Chaucer-SY 951102~. PhOton, BuFke b, Thompson
I Engineering Consultants
POND SILTATION STUDY
CHAUCER ESTATES
HEARTZ ROAD AND PARK VALLEY DRIVE
CQPPELL, TEXAS
! ; ~ ~ .................
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November 2, 1995
10555 tlev,'kirk Street
Suite 530
Dallas. Texas 75220
214.831.1111
FAX 2i4.831.0800
The City of Coppell
255 Parkway Blvd.
P.O. Box 478
Coppell, Texas 75019
Atto: Mr. Kenneth M. Griffm, P.E.
Assistant City Manager
City Engineer
Re: Pond Siltation Study
Chaucer Estates
Heartz Road and Park Valley Drive
Coppell, Texas
PBT Project No. 101-001
Dear Mr. Griffin:
Patton, Burke & Thompson (PBT) has completed the initial phase of the pond siltation stud), for
the above referenced project, and hereby submits three (3) copies of our letter report. This assigmnent
was carried out in general accordance with our proposal dated September 29, 1995.
PROJECT CHARACTERISTICS
The pond is located in the Chaucer Estates subdivision, southwest of the intersection of Iqeartz
Road and Parkway Drive, and immediately south of the library (see Figure 1) in Coppell, Texas. We
understand that the subject pond is privately owned by the Chaucer Estates homeowners and is
approximately 1 to 1-1/2 acres in plan and was originally constructed 10-feet deep. The pond xvas
constructed 3 or 4 years back with a normal pool elevation of 460-feet and reportedly had an original
botlom elevation of 450-feet. Apparently the pond was reported to have signs of heavy siltation, due to
Pa*ton, Burke d~ Thompson
Engineering Consultants
Pond Siltation Study
Coppell, Texas
Page 2
the drainage culverts draining storm water into the pond, which is believed to be as much as 4-feet by the
Homeovmers. The purpose of this study Was to provide geotechnical subsurface information, specifically
the depth of pond water, sediment and pond bottom, to assist the City in quantifying the extent and nature
of the siltation.
FIELD INVESTIGATION
Four (4) probes, P-l, P-2 and P-3A (Note: Probe P-3 did not yield satisfactory amount of samples,
therefore probe P-3A was made) were made with a 2-man, 18-foot flat bottomed work boat using a 1.5-
inch inner diameter PVC pipe. Locations of the probes were randomly selected and are shown on the
Sampling Location Plan, Figure 1. Metal posts, with attached ropes, were driven at various locations
around the edge of the pond to guide and stabilize the boat at the selected probe locations.
Representative samples of the bottom materials were obtained by using a 1.5-inch inner 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 driven using a 30-pound hammer.
The PVC pipe was then retrieved slowly and the bottom portion of the pipe (approximately 15-inches),
wilh thc sedi~nents, portion of the weathered shale and some water, was sawed off and the top and bottom
capped, marked and sealed. Three (3) PVC samples were then transported to PBT's laboratory for
laborato%, testing and analysis. The samples were stored in a secluded area to allow the sediments to
settle before conducting any laboratory tests. This also helped to finalize the depth of water, sedi~nent
and pond bottom.
Logs of all probes showing visual descriptions of bottom materials encountered are included in
Figures 2 thru 5. Sampling information, pertinent field data, and field observations are also included.
Ps, ton, Burke & Thompson
Engineering Consultants
Pond Siltation Study
Coppell, Texas
Page 3
LABORATORY ANALYSIS
The laboratory testing program was directed toward evaluating the physical characteristics and
determining the depths of the water, sediments and weathered shale encountered at the site. Laboratory
analysis of all soil samples included visual classification, and moisture content, dry density and sieve
analysis laboratory tests were conducted on the sample from probe P-2. The probe P-1 sample was given
unopened to the City to be displayed in a meeting with the Homeowners. Results of laboratory testing
are presented on the Logs of Borings, Figures 2 thru 5.
SUBSURFACE CONDITIONS
The four (4) probes conducted for this study indicate that the siltation conditions are reasonably
uniform across the pond. In general, the bottom conditions consists of sediments at depths below the
pond water surface of 8.5 to 9.4-feet, 10 to Il.l-feet, 9.7 to 10.9-feet and 10.0 to 12.0-feet in probes P-l,
P-2, P-3 and P-3A, respectively. Dark gray weathered shale was encountered in probes at depths of 9.4,
I 1.1, 11.8 and I2-feet in probes P-l, P-2, P-3 and P-3A, respectively. Laboratory tests on the probe P-2
smnple indicated that the average dry density of the weathered shale was 102 pcf with a water content of
around 20 percent. Sieve analysis tests indicted that coarser (heavier) particles were found near the
bottom of the PVC sampling pipe, immediately over the weathered shale, and finer (lighter) particles were
found near the top and middle portion of the tube. An attempt was made to make volumetric
measurements of the sampling tube to estimate the density of the sediments above the weathered shale
in probe sample P-2. The results indicated a dry density of around 56 pcf and a water content of 38
percent. At best this data indicates, as would be expected, that the sediments are extremely loose and
super moist.
Further details conceming the subsurface materials and conditions encountered are shown on the
Logs of Probes. The stratification lines shown on the Logs of Probes represent only approximate
locations of changes between sediment and water, as indicated by the field samphng methods used. [Note:
No attempt was made to extrude or test the sample from probe P-3A].
Pa*boa, Barke & Thompson
Engineering Consultants
Pond Siltation Study
Coppell, Texas
Page 4
SUMMARY OF FINDINGS
The following summary has been developed based on the laboratory testing and materials
encountered in the test probes:
:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::.::::'..~..'.:[::"2.4:::):.:::.~:::r:.g:~':~:~?.:..:~.~~!
P-1 8.5 11 '?. -"' 13
P-2 I0.0 12 to 14 ~ ~, '~ 14-3/4
P-3 9.7 24 to 27 ~: '~ 0-
P-3A 10 24 12
LIMITATIONS
The findings and recommendations presented in this report are based on the assumption that the
depth of sediments do not vary appreciably from those encountered at the probes. The depth of sediments
presented in this report does not constitute a direct or implied warranty that the sediments depth at the
probe locations can be directly interpolated or extrapolated. Amount of sediments which are different
from those disclosed by the probes 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 warranty
either express or implied.
Environmental issues regarding this site are not addressed in this study. Only geotechnical
recommendations for use in determining the depth of pond water, sediment and pond bottom are presented
herein.
Pa**on, Burke d~ Thompson
En§inoerin§ Consultants
Pond Siltation Study
Coppell, Texas
Page 5
Our firm appreciates the oppommity 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~i~ ~k W. Burke, P..
Staff Engineer, E.I.T. Principal
Distribution: (3) Ci~' of Coppell
Patton, Burke & Thompson
Engineering Consultants
FIGURES
Parkway Bird ~
II~
Vicinity Mop
(Not to scale)
_ / · ':.
o
Normal Pool = 460.0'
'~ ~N
_ '"x P-2
·
c~ P-3A \
'x.., ¢ - 3
N.
_ Note: Drawing not to scale
· indicates opprox]mafe location
of exploratory probe
This plan was taken from sheet 2 of .q.~: ~oo ':~.~'-
2, "Offsite Drainage & Lake Plan",
Dated September 1991, prepared SAMPLING LOCATION PLAN
by Dan M. Dowdey & Associates.
POND SILTATION STUDY
-- CHAUCER ESTATES
Coppell, Texas
Job No. 101-001
Patton, Burke & Thompson F]gure 1
LOG OF PROBE NO. P-1
CLIENT: City of Coppell LOCATION: Coppell, Texas
JOB NAME: Chaucer Estates Pond RIG TYPE: 18' Work Boat
DRILLING CONTRACTOR: Geo-Marine, Inc. LOGGED BY: JWB
SURFACE CONDITIONS: Water DATE DRILLED: 10104/95
WATER ELEVATION: 460.0' JOB NO.: 101-001 PAGE 1 OF 1
FIELD DATA LABORATORY DATA I. DRILLING METHOD(S): Hand pushed and driven 1.5" I.D.
PVC (hammer approx. 30 lbs)
-- ~
;~ GROUNDWATER INFORMATION:
-- = ~- o ~ - ~ ~ SAMPLE TYPE
U~ m ~ Z ~ ~ ~ = ~ ~ HP PVC T~ RC ~ ~re SS SpEt S~n
~ ~ Z ~ O O ~ = ~ ~ ~ Q ~ ~ ~ CT C=ti~s mc THD Co~ CS ~Eforn~ Sp~n
~ ~ o ~ ........ o ~ ~ GEOTECHNICAL DESCRIPTION
~ ] WATER
i ~ BOTTOM SEDIMENTS, from 8.5' to 9.4'
Sl i 8.5-9.6 :HP 13" ,i
, : Recovery
i :
-- - 10 . Probe terminated at a depth of 9.6' below top of water
'
.
N - TANDARD PENETRATllIN TEST RESISTANCE REMARKS: Three (3) attempts were made at this location
FIELD T - THD CONE PENETRATION RESISTANCE
P - POCKET PENETRATION RESISTANCE '; before a sample was recovered. Intact, sealed sample given
TEST R. PERCENTAGE OF ROCK CORE RECOVERY ; to city Officials.
- ROD - ROCK OUALITY DESIGNATION :
Patton, Burke & Thompson Figure - 2
LOG OF PROBE NO. P-2
CLIENT: City of Coppell LOCATION: Coppell, Texas
JOB NAME: Chaucer Estates Pond RIG TYPE: 18' Work Boat
DRILLING CONTRACTOR: Gee-Marine, Inc. LOGGED BY: JWB
SURFACE CONDITIONS: Water DATE DRILLED: 10/04/95
WATER ELEVATION: 460.0' JOB NO.: 101-001 PAGE 1 OF 1
FIELD DATA LABORATORY DATA DRILLING METHOD(S): Hand pushed and driven 1.5" I.D.
PVC (hammer approx. 30 lbs}
--- ! ;~ ~ GROUNDWATER INFORMATION:
_Z ~: ~: ~ ~ ~ _ ~ O~ HP PVC Tube RC Rock Core SS Sp§t Spoon
~-' ~. ~- ~ 0._, 0 m ::0 Z ¢g n ~ ~ ~, CT Cuttings TC THD Cone CS CaEforn~ Spoon
~ ~ ~ <~ z~== ~ ~>= -~° ~ ~ ~ ~ GEOTECHNICALDESCRIPTION
WATER
, ; BOTFOM SEDIMENTS, from 10.0' to 11.1'
-- - 10; ~ i
: i 14.75' I ! CLAY, silty, sandy, black, grey
· S1 ·10.0-10.8 HP 38 56' i i 66
~ Recovery
~ S1 .i 10 8-11.1 H! -- I I! 36 -sandy, with gravel, brown
-- ' S1 =;11.1-11.3_H.P_/ 21 102' *i -- SHALE, weathered, dark gray at 11.1'
'~'" ~ ............ = I ; Probe terminated at a depth of 11.3' below top of water
,
~ N - STANDARD PENETRATION TEST RESISTANCE REMARKS: A sample was recovered from the first attempted
FIELD T - THD CONE PENETRATION RESISTANCE
P - POCKET PENETRATION RESISTANCE probe. '*': volumetric measurement from sampling tube.
TEST R - PERCENTAGE OF ROCK CORE RECOVERY '~**': average of two test results.
-" RQD - ROCK QUALITY DESIGNATION
Patton, Burke & Thompson Figure - 3
LOG OF PROBE NO. P-3
CLIENT: City of Coppell LOCATION: Coppell, Texas
JOB NAME: Chaucer Estates Pond RIG TYPE: 18' Work Boat
DRILLING CONTRACTOR: Gee-Marine, Inc. LOGGED BY: JWB
SURFACE CONDITIONS: Water DATE DRILLED: 10/04195
._ WATER ELEVATION: 460.0' JOB NO.: 101-001 PAGE I OF 1
FIELD DATA LABORATORY DATA DRILLING METHOD(S): Hand pushed and driven 1.5" I.D.
PVC (hammer approx. 30 lbs)
!
I ! ~ i ~ GROUNDWATER iNFORMATION:
-- ~ ~: m,, ~ HP PVC Tube RC Rock Core SS Split Spoon
ooze
'~ ~ ~:~',~ ~ =~'~g : ~= ~ ; ~ GEOTECHNICALDESCRIPTION
~ WATER
-- 10 -4 : I Be'I-rOM SEDIMENTS, from 9.7' to 11.8'
No
Recovery !
· ~obe terminated at a depth of 1 1.8' below top of water
! .
! N - STANDARD PENETRATION TEST RESISTANCE REMARKS: Four (4) attempts were made at this location
i FIELD T - THO CONE PENETRATION RESISTANCE
P - POCKET PENETRATION RESISTANCE with no sample recovery.
TEST R - PERCENTAGE OF ROCK CORE RECOVERY
'- : RQD - ROCK QUALITY DESIGNATION
Patton, Burke & Thompson Figure- 4
LOG OF PROBE NO. P-3A
CLIENT: City of Coppell LOCATION: Coppell, Texas
JOB NAME: Chaucer Estates Pond RIG TYPE: lB' Work Boat
DRILLING CONTRACTOR: GeD-Marine, Inc. LOGGED BY: JWB
SURFACE CONDITIONS: Water DATE DRILLED: 10/04/95
WATER ELEVATION: 460.0' JOB NO.: 101-001 PAGE 1 OF 1
FIELD DATA LABORATORY DATA DRILLING METHOD(S}: Hand pushed and driven 1.5" I.D.
'. PVC (hammer approx. 30 lbs)
z~== ~ = ~ ~ GEOTECHNICAL DESCRIPTION
WATER
I
'-- 10 --! ; BOTTOM SEDIMENTS, from 10.0 to 12.0'
i :
-TS1 1001201HP. .. . 12" ~
--- Recovery
- --~-- r ............ i Probe terminated at a depth of 1 2.0' below top o[ water
N - STANDARD PENETRATION TEST RESISTANCE REMARKS: A sample was recovered from the first attempted
FIELD T - THD CONE PENETRATION RESISTANCE
P - POCKET PENETRATION RESISTANCE probe. Sample is still kept in the sampling tube.
TEST R - PERCENTAGE OF ROCK CORE RECOVERY
'-- RQD - ROCK QUALITY DESIGNATION
Patton, Burke & Thompson Figure - 5