Freeport NIP(2.7)-CS0212061 JONES & CARTER, INC.
�+ Consulting Engineers
3030 LBJ Freeway, Suite 910 972/488 -3880
Da11as,Texas 75234 Fax 972/488 -3882
December 6, 2002
Ms. Teresa Turner
Engineering Department
City of Coppell
255 Parkway
Coppell, Texas 75019
Re: SE Corner - Burns & Freeport
Storm Drainage
Dear Teresa:
Per our meeting of December 3, 2002, it is our understanding that in order to avoid any on site detention,
we can design the storm outfall of our site to either the 25 -year, the 50 -year, or the 100 -year event
depending up on the capacity of the adjacent 36" public storm sewer to the north of our tract and the
existing storm sewer in Hammond Street. Per a brief analysis that I have performed on our tract, it
appears as if the maximum design event that the adjacent existing facilities will accommodate is, at most,
a 25 -year event. This brief analysis assumes that we can start the hydraulic grade line at approximately
the top of the pipe at the outfall of the 36 -inch storm sewer and utilizing the existing system to the fullest
possible extent in Hammond Road.
Additionally, it appears as if the utilization of the Hammond Road system requires that the system's
available capacity be analyzed based upon the original drainage design parameters and recognizing that
the drainage areas to the west of Hammond Road no longer drain into the Hammond Road system at all
and that the drainage areas to the east of Hammond Road are currently undeveloped and can be evaluated
with a "c" factor of 0.3.
Prior to our proceeding with any more analysis or design of our tract, we would like confirmation that
the City is in agreement with this letter. Should you have any questions or concerns, please feel free to
call me at 972 - 488 -3880.
Sincerely,
Mark Donohue, P.E.
cc: Mr. Jim Pritchard
I:\Pmjects\J &CDa11as\Pritchard Associates (D076) \002 Freeport & BumsTetter\CityStorm 12- 6- 02.DOC