HomeMy WebLinkAboutConsultant Review - 980 OSGOOD STREET 11/17/1995 L
November 1i, 199
Planning Board
c/o Ads. Kathleen Bradley Colwell
Town Planner
Town of North Andover
120 Main Street
North Aindover, MA 01845
RE, Engineering review
Proposed Dunkin Donuts
Proposal No, 1-50I
Dear l is Colwell:
C`.oler & C;olaritonio; Inc, is pleased to provide you with this proposal to perforfn
engineering services associated with the above project. It is our understanding that we are
to review the plans and calculations for the above referenced commercial development ill
the Town of North Andover, Specifically, our review would cover stor►.ttwater runoff
calculations and design. The plan would be reviewed under the Zoning Board regulations
covering the site plan review. The plans would also be reviewed for conformance to
standard engineering design practices. The above referenced submittal is a modification to
a previously approved plan.
Included in this proposal is a Scope of 'ei;vices which outlines the specific tasks to be
performed, a listing of Additional Services which are excluded from this contract, and
discussions of Schedule, Pee and Basis of Payment,
1.0 SCOPE OF SEWVICES
1,1 Review the plats and talc;nations for conformance with the requirements
of local regulations as well as standard engineering practice. This review
would be specific to draivage design, other factors, e,g. soil testing, which
may ultimately affect the drainage design would also be evaluated.
1,2 Visit the property to observe existing conditions on the site, if required.
1.3 .Prepare a letter report commenting can the plans and calculat:ioils.
101 Aocord Park drive, Suite Die 617-982-5400
Norwell, MA 02061-1685 Fax:617-982-54W
2.0 ADDITIONAL SERVICES
Coler& Colantonio, Inc. would be pleased to provide the following additional services, if
required or desired, ibr mutually agreed upon additional compensation, Such additional
services would involve fees in addition to what is indicated in Section 4.0 of this proposal.
Attached is a. Fee Schedule which will be used to establish billings for services not
specifically covered by this contract.
2,1 Attendance at meethibs,
2.2 Additional review or preparation of additional reports.
23 Additional field visits.
3.0 SCHEDULE
Coler & Colantonio, Inc. will commence work upon receipt of written authorization to
proceed, We will perform these services to meet your requirements. Typically one to two
weeks are required to perform the tasks listed in the Scope of Services.
4.0 FEE
The fee to perform the services listed in the Scope of Services would be $1000 for the
information in hand. This is a not to exceed fee for the tasks listed in the Scope. You will
be billed based on actual hours worked on the project. Fees for services listed cinder
Additional Services, if required, would be billed on a time and materials basis in
accordance ivith the attached Fee Schedule.
The fees described above do not include expenses. Expenses such as mileage,
reprographic costs, etc, would be billed at cast plus a fifteen percent (IS%) administrative
charge.
5.0 BASIS FOR PAYMENT
Invoices for services will be submitted monthly. By the signing; of this proposal, it is
agreed and understood that payment will be made upon receipt of the invoice. The
owner/client agrees to limit the liability ofColer & Colantonio Inc. to the owner/client and
to all construction contractors and subcontractors ova the project arising from Coler &
Colantonio, Inc?s neg igeat acts, errors or omissions such that the total aggregate, liability
of Coler& Colantonio, Inc., will not exceed the contract amount, It is further understood
that any balances on this account remaining unpaid for a period of 30 clays will incur a
service charge of 1-1/2% per month (expressed as all aiipual percentage rate, the charge ).s
18°!0). It is further agreed that if said account is turned over for collection, reasonable
attorney's fees and costs of collection shall be added to the unpaid balances wl�eti7cr or
not legal action is instituted. Color & Celantonio, Inc. reserves the ri-�,.Il-rt to stop -work on
the project.if invoices are not paid within 30 days of the date of the invoice.
Prior to doing any work on the property, hie reserve the right.to post a notice of conlracr.
The parties to this contract specifically agree that Colr�r �� Cc�lar�ton%:x, tric, has no
obligation to release drawings or other documents until the final trill for seovices has been
paid.
By signing this letter, you indicate your acceptance of the teri-m and co.ndi*ions contained
herein and you will give us authorization to proceed with the scope of work indicated,
Sincerely,
COT-ER& COLANTONIO, INIC.
j il C, r4hessia, P.1 ,
Approved By- Agreed to and Accepted
for Basis Ol foment Icy.
James j. C olantortlo, Pres
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COLIA& COILANTONIO, IrNt-I
—EE S'-U'EDULE.
Noverribel' 6, 1 99
POSLT�Iw4 R" I'E
Principal Engineer andSurve-Yor $
Division Manager
Professional Engineer/
-
Professional Land Surveyor S' 60 8,,*. ,1'
Projec,t Manager
Si o a
Level 1 Engineer Scientist ajj,,j ,,-5uiveyor �, i,5ih,
T
�Ovel 2 Engineer kientist and Surveyor
Level 3 Engineer Scientist and StirvevOr $ 35 - 40/hr,
Draftsperson `
Technician S,
Support -staff $
f TELD STURNTY
TN?,;o person field orew amd equipmem
ENGINEERS AND SCIENTISTS
r
r�R
December 18, 1995 P NNING ..,I
Ms. Kathleen Colwell
Planning Board
120 Main Street
North Andover, MA 01845
RE: Engineering Review
North Andover Texaco/Dunkin Donuts
i
Dear Ms. Colwell:
Coler& Colantonio, Inc. has reviewed the plans and calculations for the above referenced
project. Our review specifically addressed drainage and stormwater runoff aspects of the
design. It is our understanding that other aspects of the design would be reviewed by in
house staff. We also compared the design assumptions and calculations with standard
practices outlined in Soil Conservation Service (SCS) runoff calculation documents and
other standard engineering references. This correspondence is a result of the above
review and includes our comments on the submittal package. The following documents
were reviewed:
• A plan entitled "Site Plan of Land in North Andover, MA" prepared for John
Ferreira and prepared by Merrimack Engineering Services, Inc. last revised
October 31, 1995.
• Runoff Calculations and Leaching Chamber Calculations prepared for John
Ferreira and prepared by Merrimack Engineering Services, Inc, dated October
31, 1995.
The parcel is located at the intersection of Osgood Street (Rte. 125) and Old Clark Road
within the Lake Cochichewick Watershed District. The lot is currently developed with a
one story masonry gasoline station and parking area. Drainage from the site is tributary to
wetlands at the northeast corner of the site and to the subsurface storm drainage system in
Osgood Street. It is proposed to construct a 1-1/2 story, 2,560 s.f building adjacent to
the existing structure and to expand the parking/driveway area. The proposed building
will house a 1,500 s.f. Dunkin Donuts and a 1,060 s.f retail store.
101 Accord Park Drive, Suite One 617-982-5400
Norwell, MA 02061-1685 Fax: 617-982-5490
It is our understanding that a site plan for this parcel was previously submitted and
approved by the Planning Board and Conservation Commission. The previous design
proposed to discharge storm drainage into the existing storm drainage system on an
adjacent parcel of land to the north and east of the site. However, the owner of that
parcel now refuses a drainage easement on his property thereby necessitating an
alternative method of storm water control. Since the parcel is located within the Lake
Cochichewick Watershed District, the engineer has proposed infiltration of excess
stormwater runoff.
The plan provided is extremely difficult to follow. A considerable amount of information
is indicated on the plan. An existing conditions plan, which may clarify some of the
information, was not provided. Some of our comments may arise from our inability to
interpret the plan. We suspect that others, including the contractor, would have similar
difficulties following the plan. The Town may want to consider requiring the applicant to
provide revised plans which are easier to interpret. We offer the following comments
regarding the revised design:
1. No information was provided regarding drainage divides for existing and proposed
conditions. It appears that the engineer addressed only the area proposed to be
changed from open area to impervious area in the calculations.
2. No information was provided on the drainage flow paths for existing and proposed
conditions. The design as proposed would create a low area with no drainage at
the dumpster pad in the northwest side of the new building. It also appears that
runoff would collect along the proposed retaining wall on the north side of the lot.
3. It is unclear what method for calculating runoff was used. Town of North
Andover regulations require the use of either SCS TR-55 or SCS TR-20 for
performing runoff calculations. Additionally, it is required that calculations be
performed for 2, 10 and 100 year storm events. The calculations appear to use a
runoff coefficient based on the"Rational Method" however, the calculations are
not consistent with rational method calculations. Calculations appear to be for the
100 year storm event.
4. No test pit information was provided to support that the soil is suitable for
infiltration. A percolation rate of 20 min./in. was used in the calculations for sizing
the infiltration area. It is unclear if this is an assumed value or is supported by test
data. Additionally, it is unclear if groundwater was encountered on the site.
Information on soil classification, percolation rate, and depth to groundwater
should be provided. SCS soils mapping for the area indicates Paxton Series Soils,
which reportedly are slowly permeable and a limiting factor in developing
subsurface wastewater disposal systems.
5. Dead Storage Capacity appears to be incorrectly calculated. The dimensions 8' x
12' were used to calculate available volume. These dimensions include the stone
surrounding the chambers. However, the stone volume was not subtracted from
the available Dead Storage Capacity. Actual capacity should be calculated from
the inside dimensions of the chamber plus the volume of voids within the stone.
6. Infiltration Capacity appears to have been calculated using the superseded Title 5
effluent loading rates. This type of design should address the volume being
sufficient to hold the design storm event and calculate the time to discharge the
runoff. Title 5 infiltration rates have been developed for different flow conditions,
however, they may be conservative in this regard.
7. The design includes connecting existing storm drains to the subsurface leaching
area. These drains have not been included in the calculations. The impact of
discharging additional flow to the system should be described. It is likely that the
system would surcharge under severe storm events. It is not clear how excess
runoff would be handled under these conditions.
8. It is unclear how flow in the drain pipes will enter the chamber system. It appears
that existing drainage from the southerly portion of the site and from the proposed
catch basin will both be directed to the leaching chamber system. Although the
detail indicates an invert at the side of the chamber it is unclear if the site plan
coincides with this detail. There does not appear to be sufficient space in the
chamber to install the proposed drain pipes. A detail or schematic profile of the
chamber system and how the drain pipes will discharge to the system should be
provided.
9. The leaching chamber detail should state leaching chambers are to be designed to
withstand H-20 loading.
10. These types of systems require maintenance to assure that they do not become
plugged with sediment. We recommend that a maintenance schedule be provided.
The design should also incorporate permanent monitoring wells in the leaching
area. These will be used to determine if the system is working properly and has
not become clogged.
11. Filter Fabric should be placed around the 3/4" - 1-1/2" stone in the leaching area to
prevent fine material from infiltrating the stone.
12. Calculations for storm drains have not been provided. These calculations should
include flow to surface inlets, pipe capacity and velocity.
13. The site is located in a Watershed Protection District. Within the Watershed
Protection District the Town has established four zones (General,Non-discharge,
Non-disturbance, and Conservation)to provide protection for lakes and wetland
resource areas included in the District. We assume that Town staff will comment
relative to protection of the water supply.
14. Near the easterly side of the parking lot it is unclear where the proposed 146'
contour ties into the existing 146' contour. Additionally in that area, we suggest
the 144' contour be graded to maintain a minimum 3:1 slope.
15. Near the northeasterly side of the parking lot, the 144' contour appears to "tie
into" the northerly face of the retaining wall but never"exits" the wall.
16. A minimum slope of 0.01 ft/ft should be maintained across the parking lot for
proper drainage.
17. We suggest that the water service be relocated to avoid the subsurface storm
drainage chamber system.
18. It appears that an easement may be requried to construct the proposed retaining
wall.
Infiltration systems, such as proposed on this site, can be a maintenance problem. If they
become clogged it is very expensive to replace the system. There is also some risk to
proposing an infiltration system at a gasoline service station. A gasoline spill would
discharge directly into the ground through the proposed system. The Town may want to
consider requiring an oil/water separator prior to discharge to the leaching system. The
We appreciate the opportunity to assist the Planning Board on this project and hope that
this information is sufficient for your needs. If you have any questions please do not
hesitate to contact us.
Very truly yours,
COLER& COLANTONIO, INC.
f
John C. Chessia, P.E.
xc Merrimack Engineering Services
„n
COLANTONIOZ
ENGINEERS AND SCIENTISTS
n6 f% 2r,
February 20, 1996 PLANNING BOAR6)
Ms. Kathleen Colwell
Planning Board
120 Main Street
North Andover,MA 01845
RE: Supplemental Engineering Review
North Andover Texaco/Dunkin Donuts
Dear Ms. Colwell:
Coler& Colantonio, Inc. has reviewed the revised plans and calculations for the above
referenced project. Our review specifically addressed drainage and stormwater runoff
aspects of the design. It is our understanding that the Town has endorsed the concept of
discharging site runoff through a"detention/retention” facility prior to discharge to the
Massachusetts DPW system. In addition, it is understood that the applicant is responsible
for mitigating the increase in runoff from the proposed development only. This
correspondence is intended to supplement our letter of December 18, 1995. Comments
follow in the same numerical order as our previous letter. If a comment was satisfactorily
addressed we have so stated. Additional comments which result from the design changes
have been added below the original comments. The following documents were reviewed:
• A plan entitled "Site Plan of Land in North Andover, MA" prepared for John
Ferreira and prepared by Merrimack Engineering Services, Inc. last revised 2-
1-96,two sheets.
• Drainage Analysis Report prepared for John Ferreira and prepared by
Merrimack Engineering Services,Inc. dated February 1996.
The plans provided are still extremely difficult to follow. A considerable amount of
information is indicated on the plans. An existing conditions plan,which may clarify
some of the information, was not provided. Some of our comments may arise from our
inability to interpret the plan. We suspect that others, including the contractor, would
have similar difficulties following the plan. The Town may want to consider requiring
the applicant to provide revised plans which are easier to interpret. We offer the
following comments regarding the revised design:
101 /accord Park Drive, Suite One 617-982-5400
Norwell, MA 02061-1685 Fax: 617-982-5490
1. Insufficient information was provided regarding drainage divides for existing and
proposed conditions. The engineer is responsible to mitigate for the proposed
development only, however, the structures have to function for all flows tributary
to them. To properly evaluate the design clearly labeled plans at a suitable scale,
indicating the subareas and flow paths for both pre and post construction
conditions should be provided. A sketch plan indicating post construction
subareas was provided. This plan is barely legible and is not sufficient for us to
evaluate.
2. See 1. above.
3. The calculations have been revised using SCS TR-55 methodology for computing
the runoff curve number. Merrimack Engineering Services (MES) listed how the
weighted CN was calculated in their report. They did not provide information on
the cover condition. Based on our review it appears that the"lawn landscaped
area is assumed to be in fair conditions with 50 to 75% cover and the woods are
also assumed to be in"fair" condition. We could not find any correlation with
their estimate for"disturbed area" in the literature. TR-55 lists fair wooded areas
as grazed but not burned. Woods should be considered good if this is not the
case. This information should be presented in a format comparable to the TR-55
tables. It is unclear how the time of concentration was "estimated". This
information should be presented with the submittal. Hydrographs were generated
using the "Drain Calc" computer program. Peale runoff rates compare with those
generated using TR-55 and TR-20.
4. Reportedly a test pit was dug at the site. No test pit information was provided
with the application. This information should be provided to substantiate the
assumptions used in the design. Groundwater elevation readings from existing
on-site wells should also be provided if available.
5. No information has been provided to describe how storage was calculated. Our
calculations based on the proposed design did not result in the same values
presented in the routing calculations.
6. It is unclear if infiltration has been considered as part of the outflow calculations.
There is no information describing infiltration rates in the report. In addition,
MES did not provide information to describe stage-discharge characteristics for
the outlet from the detention/retention facility. This information is required to
evaluate the routing calculations.
7. The design has been revised to eliminate the connection of existing storm drains
to the subsurface "detention/retention"facility. Calculations of pipe capacity and
velocity have not been provided for the on-site structures. The proposed design
includes a 12 inch ductile iron pipe connecting to three 6 inch PVC pipes. It is
unclear how this connection would be achieved. We recommend providing a
distribution box with an access cover at this location. The 6 inch discharge from
detention/retention system enters the manhole directly opposite the 12 inch
connection from the existing drains. In addition, the invert of the 6 inch line is
lower than that of the existing drains. This design will result in turbulence in the
manhole which would impact the discharge from the detention/retention facility.
It is unclear if this factor was considered in the calculations of outflow from the
detention/retention system, see 6. above.
8. See 7. above.
9. The leaching chamber detail should state leaching chambers are to be designed to
withstand H-20 loading.
10. These types of systems require maintenance to assure that they do not become
plugged with sediment. We recommend that a maintenance schedule be provided.
The design should also incorporate permanent monitoring wells in the leaching
area. These will be used to determine if the system is working properly and has
not become clogged.
11. Satisfactory.
12. Calculations for storm drains have not been provided. These calculations should
include flow to surface inlets,pipe capacity and velocity.
13. Satisfactory.
14. Satisfactory.
15. It is unclear how the finish grading is accommodated near the CB adjacent to the
existing swale to the Landers Property..
16. A minimum slope of 0.01 ft/ft should be maintained across the parking lot for
proper drainage. This has not been accomplished at several locations on the site
plan.
17. Satisfactory.
18. An easement will be required to construct the proposed retaining wall. A portion
of the wall would be on the abutting property.
19. The proposed oil/water separator is a PVC tee in the catch basin. Since the only
part of the site discharging to the detention/retention system is the Dunkin
Donuts/Retail facility this type of design may be sufficient. We recommend that
the catch basin sump be increased to a minimum of three feet and that the "Tee"
extend 12 inches below the invert elevation.
We appreciate the opportunity to assist the Planning Board on this project and hope that
this information is sufficient for your needs. If you have any questions please do not
hesitate to contact us.
Very truly yours,
COLER& COLANTONIO, INC.
l `
John C. Chessia, P.E.
xc Merrimack Engineering Services
COLER &
COLANTONIOZ
ENGINEERS AND SCIENTISTS
ii
fl �
u
March 13, 1996
f n.
Ms. Kathleen Colwell
Planning Board
120 Main Street
North Andover, MA 01845
RE: Supplemental Engineering Review
North Andover Texaco/Dunkin Donuts
Dear Ms. Colwell:
Coler & Colantonio,Inc. has reviewed supplemental data provided by Merrimack
Engineering Services (MES) dated March 2, 1996. In addition,we have discussed the
design criteria with both you and MES. Based on our discussions we have agreed upon
the following:
• It is in the best interest of the Town to have runoff from the site discharge to
the State drainage system,which ultimately flows to the Merrimack River,
instead of the current discharge point, which is tributary to Lake
Cochichewick.
• Since the discharge point is reportedly tributary to an area which is not know
to experience flooding problems, and the design of this system is subject to
review and approval by the State, it is not necessary for Coler& Colantonio,
Inc. (CCI)to review the hydrologic calculations.
• CCI will review the design relative to plan information, construction details
and some of the design assumptions.
This correspondence references our previous review letters. The numbering sequence is
consistent with past correspondence. As discussed in the earlier letters the plans provided
are still extremely difficult to follow. A considerable amount of information is indicated
on the plans. An existing conditions plan has been provided and does help with some of
the information. Reportedly,MES intends to assist during construction with site layout
and plan interpretation. The Town may want to consider requiring the applicant to
provide construction drawings which are easier to interpret for both the Town and the
Contractor. We offer the following comments regarding the revised design:
1. As discussed above, review of this information will be performed by the State.
101 Accord Park Drive, Suite One 617-982-5400
Norwell, MA 02061-1685 Fax: 617-982-5490
2. See 1. above.
3. See 1. above.
4. Based on the test pit information provided the site is not suitable for infiltration.
The proposed design could function as a detention basin with discharge to the
State system. Groundwater elevation readings from existing on-site wells, or new
test pits, should be provided to assure that the proposed detention system will not
be in groundwater. If well readings indicate that the detention area would be
constructed in groundwater the design should be revised to a sealed system of
pipes or the equivalent.
5. See 1. above.
6. See 1. and 4. above.
7. The proposed design includes a 12 inch ductile iron pipe connecting to three 6
inch PVC pipes. It is proposed to accomplish this connection with various
fittings. We recommend providing a distribution box with an access cover at the
12 inch to three 6 inch pipe connections. The 6 inch discharge from detention
system enters the converted manhole directly opposite the 12 inch connection
from the existing drains. In addition,the invert of the 6 inch line is lower than
that of the existing drains. This design will result in turbulence in the manhole
which would impact the discharge from the detention facility. We recommend
relocating the outlet from the detention system further west by two precast units.
In addition, the manhole should be provided with an invert channel to avoid
problems with turbulence.
8. Satisfactory.
9. The leaching chamber detail should state leaching chambers are to be designed to
withstand H-20 loading.
10. We recommend that a maintenance schedule be provided. Since leaching should
not be included as part of the design inspection and maintenance requirements
would be reduced.
11. Satisfactory.
12. Calculations for on-site storm drains have not been provided. These calculations
should include flow to surface inlets, pipe capacity and velocity. The pipe slopes
of the proposed pipes discharging to the detention system appears to be 1%.
Three six inch pipes at a 1%slope have a capacity of 1.7 cfs which is a little less
than the predicted 100 year runoff rate to the system.
13. Satisfactory.
14. Satisfactory.
15. It is unclear how the finish grading is accommodated near the CB adjacent to the
existing swale to the Landers Property. The proposed 144 contour is not indicated
in this location.
16. A minimum slope of 0.01 ft/ft should be maintained across the parking lot for
proper drainage. This has not been accomplished at several locations on the site
plan.
17. Satisfactory.
18. An easement will be required to construct the proposed retaining wall. A portion
of the wall would be on the abutting property.
19. Satisfactory.
20. We recommend providing a positive pitch in the detention basin from the inlets to
the outlet. This could be accomplished by grading the crushed stone. No storage
volume should be calculated below the outlet pipe elevation since the soils are not
suitable for leaching.
We appreciate the opportunity to assist the Planning Board on this project and hope that
this information is sufficient for your needs. If you have any questions please do not
hesitate to contact us.
Very truly yours,
COLER& COLANTONIO, INC.
C
/�John C. Chessia, P.E.
xc Merrimack Engineering Services
U k, � MAY 16
ENGINEERS AND SCIENTISTS -
t
May 13, 1996
Ms. Kathleen Colwell
Planning Board
120 Main Street
North Andover, MA 01845
RE: Supplemental Engineering Review
North Andover Texaco/Dunkin Donuts
Dear Ms. Colwell:
Coler& Colantonio, Inc. has reviewed supplemental data provided by Merrimack
Engineering Services (MES) dated April 24, 1996. This data was addressed to the
Massachusetts Highway Department and copied to us. As previously discussed much of
our review would be redundant given the need for a Massachusetts Highway Department
Permit and corresponding review.
This correspondence references our previous review letters. The numbering sequence is
consistent with past correspondence. As discussed in the earlier letters the plans provided
are still extremely difficult to follow. A considerable amount of information is indicated
on the plans. An existing conditions plan has been provided and does help with some of
the information. Reportedly, MES intends to assist during construction with site layout
and plan interpretation. The Town may want to consider requiring the applicant to
provide construction drawings which are easier to interpret for both the Town and the
Contractor. We offer the following comments regarding the revised design:
II
1. As discussed above, review of this information will be performed by the State.
2. See 1. above.
i
3. See 1. above.
4. Infiltration of runoff has been eliminated from the design. Groundwater elevation
readings from existing on-site wells, or new test pits, should be provided to assure
that the proposed detention system will not be in groundwater. If well readings
indicate that the detention area would be constructed in groundwater the design
should be revised to a sealed system of pipes or the equivalent unless the state
accepts directing groundwater into their system.
101 Accord Park Drive, Suite One 617-982-5400
Norwell, MA 02061-1685 Fax:617-982-5490
5. See 1. above.
6. See 1. and 4. above.
7. The proposed design includes a 12 inch ductile iron pipe connecting to three 6
inch PVC pipes. It is proposed to accomplish this connection with various
fittings. We recommend providing a distribution box with an access cover at the
12 inch to three 6 inch pipe connections. The 6 inch discharge from detention
system enters the converted manhole directly opposite the 12 inch connection
from the existing drains. In addition,the invert of the 6 inch line is lower than
that of the existing drains. This design will result in turbulence in the manhole
which would impact the discharge from the detention facility. We recommend
relocating the outlet from the detention system further west by two precast units.
In addition, the manhole should be provided with an invert channel to avoid
problems with turbulence. This issue was not addressed in the latest submittal.
8. Satisfactory.
9. Satisfactory.
10. We recommend that a maintenance schedule be provided. Since leaching should
not be included as part of the design inspection and maintenance requirements
would be reduced. This issue was not addressed in the latest submittal.
11. Satisfactory.
12. It is unclear if calculations for on-site storm drains have been provided. It appears
that some information on on-site catch basins tributary to the state system is
included, however, no schematic plan to identify them was included. Some
duplicate catch basin names are listed in the calculations further complicating
review. These calculations should include flow to surface inlets,pipe capacity
and velocity. The pipe slopes of the proposed pipes discharging to the detention
system appears to be 1%. Three six inch pipes at a 1% slope have a capacity of
1.7 cfs which is a little less than the predicted 100 year runoff rate to the system.
13. Satisfactory.
14. Satisfactory.
15. The proposed 144 contour has been indicated but ties into the existing grade
improperly.
16. A minimum slope of 0.01 ft/ft should be maintained across the parking lot for
proper drainage. This has not been accomplished at several locations on the site
plan. This issue was not addressed in the latest submittal.
17. Satisfactory.
18. An easement will be required to construct the proposed retaining wall. A portion
of the wall would be on the abutting property. Reportedly,the abutter will allow
the construction.
19. Satisfactory.
20. We recommend providing a positive pitch in the detention basin from the inlets to
the outlet. This could be accomplished by grading the crushed stone. No storage
volume should be calculated below the outlet pipe elevation since the soils are not
suitable for leaching. The elevation of the outlet in the calculations and the plans
is inconsistent.
We appreciate the opportunity to assist the Planning Board on this project and hope that
this information is sufficient for your needs. If you have any questions please do not
hesitate to contact us.
Very truly yours,
COLER& COLANTONIO, INC.
C t
John C. Chessia, P.E.
xc Merrimack Engineering Services
�I .
�����
TISTS
ENGINEERS AND SCIEN
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July 31, 1996
Ms, Kathleen Colwell
Planning Board
120 Main Street
North Andover,MA 01 845
RE: Supplemental Engineering Review
North Andover Texaco/Dunkin Donuts
Dear Ms. Colwell:
Coler& Colantonio, Inc.has reviewed supplemental data provided by Merrimack
Engineering Services (MES) dated July 15, 1996. This data was provided in response to
our review of May 13, 1996.
This correspondence references our previous review letters. The numbering sequence is
consistent with past correspondence. We offer the following comments regarding the
revised design:
1, As discussed above, review of this information will be performed by the State.
2. See 1. above.
3. See 1. above,
4. Groundwater has been measured in existing monitoring wells at depths of 27 and
47 inches below grade on 3/29/96. We disagree with MES contention that the
measured depths to groundwater are questionable with respect to actual
groundwater elevations. It appears that the measurements were taken in
permanent monitoring wells. These wells are typically the most accurate way of
determining groundwater elevations. MES provided no support information to
justify that measured elevations were due to an abnormal condition or defective
wells. Based on these results and the proposed design data the system will
intercept groundwater during some periods of the year and discharge to the state
system. If the Massachusetts Highway Department(MHD)has seen this data and
approved the plan knowing these conditions exist we would not request revising
the design in this regard. We request confirmation that MHD is aware that these
conditions exist on the site.
101 Accord Park Drive, Suite One 617-982-5400
Norwell, MA 02061-1685 Fax: 617-9£325490
5. See 1. above.
6. See 1. and 4. above.
7. We disagree with MES response to this comment. We recommend providing a
distribution box with an access cover at the 12 inch to three 6 inch pipe
connections. The 6 inch discharge from detention system enters the converted
manhole directly opposite the 12 inch connection from the existing drains. In
addition,the invert of the 6 inch line is lower than that of the existing drains. This
design will result in turbulence in the manhole which would impact the discharge
from the detention facility. We recommend relocating the outlet from the
detention system further west by two precast units. In addition, the manhole
should be provided with an invert channel to avoid problems with turbulence.
Providing a sump in the manhole will not address turbulence as well as an invert
channel. These modifications would improve the owner's ability to maintain the
system with a minimal impact on overall system cost.
8. Satisfactory.
9. Satisfactory.
10. We recommend that catch basins be inspected as described in MES
correspondence of July 15, 1996 and that the detention area also be inspected at
this time to determine if it is operating properly.
11. Satisfactory.
12. Satisfactory.
13. Satisfactory.
14. Satisfactory.
15. The proposed 144 contour has been indicated but ties into the existing grade
improperly. Details indicate a curb around the pavement which is not represented
by proposed contours in this area.
16. The proposal indicates a 0.5%minimum pitch in the pavement. Typically,
pavement contractors will not guarantee positive drainage with slopes this flat. If
the Owner and Planning Board are aware that some puddling of water is likely
with the proposed design and find this condition acceptable in this case we would
not recommend revising the design.
17. Satisfactory.
2
1 8. An easement will be required to construct the proposed retaining wall. A portion
of the wall would be on the abutting property. Reportedly, the abutter will allow
the construction and the terms of the easement are being discussed.
19. Satisfactory.
20. The revised calculations, on page 6, indicate that there are 451 cubic feet of
storage at elevation 142.0, the invert out. In MES response they indicate that 1
cubic foot of storage is provided prior to the storm event. The calculations should
reflect a storage of 0 at elevation 142.0. In addition, the proposed design would
result in stagnant water in the bottom of the facility. It is unclear if any changes
in this regard would impact the Permit to Access a State Highway.
We appreciate the opportunity to assist the Planning]hoard on this project and hope that
this information is sufficient for your needs. If you have any questions please do not
hesitate to contact us.
Very truly yours,
COLER& COLANTONIO, INC.
/John C. Chessia, P.E.
xc Merrimack Engineering Services
3
COLER
COLANTONIO �
fiNdiN�EFi9
FACSIMILE COVERSHEET
:To: Kathleen C'.olwelI
Compilny: Town of North Andover
Phone: (508) 688-9535
fax: (508) 688-0?542
From. John Chessia
Company: Coley c'. C'olantonioy Inc.
Phone: (617) 982-5443
Fax: (617) 982-5490
Date: August 23, 1 996
pages including this
cover page: 3
Review of"It cxac.0
copy to Mef`t Mack Enfainoering 15-orvices.
Kathlcen,
I di.dn t tviceive the complete response from Tyree consulting Co. Page three was incomplete,
Fd appreciate it i:t'you could semi page three agai#i wben you have a chance.
Thanks,
John.
_,rj
n
i
,
COLANTONIO
��
AugIas±. - , 1496
Ms. Kathleen Colwell
Plaiming Board
l 20 ..1� -in Street
North Andover, MA !01845
: 13 1j?IeI71 iifa1.3ngit1eeririg Review
North Andover Texaco/Dunkin Do.n.(tts
Door Ms. Colwell:
Coler& Colantonio.Inc. has reviewed sul)plernental data provided by Merrimack
Etigiricering 8eivices!'(MES) dated August 8, 1996. This data was provided in response
to otir review of July i 1, 1996,
This correspondence references mir pr viotis review letters. The numbering sequence is
consistent with past.correspondence:. We offer the followil).g cols meat;regarding the
revised design:
1. As discussed'bove,review of this infomiation wlll be.performed by the State,
See 1. above.
3. See 1. above.
4. We under stolid tirlat the issue of groundwater intrusion will be discussed with the
massachlisetts highway Department.
5. See 1, above.
6, See 1. and 4, drove.
7. Satisfactor .
8. Satisfacto-n,.
9, Satisfactory,
101 Accord Park Drive, 'Quite IOne 617-982-5400
Norwell, MA 02061.116$5 Fax;617-982-541.00;
10. We reconinieno that catch basins be inspected as described In MESS
cony-spondettcO of July IS, 1996 and that tr,o detention area also be inspected at
this time to det6miire if it is o1)erating properly,
l,1 Satisfactory, -
12. Satisfactory.
13, Sati sfactory.
14, Satisfactory.
15. Satisfactorv.
16. The proposal inOic,atos a 0.5% T inin-lun).pitch in the pavSl enf, Typically,
p avefneTlt contra c-tors will not guarantee positive draimige with slopes this flat. If
the Owner and Planning Board are aware that some puddling of water is likely
with.the propos4d design.and find this condition acceptable iii.this case we would
not recommend�evisingjhe design,
17. Satisfactory,
18. An easement will be required to construot the proposed retaining wall, A portion
of the wall would be on the abutting property. Reportedly, the abutter will allow
the constrElcti011:and a letter should be forthcoming,
19, SaLisractory,
2o. S ` d,_
-We appreciate the o.Ppolitunity to assist tllc� Pla;lning Board oil this project and hope that
tr.is information.is siiff 6ient for your needs. If'you have any questions please do not
hesitate to cotltact US,
Very traly yours,
COLER& COLANTONIO, INC.
I
/John a., Cllessia, PEE.
Y
xe Merrimack Lngi4eering Service;
I