Chaucer-SY 951130 ~-~.~,,_~ ~, Burke ~ Thompson
~.~._~ .?, .~., .... :.~. ,. ................
.... Engineering Consultants
POND SILTATION STUDY
ADDENDUM NO. 1
CHAUCER ESTATES~-~'~'"~-'
HEARTZ ROAD AND PARK VALLEY DRIVE
COPPELL, TEXAS
November 30, 1995
10555 I~lewkirk Street
Suite 530
Dallas, Texas 75220
21 4.831 .1 11 1
FAX 2i4.831.0800
- The City of Coppell
255 Parkway Blvd.'
P.O. Box 478
Coppell, Texas 75019
- Attn: Mr. Kenneth M. Griffm, P.E.
Assistant City Manager
City Engineer
Re: ADDENDUM NO. 1
_ Pond Siltation Study
Chaucer Estates
Heartz Road and Park Valley Drive
- Coppell, Texas
PBT Project No. 101-001
Dear Mr. Griffin:
- This letter report is issued as Addendum No. 1 to the referenced original Pond Siltation Study,
dated Novcmber 2, 1995. The purpose of the original study was to provide geotechnical information.
-- specifically on the depth of pond water, sediment and pond bottom materials, to assist the Cit3' in
quantifying the extent and nature of the siltation. We understand that the Homeowners believe that the
extent of siltation is relatively thicker near the existing drainage outlet on Park Valley Drive (see Figure
1), as compared to the other locations of the pond probed in the original investigation. This addendum
report provides geotechnical information regarding the depth of pond water, and sediment and pond
-.- bottom materials approximately 13-feet north of the subject drainage outlet.
- One (1) probe, P-4 was made with a 2-man, 18-foot flat bottomed work boat using a PVC pipe
sampler. Approximate location of the probe (as projected to the pond's bank) was staked out by the City'.
Pai~on, Burke d~ Thompson
Engineering Consultants
Pond Siltation Study
Coppell. Texas
Page 2
- Five attempts were made to recover a sample starting from a point approximately 2-feet north of the
drainage outlet and proceeding northward until a sample was recovered. Visual observation indicated the
presence of gravel and sand at the surface of the current pond bottom near the drainage outlet. This made
it difficult to recover samples as the samples slipped out of the PVC sampling pipe due to the weight of
the sand and gravel, and also due to reduced cohesion of the material as compared to only clayey material.
A representative sample of the bottom materials was obtained by using a 1.5-inch inside diameter,
- clear PVC pipe. The pipe was initially pushed by hand into the pond bottom and upon encountering the
weathered shale stratum (interpreted as the original pond bottom), was hand driven using a 30-pound
'-- hammer. The PVC pipe was then retrieved slowly and the pipe with the sediments (and some water), was
sawed off and the top and bottom capped, marked and sealed. The PVC sample was then transported to
PBT's geotechnical laboratory for laboratory testing and analysis. The sample was stored vertically in
a secluded area to allow the sediments to settle before conducting any laboratory tests. This also helped
to finalize the depth of water and sediment. A log of the probe showing visual descriptions of bottom
_ materials encountered is included in Figure 2. Sampling information, pertinent field data, and field
observations are also included.
The laboratory testing program was directed toward evaluating the physical characteristics and
- determining the depths of the water and sediments encountered at the single probe site. The sample
obtained from Probe P-4 was approximately 32-inches long, from a depth of 5.0 to 7.7-feet below the
pond surface water. The sample was divided into two parts, the top 16 and the bot~tom 16-inches.
Laboratory analysis included visual classification, moisture content and sieve analysis laboratory tests
on the samples from Probe P-4. Results of laboratory testing are presented on the Log of Probe, Figure
2 and grain size distribution analysis results, Figure 3.
In general, the bottom conditions at the time of performing probe P-4 consisted of sediments at a
depth below the pond water surface of 5-feet and a gray weathered shale at a depth of approximately 7.7-
_ feet. Sieve analysis tests indicated the following:
Patton, Burke · Thompson
Pond Siltation Study
Coppell, Texas
Page 3
_ top 16-inches 8 80 12
bottom 16-inches 4 63 33
An attempt was made to determine the water content of the sediment sample and water contents
- of 26 percent for a sample near the middle and 120 percent near the top was measured in the laboratory.
- Further details concerning the subsurface materials and conditions encountered are shown on the
Log of Probe. The slratification lines shown on the Log of Probe represents only approximate locations
of changes between sediment and water, as indicated by the field sampling methods used.
The following summary has been developed based on the laboratory testing and materials
- encountered in the Probe P-4:
The depth of sediments presented in this report does not constitute a direct or implied warranty that
the sediment depth at the Probe P-4 location can be directly interpolated or extrapolated. Amount of
sediment which are different from those disclosed by the probe may be found at other locations in the
pond.
- Patton, Burke & Thompson has prepared this report to aid in the evaluation of the site and to assist
in evaluation of the amount of siltation. We have developed our summary in accordance with generally
accepted professional geotechnical engineering principles and practices. We make no other warrant3"
_ either express or implied.
Patton, Burke & Thompson
Engineering Consultants
Pond Siltation Study
Coppcll, Texas
Page 4
Environmental issues regarding this site are not addressed in this study. Only geotechnical
information for use in determining the depth of pond water, sediment and pond bottom are presented
herein.
Our firm appreciates the opportunity to be of professional service to you. We would be pleased
- to discuss any questions which may arise concerning this report. If we can be of further assistance, please
contact us at your convenience.
Respectfully submitted,
PATTON, BURKE & THOMPSON
-- S~ Di~karan a . urke, P.E.
- Staff Engineer Principal
Distribution: (3) City of Coppell
Pn~ton, Burke & Thompson
FIGURES
Parkway Hlvd.
~ ' Site
N
Vicinity
(NoI i~ scal~)
--- j Normal Pool = 460.0'
Outlet J
_ Note: Drawing not to scale
· indicates approximate location
of exploralory probe for original study
0 indicoles approximate location
of exploratory probe for this study
-- This plan was taken from sheet 2 of
2, 'Offsite Drainage & Lake Plan",
Dated Seplember 1991, prepared SAMPLING LOCATION PLAN
_ by Don M. Dowdey & Associates. POND SILTATION STUDY
ADDENDUM No.
CHAUCER ESTATES
Job No. 101-001 Coppell,-Texas
_ Patton, Burke & Thompson Figure 1
GRAIN SIZE (mm)
-- 100 10 I 0.1 0.01 0.001
90 -t ............................
- ~: '° ......................... ~~ .......... ~ .............. I ....... ' ...............................
Z
_ rr =° ~ ................................. , ~
10 .................................................
o 3..0," 'l~s" 3~4" 3,8" ~ .40 moo .200
U.S. STANDARD SIEVES
-- P-4, Top 16" = P-4, Bottom 16"
GRAIN SIZE DISTRIBUTION ANALYSIS
Pond Siltation Study
Addendum No. 1
Chaucer Estates
Job No. 101-001 Coppell, Texas Figure 3
__ Patton, Burke & Thompson
LOG OF PROBE NO. P-4.
CLIENT: City Of Coppell LOCATION: Coppell, Texas
JOB NAME: Chaucer Estates Pond RIG TYPE: 18' Work Boat
DRILLING CONTRACTOR: Geo-Marine, Inc. LOGGED BY: SD
SURFACE CONDITIONS: Water DATE DRILLED: 11/07/95
WATER ELEVATION: 460.0' JOB NO.: 101-001 PAGE I OF 1
FIELD DATA LABORATORY DATA I DRILLING METHOD(S): Hand pushed and driven 1.5" I.D.
i PVC (hammer approx. 30 lbs)
GROUNDWATER INFORMATION:
.
· ..................
d ', ~u ~..1~O1-,~, __ ~ ,~ SAMPLE TYPE
3: u{, z_3: ~ Oo~_n'n~: ~: ~ ~ ~ ~ .z, Q~ ~ ~ ~1 HP PVC Tube RC Rock Core SS Split Spoon
· ~3 ~ CT Cuttings TC THD Cone CS California Spoon
z~-=-'~ = ¢3 '~ ~ ~ GEOTECHNICAL DESCRIPTION WATER
-- 5 4 i ! BOTTOM SEDIMENTS, from 5.0' to 7.7'
st s.o-7.7 ,HP, 32'
. I I Recovery
- I Probe terminated at a depth of 7.7' below top of water
-10-
!
-- 15 --! I
.J
! ,
-- -20 ~ ~
-25-~,
-
- 30-~ ~
-- N - TANDARD PENETRATION TEST RESISTANCE REMARKS: Five (5} attempts we[e made at this location
FIELD T - THD CONE PENETRATION RESISTANCE
P - POCKET PENETRATION RESISTANCE before a sample was recovered.
TEST R - PERCENTAGE OF ROCK CORE RECOVERY
ROD - ROCK QUALITY DESIGNATION
'- Patton, Burke & Thompson Figure - 2