HomeMy WebLinkAbout1987-07-23 Drainage Calculations SPR fl
CHANNEL
May 11 1987
Ms. Tticia Wrenn
To,wn Planner
Planning Office,
120 Main Stir t
North Andoverl MA 01,845
Re: S ecial Permit Application
Eaatprint, Inc, Addition
North Andover Busine,55 Park
350 Willow Str t
North Andover MA
Dear Tricia:
Enclosed is a copy of the drainage r-alculat,ion which Chairman Nitzsche
reque,5ted at, the hearing on April 27. If you have any questions, do not
hasitate to call inc-. Thank you.
Sii, rely,
je
Jain,r--5 Bourgeois, R.A.
Vice President Architectural & Engineering Services
on behalf of Bianchi Realty Trust and Fastptint, Inc.
abs,
Enclosures
9M Mahn Stecant 0 P.0. 631D,x5122 9 Andover 0 Mbusanchume,ttoolE310 a 617,47,15*11651
THOU G E. NEVE ASSOCIATES. INC. DATE
OJT T: NA§P-■7 SHEET O _
ENTER SUS CATCHMENT a 4 AREA - 3.09 ACRES CN - 89.7 Ic - § MIN
VOLUME UNDER THE HYDROGRAP14 - 1 .35 ACRE-FT. PEAK - 27.7 CF5
fEA H DROGR§Pw FOR SUBCATCH wTcur + 4
2 \ \ PERK - 2: . 2
I ]| HHIGERLL - 7
- ln � NMEM
R � I �
j [
-
]D ! ! 12 !j 14 15 IS I} 18 | § 20
TIME <HGURS,
ENTER SU8GATCHMENT # 5 AREA - 3.09 ACRES CN - 90.2 Tc • E MIN
LUG UNDER THE HYDROGRAPH = 1 .37 ACRE-FT, PEAK = 28 CFS
R¥gROGRRPH FOR SURCPTCHMENT + 5
}\[
LD'4 � PEAK = 28
je[ RRINrALL - 2
@
ff [ | HREH = ] .OB
�o CN = 50.2
!q ] �
/ 12 a
�
® r
2
10 | ! 12 12 14 15 15 17 !e |S 22
TIME <HOURS)
A hydrologio analysis of Lot 07-A North Andover Business Park was performed F
by utt r of flee. 'I'Ile analysis compares the peak rate of runoff of the site Under
two different site layout designs With two di f f erci t sets of hydrologic condi-
tions.
- Master Plan (1983)
- Proposed Design (1 8611
The IGO year storm event will be used. The desigr1 point will be the wetlands
abm ing the east side and west sidc of the proposed development. The area
of the lot involved in the study will be the uplands portion of the lot alori;,
with any portion of the wetlands which will be filled or altered; as shown on
either plan.
Master Plan
C N Arf`a
impervious Area 98 1.93
Regraded-Lawn 79 .57 Weighted G 89.7
Woods (same wetlands) 73 .59
3.N acres
HydralLi is Length = 305' Q 3%
Tc = 5 min. - 6 mill.
Pcak Runoff f 27.71 c f s
t'ra�osed Plan
N Area
Impervious Area 98 1.91
Itegraded-Lawn 79 .92 Weighted C
Woods (some. wetlands) 73 .26
3. 99 acres
Hydraulic Lefgth = 300' Cd 3%
Te = 5 min. to 6 miry.
Peak RL;noff = 28.0 c£s
Conclusion:
The peak vates of rvrioff for the Alaster Plan Dcsign and Proposed
Plat Design were round to be jdentioal. The differeuc�_- of 0.3 cfs
is not considered significant..