9204_Wake_Sorrell_MSWLF_LFCoverMaint_FID1693707_20220707

July 7, 2022
Division of Waste Management
217 West Jones Street
Raleigh, North Carolina 27603
Attn: Ms. Jackie Drummond via email: [e-mail]
Reference: Landfill Cover Inspection — June 2022
Sorrell Landfill (Permit #92-04)
Apex, Wake County, North Carolina
S&ME Project No. 1054-07-251
Dear Ms. Drummond:
On June 24, 2022, representatives from S&ME, Inc. (S&ME) performed a visual inspection of the landfill cover and
the storm water/surface water conveyance features at the closed Sorrell Landfill located in Apex, North Carolina.
This letter report is provided to document the findings of our inspection. Services conducted by S&ME were
performed in general accordance with S&ME Proposal No. P4258-07V, dated April 25, 2007, S&ME's
memorandum 2027 Landfill Cover Maintenance Cost Estimate, dated March 25, 2022, and the NCDEQ
memorandum Authorization to Conduct the Spring 2022 and Fall 2022 Landfill Cover Maintenance Activities Closed
Sorrell MSW Landfill, dated March 29, 2022.
BACKGROUND INFORMATION
Sorrell Grading Company initially operated a construction and demolition (C&D) landfill at this site, which
subsequently also accepted municipal solid wastes (MSW) and similar waste materials. A Closure Plan and a Post -
Closure Plan for the landfill were prepared by Stuart Jones Consulting Engineering, dated June 20, 1996 and
submitted to the Section on behalf of Sorrell Grading Company. The Closure Plan provided criteria for the
construction of a landfill cover consisting of a clay cap over the top 24 acres of the landfill and a vegetative layer
of the top and side slopes of the landfill. The Closure Plan indicated that the side slopes were already largely
constructed at that time and that the cap construction was underway.
A Closure Report, dated September 7, 2001, was prepared by S&ME and submitted to the Section on behalf of
Sorrell. The report detailed S&ME's evaluation of the landfill cover after the landfill had been closed and the clay
cap had been placed on top of the landfill. The Closure Report described testing of the cover on the top and the
side slopes of the landfill, verifying the placement and thickness of the infiltration layer and the erosion layer.
Locations on the side slopes and the top of the landfill were tested. Most of the locations were found to contain
adequate thicknesses of cap material. Where the thickness of the cap was insufficient, these locations were
identified, and repairs were to be made by the owner. Additional information on the construction and condition of
the landfill cover system was described in S&ME's letter report Response to Notice of Violations, submitted to
NCDENR-DWM on January 26, 2009.
The December 6, 2021, landfill cover inspection was limited to an evaluation of one area of compliance:
S&ME, Inc. 13201 Spring Forest Road I Raleigh, NC 276161 p 919.872.2660 1 www.smeinc.com

Landfill Cover Inspection — June 2022
Sorrell Landfill (Permit #92-04)
Apex, Wake County, North Carolina
S&ME Project No. 1054-07-251
A visual inspection of the landfill cap over the top 24 acres of the landfill and the storm water/surface
water conveyance features. Cutting and maintenance was performed June 6-8, 2022, by Heritage
Stormwater Management, subcontractor to S&ME, under a separate task.
S&ME personnel did not inspect the landfill side slopes which are covered by growths of pine trees, hardwoods,
and underbrush.
OBSERVATIONS
Overall, the cap and stormwater conveyance features appear to be in good condition with adequate vegetation.
Three deficiencies in need of corrective measures were observed. The following features were visually identified as
1) deficient and in need of corrective measures, 2) as minor functional issues requiring monitoring or 3) as
functional and not in need of corrective measures. The numbered items below correspond to the numbers on
Figure 1 and to the numbered photos in the photographic log.
Deficiencies
A slope failure was observed on the upper portion of the steep slope on northwestern portion of the
landfill property (photograph 1 & 14). The slope failure was reported in the last eight cover inspections
S&ME performed for the site.
Around the flexible slope pipe draining the stormwater from slope drain No. 1 inlet to the southern
access road, several dead and/or up -rooting trees were observed beginning to dislodge the side slope
cover soil (photos 2a-2c).
A depression with standing water was observed along the east side of the base of the access road on the
southwestern portion of the landfill cap, where the southern access road connects the landfill cap to the
along the southern border of the landfill. Evidence of this standing water was previously observed
during S&ME's November of 2018, June 2020, and October 2020 inspections. During the May 2021
maintenance, soil and gravel was placed in the depression to promote water drainage. When S&ME
inspected the area in June 2021 and December 2021, some standing water was again observed within
the depression and adjacent access road. On June 8, 2022 Heritage installed a flexible drainpipe in the
depression to transport the water under the access road and the depression was drained of standing
water. During S&ME's inspection on June 14, 2022 standing water was present in the depression
(photographs 3a and 3b).
Minor Functional Issues
The stormwater outfall for the pipe draining the stormwater ditch parallel to the southern access road
appears to be functioning based on evidence of water flow. However, sections of the concrete pipe
beneath the southern access road appear to be separated and the pipe has settled on the discharge end.
Furthermore, evidence of scouring was visible below the discharge end of the culvert (photos 4a & 4b).
A small slope subsidence was noted along the southern slope. The subsidence was approximately 1.5
feet deep and 2 feet wide. No trash is visible, and vegetation appears to be filling in the subsidence
(photo 5).
January 17, 2021

Landfill Cover Inspection — June 2022
Sorrell Landfill (Permit #92-04)
I I Apex, Wake County, North Carolina
S&ME Project No. 1054-07-251
Functional Items
Inlets for diversion ditch/diagonal water bar no. 1 & no. 2 were not obstructed by vegetation and appear
to be functional and are preventing erosion of the access road (photo 6).
7. Evidence of vehicular traffic has been observed on the landfill. These vehicles appear to be accessing the
landfill via an access road from an adjacent natural gas easement (photo 7).
8. The inlet and outfall of the flexible slope drain at the western tip of the landfill is functional and free of
significant vegetation build-up (photo 8).
The culvert pipe conveying runoff under the access road just west of MW-6 has been repaired and is now
functional (photograph 9).
10. The outfall in the sediment pond is functional and free of any major debris (photo 10).
11. The access roads to monitor well MW-4 and MW-7 were observed to have to have been cleared and are
functional (photograph 11 & 13).
12. The gravel access road traveling around the base of the landfill appeared to be in good condition.
(photograph 19)
13. Depressions were observed across the cap, but no standing water was observed in the depressed areas
(photos 12 & 20).
Grass and vegetation across the landfill cap and roads have been mowed. This maintenance item has
been completed twice a year over the past several years, substantially improving the vegetative cover at
the site. The grass and vegetation are currently an acceptable height (photo 12)
15. The vegetation growing on the western hill slope of the landfill cap has been mowed and removed from
the slope (photographs 14 & 15).
16. The headwall structures at the entrance of the slope drains on the south slope were not blocked by any
substantial vegetation and are functional (photos 17 & 18).
The vegetation growing in the drainage ditch running parallel to the landfill along the southern access
road has been removed and chemically treated (photo 19).
The approximate location of each of the above items is labeled on the attached Site Plan drawing (Figure 1).
RECOMMENDED CORRECTIVE MEASURES
S&ME recommends the following corrective measures for each observed item:
Deficiencies
The slope failure should be evaluated by a qualified professional to determine the cause of the failure
and repaired according to their recommendations to prevent further damage to the landfill cap, soil
erosion, or exposure of waste.
Along slope drain No. 1 inlet to the southern access road appears to be disconnected at a joint. The
plastic flexible slope pipe should be repaired to promote surface water draining off the landfill cap.
The area of subsidence collecting surface water at the base of the landfill has consistently been observed
to have standing water in consecutive inspections. During the June 2022 maintenance, a flexible
drainpipe was placed in the depression and run under the access road to the drainage ditch on the
southside of the road to promote water drainage. When S&ME inspected the area on June 14, 2022,
January 17, 2021

Landfill Cover Inspection — June 2022
Sorrell Landfill (Permit #92-04)
Apex, Wake County, North Carolina
S&ME Project No. 1054-07-251
some standing water was again observed within the depression. This area should be further repaired to
continue to promote drainage.
Minor Functional Issues:
The disconnected joint in the pipe should be monitored for evidence of scouring or erosion between the
joints. Should the level of erosion or scouring reach levels where it could impact the integrity of the road,
the pipe should be repaired or replaced.
The small slope subsidence should be monitored for an increase in depth or size. If the area increases in
size, it should be filled, graded, and stabilized with vegetation. The subsidence has not increased in size
since the last inspection.
Functional Issues:
S&ME recommends that the landfill cap continue to receive regular, bi-annual mowing of the landfill cap in the
spring and fall to promote the health of the vegetative cover. Areas of settlement, and depressions, holding water
should continue to be identified, monitored, and repaired to promote water draining off the landfill cap and
minimize standing water above waste.
CLOSING
S&ME appreciates the opportunity to provide these services and hopes that you find this report to be complete
and informative. We would appreciate an opportunity to discuss our findings and recommendations with you.
Please call us at [phone] if you have any questions or comments, or if we can be of further assistance.
Sincerely,
S&ME, Inc.
//�V-
oeuir-" W-10-C I
Devin Kehoe Samuel P. Watts, P.G.
Staff Professional Senior Project Manager
[e-mail] [e-mail]
Attachments: Photographic Log
Figure 1 — Cover Inspection Site Map
cc: Mr. James Easthom - Kennon, Craver, Belo, Craig & McKee, PLLC ([e-mail])
Mrs. Teresa Sorrell Atkins ([e-mail])
January 17, 2021 4

Attachments

';•JJ�y.y
�a View of flexible slope drains from Slope Drain Inlet #1 (looking
south). The slope drain #1 disconnect has been repaired.
C Dead up -rooting trees next to slop drain #1.
a Site Photographs S&ME Project No. 1054-07-251
III _ Sorrell Landfill Taken by: D. Kehoe Date Taken: 6/14/2022
Apex, Wake County, North Carolina

..
3a Depression with standing water along access road in the
southwestern portion of the landfill. Drainpipe installed but
4a View through the concrete pipe beneath the southern access
road. Note apparent pipe settlement and separation of the pipe
sections.
LAMM
r-I
�y
'standing
View of new drainpipe installed under access road to drain
water.
A , Y
•
� Yam:: M ° i �.Z �• f`• 1 - �.V} .'..
F74x'%• �3 i •x ��
��••rr 1
f ax J V'
`
'` �
�
a
`u /ITS • � �
\ � ���� "R
: Ml
.-
S�
t
A.
^' i�3wr•}'„S
road.2 southern access
Site Photographs S&ME Project No. 1054-07-251
Sorrell Landfill Taken by: D. Kehoe Date Taken: 6/14/2022
Apex, Wake County, North Carolina

0 274°W (T) h 35,70165,-78.812685 ±4 m ♦ 127 m
%4'
.1 1
„t
5
View of small slope subsidence in landfill cap on southern slope
just north of MW-8 (looking north).
r,A
V= �
V'
r�
+ t
y {-
R
7
View of off -site access path coming onto the property from the
west. Appears to have been used recently.
77 4
I
6
View of the entrance to the slope drains installed within
Diversion Ditch/ Diagonal Water Bar no. 2.
II
l
4
F
f
M
�•
8
View of the flexible slope drain running down the western tip of
the landfill.
LA Site Photographs S&ME Project No. 1054-07-251
I I I _ Sorrell Landfill Taken by: D. Kehoe Date Taken: 6/14/2022
Apex, Wake County, North Carolina

9
View of flexible culvert pipe running under access road on
northwest side. Previous damage has been repaired.
v-
x
r v
�
11
View of access road leading to MW-4.
Site Photographs S&ME Project No. 1054-07-251
Sorrell Landfill Taken by: D. Kehoe Date Taken: 6/14/2022
Apex, Wake County, North Carolina

Sf ''
,a
4 3 A
}'t t
4
View of access road leading to MW-7.
L
View of the recently mowed b. ..- of the landfil I
.. looking.. . the access road.
C:
a
rtirfisi!P7.Yw"!,'.`:.AU°.A��It�4
14
View of slope on northwest side of landfill. Mowing was
completed and there were no observable signs of further slope
failure rrnl
r'
..iy •�
•. '' ' � '•J'' ram` '�'f � ��� �ir?ti•
4,-,
7j
}M
16
View of entrance point for flexible slope drain on western tip of
the cap.
Site Photographs S&ME Project No. 1054-07-251
Sorrell Landfill Taken by: D. Kehoe Date Taken: 6/14/2022
Apex, Wake County, North Carolina

17 (View of Slope Drain #2 Inlet/ Headwall.
19 View of the drainage ditch running parallel to the southern
landfill boundary.
h
r .
-
--,`
8
View of Slope Drain #1 Inlet/ Headwall.
r
20 View of vent 6, mowing was completed and there are no signs o
ponding water.
Site Photographs S&ME Project No. 1054-07-251
Sorrell Landfill Taken by: D. Kehoe Date Taken: 6/14/2022
Apex, Wake County, North Carolina

N
N
O
04Lu
y
Z
m
°
/LiiZD
z
CO
w
�
\
0
U
lu Lo
N
W
m
m
1
cl N
Z o
Z Zo
II
o
CD
Z
w
�
Lu
Q o0
U
fn
K
a
of
°
SEDIMEN � p -
POND
10 ♦ GV-11 ♦ r J
2 ♦ GV-13 I m
-12 ♦ \ o
-5 A - FADED TO
-DI SURFACE VT-11 w
1
SLOPE D
n�
FL X
LEGEND
1❑ OBSERVATION WITH CORRESPONDING PHOTOGRAPH
ti MONITORING WELL
DEEP MONITORING WELL
OO METHANE MONITORING WELL
1 SURFACE WATER SAMPLE LOCATION
• LANDFILL GAS VENT
© POTABLE WELL
APPROXIMATE LIMITS OF CAP
ME MEN MEN APPROXIMATE WASTE BOUNDARY
6 TOPOGRAPHIC CONTOUR LINES
HYDROLOGIC FEATURE
X FENCE LINE
pop
• �s•
1
�1\1UN1 A.i.
talk irli . WA • c4 a l "' _.
•
O —
•Gv
;III
O
© G
Oft
pLL- c-
U' Z
W LL
UZ-2
zXt
Z d (D
C/)
�` N
W J
cdow
W DJ
N
Cn MX
0C)
ZJ
CV
CV
0
CV
1
i
Z
Q
p
Jz
I—
O
�U
U-
o�
Q W
z v
J
LU Z
H—
�O
�
z
W
OX
>
�LU
O
a
J
J_
LL
0
Z
Q
J
GRAPHIC SCALE
200 0 100 200
FIGURE NO.
( IN FEET )
11