing Pump System from East Basin

E-Pump.

CB

Existing Pump System from East Basin

P-Pond 1

Existing East Detention Basin & New Trench

Systems

P-Pond 2

Existing West Detention Basin

Drainage Diagram for Three Country Fairgrounds Phase 1- Stormwater Permit rev110310

Prepared by The Berkshire Design Group 11/3/2010HydroCAD® 8.00 s/n 000752 © 2006 HydroCAD Software Solutions LLC

Subcat Reach Pond Link

Revised 11/3/10

Three Country Fairgrounds Phase 1- Stormwater Permit rev110310Page 2Prepared by The Berkshire Design Group

11/3/2010HydroCAD® 8.00 s/n 000752 © 2006 HydroCAD Software Solutions LLC

Area Listing (selected nodes)

Area (acres) CN Description (subcats)

58.105 61 >75% Grass cover, Good, HSG B (E-1,E-2,E-3,E-4,E-5,E-6,P-1,P-1,P-2,P-3,P-4,P-5,P-6)

4.859 74 >75% Grass cover, Good, HSG C (E-4,E-5,P-4,P-5)

1.586 85 Existing Gravel/Stone Dust (P-1)

15.840 85 Gravel/Stone Dust (E-1,E-2,E-3,E-4,P-2,P-3,P-4)

0.968 96 Morgan Rings (stonedust) (P-3)

7.181 96 Proposed TRG Paving (P-1,P-1,P-3)

0.413 98 (P-1)

1.362 98 Basin (E-2,E-4,P-2,P-4)

0.460 98 Basins (E-1,P-1)

1.949 98 Paved parking (E-5,E-6,P-5,P-6)

0.702 98 Paved parking & roofs (P-1)

2.140 98 Road (E-4,P-4)

17.585 98 Road/Roof (E-1,E-2,E-3,P-1,P-2,P-3)

0.448 98 Roof (E-4)

113.597

Revised 11/3/10Type III 24-hr 2 YRS Rainfall=3.00"Three Country Fairgrounds Phase 1- Stormwater Permi

Page 3Prepared by The Berkshire Design Group11/3/2010HydroCAD® 8.00 s/n 000752 © 2006 HydroCAD Software Solutions LLC

Time span=0.00-24.00 hrs, dt=0.05 hrs, 481 points

Runoff by SCS TR-20 method, UH=SCS

Reach routing by Dyn-Stor-Ind method - Pond routing by Dyn-Stor-Ind method

Runoff Area=1,048,195 sf Runoff Depth>0.85"Subcatchment E-1: Area to Easterly Basin Flow Length=888' Tc=17.0 min CN=73 Runoff=15.84 cfs 1.712 af

Runoff Area=468,308 sf Runoff Depth>1.25"Subcatchment E-2: Area To Westerly Basin Flow Length=1,136' Tc=16.9 min CN=80 Runoff=11.10 cfs 1.116 af

Runoff Area=451,921 sf Runoff Depth>0.85"Subcatchment E-3: Direct to Road Drainage Infrastructure Flow Length=100' Slope=0.0050 '/' Tc=19.5 min CN=73 Runoff=6.47 cfs 0.737 af

Runoff Area=327,415 sf Runoff Depth>0.76"Subcatchment E-4: Southeast Area of Site to South Property Flow Length=750' Tc=17.3 min CN=71 Runoff=4.21 cfs 0.474 af

Runoff Area=148,626 sf Runoff Depth>0.90"Subcatchment E-5: Area north of site (includes basketball c Flow Length=545' Tc=22.7 min CN=74 Runoff=2.15 cfs 0.257 af

Runoff Area=29,661 sf Runoff Depth>1.19"Subcatchment E-6: Northeast of Site (Road and abutting prop Flow Length=625' Tc=12.3 min CN=79 Runoff=0.74 cfs 0.067 af

Runoff Area=27.478 ac Runoff Depth>1.18"Subcatchment P-1: Area to Easterly Basin Flow Length=888' Tc=17.0 min CN=79 Runoff=26.74 cfs 2.711 af

Runoff Area=403,083 sf Runoff Depth>1.37"Subcatchment P-2: Area To Westerly Basin Flow Length=1,136' Tc=16.9 min CN=82 Runoff=10.64 cfs 1.060 af

Runoff Area=8.458 ac Runoff Depth>0.96"Subcatchment P-3: Direct to Road Drainage Infrastructure Flow Length=100' Slope=0.0050 '/' Tc=19.5 min CN=75 Runoff=6.07 cfs 0.674 af

Runoff Area=327,415 sf Runoff Depth>0.76"Subcatchment P-4: Southeast Area of Site to South Property Flow Length=750' Tc=17.3 min CN=71 Runoff=4.21 cfs 0.474 af

Runoff Area=148,626 sf Runoff Depth>0.90"Subcatchment P-5: Area north of site (includes basketball c Flow Length=545' Tc=22.7 min CN=74 Runoff=2.15 cfs 0.257 af

Runoff Area=29,664 sf Runoff Depth>1.19"Subcatchment P-6: Northeast of Site (Road and abutting prop Flow Length=625' Tc=12.3 min CN=79 Runoff=0.74 cfs 0.067 af

Inflow=7.52 cfs 2.696 afReach E-CP1: Williams St. Brook Infrastructure Outflow=7.52 cfs 2.696 af

Inflow=4.21 cfs 0.879 afReach E-CP2: South Property Line Outflow=4.21 cfs 0.879 af

Inflow=0.00 cfs 0.000 afReach E-CP3: Cross Paths Road Outflow=0.00 cfs 0.000 af



Inflow=7.14 cfs 2.582 afReach P-CP1: Williams St. Brook Infrastructure Outflow=7.14 cfs 2.582 af

Inflow=4.21 cfs 0.474 afReach P-CP2: South Property Line Outflow=4.21 cfs 0.474 af

Inflow=0.00 cfs 0.000 afReach P-CP3: Cross Paths Road Outflow=0.00 cfs 0.000 af

Peak Elev=116.42' Storage=46,413 cf Inflow=16.49 cfs 1.779 afPond E-Pond1: Existing East Detention B Discarded=0.45 cfs 0.470 af Primary=0.68 cfs 0.405 af Secondary=0.00 cfs 0.000 af Outflow=1.13 cfs 0.876 af

Peak Elev=117.32' Storage=27,837 cf Inflow=13.03 cfs 1.372 afPond E-Pond2: Existing West Detention B12.0" x 55.0' Culvert Outflow=2.01 cfs 1.064 af

Peak Elev=116.60' Inflow=0.45 cfs 0.894 afPond E-Pump: Existing Pump System from East Basin Outflow=0.45 cfs 0.894 af

Peak Elev=116.60' Inflow=0.45 cfs 0.894 afPond E-Pump.: Existing Pump System from East Basin Outflow=0.45 cfs 0.894 af

Peak Elev=115.73' Storage=107,696 cf Inflow=27.40 cfs 2.778 afPond P-Pond 1: Existing East Detention Discarded=0.45 cfs 0.894 af Primary=0.00 cfs 0.000 af Secondary=0.00 cfs 0.000 af Outflow=0.45 cfs 0.894 af

Peak Elev=117.30' Storage=27,284 cf Inflow=12.56 cfs 1.316 afPond P-Pond 2: Existing West Detention 12.0" x 55.0' Culvert Outflow=1.95 cfs 1.014 af

Total Runoff Area = 113.597 ac Runoff Volume = 9.605 af Average Runoff Depth = 1.01"

77.94% Pervious Area = 88.539 ac 22.06% Impervious Area = 25.058 ac



Subcatchment E-1: Area to Easterly Basin

Runoff = 15.84 cfs @ 12.26 hrs, Volume= 1.712 af, Depth> 0.85"

Runoff by SCS TR-20 method, UH=SCS, Time Span= 0.00-24.00 hrs, dt= 0.05 hrsType III 24-hr 2 YRS Rainfall=3.00"

Area (sf) CN Description

10,000 98 Basins574,174 61 >75% Grass cover, Good, HSG B115,775 98 Road/Roof348,246 85 Gravel/Stone Dust

1,048,195 73 Weighted Average922,420 Pervious Area125,775 Impervious Area

Tc Length Slope Velocity Capacity Description(min) (feet) (ft/ft) (ft/sec) (cfs)

14.6 100 0.0080 0.11 Sheet Flow, Grass: Short n= 0.150 P2= 3.00"

2.4 788 0.0100 5.36 4.21 Circular Channel (pipe), Diam= 12.0" Area= 0.8 sf Perim= 3.1' r= 0.25'n= 0.011 Concrete pipe, straight & clean

17.0 888 Total

Subcatchment E-2: Area To Westerly Basin




29,666 98 Basin190,948 61 >75% Grass cover, Good, HSG B126,576 98 Road/Roof121,118 85 Gravel/Stone Dust

468,308 80 Weighted Average312,066 Pervious Area156,242 Impervious Area




7.3 100 0.0050 0.23 Sheet Flow, Fallow n= 0.050 P2= 3.00"

7.5 376 0.0070 0.84 Shallow Concentrated Flow, Nearly Bare & Untilled Kv= 10.0 fps


16.9 1,136 Total

Subcatchment E-3: Direct to Road Drainage Infrastructure




292,465 61 >75% Grass cover, Good, HSG B139,412 98 Road/Roof20,044 85 Gravel/Stone Dust



19.5 100 0.0050 0.09 Sheet Flow, Cultivated: Residue>20% n= 0.170 P2= 3.00"

Subcatchment E-4: Southeast Area of Site to South Property Line




0 98 Basin207,984 61 >75% Grass cover, Good, HSG B36,840 98 Road19,517 98 Roof27,926 85 Gravel/Stone Dust35,148 74 >75% Grass cover, Good, HSG C





1.8 100 0.0080 0.92 Sheet Flow, Smooth surfaces n= 0.011 P2= 3.00"

15.5 650 0.0100 0.70 Shallow Concentrated Flow, Short Grass Pasture Kv= 7.0 fps

17.3 750 Total

Subcatchment E-5: Area north of site (includes basketball court)




50,138 61 >75% Grass cover, Good, HSG B27,807 98 Paved parking70,681 74 >75% Grass cover, Good, HSG C




4.7 270 0.0040 0.95 Shallow Concentrated Flow, Grassed Waterway Kv= 15.0 fps

1.3 125 0.0060 1.57 Shallow Concentrated Flow, Paved Kv= 20.3 fps


22.7 545 Total

Subcatchment E-6: Northeast of Site (Road and abutting property)




15,016 61 >75% Grass cover, Good, HSG B14,645 98 Paved parking








12.3 625 Total

Subcatchment P-1: Area to Easterly Basin



Area (ac) CN Description

0.230 98 Basins12.908 61 >75% Grass cover, Good, HSG B4.046 98 Road/Roof1.586 85 Existing Gravel/Stone Dust6.837 96 Proposed TRG Paving0.702 98 Paved parking & roofs0.323 96 Proposed TRG Paving0.433 61 >75% Grass cover, Good, HSG B0.413 98

27.478 79 Weighted Average22.087 Pervious Area5.391 Impervious Area




17.0 888 Total

Subcatchment P-2: Area To Westerly Basin












16.9 1,136 Total

Subcatchment P-3: Direct to Road Drainage Infrastructure




4.945 61 >75% Grass cover, Good, HSG B2.085 98 Road/Roof0.439 85 Gravel/Stone Dust0.021 96 Proposed TRG Paving0.968 96 Morgan Rings (stonedust)




Subcatchment P-4: Southeast Area of Site to South Property Line






0 98 Basin207,984 61 >75% Grass cover, Good, HSG B56,357 98 Road27,926 85 Gravel/Stone Dust35,148 74 >75% Grass cover, Good, HSG C





17.3 750 Total

Subcatchment P-5: Area north of site (includes basketball court)











22.7 545 Total



Subcatchment P-6: Northeast of Site (Road and abutting property)










12.3 625 Total

Reach E-CP1: Williams St. Brook Infrastructure

Inflow Area = 24.538 ac, Inflow Depth > 1.32" for 2 YRS eventInflow = 7.52 cfs @ 12.33 hrs, Volume= 2.696 afOutflow = 7.52 cfs @ 12.33 hrs, Volume= 2.696 af, Atten= 0%, Lag= 0.0 min

Routing by Dyn-Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrs

Reach E-CP2: South Property Line



Reach E-CP3: Cross Paths Road

Inflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 afOutflow = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af, Atten= 0%, Lag= 0.0 min




Reach P-CP1: Williams St. Brook Infrastructure



Reach P-CP2: South Property Line



Reach P-CP3: Cross Paths Road



Pond E-Pond1: Existing East Detention Basin

Inflow Area = 24.744 ac, Inflow Depth > 0.86" for 2 YRS eventInflow = 16.49 cfs @ 12.26 hrs, Volume= 1.779 afOutflow = 1.13 cfs @ 16.24 hrs, Volume= 0.876 af, Atten= 93%, Lag= 238.7 minDiscarded = 0.45 cfs @ 11.85 hrs, Volume= 0.470 afPrimary = 0.68 cfs @ 16.24 hrs, Volume= 0.405 afSecondary = 0.00 cfs @ 0.00 hrs, Volume= 0.000 af

Routing by Dyn-Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrsPeak Elev= 116.42' @ 16.24 hrs Surf.Area= 42,251 sf Storage= 46,413 cf

Plug-Flow detention time= 328.8 min calculated for 0.874 af (49% of inflow)Center-of-Mass det. time= 196.4 min ( 1,072.9 - 876.5 )

Volume Invert Avail.Storage Storage Description

#1 112.00' 432,726 cf Custom Stage Data (Prismatic) Listed below (Recalc)



Elevation Surf.Area Inc.Store Cum.Store(feet) (sq-ft) (cubic-feet) (cubic-feet)

112.00 6,800 0 0113.00 7,463 7,132 7,132114.00 8,704 8,084 15,215115.00 10,000 9,352 24,567116.00 11,362 10,681 35,248117.00 85,524 48,443 83,691118.00 272,423 178,974 262,665118.50 407,822 170,061 432,726

Device Routing Invert Outlet Devices

#1 Secondary 117.00' 100.0' long x 5.0' 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 Coef. (English) 2.34 2.50 2.70 2.68 2.68 2.66 2.65 2.65 2.65 2.65 2.67 2.66 2.68 2.70 2.74 2.79 2.88

#2 Primary 116.00' 12.0" Vert. Invert of 12" CMP Outlet on Fair Street C= 0.600 #3 Discarded 0.00' 0.45 cfs Existing Pump (200gpm) to E-CP1 at all elevations

Discarded OutFlow Max=0.45 cfs @ 11.85 hrs HW=112.07' (Free Discharge)3=Existing Pump (200gpm) to E-CP1 (Exfiltration Controls 0.45 cfs)

Primary OutFlow Max=0.68 cfs @ 16.24 hrs HW=116.42' TW=0.00' (Dynamic Tailwater)2=Invert of 12" CMP Outlet on Fair Street (Orifice Controls 0.68 cfs @ 2.20 fps)

Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=112.00' TW=0.00' (Dynamic Tailwater)1=Broad-Crested Rectangular Weir ( Controls 0.00 cfs)

Pond E-Pond2: Existing West Detention Basin

Inflow Area = 14.163 ac, Inflow Depth > 1.16" for 2 YRS eventInflow = 13.03 cfs @ 12.26 hrs, Volume= 1.372 afOutflow = 2.01 cfs @ 13.31 hrs, Volume= 1.064 af, Atten= 85%, Lag= 63.4 minPrimary = 2.01 cfs @ 13.31 hrs, Volume= 1.064 af


Plug-Flow detention time= 220.1 min calculated for 1.064 af (78% of inflow)Center-of-Mass det. time= 135.4 min ( 994.0 - 858.6 )






116.00 19,210 0 0117.00 21,276 20,243 20,243118.00 35,033 28,155 48,398119.00 64,989 50,011 98,409119.50 75,000 34,997 133,406


#1 Primary 116.26' 12.0" x 55.0' long Culvert CMP, projecting, no headwall, Ke= 0.900 Outlet Invert= 116.13' S= 0.0024 '/' Cc= 0.900 n= 0.011 Concrete pipe, straight & clean

Primary OutFlow Max=2.01 cfs @ 13.31 hrs HW=117.32' TW=0.00' (Dynamic Tailwater)1=Culvert (Barrel Controls 2.01 cfs @ 2.99 fps)

Pond E-Pump: Existing Pump System from East Basin

Inflow = 0.45 cfs @ 0.00 hrs, Volume= 0.894 af, Incl. 0.45 cfs Base FlowOutflow = 0.45 cfs @ 0.00 hrs, Volume= 0.894 af, Atten= 0%, Lag= 0.0 minPrimary = 0.45 cfs @ 0.00 hrs, Volume= 0.894 af

Routing by Dyn-Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrsPeak Elev= 116.60' @ 0.00 hrs


#1 Primary 116.13' 6.0" Vert. 6" Force Main C= 0.600

Primary OutFlow Max=0.45 cfs @ 0.00 hrs HW=116.60' TW=0.00' (Dynamic Tailwater)1=6" Force Main (Orifice Controls 0.45 cfs @ 2.34 fps)

Pond E-Pump.: Existing Pump System from East Basin








Pond P-Pond 1: Existing East Detention Basin & New Trench Systems


Routing by Dyn-Stor-Ind method, Time Span= 0.00-24.00 hrs, dt= 0.05 hrsStarting Elev= 112.84' Surf.Area= 55,135 sf Storage= 25,602 cfPeak Elev= 115.73' @ 24.00 hrs Surf.Area= 58,769 sf Storage= 107,696 cf (82,094 cf above start)

Plug-Flow detention time= 490.4 min calculated for 0.306 af (11% of inflow)Center-of-Mass det. time= (not calculated: outflow precedes inflow)


#1 112.00' 329,498 cf Surface Storage (Prismatic) Listed below (Recalc)#2 112.34' 31,003 cf Trench A (all) (Prismatic) Listed below (Recalc)

80,488 cf Overall - 2,981 cf Embedded = 77,506 cf x 40.0% Voids#3 112.34' 4,408 cf Trench C (west) (Prismatic) Listed below (Recalc)

11,021 cf Overall x 40.0% Voids#4 112.34' 5,735 cf Trench C (east) (Prismatic) Listed below (Recalc)

14,337 cf Overall x 40.0% Voids#5 112.34' 1,682 cf Trench D (north) (Prismatic) Listed below (Recalc)

4,205 cf Overall x 40.0% Voids#6 112.34' 1,682 cf Trench D (south) (Prismatic) Listed below (Recalc)

4,205 cf Overall x 40.0% Voids#7 112.84' 2,981 cf 18.0"D x 168.70'L Pipe In West Trench System x 10 Inside #2#8 111.84' 2,138 cf 18.0"D x 121.00'L Pipe In East Trench System x 10 Inside #11#9 111.34' 14,057 cf Trench E (west) (Prismatic) Listed below (Recalc)

35,142 cf Overall x 40.0% Voids#10 111.34' 15,494 cf Trench E (east) (Prismatic) Listed below (Recalc)

38,734 cf Overall x 40.0% Voids#11 111.34' 11,139 cf Trench B (all) (Prismatic) Listed below (Recalc)

29,985 cf Overall - 2,138 cf Embedded = 27,847 cf x 40.0% Voids

419,816 cf Total Available Storage


112.00 6,800 0 0113.00 7,463 7,132 7,132114.00 8,704 8,084 15,215115.00 10,000 9,352 24,567116.00 11,362 10,681 35,248117.00 95,677 53,520 88,768118.00 385,783 240,730 329,498




112.34 17,272 0 0117.00 17,272 80,488 80,488


112.34 2,499 0 0116.75 2,499 11,021 11,021


112.34 2,920 0 0117.25 2,920 14,337 14,337


112.34 1,054 0 0116.33 1,054 4,205 4,205


112.34 1,054 0 0116.33 1,054 4,205 4,205


111.34 6,460 0 0116.78 6,460 35,142 35,142


111.34 9,311 0 0115.50 9,311 38,734 38,734


111.34 7,208 0 0115.50 7,208 29,985 29,985


#1 Primary 116.23' 12.0" Vert. Invert of 12" CMP Outlet on Fair Street C= 0.600 #2 Discarded 0.00' 0.45 cfs Existing Pump (200gpm) to P-CP1 at all elevations #3 Secondary 117.20' 550.0' long x 2.0' breadth New Berm on Cross Path Rd (117.15')

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



Discarded OutFlow Max=0.45 cfs @ 0.00 hrs HW=112.84' (Free Discharge)2=Existing Pump (200gpm) to P-CP1 (Exfiltration Controls 0.45 cfs)

Primary OutFlow Max=0.00 cfs @ 0.00 hrs HW=112.84' TW=0.00' (Dynamic Tailwater)1=Invert of 12" CMP Outlet on Fair Street ( Controls 0.00 cfs)

Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=112.84' TW=0.00' (Dynamic Tailwater)3=New Berm on Cross Path Rd (117.15') ( Controls 0.00 cfs)

Pond P-Pond 2: Existing West Detention Basin







116.00 19,210 0 0117.00 21,276 20,243 20,243118.00 35,033 28,155 48,398119.00 64,989 50,011 98,409119.50 75,000 34,997 133,406



Primary OutFlow Max=1.95 cfs @ 13.26 hrs HW=117.30' TW=0.00' (Dynamic Tailwater)1=Culvert (Barrel Controls 1.95 cfs @ 2.97 fps)

Revised 11/3/10Type III 24-hr 10 YRS Rainfall=4.50"Three Country Fairgrounds Phase 1- Stormwater Per

























Peak Elev=117.03' Storage=86,787 cf Inflow=38.97 cfs 3.922 afPond E-Pond1: Existing East Detention B Discarded=0.45 cfs 0.520 af Primary=2.77 cfs 2.046 af Secondary=1.52 cfs 0.178 af Outflow=4.74 cfs 2.745 af

Peak Elev=118.29' Storage=59,913 cf Inflow=26.83 cfs 2.756 afPond E-Pond2: Existing West Detention B12.0" x 55.0' Culvert Outflow=3.70 cfs 2.365 af


















17.0 888 Total













16.9 1,136 Total




















17.3 750 Total












22.7 545 Total













12.3 625 Total










17.0 888 Total













16.9 1,136 Total




















17.3 750 Total












22.7 545 Total













12.3 625 Total













112.00 6,800 0 0113.00 7,463 7,132 7,132114.00 8,704 8,084 15,215115.00 10,000 9,352 24,567116.00 11,362 10,681 35,248117.00 85,524 48,443 83,691118.00 272,423 178,974 262,665118.50 407,822 170,061 432,726






Secondary OutFlow Max=1.52 cfs @ 13.70 hrs HW=117.03' TW=0.00' (Dynamic Tailwater)1=Broad-Crested Rectangular Weir (Weir Controls 1.52 cfs @ 0.44 fps)










116.00 19,210 0 0117.00 21,276 20,243 20,243118.00 35,033 28,155 48,398119.00 64,989 50,011 98,409119.50 75,000 34,997 133,406



Primary OutFlow Max=3.70 cfs @ 13.31 hrs HW=118.29' TW=0.00' (Dynamic Tailwater)1=Culvert (Inlet Controls 3.70 cfs @ 4.71 fps)































112.00 6,800 0 0113.00 7,463 7,132 7,132114.00 8,704 8,084 15,215115.00 10,000 9,352 24,567116.00 11,362 10,681 35,248117.00 95,677 53,520 88,768118.00 385,783 240,730 329,498




112.34 17,272 0 0117.00 17,272 80,488 80,488


112.34 2,499 0 0116.75 2,499 11,021 11,021


112.34 2,920 0 0117.25 2,920 14,337 14,337


112.34 1,054 0 0116.33 1,054 4,205 4,205


112.34 1,054 0 0116.33 1,054 4,205 4,205


111.34 6,460 0 0116.78 6,460 35,142 35,142


111.34 9,311 0 0115.50 9,311 38,734 38,734


111.34 7,208 0 0115.50 7,208 29,985 29,985








Secondary OutFlow Max=0.00 cfs @ 0.00 hrs HW=112.84' TW=0.00' (Dynamic Tailwater)3=New Berm on Cross Path Rd (117.15') ( Controls 0.00 cfs)








116.00 19,210 0 0117.00 21,276 20,243 20,243118.00 35,033 28,155 48,398119.00 64,989 50,011 98,409119.50 75,000 34,997 133,406









Peak Elev=117.28' Storage=114,893 cf Inflow=73.20 cfs 7.245 afPond E-Pond1: Existing East Detention Discarded=0.45 cfs 0.573 af Primary=3.34 cfs 2.486 af Secondary=35.51 cfs 2.779 af Outflow=39.30 cfs 5.838 af

Peak Elev=119.24' Storage=114,441 cf Inflow=46.70 cfs 4.805 afPond E-Pond2: Existing West Detention 12.0" x 55.0' Culvert Outflow=4.70 cfs 4.044 af


















17.0 888 Total













16.9 1,136 Total




















17.3 750 Total












22.7 545 Total













12.3 625 Total










17.0 888 Total













16.9 1,136 Total




















17.3 750 Total












22.7 545 Total













12.3 625 Total













112.00 6,800 0 0113.00 7,463 7,132 7,132114.00 8,704 8,084 15,215115.00 10,000 9,352 24,567116.00 11,362 10,681 35,248117.00 85,524 48,443 83,691118.00 272,423 178,974 262,665118.50 407,822 170,061 432,726






Secondary OutFlow Max=35.37 cfs @ 12.53 hrs HW=117.28' TW=0.00' (Dynamic Tailwater)1=Broad-Crested Rectangular Weir (Weir Controls 35.37 cfs @ 1.27 fps)










116.00 19,210 0 0117.00 21,276 20,243 20,243118.00 35,033 28,155 48,398119.00 64,989 50,011 98,409119.50 75,000 34,997 133,406


































112.00 6,800 0 0113.00 7,463 7,132 7,132114.00 8,704 8,084 15,215115.00 10,000 9,352 24,567116.00 11,362 10,681 35,248117.00 95,677 53,520 88,768118.00 385,783 240,730 329,498




112.34 17,272 0 0117.00 17,272 80,488 80,488


112.34 2,499 0 0116.75 2,499 11,021 11,021


112.34 2,920 0 0117.25 2,920 14,337 14,337


112.34 1,054 0 0116.33 1,054 4,205 4,205


112.34 1,054 0 0116.33 1,054 4,205 4,205


111.34 6,460 0 0116.78 6,460 35,142 35,142


111.34 9,311 0 0115.50 9,311 38,734 38,734


111.34 7,208 0 0115.50 7,208 29,985 29,985








Secondary OutFlow Max=34.80 cfs @ 12.62 hrs HW=117.29' TW=0.00' (Dynamic Tailwater)3=New Berm on Cross Path Rd (117.15') (Weir Controls 34.80 cfs @ 0.74 fps)








116.00 19,210 0 0117.00 21,276 20,243 20,243118.00 35,033 28,155 48,398119.00 64,989 50,011 98,409119.50 75,000 34,997 133,406







Appendix B – Soil Test Pit Information

The ~Berkshire = Design ~ Group, Inc. 4 Allen Place Northampton. Massachusetts 01060 (413) 582-7000 • FAX (413) 582-7005

Figure Title:

Test Pit Location Plan


Reference:

Date: Scale: 10/20109 1"=300'

Figure Number:

TP

Location Address or Lot No. Three County Fairgrounds, Northampton, MA

Test Pits Performed By B. Darnold, The Berkshire Design Group Witnessed By:Felix Harvey, Noho DPW

Deep Hole Number TP 1 Date: 08/20/09 Time: 2:00 pm Weather P. Cloudy 65 F

Location (identify on site plan) See Plan

Land Use Grass Slope (%) See Plan Surface Stones n/o

Vegetation Grass

Landform Floodplain

Position on Landscape (sketch on back)

Distances from: See Plan Open Water Body Feet Drainage way Feet

Possible Wet Area Feet Property Line Feet

Drinking Water Well Feet Other

DEEP OBSERVATION HOLE LOG *

Depth from

Surface(Inches) Soil

Horizon Soil Texture

(USDA) Soil Color (Munsell)

Soil Mottling Other (Structure, Stones, Boulders,

Consistency, % Gravel)

0-37” Fill SL ---- ---- Buried asphalt, 10-20% gravel, horse shoe fragments found

37”-55” Ab Silty Loam

2.5Y3/2 ---- <5% Gravel, Friable, Massive

55”-110” C1 Silty Loam

5Y4/1 5%@55” 10yr6/8

<5% Gravel, Friable, Massive

* MINIMUM OF 2 HOLES REQUIRED AT EVERY PROPOSED DISPOSAL AREA

Parent Material (geologic) Alluvial Depth to Bedrock: > 120”

Depth to Groundwater: Standing Water in the Hole: ---- Weeping from Pit Face: ----

Estimated Seasonal High Ground Water: 55”

Percolation Test:

Depth to Perc:

Start Pre-Soak 12”:

End Pre-Soak 12”:

Time at 12”:

Time at 9”:

Time at 6”:

Time (9”-6”):

Rate:

Note: This test pit was performed for

investigation of general soil conditions and

should not be used for purposes related to

Title 5 and/or soil suitability assessments for

on-site sewage disposal.


Test Pits Performed By B. Darnold, The Berkshire Design Group Witnessed By:

Deep Hole Number TP 2 Date: 08/20/09 Time: 10:48am Weather Sunny 65 F



Vegetation Grass

Landform Floodplain






Depth from






0-19” Ap Silty Loam

2.5Y3/2 ---- 5% Gravel, Some sands, Firm in place, Friable in hand, Massive

19”-53” B Silty Loam


53”-122” C1 Fine Sandy Loam

5Y4/4 5%@53” 5Y6/2 <2% Gravel, Friable, Massive



Depth to Groundwater: Standing Water in the Hole: 114” Weeping from Pit Face: 116”


Percolation Test:

Depth to Perc:


End Pre-Soak 12”:

Time at 12”:

Time at 9”:

Time at 6”:

Time (9”-6”):

Rate:











Vegetation Grass

Landform Floodplain






Depth from







2.5Y4/3 ---- 10% Gravel, Friable, Single grained, some sands




5Y4/3 5%@52” 10YR6/8

<2% Gravel, Friable, very moist, Massive





Percolation Test:

Depth to Perc:


End Pre-Soak 12”:

Time at 12”:

Time at 9”:

Time at 6”:

Time (9”-6”):

Rate:











Vegetation Grass

Landform Floodplain






Depth from







10YR3/3 ---- 10% Gravel, Firm, Single grained




2.5Y4/4 5-10%@36” 10YR5/8

<2% Gravel, Friable, very moist, Massive





Percolation Test:

Depth to Perc:


End Pre-Soak 12”:

Time at 12”:

Time at 9”:

Time at 6”:

Time (9”-6”):

Rate:








Deep Hole Number TP 5 Date: 08/20/09 Time: 12:18pm Weather Sunny 65 F


Land Use Riding Ring Slope (%) See Plan Surface Stones n/o

Vegetation Grass/stonedust

Landform Floodplain






Depth from







2.5Y3/2 ---- 10% Gravel, Friable, Single grained




2.5Y4/4 5%@16” 7.5YR4/6

5-10% Gravel, Friable, very moist, massive, could possibly

be a buried A layer


5Y4/1 10%@37” 7.5YR5/6

5-10% gravel, firm in place, friable in hand, massive




Estimated Seasonal High Ground Water: 16” Possibly Perched

Percolation Test:

Depth to Perc:


End Pre-Soak 12”:

Time at 12”:

Time at 9”:

Time at 6”:

Time (9”-6”):

Rate:







Test Pits –NOT CONDUCTED DUE TO EXPOSED CONDUIT Performed By B. Darnold, The Berkshire Design Group Witnessed By:Felix Harvey, Noho DPW

Deep Hole Number TP 6 Date: 08/20/09 Time: 12:00pm Weather Sunny 65 F


Land Use Dirt road Slope (%) See Plan Surface Stones n/o

Vegetation none

Landform Floodplain






Depth from







Parent Material (geologic) Depth to Bedrock:

Depth to Groundwater: Standing Water in the Hole: Weeping from Pit Face:

Estimated Seasonal High Ground Water:

Percolation Test:

Depth to Perc:


End Pre-Soak 12”:

Time at 12”:

Time at 9”:

Time at 6”:

Time (9”-6”):

Rate:








Deep Hole Number TP 7 Date: 08/20/09 Time: 1:15pm Weather Partly Cloudy 65 F


Land Use Inside of track Slope (%) See Plan Surface Stones n/o

Vegetation Grass

Landform Floodplain






Depth from







2.5Y4/3 ---- 10% Gravel, Friable, Single grained, some sands


2.5Y4/4 ---- 2-5% Gravel, Friable, Massive


2.5Y4/4 5%@55” 10YR5/8

<2% Gravel, Friable in hand, somewhat firm in place, Massive


Parent Material (geologic) Alluvial Depth to Bedrock: >103



Percolation Test:

Depth to Perc:


End Pre-Soak 12”:

Time at 12”:

Time at 9”:

Time at 6”:

Time (9”-6”):

Rate:








Deep Hole Number TP 8 Date: 08/20/09 Time: 8:00am Weather Partly Cloudy 65 F


Land Use Lawn area Slope (%) See Plan Surface Stones n/o

Vegetation Grass

Landform Floodplain






Depth from







5YR 2.5/1 ---- <5% Gravel, Friable, Single grained, some sands


10YR 3/2 ---- 2-5% Gravel, Friable, Massive


5Y 3/1 10%@54” 10YR6/8

<1% Gravel, Massive, very moist


Parent Material (geologic) Alluvial Depth to Bedrock: >108”



Percolation Test:

Depth to Perc:


End Pre-Soak 12”:

Time at 12”:

Time at 9”:

Time at 6”:

Time (9”-6”):

Rate:









Appendix C – TSS Removal Summary

V

INS

TR

UC

TIO

NS

:V

ers

ion 1

, A

uto

mate

d:

Mar.

4,

2008

1. In

BM

P C

olu

mn, clic

k o

n B

lue C

ell

to A

ctivate

Dro

p D

ow

n M

enu

2. S

ele

ct B

MP

fro

m D

rop D

ow

n M

enu

3. A

fter

BM

P is s

ele

cte

d, T

SS

Rem

oval and o

ther

Colu

mns a

re a

uto

matically

com

ple

ted.

Location:

BC

DE

F

TS

S R

em

oval

Sta

rtin

g T

SS

Am

ount

Rem

ain

ing

BM

P1

Rate

1Load*

Rem

oved (

C*D

)Load (

D-E

)

Pro

pri

eta

ry T

reatm

en

t

Pra

cti

ce

0.8

11.0

00.8

10.1

9

0.0

00.1

90.0

00.1

9

0.0

00.1

90.0

00.1

9

0.0

00.1

90.0

00.1

9

0.0

00.1

90.0

00.1

9

To

tal

TS

S R

em

oval

=81%

Sep

ara

te F

orm

Need

s t

o

be C

om

ple

ted

fo

r E

ach

Ou

tlet

or

BM

P T

rain

Pro

ject:

Th

ree

Co

un

ty F

air

gro

un

ds

-P

H1

,

No

rth

am

pto

n, M

A

Pre

pare

d B

y:

Bri

an

Darn

old

*Equals

rem

ain

ing load f

rom

pre

vio

us B

MP

(E

)

Date

:10/1

/2010

whic

h e

nte

rs the B

MP

TSS Removal

Calculation Worksheet

New

ST

C900 f

or

Exis

ting E

ast B

asin

Non-a

uto

mate

d T

SS

Calc

ula

tion S

heet

must

be u

sed if

Pro

prieta

ry B

MP

Pro

posed

1.

Fro

m M

assD

EP

Sto

rmw

ate

r H

andbook V

ol. 1

Mass.

Dept.

of

Environm

enta

l P

rote

ction

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arc ,"100 .~ ., life l:iCOl .". ~

ITC .tiIQ) ••• ••

Three County Fairgrounds-Phase 1 October 1, 2001 Revised 11/1/10 & 11/3/10



Appendix D – Recharge Calculations

~~The Berkshire Design Group,Inc.

4 Allen Place NorthaJTl£!on, ~assachusens 0 I 060 •

~, -+1 -!-----'- + - • -r 1 I !

+-+-

T

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t + + ~

Landscape Architecture

Civil Engineering

Planning

JOB11t#4'-eru..~t"1t".,..J,~ ~ \ SHEET NUMBER :.l OF ~ CALCULA TED By"B4? DA ~~--U.J.3.J1O CHECKED BY DATE, __ _

Urban Design

Environmental Services

t - 1

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+ r~ ~, +-+- - ~ . 1- -'- - +- i-

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~~~The i; Berkshire Design Group, Inc.

4 Allen Place

•

Northam-E!on, Massachusetts 0 I 060

~+

Landscape Architecture

Civil Engineering

Planning

Urban Design

Environmental Services

- +

JOB 1Luze. COVtI\! "WorQVol\J.s .1-SHEETNW.tBER Z 'OF Zz CALCULA TED BY KD DATE ':i7 31m CHECKED BY DATE, __ _

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+

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+

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Three County Fairgrounds-Phase 1 October 1, 2001 Revised 11/1/10 & 11/3/10



Appendix E – Proposed Stormwater Management

System Operation & Maintenance Plan

Three County Fairgrounds October 1, 2010 Revised 11/1/10& 11/3/10

Northampton, MA Operation & Maintenance Plan

1

Proposed

Stormwater Management System

Operation & Maintenance Plan

During Construction

The Contractor shall be responsible for inspection and maintenance during

construction.

At all times, siltation fabric fencing, stakes and hay bales sufficient to construct a

sedimentation control barrier a minimum of 50 feet long will be stockpiled on the

site in order to repair established barriers which may have been damaged or

breached.

An inspection of all erosion control and stormwater management systems shall be

conducted by the Contractor at least once a week and during all rain storms until

the completion of construction. In case of any noted breach or failure, the

Contractor shall immediately make appropriate repairs to any erosion control

system and notify the engineer of any problems involving stormwater

management systems.

A rain storm shall be defined as all or one of the following:

• Any storm in which rain is predicted to last for twelve consecutive hours or

more.

• Any storm for which a flash flood watch or warning is issued.

• Any single storm predicted to have a cumulative rainfall of greater than one-

half inch.

• Any storm not meeting the previous three thresholds but which would mark a

third consecutive day of measurable rainfall.

The Contractor shall also inspect the erosion control and stormwater management

systems at times of significant increase in surface water runoff due to rapid

thawing when the risk of failure of erosion control measures is significant.

In such instances as remedial action is necessary, the Contractor shall repair any

and all significant deficiencies in erosion control systems within two days.

The Department of Public Works shall be notified of any significant failure of

stormwater management systems and erosion and sediment control measures and

shall be notified of any release of pollutants to a water body (stream, brook, pond,

etc.) or into a conveyance system to a water body.



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The Contractor shall remove the sediment from behind the fence of the

sedimentation control barrier when the accumulated sediment has reached one-

half of the original installed height of the barrier.

Post-Construction

Stormwater Management System Owner:

The Owner,


Fair Street

Northampton, MA 01060

shall own the stormwater management system.

Party Responsible for Operation & Maintenance:

The Owner,


Fair Street


shall operate and maintain the stormwater management system.

Inspection & Maintenance Schedule:

1) Street Sweeping

Street and parking area sweeping shall take place twice annually.

2) Existing Detention Basins (The following recommendations follow the MADEP

Stormwater Policy guidelines.)

Inspections

. Twice per year.

Examine basin for the following: differential settlement, cracking,

erosion, leakage, or tree growth on embankments, condition of

riprap, sediment accumulation, and health of turf where applicable.

Any adverse conditions noted during any inspections shall be addressed by

repair or reconsideration of design components.



3

Mowing and General Maintenance

Occasional mowing (2 times per year min.) shall be performed on the side

slopes and basin bottom where turf is present. Accumulated grass

clippings and/or organic matter and trash and debris shall be removed.

Any clogged surface areas can be loosened by deep tilling; tilled areas

must be immediately revegetated. Tilling may be used in this manner for

no more than two consecutive maintenance periods. Thereafter, sediment

in the clogged areas shall be removed, liner material replaced, and

revegetation established.

Dredging/Sediment Removal

Accumulated sediment shall be removed from the basin at five (5) year

intervals, or as required to maintain the function of the stormwater

management system as designed. During this process and until the

disturbed sediment has settled, the outlet pipe shall be sealed so as to

minimize the risk of conveying sediment beyond the basin.

3) Subsurface Trench Systems

Subsurface Trench ‘D’

Inspect for trench damage monthly. A minimum of twice annually, following

heavy storm events and otherwise as needed perform visual inspection of all

overflow inlets. Rake to remove leaves and debris during the spring and fall. Mow

plantings a minimum of twice annually and otherwise as needed. Add additional

loam to cover GrassPave units and replant as needed. Remove all areas of

collected sediment following occurrences and restore to original conditions. For

trenches in high traffic areas, at least once every 5 years plantings and planting

media shall be removed from GrassPave units and replaced with new.

Subsurface Trench ‘C’



overflow inlets. Rake to remove leaves and debris during the spring and fall. Mow

plantings a minimum of once annually. Sediment shall also be removed following

any occurrence and trench shall be restored to original conditions.

Subsurface Trench ‘E’



overflow inlets. Rake to remove leaves and debris during the spring and fall.



4

Following events, inspect for proper grading and remove all areas of collected

sediment. Sediment shall also be removed following any occurrence and trench

shall be restored to original conditions.

Subsurface Trench Section ‘F’



overflow inlets. Maintain visible concrete walk at all times ‘non-cleaning’ times.

During barn cleaning, all inlet grates shall be replaced with a solid cover until

manure and other debris has been removed. Following all events inspect for

proper grading and remove all areas of collected sediment. Sediment shall also be

removed following any occurrence and trench shall be restored to original

conditions.

4) Phase 1 Infiltration Trench



overflow inlets. Rake to remove leaves and debris during the spring and fall.

Following events, inspect for proper grading and remove all areas of collected

sediment. Sediment shall also be removed following any occurrence and trench

shall be restored to original conditions.

5) Hooded Catch Basin, Drain Basin, and/or Drain Manhole with Sump

Oil and water separators should be inspected at least four times per year and

cleaned annually or more often if required. Oil and sediments should be removed

and disposed of in accordance with local, state and federal guidelines and

regulations. In the case of an oil or bulk pollutant release, the system must be

cleaned immediately following the spill and the proper authorities notified.

6) Stormwater Treatment Chamber

The Stormwater Treatment Chamber, of which there is 1 StormCeptor (Model #

900) water quality structure or equal treatment chambers, shall be inspected and

maintained according the manufacturer’s specifications. Rinker, the manufacturer

of Stormceptor recommends that maintenance be completed on the structures at

least once per year, but advises that the units be checked once every three months

during the first year to determine the rate of sediment and oil accumulation and to

establish an appropriate maintenance schedule. The rate at which the system

collects pollutants will depend on site activities. Maintenance or cleaning shall be

performed when the stored volume reaches 15% (6 inch sediment depth) of the

Stormceptor capacity, when oil (hydrocarbon) has accumulated to 1 inch or

greater depth, or immediately in the event of a fuel or oil spill according the



5

manufacturer’s specifications. All material removed from the Stormceptor shall be

disposed in accordance with applicable local, state, and federal guidelines and

regulations. For more detail of how the StormCeptor should be maintained see the

StormCeptor's Owner Manual.

7) Pump System for Stormwater

The existing pump system shall be operated after every significant storm and shall

remain on until the system has been drawn down completely. The standard

operating rate for the pump shall be 200gpm and the system shall be drawn down

to elevation 112.84’ (minimum) in less than 72 hours. The owner shall maintain a

story pole within the existing east detention basin showing elevations for

reference.

Volume of Pond below Outlet to be Pumped (below elev. 116’) = 115,373cf

Pump Rate = 200gpm or 0.45cfs

Pond Drawdown Time = 115,373cf/(0.45cfs X 60seconds/min X 60min/hour X

24hours/day X 3 days) = 115,373cf/116,640cf = 71.2hours




Appendix F – Long Term Pollution Prevention

Plan

Three County Fairgrounds October 1, 2010 Revised 10/25/10 & 11/1/10

Northampton, MA Long Term Pollution Prevention Plan

1

Long Term Pollution Prevention Plan

This plan was developed in compliance with the Massachusetts Department of

Environmental Protection Stormwater requirements.

Good Housekeeping

The proposed site is designed to maintain high water quality treatment for all runoff. A

general maintenance plan has been prepared and will be followed in a strict and complete

manner as required.

Spill Prevention Plan

No hazardous materials are will be stored on site. However the following spill prevention

plan will be incorporated into the Long Term Pollution Prevention Plan:

• Manufacturers’ recommended methods for spill cleanup will be clearly posted and

site personnel will be made aware of the procedures and the location of the

information and cleanup supplies.

• Materials and equipment necessary for spill cleanup will be kept in the on-site

material storage area. Equipment and materials will include, but is not limited to,

brooms, dust pans, mops, rags, gloves, goggles, kitty litter, sand, sawdust and

plastic and metal trash containers specifically for this purpose.

• All spills will be cleaned up immediately after discovery.

• The spill area will be kept well ventilated and personnel will wear appropriate

protective clothing to prevent injury from contact with a hazardous substance.

• Spills of toxic or hazardous material will be reported, regardless of size, to the

Massachusetts Department of Environmental Protection at 888-304-1133.

• Should a spill occur, the spill prevention plan will be adjusted to include measures

to prevent another spill and to cleanup up the spill should another occur. A

description of the spill, along with the causes and cleanup measures will be

included in the updated spill prevention plan.

• The construction superintendent responsible for daily operation on the

construction site will be the spill prevention and cleanup coordinator. The

superintendent will designate at least three site personnel to receive spill

prevention cleanup and training. These individuals will each become responsible

for a particular phase of prevention and cleanup. The names of responsible spill

personnel will be posted in the material storage area and in the on-site job trailer.

Stormwater BMP Maintenance

A full stormwater operation and maintenance plan has been prepared (see Appendix D of

this report) in order to ensure that the system will function properly throughout the year.

Landscape and Lawn Maintenance

Routine mowing and associated maintenance of all landscape features will occur weekly

or as needed to prevent excessive growth and debris from occurring on site.

Three County Fairgrounds October 1, 2010 Revised 10/25/10 & 11/1/10

Northampton, MA Long Term Pollution Prevention Plan

2

Solid Waste Management

Solid waste is handled on site and will comply with all requirements on a local, state, and

federal level.

Parking/Road Area Maintenance

Street sweeping shall occur 2-4 times per year. A snow management plan has been

prepared (see Appendix D) to prevent reduce impacts of dirty snow on the resource area.

Training of Staff

All personnel on site will be well briefed on all requirements for implementing the Long

Term Pollution Prevention Plan.

Emergency Contact for Implementing Long Term Pollution Prevention Plan


Fair Street


three county fairgrounds stormwater drainage report 11-03-2010

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