Pecan Hollow/FP-CS 900402DAN M, DOWDEY & ASSOCIATES
CIVIL ENGINEERS
16250 DALLAS PARKWAY SUITE 100
DALLAS, TEXAS 75248
(214) 931-0694
April 2, 1990
Ms. Shohre Daneshmand
City of Coppell
255 Parkway Blvd.
Coppell, Texas
Re: Pecan Hollow Addition
Coppell, Texas
Dear Shohre:
After the March 29, 1990 D.R.C. meeting, I reviewed the comments that were
suggested by the City Staff and their consultant. I have concerns about the
following issues.
1. I have approximately ten locations where the centerline radius is less
425 feet. The reason for this decreased radius is to accomodate the design
of the final plat based on the approved preliminary plat. I used an
acceptable radius to most cities, such as Plano and the City of Dallas.
The subdivisions in the City of Coppell listed below have radii similar
to those in question.
NORTHLAKE WOODLANDS, SECTIONS 1,2,3,4,5,6,7 & 8.
NORTHLAKE WOODLANDS EAST, PHASE 3,4 & 6.
MEADOWS SECTION 1 & 4.
PARK MEADOWS SECTION 1.
PARKWOOD SECTION 1 & 3.
RAINTREE VILLAGE
SAMUEL BLVD. @ MacAUTHUR
SHADOWRIDGE ESTATES
SHERWOOD PARK SECTION 1
SUMMER PLACE
WATERSIDE ESTATES, PHASE 1
WHISPERING HILLS
WILLOWWOOD NO. 2
WOODRIDGE, SECTION 1,2 & 5.
Cont'd
We could ask for a variance from the Subdivision Ordinance, however, I did
not notice any variances listed on the final plat for these Subdivisions.
Please consider this issue at the staff level to avoid a variance request.
2. The centerline radius selected for the sanitary sewer lines was selected
based on the engineering criteria that P.V.C. pipe manufacturers recommend.
I am requesting that we be allowed to develop our system for the following
reasons.
A. By locating the sewer lines (and water) parallel to the curb lines, the
following construction related items are enhanced.
a) Repair of the system is easier because you limit the irregular trench/
pavement locations. This allows for a regular sawcut (if necessary) '
pattern.
b) Other utilities can be prepared to locate their facilities a given
distance from the City facilities.
c) As long as minimum radius criteria is met, you avoid excessive use
of manholes, an area that is susceptable to clogging.
d) All service repair occurs at a uniform distance from the curb line.
e) Initial construction reduces the number of situations where manholes
would be located in pavement and/or sewer mains falling in front yard
easements.
B. The additional cost of manholes is significant in subdivisions with
curvilinear streets.
C. Additional manholes require additional grade differential (enter/outer)
where slope is extremely critical.
D. The only advantage of straight alignment is for "cross-country" installation
where a curb line is not present to locate the system.
Due to a "very" tight grade design, I am requesting that we be allowed
to encase the sanitary sewer main in concrete where the depth is less than
normally designed. Please note that the finished pads are above the
necessary minimum to provide proper service. If acceptable, we can show
minimum Finish Floor Elevations on the plat.
I feel that we have addressed your concerns, and we are submitting two sets
of plans for your review.
Very truly yours,
/'3///'
William A. Anderson, P.E.
WAA: jma