Drainage CalculationsTERRA ENGINEERING, INC.
ClX/IL ENGINEERING * LAND PLANNING · CONSULTING
600t Glenwood Ave,
Minneapolis, Minnesota 55422
Phone: 763-5~3-9'J25
Fax: 763-512-0717
)'une 16, 2004
Raad~ Stem
Stern Sur,,,c~g
6~0] V~mon Court
Edina, MN 55436
(fax 952-9354X)63)
Drainage Calculations
Lotus View Addition
Chanhassen, MN
Per our discussion, the following area the drainage calculation:~ required by the City for
your submittal, Based on these calculations, it does not appear'tha~ any pending should be
· required., as the increased flow rates for the 10 year and 100 year storms are minimal.
Ar~A AmaB
Area 1.0lac. 2.02 ac
43,800 sf 87,850 sf
Ex. impervious 10,800 sf 6000 sf
Prop, impexvious 10,800 sf 18,800 sf
'Ex. wooded/green 39,000 sf 81,850 sf
Prop. Wooded/green 39,000 sf 69,050 sf
Impervious cUrVe no. 98
Wooded/green CN 76
98
CiTY OF CHANHASSEN
RECEIVED
Ex, composite CN 92
Prop. composite CN 92
78
81
~,PIANHASSEN PLAN~, NG DEPT
FROM : TERRA Et.4GD4EERIHG INC. FA?< HO. : 763-512-0717 .I~.n. 16 L~04 01:46PM P2
Ex, time of eoncen, I 0
Prop. time of concert, I0
10 year storm 4.2"
100 year storm 6.0"
Ex. 10 yr, (per SCS) 3.6 cf~
Prop. 10 yr,(per SCS) 3.6 cfa
Ex. 100 yr.(l~r SCS) 5.4 cfs
Prop. 100 yr.(SCS) 5.4 cfs
15
15
4.2"
6,0"
4.5 cfs
5.1
8.0 cf$
8,7 cfs
Attached is the drainage area map for this site, fi.you need any additional information,
please call.
Sinc~rely,
Petw J. Knaeble, PE
Terr~ Engine~dng Inc.
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