Chapel Street Sewer Service Evaluation MemoMEMORANDUM Tighe&Bond
Basis of Design Memorandum
Chapel Street Gravity Sewer Feasibility Study
TO: Wayne Feiden, FAICP, Director of Planning and Sustainability, City of
Northampton
FROM: Matthew Kirk, PE, Project Engineer, Tighe & Bond
Zach Chornyak, PE, Senior Project Manager, Tighe & Bond
DATE: April 13, 2022
Background
The City of Northampton and the Valley Community Development are interested in the
feasibility of extending sewer service to a proposed housing development on Chapel Street
adjacent to the intersection with Rust Avenue in Northampton. Tighe & Bond has initially
evaluated the feasibility of extending gravity sanitary sewer to this location as described in
this memorandum.
For the purposes of this evaluation, it has been assumed that as part of the development,
on-site gravity sewers will collect flow from all units and discharge to a common location
where City sewers will then convey flow off-site. Four options were evaluated for
connections to available City sanitary sewers as follows:
· Installation of new gravity sewer main on Chapel Street southwest to Grove Street
· Installation of new gravity sewer main on Chapel Street to northeast to Laurel Street
· Installation of new gravity sewer main across private property across Chapel Street
to the South
· Installation of a low pressure pumped system
Gravity sanitary sewers exist on Rust Avenue which convey flows to Chapel Street, then
northeasterly to Laurel Street, then southerly to Grove Street. The Grove Street sanitary
sewer extends west approximately to the intersection with Chapel Street, and conveys flows
east. Additionally, a private cross-country sewer main exists behind #48 Chapel Street
(Wildwood Court Condominiums) which conveys that properties sewer flows to Grove
Street.
Gravity Sewer Feasibility Evaluation
Tighe & Bond collected available GIS data from the DPW, and performed field investigations
to verify accuracy to the extent possible. Using this data, field measurements, and
available topographic information, the following four options were evaluated.
Gravity Sewer Alignment - Option 1
Extending gravity sewer from the proposed development westerly on Chapel Street is
physically possible. This project would require approximately 1,200 linear feet of new 8-
inch diameter pipe and associated manholes from the southern end of the proposed site
development to the existing 8-inch diameter gravity sewer main located on Grove Street. It
would generally be installed within a corridor between the existing water main and storm
drain. Appendix A includes Figure 1 which depicts the approximate layout for this option.
MEMORANDUM Tighe&Bond
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Some important considerations regarding this option are as follows:
· In some locations there is limited clear distance between the existing water main and
storm drain piping. Some water main relocation may be required to accommodate
the required corridor for the new gravity sewer piping.
· The majority of this work is within the Route 66 (Chapel Street) corridor. As a
result, MassDOT prequalified Contractors will be required, and the project will need
to adhere to MassDOT design/construction standards.
· Depending on the amount of water main relocation needed, overall project costs for
this alternative are expected to be in the $580,000 dollar order of magnitude.
Appendix B includes an Opinion of Probable Project cost for the various options.
Gravity Sewer Alignment - Option 2
Extending gravity sewer from the proposed development easterly on Chapel Street is
physically possible. This project would require approximately 1,180 linear feet of new 8-
inch diameter pipe and associated manholes from the northern end of the proposed site
development to the Laurel Street/Chapel Street intersection, and then to the Laurel
Street/Grove Street intersection. This would require replacement of the existing gravity
sewers from Rust Avenue to Grove Street due to vertical grade issues (the new sewer would
need to be deeper to be able to connect to the proposed development. Although this option
is physical possible, we recognize that it is likely not something that will be considered due
to the sewer on Laurel being recently replaced, at an elevation that still is not conducive to
connecting piping from the proposed development. Appendix A includes Figure 2 which
depicts the approximate layout for this option.
Some important considerations regarding this option are as follows:
· The existing sewer from Rust Avenue to Grove Street needs to be replaced deeper to
accommodate the development connection. The benefit is that a corridor is available
already in the existing alignment, but sewer services to houses will need to be
reconnected from the property lines to the new mainline.
· Existing sewer flows will need to be maintained via bypass pumping during
replacement of the existing sewer piping.
· A portion of this work is within the Route 66 (Chapel Street) corridor. As a result,
MassDOT prequalified Contractors will be required, and the project will need to
adhere to MassDOT design/construction standards.
· Overall project costs for this alternative are expected to be in the $507,000 dollar
order of magnitude. Appendix B includes an Opinion of Probable Project cost for the
various options.
Gravity Sewer Alignment - Option 3
Connecting gravity sewer from the proposed development to the private sanitary sewer
piping within the Willwood Condominiums is physical possible. The Willwood piping is 8-inch
diameter PVC and should have adequate capacity. Appendix A includes Figure 3 which
depicts the approximate layout for this option.
MEMORANDUM Tighe&Bond
-3-
Some important considerations regarding this option are as follows:
· The costs for this option are less expensive than Options 1 and 2, however formal
easements will be required.
· It is likely that as a result of this project that the City would encumber the operations
and maintenance of the entire cross-county piping alignment from Chapel Street to
Grove Street.
· A portion of this work is within the Route 66 (Chapel Street) corridor. As a result,
MassDOT prequalified Contractors will be required, and the project will need to
adhere to MassDOT design/construction standards.
· Overall project costs for this alternative are expected to be in the $140,000 dollar
order of magnitude. Appendix B includes an Opinion of Probable Project cost for the
various options.
Low Pressure Sewer - Option 4
Installing a low-pressure sewer system from the proposed development to the terminal
manhole on Chapel Street at Rust Avenue is physically possible. This project would require
the installation of an onsite grinder pumping station and associated electrical work and
approximately 215 linear feet of 1.5” HDPE pressure discharge piping. Appendix A includes
Figure 4 which depicts the approximate layout for this option.
Some important considerations regarding this option are as follows:
· The operation and maintenance of the grinder station would become the onus of the
property owner/manager.
· The cost of this work is expected to be less expensive than any of the gravity sewer
options outlined above.
· A portion of this work is within the Route 66 (Chapel Street) corridor. As a result,
MassDOT prequalified Contractors will be required, and the project will need to
adhere to MassDOT design/construction standards.
· Overall project costs for this alternative are expected to be in the $95,000 dollar
order of magnitude. Appendix B includes an Opinion of Probable Project cost for the
various options.
Low Pressure Sewer - Option 5
Similar to Option 4. An option utilizing a septic tank effluent pump (STEP) system was
considered. This type of system uses a large septic tank, and pumps clear effluent to the
City sewers via a forcemain. It was determined that it would not be advantageous to
consider further for the following reasons:
· This system has more equipment to install and is more complex. It requires
pumps, a forcemain, and a septic tank.
· There is more maintenance required including yearly septic tank pump outs.
· Due to the size of the septic tank, it will be more expensive to install the
system.
MEMORANDUM Tighe&Bond
-4-
Recommendations
Tighe & Bond recommends that a low-pressure sewer system to serve the proposed
development (Option 4), be implemented. Largely because of the cost effectiveness of the
project, but also because of the simplicity of the system, minimal maintenance, and the
project results in minor impacts to the surrounding infrastructure and roadway. Tighe &
Bond understands the reluctance for communities to rely on mechanical equipment rather
than gravity flow, and in most cases, this makes sense. In this case the cost difference of
up to $500,000 makes it much more attractive. Additionally, it is not uncommon for the
grinder pump to be maintained by the owner of the development, and the only asset to be
maintained is the small diameter low pressure force main within the City right-of-way. The
required maintenance is infrequent flushing of the main by connecting a jetting truck to the
clean out connection that would be installed.
J:\N\N0936 Northampton DPW\045 - Chapel Street Sewer Feasibility Study\Deliverables\Gravity Sewer Analysis Memo.doc
MEMORANDUM Tighe&Bond
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Appendix A
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!R CHAPEL STREETGR OVE S T R E ET
RUST AVENUE
FIGURE 1Site PlanOption 1
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1:1,200
NOTES
LOCUS MAP
G:\GIS\MA\NorthamptonMA\MA_11x17_ChapelStreetDevelopment_Option1.mxd [Exported By: JWebb, 4/5/2022, 4:28:05 PM]
1. Based on MassGIS Orthophotography (2021), Town of Northampton Utility Mapping (2022), and Approximate Parcel Boundaris from the Town of Northampton (FY2021).2. Gas Lines are approximate and based off on-site utility markings.
0 50 100
Feet
Chapel StreetHousing DevelopmentRoute 66Northampton, Massachusetts
April 2022
¹
Tighe&Bond
!R Exisiting Sewer Manhole
?Exisiting Private Sewer Manhole
Proposed Sewer Alignment
Exisiting City Sewer Pipe
Exisiting Private Sewer Manhole
G!.Hydrant
Water Main
!R Storm Drain Manhole
"¥Storm Drain Catch Basin
#Storm Drain Outfall
Storm Drain Main
Storm Drain Culvert
Gas Main
Site Parcel Boundary
Approximate Parcel BoundaryÈProposed SiteDevelopment Location
ÈExisting Dainage Culvert È
Proposed Sewer Alignment
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CHAPEL STREETLAUREL STREET
GROVE S TREE T
RUST AVENUE MEMORIAL ROADFIGURE 2OrthophotographSite PlanOption 2
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1:1,000
NOTES
LOCUS MAP
G:\GIS\MA\NorthamptonMA\MA_11x17_ChapelStreetDevelopment_Option2.mxd [Exported By: JWebb, 4/5/2022, 3:49:59 PM]
1. Based on MassGIS Orthophotography (2021), Town of Northampton Utility Mapping (2022), and Approximate Parcel Boundaris from the Town of Northampton (FY2021).2. Gas Lines are approximate and based off on-site utility markings.
0 50 100
Feet
Chapel StreetHousing DevelopmentRoute 66Northampton, Massachusetts
April 2022
¹
Tighe&Bond
!R Existing Sewer Manholes
?Existing Private Sewer Manholes
Proposed Sewer Alignment
Existing City Sewer Pipe
Existing Private Sewer Pipe
G!.Hydrant
Water Main
!R Storm Drain Manhole
"¥Storm Drain Catch Basin
#Storm Drain Outfall
Storm Drain Main
Storm Drain Culvert
Gas Main
Site Parcel Boundary
Approximate Parcel BoundaryÈProposed SiteDevelopment Location ÈProposed Sewer Alignment(Replaces Sewer on Chapel Street)
È
Proposed Sewer Alignment(Replaces Sewer on Laurel Street)
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CHAPEL STREETGR OVE STR EET LAUREL STREETRUST AVENUE
FIGURE 1Site PlanOption 3
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NOTES
LOCUS MAP
G:\GIS\MA\NorthamptonMA\MA_11x17_ChapelStreetDevelopment_Option3.mxd [Exported By: JWebb, 4/4/2022, 7:42:45 PM]
1. Based on MassGIS Orthophotography (2021), Town of Northampton Utility Mapping (2022), and Approximate Parcel Boundaris from the Town of Northampton (FY2021).2. Gas Lines are approximate and based off on-site utility markings.
0 50 100
Feet
Chapel StreetHousing DevelopmentRoute 66Northampton, Massachusetts
April 2022
¹
Tighe&Bond
G!.Hydrant
Water Main
!R Storm Drain Manhole
"¥Storm Drain Catch Basin
#Storm Drain Outfall
Storm Drain Main
Storm Drain Culvert
!R Exisiting Sewer Manhole
?Exisiting Private Sewer Manhole
Proposed Sewer Alignment
Exisiting City Sewer Pipe
Exisiting Private Sewer Manhole
Gas Main
Site Parcel Boundary
Approximate Parcel Boundary
ÈProposed SiteDevelopment Location
ÈProposed Sewer Alignment(New alignment from development to private sewer)
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GROV E STREE TCHAPEL STREETLAUREL STREET
RUST AVENUE MEMORIAL ROADFIGURE 4OrthophotographSite PlanOption 4
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1:1,200
NOTES
LOCUS MAP
G:\GIS\MA\NorthamptonMA\MA_11x17_ChapelStreetDevelopment_Option.mxd [Exported By: JWebb, 4/5/2022, 4:09:43 PM]
1. Based on MassGIS Orthophotography (2021), Town of Northampton Utility Mapping (2022), and Approximate Parcel Boundaris from the Town of Northampton (FY2021).2. Gas Lines are approximate and based off on-site utility markings.
0 50 100
Feet
Chapel StreetHousing DevelopmentRoute 66Northampton, Massachusetts
April 2022
¹
Tighe&Bond
G!.Hydrant
Water Main
!R Storm Drain Manhole
"¥Storm Drain Catch Basin
#Storm Drain Outfall
Storm Drain Main
Storm Drain Culvert
!R Existing Sewer Manholes
?Existing Private Sewer Manholes
Proposed Sewer Alignment
Existing City Sewer Pipe
Existing Private Sewer Pipe
Gas Main
Site Parcel Boundary
Approximate Parcel Boundary
ÈProposed SiteDevelopment Location
È
Proposed Low PressureSewer AlignmentÈProposed GrinderPump Station
4SP
MEMORANDUM Tighe&Bond
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Appendix B
Tighe&Bond
Date: 4/12/2022
Quantity Unit Unit Price Cost
1 Mobilization/Demobilization (5%)1 Lump Sum 17,900.00$ 17,200.00$
2 12" DI Water Main Relocation 275 Linear Feet 150.00$ 41,250.00$
3 6" PVC for Sanitary Sewer Services 60 Linear Feet 115.00$ 6,900.00$
4 8" PVC Sanitary Sewer Main 1200 Linear Feet 150.00$ 180,000.00$
5 48" Diameter Sewer Manhole 7 Each 5,500.00$ 38,500.00$
6 8"x6" Sanitary Sewer Service Wye 2 Each 200.00$ 400.00$
7 Permanent Trench Patch 380 Ton 200.00$ 76,000.00$
8 Loam and Seed 80 Square Yard 10.00$ 800.00$
361,100.00$
144,500.00$
36,200.00$
541,800.00$
40,000.00$
581,800.00$
Engineering During Bidding and Construction (Estimated at 10% of Construction)
Total Construction Cost
Engineering Design and Permitting
Total Project Cost
Chapel Street Sewer Feasibility Study Option 1 Sub-Total
40% Construction Contingency
City of Northampton
Chapel Street Sewer Feasibility Study Option 1
Northampton, MA
Description
Opinion of Conceptual Project Cost
J:\N\N0936 Northampton DPW\045 - Chapel Street Sewer Feasibility Study\Design\Opinion of Probable Cost.xlsx
Tighe&Bond
Date: 4/12/2022
Quantity Unit Unit Price Cost
1 Mobilization/Demobilization (5%)1 Lump Sum 15,600.00$ 15,600.00$
2 6" PVC for Sanitary Sewer Services 60 Linear Feet 115.00$ 6,900.00$
3 8" PVC Sanitary Sewer Main 1180 Linear Feet 150.00$ 177,000.00$
4 48" Diameter Sewer Manhole 7 Each 5,500.00$ 38,500.00$
5 8"x6" Sanitary Sewer Service Wye 12 Each 200.00$ 2,400.00$
6 Reconnect Existing Sanitary Sewer Services 12 Each 1,000.00$ 12,000.00$
7 Permanent Trench Patch 295 Ton 200.00$ 59,000.00$
8 Loam and Seed 25 Square Yard 10.00$ 250.00$
311,700.00$
124,700.00$
31,200.00$
467,600.00$
40,000.00$
507,600.00$ Total Project Cost
Opinion of Conceptual Project Cost
City of Northampton
Chapel Street Sewer Feasibility Study Option 2
Northampton, MA
Description
Chapel Street Sewer Feasibility Study Option 2 Sub-Total
40% Construction Contingency
Engineering During Bidding and Construction (Estimated at 10% of Construction)
Total Construction Cost
Engineering Design and Permitting
J:\N\N0936 Northampton DPW\045 - Chapel Street Sewer Feasibility Study\Design\Opinion of Probable Cost.xlsx
Tighe&Bond
Date: 4/12/2022
Quantity Unit Unit Price Cost
1 Mobilization/Demobilization (5%)1 Lump Sum 4,000.00$ 4,000.00$
2 8" PVC Sanitary Sewer Main 255 Linear Feet 150.00$ 38,250.00$
3 48" Diameter Sewer Manhole 4 Each 5,500.00$ 22,000.00$
4 Core into Existing Structure 1 Each 1,000.00$ 1,000.00$
5 Remove and Reset Granite Curb 20 Each 50.00$ 1,000.00$
6 Permanent Trench Patch 30 Ton 200.00$ 6,000.00$
7 Loam and Seed 150 Square Yard 10.00$ 1,500.00$
73,800.00$
29,600.00$
7,400.00$
110,800.00$
30,000.00$
140,800.00$ Total Project Cost
Opinion of Conceptual Project Cost
City of Northampton
Chapel Street Sewer Feasibility Study Option 3
Northampton, MA
Description
Chapel Street Sewer Feasibility Study Option 3 Sub-Total
40% Construction Contingency
Engineering During Bidding and Construction (Estimated at 10% of Construction)
Total Construction Cost
Engineering Design and Permitting
J:\N\N0936 Northampton DPW\045 - Chapel Street Sewer Feasibility Study\Design\Opinion of Probable Cost.xlsx
Tighe&Bond
Date: 4/12/2022
Quantity Unit Unit Price Cost
1 Mobilization/Demobilization (5%)1 Lump Sum 3,700.00$ 2,400.00$
2 Grinder Pump Station 1 Lump Sum 25,000.00$ 25,000.00$
3 1.5" Low Pressure Sewer Main 215 Linear Feet 50.00$ 10,750.00$
4 Core into Existing Structure 1 Each 1,000.00$ 1,000.00$
6 Permanent Trench Patch 50 Ton 200.00$ 10,000.00$
7 Loam and Seed 80 Square Yard 10.00$ 800.00$
50,000.00$
20,000.00$
5,000.00$
75,000.00$
20,000.00$
95,000.00$ Total Project Cost
Opinion of Conceptual Project Cost
City of Northampton
Chapel Street Sewer Feasibility Study Option 4
Northampton, MA
Description
Chapel Street Sewer Feasibility Study Option 4 Sub-Total
40% Construction Contingency
Engineering During Bidding and Construction (Estimated at 10% of Construction)
Total Construction Cost
Engineering Design and Permitting
J:\N\N0936 Northampton DPW\045 - Chapel Street Sewer Feasibility Study\Design\Opinion of Probable Cost.xlsx