PD131-CS 940225 "~:-~_D:EVELOPM ENT, I NC.
FEB 2 5 199 '
Februarv
Mr. & Ms. Dennis Birdsong
c/o Precision Landscaping
13337 Bee Street
Farmers Branch, Texas 75234
Dear Mr. & Ms. Birdsong:
Reference our telephone conversation, February 15, 1994, regard!hq
your concern as to the possibility of interruption of the natural
flow of water on your present property, being situated due east
of the Long property, when Beamer Development excavates to form
a lake which will be approximately six (6) acres in s~ze.
The following information relating to your concerns were gathered
and assembled by Mr. Bill Anderson (Dowdey, Anderson and Associ-
ates Engineering) for your review:
In response to Mr. Birdsong's concern over the proposed
six (6) acre lake located along the eastern portion of
the proposed Estates of Cambridge Manor, ! offer tine
following comments:
The proposed lake was planned and situated in a location
that would enhance the overall value of the general area.
From a hydraulic perspective, this lake offers the opportun-
ity to serve as both a retention and detention facility.
The floodplain of Denton Creek has a unique characteristic.
When Vista Ridge developed the property due north of Denton
Creek, they created a channel adjacent to the "old" Denton
Creek. The top of the bank of "old" Denton Creek is above
the 100 Year Floodplain, however, the area due south of this
bank is situated in a depression, commonly referred to as
a "saddle." The "saddle" conveys local water in an east-west
direction on an extremely flat slope.
The property north of Deforest Road has experienced flood-
ing by way of two (2) sources:
1. The first source is from Denton Creek. The water
in Denton Creek rises during a storm or immediately
thereafter. When the water surface peaks, Denton
Creek cannot contain the water. The "saddle" area,
previously mentioned, accepts this overflow of
water. This type of inundation is commonly referred
to as a "backwater effect." The backwater surface
elevation matches the water surface in Denton Creek.
POST OFFCE BOX 2312 · COPPELL, TEXAS 753:9
Mr. & Mrs. Dennis Birdsong February 25, 1994
Natural Flow of Water - Page Two -
2. The second source of flooding is due to "local
water." This is water that generates in a drain-
age area extending from the City of Coppeli Service
Center on the west side; Deforest Road on the south
side; the south bank of Denton Creek on the north
side and the west bank of Denton Creek on the east
side.
The excavation of the proposed six (6) acre lake will have
no adverse effect on the BIRDSONG tract provided that the
lake is properly maintained. It is my understanding that
a Homeowners Association will ultimately be responsible for
the maintenance of this lake.
The lake will have a "weir" structure located on the north
end of the lake to control the normal pool elevation of the
water. The "weir" will be sized to prevent excessive pond-
ing of water attributed to local run-off during a 700 Year
Flood event. However, the creation of this lake will not
prevent the "backwater effect" from the east.
The Estates of Cambridge Manor is located upstream from the
BIRDSONG tract. A comprehensive f±oodplain analysis has
been performed on the aforementioned development to insure
that we are not increasing the water surface upstream and
downstream of The Estates of Cambridge Manor.
The excavation and creation of the six (6) acre lake, which
will have a water surface lower than natural ground, will
enable the area to store additional valley storage, which
the United States Army Corps of Engineers has strongly
encouraged.
In summation, with proper design and periodic maintenance,
the BIRDSONG tract will not receive additional run-off of
storm water due to the proposed development of The Estates
of Cambridge Manor.
Mr. & Mrs. Birdsong, I hope the aforementioned findings by Mr.
Anderson, have answered the concerns you expressed to me and to
the City of Coppell Planning and Zoning Commission, on Thursday,
February 17, !994.
:.Ir. & Mrs. Birdsong Fc. bruary 25, 1994
Natural Flow of Water - i~ac-~r'' Three -
In closing, if either one of you have any questior:s or inquiries,
whatsoever, regarding any item in this letter, please feel free
to call me anytime ,_~ 2]4/ 908-]068 or you may call Bill Anderson
direct ,~ 2]4/ 93]-0694.
Sincerely,
/~eA~ra, Ma.a.er ,..,./
cc: Mr. Gary Sieb (City of Coppell)
Director of Planning and Community Services
Mr. Ken Griffin (City of Coppell)
City Engineer
Mr. Bill Anderson
Dowdey, Anderson & Associates