Wynnpage-CS 920402 (4)April 2, 1992
Mr. Ken Griffin, P.E.
city of Coppell
P.O. Box 478
Coppell, Texas 75019
Re:
CoDpell, Texas
90051-0
Dear Ken:
Per the request of Mr. Larry Davis of your office, I am writing
this letter in order that the referenced subdivision be accepted
by the City of Coppell. Mr. David has met several times with Greg
Rich, the developer's representative and construction coordinator,
and myself, regarding the grate inlet in alley "A" within the
referenced addition. This two grate inlet system is located along
the South line of this tract near the storm sewer outfall into the
unnamed creek behind the Shadow Ridge subdivision.
The design of this grate inlet was situated such that in case the
60 inch storm sewer was ever in disrepair and had to be repaired
or replaced, the inlet could be preserved. In our opinion, a good
design should minimize the needless destruction of nearby
improvements (when possible). Apparently, some "warping" of the
alley grade at this tee intersection was made by the paving
contractor in order to get positive drainage into the inlet. My
biggest concern with this was preserving the structural integrity
of the paving as well as providing a positive drainage to the
inlet. In our opinion, standing water within any paved area is
unacceptable. I believe Mr. Davis has approved the "grinding" of
the pavement section which has provided positive drainage.
As far as protecting the public from any potential flooding, I
believe our design provides adequate freeboard between the alley
and finished pad elevations of all lots adjacent to this inlet,
and we have also required that the landscape architect provide a
positive overflow area beneath the wall along the perimeter of the
tract. This six inch opening, which spans between two wall piers,
provides adequate conveyance if these grate inlets become
"clogged" by newspapers, plywood, etc. Also, the amount of
drainage collected within this system is less than the capacity of
the grade inlet system itself.
PAJL S iJNZICKER. PE DAVI~ M SCHNURBUSCH. PE. KEVIN RAY KF. NDRICK. PE DAVID F McCUL~.AH. R P.L.S
Pres,der': V, ce Pres,de'~! Proioct Manager- Associate Sun, ey Manage--Associa;e
Mr. Ken Griffin, P.E.
April 2, 1992
Page Two
If you have any questions or comments, please feel free to call at
your convenience.
Sincerely,
Kevin R Kendr' ,
Project Manager, Associate
KRK/bp
xc: Mr. Greg Rich / Siepiela Interests, Inc.
Mr. Larry Davis / City of Coppell, Engineering