HomeMy WebLinkAbout2006-02-13 Drainage Analysis GHRISTIANSEN & SERGI, INC
PROFESSIONAL ENG1NEERS AND LAND SURVEYORS
(�78) :j 7 C- 0 FAX: (978)
PTGject No.,. 05,018
November 2, 2005
Mr- SGott L_ Giles, P-L.S.
50 Deermeadow Road
North Andover, MA 01845
RE: Drainage Analysis—Sutton Street, North Andover
I)eaT-MT, Gibes:
Per your request we lave prepared a drainage analysis tar the project 811te on Sutton Street in
North Andover. DraiTiage calculations were peftrForrred using the SCS Method- Model parameters
were developed using topographic information provided on a plan titled, "Plan of Land in North
Andover, Ma-3s Owned by Peter and Juh8 CiairaWdated October 11. 2005, prepared by your
office.
In both the pre anti past development condition, Surface runoff from the parcel flaws toward
Sutton Street. The soils c n site are clasrffied"U rba n Land Complex" by the Natu nal Resource
CiDnservafion Service and were modeled as hydrologic s61 group" _" Peak Flow rates to the
sdeltne of Sutton Street @T-e summarized for the 2, 10, arid 1 00-year desigii SW4IT4s in the ta b€e
below:
perk Qpaak
2-yr Storm Evani a.5 0.8
I 0-yr Storm Evont
(4.5"124-hrj
100-yr Storm Event 1-4 1.7
Calculations performed using HydroCAD software are anclosed with this letter- 9 hou Id you have
any 9 Liestions or comments pf8ase feel frea to c'Ontact me at the dumber listed above.
Regards;
4:P
pl iftp' Ch r'rstiansen' P E_ NGF_N
Rre.Adent r,!"ell. rn
Giles Type H 4-hr 2yr Rainta#=3. 10"
Prepared by Christiansen & Sergi, Inc. Page I
Hydro CA 7.00 &Irk 001057 0 1986-2003 Applied,Microcomputer Systems 11/312005
ubcatchment EXISTING:
Runoff = 0_48 cfs @ 11.97 hrs, Volume= 924 cf, Depth;-- 1,34"
Runoff by SCS TR-20 method. UH=SCS, Time Span= 5.00-20.00 hrs, dt= 0.05 hrs
Type 11 24-hr 2yr Rainf all= _10"
Areas Descri.lion
2,905 98 Paved parking & roofs
5,381 74 >75% Grass cover, Good, H
8,286 82 Weighted Average
Tc Length Slope Velocity Capacity Description
(min) (feet) (tuft) (itlsec) fgfs� _
6.0 Direct Entry, Min. Tc
ubcatch ent PROPOSED:
Runoff = 0,75 cfs @ 11.96 hrs, Volume- 1,585 cf, Depth- 2.29"
Runoff by SCS TR- 0 method, UH=SG , Time Spat= 5.00-20,00 hrs, dt= 0.05 hrs
Type 11 4-hr 2yr Rainfall=3_ or,
Area (an CN Description
6,767 98 Paved parking & roofs
1,519 74 >75% Grass cover, Good, H
8,286 94 Weighted Average
To Length Slope Velocity Capacity Descdption
(� � .........f ).. .. (ft) ). Ytlsec) ci s ........................ .
6.0 Direct Entry, Min. Tc
Giles Type 11 4-hr 10yr ainfafl=4,50,E
Prepared by Christiansen & Sergi, Inc. Page HydfoCADO 7-00 s!n f}01570 15 - 3 A or € JJ206t €
ubcatchment EXISTING:
Runoff = 0-85 cis a 11.97 Ears, Volume= 1,688 cf, Depth= 2-44"
Runoff by SCS TIC- 6 method, UH=SCS, Time Sparc- -00-20-00 }ors, dt= G.05 hTS
Type II 24-hr 1Cyr Rainfall 4.5G,'
Area sf} CIS Description _
2.905 98 Paved park1rig & roofs
881 74 >75% Grass cover, Goad, SI G
8,286 82 Weighted Average
Tc Length Slope Velocity Capacity Description
(rain) {feet) Olt Wsec) {cfs}
-- 6.0 Direct Entry, Min. Tc
Sub catchment PROPOSED:
Runoff - 1,98 c#a @ 11.9E hrs, V01UMe= 2,4G5 cf. Depth= -57"
Runoff by SGS TR-20 methadr UH=S S, Time Spar= 5.00-20.00 errs, dt= 0.05 firs
Type I€ 24-hr 10yr Rainfa}I=4,50"
--- Ares ...-._ N_ Description - -- -...----- - --- -- ----
6,767 9B Paved parking & roofs
1,519 74 >75% Grass cover, Good, HS
8,286 94 Weighted Average
Tc Length Slope Velocity Capacity Description
(min) (feet) (fflft) {fflsec} (cfs)
6.0 Direct Entry, Min. Tc
i
Giles Type H -fir 10 yr- Rainfalf= .50„
PT-Spared by Chfistianseri & Sergi, Inc- Page 3
!j droCAD 7.00 sin 001057 V 1986-200� Applied Microrom uter Sy5tems :11312,005
Sm heatchman E ISTIf� �
Runoff - 1.41 efs 11- 7 hrs, Volume= 2,86 cf.. LUepthz-; 4.1C`
Runoff by SCS TR-20 method, UFO=SCS_ Tire Sparr= 5,00-20.00 hrs. dt=; 0-05 hrs
Type iJ 4-hr IDOyr Rainfal€T6.50`
areas CN Descrlption
,905 98 Paved parking & roofs
5:3BI 74 >75% Grass cover, Good, H G C
8.286 82 Weighted Average
Tc Length Slope Velocity Capacity Description
(Fr'jii) F E4' { ffe) ifi�sec (L;!a
6.0 Direct Enhy, Min. Tc
Subcatc ment PROPOSED'.
Rlurloff - -67 cis @ 11,96 lrr�. Volurn = r:7 _, a ;h- 5.40"
I !.'" w lir-fll6t, U; {.nn4 41. 6 inl3 - ia�.Gf:l I- .�0.2
I'S�.rr1'-iii 4 ..�."'
6-28b 94 'heigii tau AverayL
Tc Length Slopa Velocity Capac y Description
(min) {fl•}sec) (cfs)
6.0 Dirert Ejitry, Mh-t. To --