HomeMy WebLinkAbout1995-08-15 Engineer Review DEF SUB i r
COLANTONIOZ
ENGINEERS ANO SCIENTISTS
NORTH ANDOVER
February 21, 1995 CONSERVATION CONIIvIIISSION
Mr. Michael Howard
Natural Resources/Land Use Planner
Conservation Commission
120 Maui Street
North Andover, MA 01845
RE: Engineering Review
Evergreen Estates
Residential Development
Dear Mr. Howard:
Coler&Colantonio,Inc. has visited the above site and reviewed the submittal package as
described in our proposal of February 8, 1995. Our review specifically addressed drainage and
stormwater runoff aspects of the design. It is our understanding that conformance with other
aspects of the regulations would be handled by Town 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 information was reviewed:
Plans Entitled:
• "Definitive Subdivision Plan Evergreen Estates Located in North Andover" Sheets 1
and sheets 3 through 13 dated 12/28/94,Prepared by Christiansen & Sergi
Engineering, Inc.
Also reviewed was the"Supplement to the Definitive Subdivision Plan of Evergreen
Estates in North Andover, MA" dated December 20, 1994,
We offer the following comments:
l. The site is located on the southerly side of Salem Street. The property is bounded on three
sides by the Harold Parker State Forest and is across the street from the Harold Parker State
Forest. The site is currently wooded. Boston Brook passes through the site along the
northeastern side of the property. There are several depressions, some of which contain
wetland vegetation, scattered over the site. Larger wetland areas are located along Boston
Brook and at the southern and western sides of the parcel.
2. Roadway staking is inconsistent with the plans in some areas. The location of the brook
crossing, as staked in the field, is different than that indicated on the plans. Station
numbering on stakes in the field near the intersection of Pheasant Brook and Beaver Brook
Roads is not consistent with stations indicated on the plans.
101 Accord Park Drive, Suite One 617-982-5400
Norwell, MA 02061-1685 Fax: 617-982-5490
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3. Significant outcrops of ledge exist on the site. These outcrops are not indicated on the plans
as required under Section 3.),k),k.),n.). The presence of ledge may impact lot development
and complicate roadway and utility construction.
4. Catch basins in several locations are linked in a catch basin to catch basin arrangement. CB
#3 has runoff from three other catch basins flowing through it. Section N.4.)requires a
catch basin to manhole configuration.
5. CB 44 has less than 2.5 feet of cover.
6. The storm drain between CB#2 and CB# l conflicts with the watermain.
7. CB# 12 and CB # 13 are over 400 feet from the crest of the vertical curve.
8. The depth of the sump in the catch basin detail is not specified. The Regulations require a
30" minimum sump.
9. The concrete headwall detail indicates a depth of footing of 2 feet and a width of 18". The
Regulations require a depth of 3 feet and a width of 24".
10. Rip rap erosion protection should be requited at all stormwater outlets. No rip rap is shown
in the plans or details. Rip rap should be sized based on the flow rate and velocity of the
outlet pipe.
11. No calculations of storm sewer capacity and velocity have been provided,therefore we
cannot comment on the adequacy of the design.
12. 1t is likely that subdrains will be required in certain locations due to the presence of ledge.
Actual subdrain locations may need to be determined in the field during construction,
however;consideration of the impact of subdrains on storm sewer capacity and detention
basin volume should be addressed in the calculations.
13. The detention basins should have emergency overflow spillways sized to pass a 100 year
storm in the event that the outlet is blocked.
14. A typical detail of the construction of the detention basin dikes should be provided.
15. The design of detention basin dikes should include an access route to and along the top for a
maintenance vehicle to access the outlet.
16, No calculations have been provided to justify the design of the metal arch stream crossing.
Calculations should be provided which describe the capacity of the culvert to pass runoff
flow and address the impact of the crossing on flood elevations in the vicinity. The crossing
lies within a mapped FEMA flood zone. Compensatory flood storage should be provided for
the flood storage volume displaced by construction of the road.
17. The Board of Health should review the plans and soil testing to determine the suitability of
the site for wastewater disposal systems. Based on our site visit and review of test pit data.
high groundwater and ledge will impact the developability of the lots.
18. It is our understanding that the hydrologic calculations have been performed utilizing a
program developed by the Engineer(Christiansen and Sergi), This program reportedly was
developed based on the same methodology used to develop TR-20. The methodology is
described in the National Engineering Handbook NoA (NEH4). In general: development of
runoff curve numbers(CN) is consistent with TR-55 and TR-20 methodology; development
of times of concentration(To) is based on the"Lag Method"which was used in NEH4,
according to Dennis Verdi of the SCS TR-55 methods are now used to develop this data.
The Lag Method is no longer used by SCS. To develop runoff hydrographs,the acreage of
the subarea, CN and Tc are input into the program. We have compared the hydrographs
using both TR-55 and TR-20 for subarea"L"under pre- and past-developed conditions to
the output from the Engineers program under the same conditions. The peak runoff rates are
slightly higher using both TR-55 and TR-20. The hydrograph shape is also somewhat
different. The program developed by the Engineer does not list total runoff volume. The
Regulations require the use of TR-55 or TR-20 for drainage analysis. The program
developed by the Engineer appears to give generally similar results to SCS programs,
however there appear to be some limitations to the program as well. Specific comments
regarding the calculations follow.
19. For the purpose of performing runoff calculations,20 subareas have been identified under
existing conditions, Watershed limits for existing conditions subareas appear reasonable
excepting the following:
• Subareas B and P should be combined in the model or subarea P could be ignored
since no work is proposed within it. Subarea P is a wetland.
• Subareas Q and Q2 should be combined in the model or subarea Q2 could be ignored
since no work is proposed within it. Subarea Q2 is a wetland.
• The watershed limit of subarea S should follow the thread of Boston Brook. This
subarea should be combined with DI and D2 subareas.
20. CN values for existing conditions appear reasonable.
21. Flow paths are not indicated on Figure 1,therefore we could not check To values. As
discussed above, To values were computed using the Lag Method not the TR-55 method.
22. The site has several depressions some of which include wetland vegetation. Runoff from
subareas A, C,E, J and K are tributary to and reportedly contained within the depression
within the respective subarea. At these locations the volume of runoff and the flood
elevation for the design storms used should be calculated. This information will provide a
base for comparison with post-development conditions. Subareas F, G and I have
depressions which are assumed to overflow into adjacent subareas. Similar calculations
should be performed for these subareas to justify these assumptions.
23. Under proposed conditions,29 subareas have been identified. Watershed limits for proposed
conditions subareas appear reasonable excepting the following:
• Detention basin locations and grading should be indicated on Figure 2.
• Subareas B and P should be combined in the model or subarea P could be ignored
since no work is proposed within it. Subarea P is a wetland. The limits of subarea B
have been reduced along the northwest side of the subarea on Figure 2,the proposed
conditions watershed plan, however,no work is proposed in this area to justify the
change. At other locations along the eastern watershed limit the subarea is not
consistent with the proposed grading.
• The watershed limits for subarea D3, R3 and DI are not consistent with the location
of the detention basin.
• Subarea E is inconsistent with the grading indicated on Figure 2.
• The watershed limits for H and H2 subareas are not consistent with the location of
the detention basin.
• Subareas Q and Q2 should be combined in the model or subarea Q2 could be ignored
since no work is proposed within it. Subarea Q2 is a wetland.
• The watershed limit of subarea S should follow the thread of Boston Brook. This
subarea should be combined with Dl, D2 and D3 subareas.
24. CN values for proposed conditions appear reasonable with the following exceptions:
• Subarea D2 and R2 CN values for Type C soil with woods and grass cover
conditions are incorrect.
• Subarea D3 indicates woods remaining in Type C soils after development, this is
inconsistent with the grading shown on Figure 2.
• Subarea E indicates pavement associated with the driveway to lot 14 is in the
subarea,however,no pavement is indicated in the calculations for this lot. Refer
also to 23. above.
• Calculations for driveway area in subarea J may have been underestimated.
• The acreage of woods in subareas R2 and R3 may be overestimated.
• Subarea R6 does not include a value for streets,this is incorrect.
25. Tc values were computed using the Lag Method,refer to comments 18 and 21. We do not
agree with the length or slope of the flow path for subareas G, 02,P, Q2,R3, R4,R6, S.
Flow paths may be altered in response to issues discussed in comments 18 and 23.
26. Existing depressions which are proposed to serve as storage under developed conditions
should have calculations performed as discussed in comment 22. An easement should bep�,
provided in these locations,which encompasses the 100 year flood elevation,to prevent YY��
these areas from being filled. If these areas are filled subsequent to lot development runoff
may be directed to an area which does not have the capacity to handle the flow.
27. No information has been provided to indicate how stage-discharge values have been
calculated. Since this information has not been provided we cannot comment on the
calculation results.
28. It is not clear how the timing of peaks is accommodated in the program. Runoff hydrographs
list a time in hours, printouts which combine hydrographs do not indicate the hour only the
"offset". The offset is not defined in the submittal.
29. Pond routing calculations do not identify time of peaks. Again the"offset" is given but this
value is not defined. The submittal does not identify the routing methodology used. It is not
clear how detention basin storage is calculated in the program. It is not clear what the
channel velocity refers to. This information is required for us to check the adequacy of the
proposed design.
30. Contours appear to be incorrectly labeled on Lot 16. Contours on Lot 15 are inconsitent.
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31. The house on Lot 10 is inconsitent between Sheet 7 of 13 and Figure 2.
32. The calculations have not been stamped by a Professional Engineer.
We appreciate the opportunity to assist the Planning Board on this project and hope that this
information is sufficient for your needs. It is anticipated that some of the issues raised in this
correspondence may be addressed by the Applicant providing copies of support data used in the
development of the calculations. We would be pleased to meet with the Planning Board or the
design engineer to discuss this project at your convenience. If you have any questions please do
not hesitate to contact us.
Very truly yours,
COLER& COLANTONIO, INC.
— C CZ4�-'
John C. Chessia, P.E,
!qy
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t1�31ishr.(l The. .t l
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Lt;(+ �yl;s'CI ,lrt infc,r115sttt,ll provided in i1S14.tittt}il
tileY''lr„'sl\' i11 the r�11A1711('1 tt� i1G:illrr,' +;;,a{411)1fJ1ti.:(' \Yltl1 tills �i,tlrll\'f`.•:ltill i4},�;t{i:,tit,,t',.
fio,.v is not to owed 5 Net per worki 'Fhe clinsill,Q- hes xylild" A "111" 1-KRA
o'(widt-d I'm lho lttwd Jol�lw
flood Zone, Corl)l)C1l";3t0tV flood "(C)F[W(l ShOtild b(,
AN. -i'ihc }.tyld. %Nc :nt, rv)l ill te,�Cwl "I'dik lo tilt' 1110"(
iu):ler5i.,ind Hwl the Bowd of Health in loviewing 010 JWS,
19 We have received inkmenation rvg lrding t1w Owor), used to d.evolop CA S PlOgillij.
P"awdYng Uj he il1[,()jljlaljoll wedlody underesthrAmo Uw PW W of d"AMYC AN
in S,,naH juakwy Wow I Mu vori [pith um, A Ove Wal" Y'k:
om lever of FiwbnwqV IT 1991, =101h if.;IdWki in tl S11,Q'iLdy hL,{hvt i'llo
rilethods, 1.\101c that the Wollands Iio(&(k)jl icqoio,S tilt: us(: vil,cuf(Vil,
ult,,ihods to dotei-mine "Land SuQject to Flooding" both boWrw' alld
%Nth the Conservation Comriiission Which MaY recillirt,tills
injbil-natioll,
methodclogy would be wqmwd. Scs tilt; hoduiogy A, I I to f I I 0�-t ;Q!)I I k I it i y I
dMopted standard for hydroingic anal0sw W N;Inssauhiasews and many udwL'
wk,ominvi ul that all lutury subioissions be requhred to wonorrit w Uw ieguluth"Is ryaldby"
do un (4 SUE; methodologies. We CS1 has h0d lick Prolf" "Pwd 11P to'"0'S�1;1"t' k:
do not 1wel it ih joh to require that the ellibn Rw this projej<t bC leCj()lle LlSitl� -A':1 001100",
'j's rt�Fpwwe to cone hmwvw, MONAH9 Mc "w" "l
9 We do not av,re�, with C�
bol the pre and Must constriNtion WSW does nut e" the
skered. 1, our op4w()jj, stjbiroa S should iollovi the thread ofiliv 141-ook as s1lowil on dw,
pi.111, IlOwever, siitec ng a yow
we jous me jillijianged under exis(A lid Pl'( 3
awimplion sIloufd not wsuii,,
At %Yv We wdved the updated Figure I xviiih the blest Aubinitwl wd how rKy AM 10"U
jeok To Valaws As do,,wd aNwe, r c ,ys %v,,V n,,uAjmqed wig & Log WIN&
lA wot
d y
iheT`1QA5rncTod-
by discussOnn with Dennis Verdi OC±e SCS, Shve dw dw AT rui:tw'd
)0 1()Iloer Ilse it we rt-conimend dim the cunvnt StA Method of dNennhiMy tines 01
,
cx)n(%ntration be used on A lbane POINK W&I "Y "i's "lull'
Ivid it ;iecevfO oll P-,t5j pw)co ,
lotorwatimi on flood volialnes in j:;olated depressions have bet.-n provltkd, 1 he Lstiff€',
11w, he n Vrovi(Aej,j. 'I'lle 1,to0tj (jvvqjjjon Its not been Int.viAnd.
kciHs Wwr RHo A V ON umY 199A
,141 i 1A,,j jjj(jjk:,t(Cd Oil l'iV,01V
ww"wnioll would Qkan none oroul qVVjKwS ingaichy luba"In 4
folu.001 man h" &Y w 1W
loi)lc e�ifowt fur w3 to jo
di"
Rc'kx $") hinit"; I'I
lul"Invest side of me mosma on hy"M 2, Him lwpowd Con(houn.",
jl(jNyevcr, no wwk is j)j-j)ptj!jed ill fljils WV'a (0 jMkity flW ,'Ir,3l,1,'(-,,
I fin W4,116on b.,isal bake should defm�- the W;1(eV,1'W-d linlits
halt,' lilt, 1),0n,, on would pos'silfly ukal Up 6w,
.1; 11 FF I III ffliI 1 1)11 -10P
40
0 Refir to coinnien,
(N V;dkle� 1,61
a l,,utmtva D2 11.ws hevp W,� CN ypt ,,
and llrw,,, o(lver condilloils all nlcul[Qut.
in %,C
with 6l , grsldiw on 1'il4ore l, ill out opinloo it is; iik(Ay li)d:.
wclqdi Illot would nol be 01cared by we dog "Ali aind "OUIA bc W&Wvo &W
0 lite 1w1cave 4 moods in Mneat , and k j nw, he averLMHOW, 10 Wl 'Awl.
it is lik{sIv lhat tiny woOd," (11;11 NvOtIld (1,)t t)lz l4ktdill�,
I'll'.. k 1A1l lal n
�klklrea k6 Foitishicioll14'
ivivc, vvevalwited the propoL�Id clllidjflolv� stud Lind thak \vIlcit,
rsi hoq ustd a Inort- l,,onsc'rvntivc
io cononent 22 aTmdog eAs"ng dvpmsK= In our,Muoon, an canwoenl AlUbt ii4,!
provi(le(I it) thc wo: ill prcvk�lli
�,i� locmd onq whkh wwomPames the too year Wood Yknal
th ,-,e jjt.�jf, i'l-ollj licing filled. I F(hese ar(•as ail,, Idled 'juhseciuent to 1tli '-ievelopinent
may b(, (firec.led to ao awn A& does not flavt the('apacitv to llilndli:- lit:' llko ,
town Colirnsel re.iotive, to the IogAlltle�i.,i
Qown1momw hw landq hate boon
(!;l1\ 'till 1" iWl
11!,;k: L jj ii k lk
Ntsul oil oauk Plo\ 6kit-'o i-.�,
We I lllliik1' W:('d in IU- ',-)I
Fl \Vt� ltndcrSl and how N nirt Mg cawu 56NO have hCon I W"Innuo a1w the utc No AW IV"
Io ollik-'l pt"11:111oat
We Met Walui I hot a rhani 1 10 1 0 V W,
rephoation (ic) not tie t)i(k to oxisl61g (1)
-101 N ill'i��S 1-�I j
hoen pelfonw-d ill chi�; area fiiid th-,it the iW,
0115 ill 101 it
i,. uw:,kaar %vh(.thcr it k inMided U, wKe bigum 2 't'
uld �-Irljli, lool till',
the oppnnonky to aq�,lsl thl' Pial)n1'Y
;(Iooflll:llioi} k Cof Your ih:)l !,olllc of (h(..,
wit jvo slit!-l;?,copi, z
We v,ould hl,. pit
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Sjt S!'!i C'1'3!!1tl{'.�1 i1; iF '�l'O'•rr i�ih �7f(5lt ill rl� �'1 it 1f l'11110't:11�4{1E 4, )i `,Ili �Ij t' .afI%
,`' 'i iC );`e It 1, 0"k
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07/24/95 08:46 COLER C0LAI--1TCIH115 50:3 682 2397 1,10, 745 P02
CULE A-
COLANTON10 ' '
C-.t,.IC31HEER9 AND
'Juk; '21. 1995
Mr, Michael Howard
N.,itilrai Resoarces/Land Use Planner
(,�:mservation Commission
Mail) sirrvel
North Andover, MA 01845
RE: Additional Engineering Review
Evergreon Estates
Rosidential DevelOpille'll
[)or Mr, liomr&
Coler&Colantonio, inc, has reviewed additional information submitted bY(-'hrJAIaIISQII &
Sergi, Im. (C,',,). This information included packages dated TVIaY 24. 1995; June 6, 1995; and
ion submitted were,revised plates andAme 13, 1995, fricluded in the informat
together with responses to our commellts. We have also received oorrespondcnce an,lull 17,
111melIT rru)nbering in our letter of February
1995. This eorrespondcnc�,- follows rho original co
,21, 1995, Where, an itern has been satisfactorily addressed we have, so noted,
NO respr)tise necessary,
y. it is not known if staking has been C,()VrO(:Ae6-
indicated ill the VjCjjIitY ,,)j,the yo,
[.edge.OLItorops have been jd %,ay t)Ut riot j)j) the )(idi ijm
lots. Reportedly this ,iceeptable to tlie.Town Engineer.
I. Reportedly the spacing of ci'ttrli basins is acceptable to the L mvii Engineer. f i,is Is
r.,Itj,'factory to t1s if acr,eptable to tjje ,j,()wtj Eliginev
satisfactory.
10. Rip rap erosion protection 11jis been the plans afid details. Data to SLIPpoll the Size
of the rip rap has beell provided. An vigbr '0011 minimum length has bmi slio«'n on the
}
/ 08'47 "L1LER COLRIklUhd I U 508 Fj JG 239'7 NO. 745 pLt3
n
detail. We recommend that the length be increased in accordance with the following tormula
developed by the hPA:
L u I.XQD'n +7D
Where D =Pipe Diameter and 0 Maximum. HoNv Voitmie
Sizing of rip rap rock is satit factory-
11. Storm sewer calculations have been provided. Calculations were performed using the
Rational Method. The regulations require ease of the SCS method, Our experience has bee►a
that the Rational Method is the most Common method of sizing stone sewers for subdivision
roadways and is typically more conservative than the SCS method, We find C51's
catc;ulatiotas using this methodology acceptable, however, zve defier to the Board for their
interpretation of the regulations and tite acceptability of this method. Storm sewers from
DMH 2 and DMH 4 exceed the maximum permissibie velocity(10 fps) listed in the
Subdivision Regulations.
12. CST has satisfactorily addressed the subdrain issue provided this information in their
response is incorporated into their plans,
13. Calculations for the emergency spillway have been provided and appear satisfactory. The
cross section of the emergency spillway has not been indicated on the plans,only a profile 01
it. We assumed that the cross section is 4 feet wide at the Bottom with 3:1 side slopes. This
will have adequate capacity at one foot of dopth to pass the peak flow into the basins.
A typical detail of the construction of the detention basin dikes has been provided. The
detail indicates a top width of four feet with 2:1 slopes on both the Upstream and downstream
faces. We.recommend that the detail conk«rm to A5C:E standards as described in A,SCL
Manuals and Deports of Engineering Practice No, 77, This would result in a wider top width
of S feet and slightly flatter side slopes, depending upon the soils used for fill. In areas of
cut this criteria anny not apply. In response to CSVs letter of 7/17/95 note the follo-vying:
• Lot I detention basin tins a one foot width on the east side as scaled oft"tlae plan, the
spillway elevation is 106 and it is proposed to have the top of the berm I),, nt 107
according to the detail and calculatio�ris for the spillway. This doesn't work at the
east side, For a four foot width, as indicated in same locations, at the lop of the
berm the slope would be 2:1 to the top of the berm and back down the other side. oo
flat area at the top would exist in these locations.
Lot 21 is primarily cut and the elevations work for the spillway. To make the top
somewhat wider here should pose no hardship to the applicant and would improve
stability and access.
e Lot 7 basin as indicated on the plan has a wider top than the detail and would be
acceptable'.
Lot 9 rand Lot. 10 basin has a spillway elevation of 126 with a top of bextt} {acCOrdiE�g
to the detail) of 127 for a four toot top width the slope would be 2:1 with no flat area
at the (op.
15 An access route near each of the basins has been shown. Modifying the plan in accordance
witli Comment 14 should improve access.
01 '4;95 08:d: C:t]LEi<' �_IDLHFiTOf I I u i P_t F �' f!0. '7 5 Del
o
lh. Caiculations have been provided indicating tile,capacity of the arch culvert Based on
manning's equation. In addition, a calculation of the required velocity to pass the 100 year
storm flow through the culvert at the 100 year flood elevation was provided. Based on the
calculations provided it appears that the culvert would have capacity to pass the storm Clow.
1
Calculations submitted on 7/17/95 included additional analysis to cstiniate the impact of the
crossing on upstream conditions. lased on these calculations the change in flood elevation
upstream would be .068 feet or 0.8 inches, which is consistent with the FEMA section in this
area. It is not clear from the calculations that losses due to ille constriction of the bridge
were included. This may have a mitlor effect on the calculations. l'ypically, fQr this type of
crossing it backwater analysis would be performed to assure the Town and upstream abutters
that no increase in flooding will occur. It is likely that a stepped baAwater analysis or an
nlitvsls utilizing a water surface profile program would give similar results. C.`ontpensator-y
flood storage calculations are acceptable. We are aware of concerns expressed by the
upstream abutter. It would be desirable to create compensatory flood storage on the
upstream side of the crossing,, however, there dons not appear to be a suitable site otl the
upstream side.
17, We understand that the Board cat Health is reviewing the plans,
18. We have received information regarding the theory used to develop CSI's program,
According to the information SCS methods underestimate the peak rate of discharge by
approximately 6% in small drainage basins. Our comparison of one subarea, which we
discussed in our letter of February 21, 1995, actually resulted in a slightly higher peak rate
using SCS methods. Note that the Wetlands I'rotcotion Act requires the use of current 8C-S
methods to determine"Land Subject to Flooding" both bordering and isolated. For filings
with the Conservation Commission which may require this information, additional analysis
rising SCS methodology would be required. SCS methodology is the most conauoniy used
accepted standard for hydrologic analysis in Massachusetts and niany other states. We,
reel}rnmend that all future submissions he required to conform to the regulations regarding
the use of SCS methodologies. Since CSI has had their program accepted up to this date eve
do not feel it is fair to require that the effort for this project be redone using SCS methods.
19. We do not agree with CSI's response to this comment, however, irioludin;g the wetlands in
both the pre and past construotion case does not effect the inodel since the areas are not
altered. In our opinion,subarea S should follow the thread of the Brook as shown on the
plan, however, since the limits are unchanged tinder existing and proposed Goltditiorts this
assumption should not impact the results.
21. We have received the updated Figure 1 with the latest submittal and accept.the [low paths
and Tc values. As previously discussed.To values were computed using the Lag Method not
the TR-55 method. The lag method is no longer used by the SCS, this has been continnc:d
by discussions with Dennis Verdi of the SC S. 5incc the SCS developed tho lag method and
no longer use it we recommend that the current SCS method of determining times of
concentration be used on all future projects. We would accept this nlethodologY oil this
project. since CSI has had it accepted on bast projects.
�1 J4. 6-1:!E;:49 CAR..Ff, f-FILRATIDWO 508 6:3,27, 2337 NUJ. 745
'r, Infomiation on flood VOILlynes ill isollated depressions have been provided, I lie basis for
I
these cRictilations has been provided, The flood elevation lass 'tot.bt�eli plovdod,
'23. Satisfactory
24. The areas where the incons �m,llc es were located %vere in subareas that the Veak RInOli "i'le
has be
en reduced therefore CSt is correct iti stating that they should not h11 pact tile model in
this case
,-,S. W(,,have reevaluated the proposed conditions flow paths and find that where,we disagree that
CS1 liar used a mare conservative assun"PtlOn which is satisthelOrY.
6. Refer to comment 22 regarding existing depressions, In our opinion, all
provided in these locations, which encompasses the 100 yQar floode rsvation, to provent
— — C - AT
� tilled subs cent to lot develupment fulK
may e 4reate to an
these areas from b i—n—gTlTed, 7 these areas are
area w 11c i does not have the capacity to handle the tl 7,—Te defer
T07-1 r—ou—n9e, relative-i—o the 7eaa itle—Sof Te4utring easelliellis,
27. Discharge calculations for ponds have been developed based on the "Manning s LqUat1011
0
for gravit--y flow and a pressure Pipe calculation for submerged t' W. This is all acceptable
way to perfonn these Calculations,
?S. We understand the timing used in the program bused on data provided by C-;,L
We understand how routing calculations have been performed and they are satisfactory,
subject to other pertinent comments.
11. Not a oritiQal item.
.s2
We appreciate the OpportullitY to assist the Planning Board on this project and hopes lildi 1111.;
inforrnation is Sufficient for your needs. It is anticipated that some of the issues raiwd in till,
correspondence may be addressed by the Applicant providing copies of support data used it: tll(a
de,vQ1opmerit of the calculations. We would he pleased to inect with tile. plannitig Board or the
-
design engineer to discuss tiiis project at your con If),ou have and questions please do
wit hesllate to Contact
Vet-Y truly yours,
COLER R.COLANTQNIO, INC
John Clje�1,44,
v Town of North Andover ' � %AORTH
OFF,ICE OF 3=o` �to °•ea<
COMMUNITY DEVELOPMENT AND SERVICES
K = x
. 27 Charles Street
North Andover, Massachusetts 01845 ,
WILLIAM J, SCOTT Sacr+use
Director
(978)688-9531 Fax(978)688-9542
July 14, 1999
D.E.C.M. Inc.
660 Rogers Street
Lowell, MA 01852
RE: Street Acceptance for Evergreen Estates Development
Dear Developer:
The Planning Office is in the process of assessing active subdivisions to determine the
compliance with the approved plans and the decision. Our goal is to assist you in
reaching street acceptance with a completed project. In going through our files, we
noticed that you have documentation required to be submitted to our department to
maintain compliance with the Town of North Andover Subdivision Regulations and the
Notice of Decision issued relative to your project. In the absence of this information,
you will be unable to get your street accepted.
On the following page, please find a detailed list of information we will need in order for
you to get your street-accepted. The list may refer to conditions in your Notice of
Decision, which we are attaching for you to easily refer to.
Additionally, I would suggest that you set up a meeting with myself, so that I may
explain to you what is left in your subdivision to be completed. At that time we can also
schedule an inspection of your subdivision by the Department of Public Works at a
mutually convenient time in order for you to be ready for street acceptance.
This list is only a preliminary review, and there may be more items outstanding that need
to be completed once an inspection has been conducted. Upon further review your
subdivision, we will compile a more detailed comparison of your decision(s) and the
rules and regulations as it relates to your subdivision.
BOARD OF APPEALS 688-9541 8[III,DING 688-9545 CONSERVATION 688-9530 HEALTH 688-9540 PLANNING 688-9535
l J'
I am also attaching street acceptance guidelines with sample letters for you to utilize and
inform you how the process will work.
Sincerely,
Heidi Griffin
Town Planner
Cc: Tim Willett, D.P.W.
Jim Rand, D.P.W.
William Scott, CD&S Director
Board of Selectmen
Attachments: List of Outstanding Items, Samples of Certificate of Compliance, Warrant
Article & Stone Bounds, Notice(s) of Decision, Street Acceptance
Guidelines
i
1
r '
1 1
ITEMIZED LIST OF OUTSTANDING ITEMS FOR EVERGREEN ESTATES
The following items are presented in three sections. Section 1 is the Recording
information required. The information checked in this section is considered missing or
incomplete. Section 2 are the items missing or incomplete as required by the Notice of
Decision for the PRD, if applicable. Sections 3 are the remaining items missing for the
Subdivision Decision. The numbers for sections 2 and 3 represent the item number in the
respective decision. Please review your enclosed decision carefully to coordinate with
this information. Rather than handle each issue separately we would recommend that all
of the necessary research to resolve all of the below issues be conducted prior to
contacting the Planning Office. Thus will insure that meetings to resolve these issues are
productive.
Section One
Recorded Decision
Recorded Plan
Recorded Form I
Recorded Fortin-M
Recorded Growth Management Form
Recorded Form-J
Section Three
NOTICE OF DECISION ITEMS — PRD
Section Two
NOTICE OF DECISION ITEMS --SUBDIVISION
1. S (b) copy of plan depicting easement
2. 7 (a) copy of landscaping design
3. S (b)
4. 10
In accordance with section 9a of the subdivision rules and regulations of North Andover,
you must request a certificate of compliance for a street acceptance.
A copy of the subdivision rules and regulations are available in the Planning Office located at 27 Charles
Sheet for$10.00. We recommend that rf you do not have a cop),you purchase one. Obtaining specific
pages fi•oin the Regulations may not provide all of the information necessaq to address your issues.
?n A t
Mul Q Nei
:n"di Andover MA 0!MM
:\'Witloflaf t Inv Ret,it-'!
fovf rg ivun I-�im v,;
SAMOA! I Imek,pnim
Tar NO Hc�,-vard!
& (olaillonio, Tile, ha-3 Weved addhional iof'ors-nation wribimMed hy (Thrjohnsen &
let-i Inc WK). Thi!z informatinn included pa(:hLe8 dwd Nfa\ it mu 6. J91-1
i 91" 1 tx I"Ided III the infou 1)at io I., i i ti'd w rk. re,vwt 1 phlft it Ild (:aj C t I Im i 1,ri
mWer%x ith rospanqe 14*1 OUr o-Immellm I'llis Corre9ponde.-mc.e. (61lowq Ole i7cipl,11 c.ojjj)j1enj
awnhennu in our Wr of FebmOrt 21. 199Y Whmv an here ho wen "Nsh"adl, Mew
V� W 1-11(11A.-n 't 41 ~),J,-, jjq•`' t')Oell c j e'.ItE
Lvklv k1317c1`ops haw been indimed in W N wMay af old lon,mm,bill 1)(4 on rhe� m(fivfd'1j;1l
lots Revomdh,th iz accentable ff,tho Tn,, 'n F ngweer
I-, -ntch wc�jm.jbtC m 'rwvf1
-a I i f".1
k Vic
1
E
i4t, kip rap ero5tnti frtotectfol) lies heon ghoc In(An tuft pinl)s ari(1 r:li t iils Dam to 5lir))nrt file Size I
of the.rill rap has not been provide€l, Ali emits f•nnt inin1111-aw length 11,14- beer) Shmml tvliiell
rs 8110110r thail nlily N required. The phlms indiciit,' a lot)aer-length oerip rap, it is t€nale..ar
which ciuimisions arc irlien(led 1c, be wted
l 1, Storm sewer calcul,,til)tir,littve been provided. A eatchment area plan for fhcy i~11kolighons
slt 5l c lid be provl gd wall fl)e clili�ulatior1s ft)r €J.' t)c these c � i s s s al�ulat OttS We Alto iCclitr.t
that the folYrlula IUSGd to cletenuine the Tin)Q of C()nceptration be* prnvidpr{, C'ttl4uJtttirylis
were pertorillecl using:the Rational lvlatllod. The regulations require use r)f the 5CS metbod.
OPI.experience 11tts biter) that the Ra i011til lvletllOd is 1110 11105t COM11101.I 1110110d Of S1711ap
storm sewers for vbdivision roadways and is ty icall), more Gonservative than the SC`�
method, Wt�- tillcl l:his iiletllodolony acceptabIc, however, defer to site Board for thoir
interpretad0fi of(he re}ltllatioils and the itxe IsIbilit « t11i��1�etl��iri. Storm .�cwm Orom
1)_Ylrl'2 and DM.H -1 exceed the rmaximuni rcrniisslble eloeitN i 1t] fps) listed in the
�fibilll'351fti1 f�.e�itlaticl#lti
iL. U S I stake tfrti a 11ote Oil tl)e Plates regai:dw4 subdrains has keen provided. We havono, been
able to tine#Mis Dote on the.latest platys revised %95 Wo agree the impact to the el0entiolt
basins would be minimal, lbe majority of the stort-n drains 11ppeat•to leave excess, capacity as
Weil, l;'a sul)d1Fitt is ttec� 111t(7 t'l3 l�? �f C13 l�1 flryw in Sho strlldr,,dn sliould be caloulitted
Since dim is lttinitlial excess capacity rlt these structures.
�. Emergency spillways have been added to the plans,howowor no aalculataons to suppoll the
,size of the spillways linve been provided. As previoltsly rogttested spil.lWays 8110111d be sized
to pass the 10t1 year storni with the Outlet blocked. The basin could be modeled its empty at
t11+3 wfi11'7 of The 5torill
4. A typfoai dol it of'the construction of talc deici)tion l aNm dikes ))as been provided. The
detail rr)(t)CRt1'5 a lnp Width QI fnul-feet with 2!1 sl„saes(it) hoUl dit upstream and dowl).stresini
ftleus. We recoit)r)lend that ille detail�:an orni to ASC E �;tanclard,, a4 in '1S(+
It aritiakg and Repttts of EnginQering Practice; No. "I Thl, Avolild tesult ill a bider tor. ttidtli
yf 8 feet and slightly Patter Side slopes, depending 71pon the Roils usc7 r.1 for till,
15, All access routo)rear the ba.sios bavo been shown. No access to thih top has been provj(lf d
-Aodifymp the plan n1 aef;orcian e: vyith Coto n)ent €4 sbou.ld allow t1115 access to be provided.
16, C:nloulanoils 11,1ve beell pr•cjdQd indictiting the.capacity of the arch ctilvort based mi
manning's cyuation, hi atlditioll. a r alculation cat the required velocity to pass the l itil voar
storirl slaw through the,.ulveri'lit the 100 yeaz flood elo-Yation Ava,-i provided. Based on thl�
calculations provided it appoars that t;ho culvert would leave eal-irlcity to puss the stern) flo'ly,
`l'ypically, for this tvl)e of 01-ming a backwaler at)alvsJ4 would be performed to assure the
Town aide# upstream rebutters tllktt M) hlcl'IM50 ire flOO(1414 Will occur, We.recoIllmu d that
this be accomplished. Tho culvea is ]argot' thati a typical highkva�- euk.-eve. I)owever, the
Cross flow area for a 100 veal stern) Gvetll:location has been reduced by over 30�a
rrom wi- c.k,u jet ,case, bused on inibrination prlvrrled, in addition . oaloulations sht)LL]d
lndlcai'� the velt,city in the channel 1, 7s.are c:.onlri'iatl& wills (lie subclivi;ion regida.tions,
Chaimel flow ij riot to c'Sc°hr.'il " P;:r SQ(,"T=.€. i l;e crnssiory , toes within.a tllal)ped i l_.",°lt�
flood zofir. slit?lild N l)rox-i d for(lie flood Storage voltitne
i
displaced by construction tit the road. We are not in receipt.at this ►n tot elation tot,the must
17. We understand that the Board of I lealth is reviewing the plans.
18. To date the have been give-n a brief 6mr€ptlon of 0o thieory tipon which the CSI program is
based at the mooting of Maroll 17, 1995 and a listing of The reference from which it was
developed. We do not have the partiucliar roferojiee fisted and no further information hay
been provided tllorefo€v it is ditttcuit for us to comment oil t1w program. Based oil the
information Nvo have, it appears to be a unite elemetit type apt'analysis, Btt fore apend►►ig
additional review fees, the would request that additional data he provided to allow us to
properly assess tl)e model. Otherwise we could input the data into our SCS model and
vc7mpare the reships.
Note that the Wetlands Protoctkm Act roquirl.,s the use of current SCS awthods to determine
"T_and Sutsjeet tci T{loc�tlln�„lif�►ih lr��rdetitl�aFid. i5��latGcl �'nr t��l€tr�s t��ith tf�e t._ni�servar€crsl
Comnirssion which may regjire.this additional analysis using S[_:S
methodology would be.required. SCS methodology is the most commonly used accepted
standard for llvdirologic analysts in iMassachtrsetts and litany other states. We recommend
that all future submissions be required to conform to the regulations regarding the Else of
SCS metliodologies. Since CSl has had their Program accepted up to this date we do not feel
it ib fair to regUire thllt the effall far this project be redone using SUS' methods,
►9. We do not;agree with C81's response to this vomment, however, iurluding the A edands m
both the pre and post 00115MIGtion Qase,does not ettee•t the modei*u't► ce the tlrelas ata not:
mitered. In our opinion. :ubat,ea 5 should follow the Thread of the Brook its shown on the
{Tin, however. since the limits are unchanged Eider existing rued proposed con dit ono this
assumption should nDr impact the results,
i iS.lmfi-V'tory
_`,i We have clot received the updated F iguro 1,therefore we could not check Io!'€Hilo~, As
discussed above, 'l'c values were.computed Using the Lag Mothod n0l;the Its-tic method,
The lag ttiethod is no longor used by the SC). Tills has beer Confirmed by di5eussiom wah
Dennis -Verdi of the SCS. Since the SCS developed the iag method and Im loylger we it we
rticommend that the current SE,S method of determining times of ortcetltratioo he used on
alI tEi[tire projects. We would accept this rilethodology' can this firojuut, sitlee CS1 has llrtd i,
mt•epterl Oil past proietts.
2 tztiormat.ixi on flood vulumos in isolated depressions have bean provided, Phe 1 azmq kv
these oaietila+cons have.nut beers provided. 1 lie flood elevation has not been provided,
;; Comments regarding bullet items in our letter of February 21, 1995 an m to lows:
Detention btisin lciciitiomt and gading srrould be indicated oil figure this
information would possibly nddress some of our gkiestionw rvgardifig subamcm it is
considerably more e:tfort fOr Eli to pioce together the mformatioit man for C �l to plot
th4: ililelt'{1iEilf`)ll,
a
$ Kci'cr to corm ont 19, The imlitsof Subarea 13 Have been rediwed along the
nortl)tvest side of the subarea on Figure 2. the proposed Conditic'm watotshed pltin.
however, no wo* 15 pr•olpitsed in tltts area to lustily the chal)re.
The detection basin bei't)1 should Win the wraer,41ied ffinits for stil)tlrea R.i• .Again
have The basins on Figure n would possib)y r•lcJ,ar up ribs i3sue,
Refer to col-tlitli:nt 19 regarding:sut)atre;a:s t,)"hill t 2,
$ Refer to cc,mmem 19 regarding the wig#erslicci limit of sul?area '►•
4. (-N values liar proposed conditions appear masonable'A•it.1)the following exceptions:
Subarea D2 has bl c-n cornmed ?_r iNrea R2 CN values for I'vpe C 9tiil with woods
and gmsq UQver c:cm(lawns are ilia,ۥreef.
Subarea W inch)ate woods retriitirirng ill t Vve i;• sails afror devr:lcpmom, this i*
nlconsistent Nvith the grading slrm\i} on Figurt, In ow Opinion it is ttkelti' that fitly
woods chat would not be clued by tllo grading indicated %,vo-Od he cleared fc,r lentil
rl Cttr
� +�llk,tirea t~a s,ttt•tstlrttsrily a.tlUt'c;�sCi1,
-Subarea.i satistactortly addr,gwd.
Thu nureage of woods in subarea4 R2 atld R3 mat} be overestimated. In our opinion
it €S likelie that H11V v'oods that Zvould not bo CIOarC-d by the gradiltw indicated wonl,t
1)i Oeitrod for IMN'ii trtert
�)ubarca ko -safisfiwtorily addressed,
5 We ha'v�e rcrr-vatlll mxl the proposed conditions flout-piltiis and f�od Coal wllef( ct e disa luree that
t ;5i has used at more conservative assumption vvmch is yamlaclor.y.
Meter rep corrltnorit.22 regarding existing&presaions, lie our Opinion, an Cs.�c�tl)cril shouldl1(:
providod In t.hoe locations.which encompasses the 10()Vear flood eli:vatioll. to prevent
these areas trout boing filled. If these areas are killed-.'ubsetluent to Wit dc�v't<ioprXStcm f tltym
ma be directed to an -,rVen Mitch skies not have; the spat~Jtv to handle ttm� Maw Liao ticJc:r to
Iowii t_mmsO rclatt.ive to the legallititrs ofieottOnn easenwnts.
.' Discl)a ge,calettlat€otis for ponds hive been developed based oil the"Manning's l:ytt:ltion"
lof gravity lfoly and a JATe5suvo pipo ulculat•itrn for submerged flow. 'I'1)ts is at) a-cceptablo,
k�•it} ill I.�+<!'rL>l'lll tl)i-".3�Cr'11GLtliillC)F1Ci
_n 1k v untje-mimd the fulling Used in the program based tv iiatt.al provided by i;'8I,
it,is itot clem when nierllod has been used to perfol-111 votitina cedes€latioas, [.oiler rsrrles hnt'e
t\�1.•r= .i.l•h•,S:Ictii
-ii t.ontum s hm,e bead corrected on Lot 16 and Lot 15. Propmeii k:oj1U'm1's as the 14etla ill
remitcation tit ea do not tie back to exls mi coniours.
.`1. It is tincleal whether it is interided to roviac FilZiire:I to update mformallon on L or 10,
k
We- aPI)FC01alu the�,p}}>~runit� to asp,€tr the 1-11,3runa 130,110 of) [III s vl't.rc O:ld 11'-p that this
Inlo1'malfou tS suf c.ient fni' Four roI e I.y It is anticip�lc l that soave of the I4Slie," mised in Ihk
6:OM!"'POl toe ce rives be addreysed I)v the: App, prop,tijini.? lopwt - of �uuooji tkim os'Q l' Ili the,
dCX("I(Jp cI1tQf the calculmio VvvC wout(t hf. olAmwd to t wet with lire Pki1117ing H+4i d or the
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