WA0003-CS001219tA_.,o A � 0 3
SHIMEK, JACOBS & FINKLEA, L.L.P.
CONSULTING ENGINEERS
8333 Douglas Avenue, #820 Dallas, Texas 75225 -5816 Fax (214) 361 -0204 Phone (214) 361 -7900
RONALD V. CONWAY, P.E.
JOHN W. BIRKHOFF, P.E.
JOE R. CARTER, P.E.
GARY C. HENDRICKS, P.E.
PAUL A. CARLINE. P.E.
MATT HICKEY, P.E.
ROSS L. JACOBS, P.E.
I. C. FINKLEA, P.E.
Mr. Kenneth M. Griffin, P.E.
City Engineer
City of Coppell
Post Office Box 478
Coppell, Texas 75019
Re: Water Distribution System Hydraulic Analysis
Dear Mr. Griffin:
December 19, 2000
As you requested, we have analyzed the City of Coppell's existing water distribution system using the
Cybernet hydraulic modeling software to determine what operating pressures could be expected at the end of
the Hunterwood cul -de -sac during the maximum hour demand condition. Some of the basic assumptions
utilized in this analysis are summarized below:
• Existing System Maximum Daily Demand of 25.3 mgd per Mr. Glenn Hollowell.
• Existing System Maximum Hourly Demand of 50.6 mgd.
• 1 -600 HP and 2 -450 HP Pumps in Operation at the Village Parkway Pump Station.
• Hunterwood Cul -de -Sac Consists of 4 Lots Served by a 4 -inch Non - Looped Water Line.
• Maximum Hour Demand at the end of the Hunterwood Cul -de -Sac of 0.019 mgd (13 gpm).
• Computer Analysis Performed for the Maximum Hour Demand Condition (50.6 mgd).
Using these basic assumptions, we analyzed four scenarios for the City:
1. Evaluate the expected pressure at the end of the Hunterwood cul - de - sac during the maximum hour
demand condition with no water in the elevated storage tanks and only the existing 16 -inch water line
along Sandy Lake Road from the Village Parkway Pump Station to Denton Tap Road.
2. Evaluate the expected pressure at the end of the Hunterwood cul -de -sac during the maximum hour
demand condition with ten feet of water in the elevated storage tanks and only the existing 16 -inch water
line along Sandy Lake Road from the Village Parkway Pump Station to Denton Tap Road.
3. Evaluate the expected pressure at the end of the Hunterwood cul -de -sac during the maximum hour
demand condition with no water in the elevated storage tanks and a 30 -inch water line along Sandy Lake
Road from the Village Parkway Pump Station to Denton Tap Road.
4. Evaluate the expected pressure at the end of the Hunterwood cul -de -sac during the maximum hour
demand condition with ten feet of water in the elevated storage tanks and a 30 -inch water line along
Sandy Lake Road from the Village Parkway Pump Station to Denton Tap Road.
j: lclericahcoppel hwateranalysis. doc
Mr. Kenneth M. Griffin, P.E.
City Engineer
Page No. 2
December 19, 2000
The results of the hydraulic analysis for these scenarios are tabulated below.
Scenario
Pressure
1
42 psi
2
46 psi
3
47 psi
4
51 psi
Based on the results from our computer analysis, there does not appear to be a significant pressure or delivery
problem in this portion of the distribution system. However, please note that the Scenario 1 results (which the
city operated under for a large portion of last summer) indicate a pressure of 42 psi when the elevated storage
tank is empty. You have explained that under some limited conditions this past summer the elevated tanks
may have dropped below the bottom of the bowl. For each foot the water level drops below the bottom of the
tank bowl, you may expect the system pressure to drop in the range of 1 /2 psi. Therefore, if the water column
in the tank dropped one -third the height of the tank, or approximately 33 feet below the bottom of the bowl,
the system pressure could have been as low as 25 -27 psi in the cul -de -sac. Considering system head losses
from the customer meter to the point of delivery in a two -story house, it is not unreasonable to expect low
flow and pressure given this condition.
Although construction of an 8 -inch water main from Coppell Road over to the Hunterwood cul -de -sac would
in fact eliminate a non - looped line in your distribution system, based on the results presented above, we do
not expect it would solve the low pressure problems reported in the area. It is our opinion the recent
completion of the 30 -inch water main along Sandy Lake Road combined with the addition of the new 600
horsepower pump at the Village Parkway Pump Station will enhance the operation of the distribution system
during extreme demand conditions and mitigate the problems reported in this area this last summer.
Therefore, prior to constructing ,a new 8 -inch water main in Hunterwood, we recommend the City continue to
observe and monitor the pressures in the neighborhood using both recording fire hydrant meters and hose bib
meters installed at the most problematic areas in the cul -de -sac. You may also want to consider simulating a
low pressure situation in the area by implementing a controlled lowering the elevated tanks to the minimum
level possible without jeopardizing the safety of the system.
We are available to discuss this analysis further at your convenience.
j lclericalkoppel Ilwateranalysis. doe
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Owner Name
KHORRAMI JALAL &
WALKER DWIGHT R &
HARRISON BILLY J &
COPPELL CITY OF
PARRISH EVA B FAMILY TR
FOSTER ROBERT D
WELLS MABEL I
ONSTOTT ROY DELBERT
DALLAS COUNTY FRESH WATER
ROTHENBERG LARRY J &
Zip Code Str Num Str Name StrSuf
750194417
� ' _0 - Ua I;
RD
750193908
Owner
(449 wner Address 1
City, State
556 COPPELL
AFSANEH SAHBA
W BETHEL RD
COPPELL
TX
SHANE RICHARD WALKER
316 KAYE ST
COPPELL
TX
ANN L HARRISON
141 S HOLLY ST
COPPELL
TX
ST
PO BOX 478
COPPELL
TX
%DOROTHY BEATRICE WALL
2000 CHEROKEE TRL
IRVING
734461225
605 MITCHELL
147 OAK TRL
COPPELL
601 MITCHELL ST
COPPELL
TX
14410 SOUTHERN PINES DR
FARMERS BRANCH
SUPPLY DIST 17
411 ELM ST
DALLAS
TX
VICKI L
405 W DREW ST
MADILL
OK
Zip Code Str Num Str Name StrSuf
750194417
560 COPPELL
RD
750193908
558 COPPELL
RD
750195739
556 COPPELL
RD
750190478
100 HARRIS
ST
750606705
572 COPPELL
RD
750192514
600 MITCHELL
ST
750193933
601 MITCHELL
ST
TX 752342231
500 COPPELL
RD
752023317
620 COPPELL
RD
734461225
605 MITCHELL
ST
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