Untitled (32) r ENGLAND C. TI-IIMO, INC
CONSULTING AND DESIGN ENGINEERS
513B ATLANTIC BLVD JACKSONVILLE, FL 32211
(904]724-9436
May 12, 1983
Mr. William M. Baldwin, P.E.
Consulting Engineer
Cedars Executive Center - Suite 250-E
2639 North Monroe Street
Tallahassee, FL 32303
Reference: Atlantic Village Center
E83-04-1
Dear Mr. Baldwin:
Pursuant to your request of May 9, to substitute two 60" pipes for the
6' x 8' box culvert, I have reviewed this subject and must recommend
disapproval for the following reasons:
1. Double 60" pipes require a ditch bottom width of 13' - 6"
minimum. The proposed ditch has an 8 ft. bottom width.
2. The sudden contraction from a double 60" RCP to a single
6x8 box culvert at Atlantic Blvd. would cause intolerable
local hydraulic head losses.
3. The Florida Department of Transportation recommends box
culverts be considered any time the drainage opening exceeds
25 sq. ft. in order to minimize obstructions from blocking
the drainage way. The existing box culvert has 48 sq. ft.
of opening. Since this is the only drainage outlet for 285
acres of developed public and private land this is of primary
concern.
4. The existing box culvert is marginally adequate to accommodate
the existing drainage basin. Any modifications which would
significantly increase head losses and correspondingly raise
the elevation of the backwater curve is considered unaccept-
able due to the potential flooding upstream.
Although I appreciate the economic considerations you presented, I feel
for the reasons outlined above, any piping of the outfall ditch requires
Mr. William M. Baldwin, P.E. May 12, 1983
Consulting Engineer Page 2
Reference: Atlantic Village Center
a minimum of a 6x8 concrete box culvert as your approved plans indicate.
If you should have any questions, please do not hesitate to call .
Sincerely,
ENGLAND THIMS, I�N�%j�
Dougl s C. Miller,P.E.
Vice President
DCM/cwb
cc: Bill Linkovich
Bill Moss