20081317 Ver 1_Hell Swamp Final report Addendum_20160513

From:
[e-mail]
To:
thomas.a.steffens(a)usace.armv.mil; Scarbraugh, Anthony; Haupt, Mac
Cc:
iberger(abczr-inc.com; scooper(abczr-inc.com
Subject:
Hell Swamp Final report Addendum
Date:
Friday, May 13, 2016 12:02:37 PM
Attachments:
UUoland methodoloav addendum final.odf
HSWMP CROPLAND UPLAND 2014 FIGA.odf
HSWAMP STRM ASBUILT LIDAR 2014 FIGB.odf
Tom, Anthony and Mac:
At our site visit to our Hell Swamp mitigation site last month, you
requested additional information regarding the drawing of upland boundary
lines around a few of the monitoring wells. Attached is an addendum to the
Hell Swamp Fifth Annual Report consisting of text and two figures from CZR
addressing your request.
I will send 3 -hole punched hard copies by US mail so that you can insert
the Addendum into the back of your copy of the annual report.
If you have any questions, please let me know
Sincerely,
Jeff
(See attached file: Upland methodology addendum final.pdf)(See attached
file: HSWMP_CROPLAND_UPLAND 2014_FIGA.pdf)(See attached file:
HSWAMP_STRM ASBUILT LIDAR 2014 FIGB.pdf)
Jeff Furness
Senior Scientist
PCS Phosphate Company, Inc.
1530 Hwy 306 South
Aurora, NC 27806
T: [phone]
C: [phone]
[e-mail]
www.potashcorp.com
(Embedded image moved to file: pic08456.gif)

FIFTH ANNUAL REPORT ADDENDUM PER AGENCY REQUEST
METHODOLOGY FOR DETERMINATION OF UPLANDS AT HELL SWAMP MITIGATION SITE AS
DEPICTED ON FIGURE 13 IN FIFTH/FINAL ANNUAL MONITORING REPORT (FEBRUARY 2016)
The Beaufort County soil survey (Kirby 1995) shows the Hell Swamp mitigation site as underlain by two
non -hydric soil series, Augusta fine sandy loam (14.28 acres) and Dragston fine sandy loam (185.10
acres) (See attached PC Cropland and County Soil Survey Uplands). In CZR 2009, Figure 13 of the final
mitigation plan for the Hell Swamp/Scott Creek site depicted 200 acres of upland soils (as shown in the
County soil survey) and 103 acres estimated as "potential non -wetland from edge effect" (polygons with X
on Figure 13 of the plan). The 103 acres were located adjacent to perimeter ditches that would not be
filled as part of the site restoration and the width of the X -polygon varied depending on effective ditch
depth and soils per the Scope and Effect Guide (Fleming 1998).
The Hell Swamp mitigation plan included wells scattered evenly across the prior -converted agricultural
fields in the interstream wet mineral flats; theoretically, each well was to represent approximately 10 acres
(CZR 2009.) While this metric is useful in aggregate, each well may actually represent less than, or more
than, 10 acres depending on local topography and other specific details (e.g., soil type, level of
construction equipment impact, proximity to filled or unfilled ditches). According to the Beaufort County
soil survey, 25 wells in the flats were located in non -hydric soil units. The 86.44 upland acres depicted on
the potential yield figure in the 2016 fifth annual report (also Figure 13) included polygons drawn to
represent the "potential non -wetland from edge effect' in addition to areas represented by the five wells
which failed to meet restoration success criteria.
Soil profiles were collected at the site of each well installed at the beginning of the monitoring period. The
original soil profile descriptions did not go beyond the depth of the well screen; many of the monitoring
wells in the non -riparian upper flats were Ecotone 20s with a screen length of 20 inches. Ecotone or
WL40s installed in lower elevations of the site where periods of positive water level were possible or
expected had portions of the upper 40 -inch well screen above ground level which also reduced the depth
of the soil profile described at installation.
As the fifth and final annual report was in preparation, wells that had met the restoration success criteria
for interstream non -riparian mineral flats (minimum 6 percent of the growing season during normal rainfall
in 50 percent of the five plus monitoring years) and shown on the County soil survey as underlain by non -
hydric soils were identified. The original well installation profiles for these wells were then compared to
new soil profile descriptions taken during late 2015 and early 2016 (these profiles included hydric soil
indicators recommended in the US Army Corps of Engineers 2010 Regional Supplement [USACE 2010]).
Results of this comparison in conjunction with the hydroperiods suggested the size of the areas underlain
by non -hydric soils was less than shown in the soil survey; however, the edges of the reduced non -hydric
soil series were not delineated.
Five wells failed to meet the wetland hydroperiod restoration success criteria (11, 79, 94, 120, and 122).
Regardless of the soil polygon as depicted in the Beaufort County soil survey, or the original and recent
soil profile, areas representative of these five wells were shown as upland and not included as any type of
wetland mitigation credit in the potential mitigation yield shown in the 2016 final annual report (Figure 13).
The upland polygons for these five wells were drawn initially using the well/acre metric, and then modified
based on characteristics at that given well location, including onsite knowledge and LiDAR data. In some
instances, the well/acre metric fit the data and in others it deviated.

For example, the 14.41 -acre Augusta polygon as depicted in the soil survey included both sides of the
upper Scott Creek valley and included wells 11, 19, and 20. As wells 19 and 20 met the success criteria,
the Augusta polygon was modified to exclude those wells and to follow the "ridge" evident on LiDAR on
the north side of the valley and represented — 15 acres.
In contrast, for the upland associated with well 94 (an area not shown as non -hydric soil in the County
survey), a u -shaped polygon was drawn to represent upland on the west side of lower UT6 and the north
side of lower Scott Creek. Early soil profiles dug by CZR along the north edge of Scott Creek during
investigation of the site found several small areas of non -hydric soil; some of which were thought to be
spoil piles from the canal dug along the north edge of the swamp but others were likely "native" and too
small to include in the 1995 County soil survey. This u -shaped upland polygon was drawn such that 2.8
acres were contained within the 100 -foot Tar -Pamlico riparian buffer and 8.01 acres were shown as
uplands for well 94 on Figure 13 in the 2016 annual report (see attached Modified Uplands based on
Hydrology Data and Soil Profiles).
Five wells (53, 65, 66, 78, and 79) were located within the Dragston polygon shown on the County soil
survey located between the restored upper Scott Creek and coastal plain headwater stream valleys UT1
and UT3. Wells 53, 65, 66, and 78 met the hydrology success criteria and the hydric soil criteria (either
original or recent soil profile). As well 79 was the only well of the five which failed to meet the hydroperiod
success criteria, the upland polygon for well 79 was drawn to more or less maintain the original shape of
the Dragston polygon in the soil survey, albeit smaller in size; 2.23 acres of the upland were included in
the 100 -foot Tar -Pamlico buffer and 13 acres were shown as upland in Figure 13 in the 2016 report.
Wells 120 and 122 also failed to meet success criteria and depiction of the upland to represent these
wells was somewhat complicated. Wells 121 and 122 were located within the non -hydric Dragston
polygon shown in the County soil survey but well 121 met the success criteria (soil profile and hydrology).
Plus, the portion of the site representing the drainage effect from the open perimeter ditches in this area
needed to be included as upland (polygons with X on the mitigation plan Figure 13). During preparation
of the fifth/final report, over the entire site, this drainage effect polygon was adjusted in width based on
hydroperiods of wells either within, or at the edge of, the original "potential non -wetland" polygon. While it
could be argued that a portion of the upland represented by a well as close to the site boundary as well
122 was actually "off site", CZR did not use this argument in any calculation. Therefore, uplands east of
UT8 represent the ditch effect in the vicinity and two wells that did not meet success criteria (24.88 acres).
References:
CZR Incorporated. 2009. Compensatory Mitigation Plan for Hell Swamp/Scott Creek Restoration Site,
Pantego Township, Beaufort County, North Carolina
Kirby, Robert M. 1995. Soil Survey of Beaufort County, North Carolina. US Department of Agriculture,
Natural Resources Conservation Service.
USACE. 2010. Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Atlantic and
Gulf Coastal Plain Region. Version 2.0.
Fleming, N. Eric. 1998. Scope and Effect Guide. Southeast Coastal Wetlands Team, US Department of
Agriculture, Natural Resources Conservation Service.

VVINDLEY PRESERVATi
TRACT AND
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HS -89
HS -90
HS -92 �
CONTROL FOREST
UT4
ACCESS ROAD - UPLAND
HS -102
■
WELLS WITHIN COUNTY SOIL SURVEY UPLANDS
a
WELL NUMBER
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HS-103
❑S
EXISTING JURISDICTIONAL WETLANDS
HS -11■3
PC CROPLAND (915.56 ACRES)
HS -11
At - AUGUSTA, FINE SANDY LOAM (14.28 ACRES)
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1
HS -117
(185.10 ACRES)
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TOTAL ACRES OF UPLAND SOIL PER COUNTY SOIL
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LEGEND
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CONTROL FOREST
ACCESS ROAD - UPLAND
CENTERLINE OF VALLEYS AND STREAMS
■
WELLS WITHIN COUNTY SOIL SURVEY UPLANDS
HS -1
WELL NUMBER
0
VALLEYS AND STREAMS TAR-PAMUCO BUFFER
EXISTING JURISDICTIONAL WETLANDS
PC CROPLAND (915.56 ACRES)
UPLAND SOIL SERIES:
At - AUGUSTA, FINE SANDY LOAM (14.28 ACRES)
Ds - DRAGSTON, FINE SANDY LOAM
TOTAL UPLAND SOILS PER COUNTY SOIL SURVEY
(185.10 ACRES)
TOTAL ACRES OF UPLAND SOIL PER COUNTY SOIL
SURVEY OUTSIDE OF EXISTING JURISDICTIONAL
WETLANDS (163.26 ACRES)
NOTE:
CENTERLINES OF ALL STREAMS AND VALLEYS ARE DIGITIZED FROM
THE 2012
AERIAL AND DO NOT DEPICT DESIGN CENTERLINE.
0 1200 2400
SCALE IN FEET
SOURCE -
AERIAL IMAGE PROVIDED BY: NORTH CAROLINA DEPARTMENT
OF TRANSPORTATION, 2912, NORTH CAROLINA STATE PLANE, NAD1983
WEBSITE: WWW_NCDOT.DRG
SOILS DATA OBTAINED FROM THE NATIONAL RESCUMrS CONSERVATION
SERVICE (MRCS) WEBSITE: http //sDildotamort.nres.uscro-gov
HELL SWAMP — SCOTT CREEK MITIGATION SITE
PC CROPLAND AND COUNTY SOIL SURVEY UPLANDS
PCS PHOSPHATE COMPANY, INC.
SCALE: AS SHOWN APPROVED BY: DRAWN BY: TLJ
ADDENDUM2016 HSWAMP-
DATE: 05/13/16 FILE: CROPLAND—UPLAND
��� CP#1745.59.fi5
"/� 4769 COLLEGE ACRESUI DRIVE
IN. ` R WILMINGTON. NORTH CAROLINA ZB403
INCORPORATED TEL 91O/392-9753 FIGURE A
EmmowuEw MR LTAnS FAX 91 D/392-9139

iT
WINDLEY PRESERVATION
TRACT AND
CONTROL FOREST
/ ACCESS ROAD
/ WINFIELD
CONTROL
FOREST
Lam_
SOURCE:
AS BUILT LIDAR PROVIDED BY:
JONATHAN RICKETTS ENGINEERING,
3450 NORTHLAKE BLVD., PALM BEACH
GARDENS, FLORIDA, PHONE 561_630_6700
SOILS DATA OBTAINED FROM THE NATIONAL RESOURCES CONSERVATION
SERVICE (NRCS) WEBSITE: http://soildatomart.nres.usda.goV
W
HS -1
Fu _T1
UT3
v
UT8
USC
ACCESS ROAD
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PLUM'S PIT
CONTROL FOREST J
ACCESS ROAD
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Scott
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HELL SWAMP BOUNDARY
CONTROL FOREST
ACCESS ROAD
VALLEY AND STREAMS TAR—PAMLICO BUFFER
MONITORING WELLS THAT FAILED TO MEET RESTORATION CRITERIA
WELL NUMBER
UPLAND SOIL SERIES PER COUNTY SOIL SURVEY
UPLAND SOIL SERIES:
At — AUGUSTA, FINE SANDY LOAM (14.28 ACRES)
Ds — DRAGSTON, FINE SANDY LOAM (185.10 ACRES)
TOTAL UPLANDS SHOWN ON POTENTIAL YIELD FIGURE 13 OF
2016 REPORT (86.44 ACRES)
UPLAND SOIL CONTAINED IN TAR—PAMLICO BUFFER (4.85 ACRES)
0 1200 2400
SCALE IN FEET
HELL SWAMP — SCOTT CREEK MITIGATION SITE
MODIFIED UPLANDS BASED ON
HYDROLOGY DATA AND SOIL PROFILES
PCS PHOSPHATE COMPANY, INC.
SCALE: AS SHOWN APPROVED BY: DRAWN BY: TLJ
FILE:ADDENDUM 2016 HWWAMP_
DATE: 05/13/16 ASBUILT_LIDAR_UPLAND
4709 COLLEGE ACRES DRIVE CP# 1745.59.66
CZ R SUITE 2
8403
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ENVIRONMENTAL CONSULTANTS FAX [phone]
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SCALE IN FEET
HELL SWAMP — SCOTT CREEK MITIGATION SITE
MODIFIED UPLANDS BASED ON
HYDROLOGY DATA AND SOIL PROFILES
PCS PHOSPHATE COMPANY, INC.
SCALE: AS SHOWN APPROVED BY: DRAWN BY: TLJ
FILE:ADDENDUM 2016 HWWAMP_
DATE: 05/13/16 ASBUILT_LIDAR_UPLAND
4709 COLLEGE ACRES DRIVE CP# 1745.59.66
CZ R SUITE 2
8403
r
RPORATED WILMINGTON, NORTELC9R10/392�9253 FIGURE B
ENVIRONMENTAL CONSULTANTS FAX [phone]