HomeMy WebLinkAbout20180198 Ver 1_Sassarixa_100040_MY3_2023_20240209
MONITORING YEAR 3
ANNUAL REPORT
Final
February 2024
SASSARIXA SWAMP MITIGATION SITE
Johnston County, NC
Neuse River Basin
HUC 03020201
DMS Project No. 100040
DMS Contract No. 7425
DMS RFP No. 16‐007279
USACE Action ID No. 2018‐00432
DWR Project No. 2018‐0198
Data Collection Dates: January‐November 2023
PREPARED FOR:
NC Department of Environmental Quality
Division of Mitigation Services
1652 Mail Service Center
Raleigh, NC 27699‐1652
Wildlands Engineering, Inc. (P) 919.851.9986 • 312 West Millbrook Road, Suite 225 • Raleigh, NC 27609
February 7, 2024
Jeremiah Dow
Project Management Supervisor – Eastern Region
North Carolina DEQ Division of Mitigation Services
217 West Jones Street, Raleigh, NC 27603
RE: DMS Comments on the MY3 Report
Sassarixa Swamp, Project ID #100040, DMS Contract 7425
Dear Mr. Dow:
We have reviewed the comments on the Monitoring Year 3 Report for the above referenced project
dated December 19, 2023 and have revised the report based on these comments. The revised
documents are submitted with this letter. Below are responses to each of your comments. For your
convenience, the comments are reprinted with our response in italics.
Stream Report:
1. Section 2.2 – incomplete sentence in second paragraph reads “Chinese privet in MY4.” Please
correct.
Response: The incomplete sentence was removed.
2. The meeting minutes from the May 18, 2023 IRT site visit indicate that a piping log sill on T3 was
observed and would be manually repaired. Was this work completed?
Response: The piping log sill on T3 naturally sealed itself by the time Wildlands stewardship team
was going to manually repair it. Wildlands has completed various site walks since then and has
not observed any additional piping.
If you have any questions, please contact me by phone (919) 851‐9986, or by email
(jlorch@wildlandseng.com).
Sincerely,
Jason Lorch, Monitoring Coordinator
PREPARED BY:
312 West Millbrook Road, Suite 225
Raleigh, NC 27609
Jason Lorch
jlorch@wildlandseng.com
Phone: 919.851.9986
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final i
SASSARIXA SWAMP MITIGATION SITE
Monitoring Year 3 Annual Report
TABLE OF CONTENTS
Section 1: PROJECT OVERVIEW ........................................................................................................ 1‐1
1.1 Project Quantities and Credits ................................................................................................... 1‐1
1.2 Project Goals and Objectives ..................................................................................................... 1‐2
1.3 Project Attributes ....................................................................................................................... 1‐4
Section 2: MONITORING YEAR 3 DATA ASSESSNENT ........................................................................ 2‐1
2.1 Vegetative Assessment .............................................................................................................. 2‐1
2.2 Vegetation Areas of Concern and Management ....................................................................... 2‐1
2.3 Stream Assessment .................................................................................................................... 2‐1
2.4 Stream Areas of Concern and Management .............................................................................. 2‐2
2.5 Hydrology Assessment ............................................................................................................... 2‐2
2.6 Wetland Assessment .................................................................................................................. 2‐2
2.7 Monitoring Year 3 Summary ...................................................................................................... 2‐2
Section 3: REFERENCES .................................................................................................................... 3‐1
TABLES
Table 1: Project Quantities and Credits ..................................................................................................... 1‐1
Table 2: Goals, Performance Criteria, and Functional Improvements ...................................................... 1‐3
Table 3: Project Attributes ......................................................................................................................... 1‐5
FIGURES
Figure 1a‐c Current Condition Plan View
APPENDICES
Appendix A Visual Assessment Data
Table 4 Visual Stream Morphology Stability Assessment Table
Table 5 Vegetation Condition Assessment Table
Stream Photographs
Stream Crossing Photographs
Vegetation Plot Photographs
Appendix B Vegetation Plot Data
Table 6 Vegetation Plot Data
Table 7a Vegetation Performance Standards Summary Table
Table 7b Supplementally Planted Tree Species and Quantities
Appendix C Stream Geomorphology Data
Cross‐Section Plots
Table 8 Baseline Stream Data Summary
Table 9 Cross‐Section Morphology Monitoring Summary
Appendix D Hydrology Data
Table 10 Bankfull Events
Table 11 Rainfall Summary
Bankfull Events Visual Observations
Table 12 Groundwater Gauge Summary
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final ii
Groundwater Gauge Plot
Table 13 Recorded In‐Stream Flow Events Summary
Recorded In‐Stream Flow Events Plot
Appendix E Project Timeline and Contact Info
Table 14 Project Activity and Reporting History
Table 15 Project Contact Table
Appendix F Additional Documentation
IRT MY2 Site Visit Meeting Minutes
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final 1‐1
Section 1: PROJECT OVERVIEW
The Sassarixa Swamp Mitigation Site (Site) is located in Johnston County, approximately six miles
southwest of Smithfield and five miles north of Four Oaks. The Site drains to Holts Lake, which drains to
the Neuse River. Holts Lake is a recreational lake classified as a Nutrient Sensitive Water (NSW) and the
Neuse River is a water supply for the City of Goldsboro. Table 3 presents information related to the
project attributes.
1.1 Project Quantities and Credits
The Site is located on 10 parcels under 7 different landowners and a conservation easement was
recorded on 65.06 acres. Mitigation work within the Site included restoration, enhancement II, and
preservation of perennial and intermittent stream channels. Table 1 below shows stream credits by
reach and the total amount of stream credits expected at closeout.
Table 1: Project Quantities and Credits
PROJECT MITIGATION QUANTITIES
Project
Segment
Mitigation
Plan
Footage
As‐Built
Footage
Mitigation
Category
Restoration
Level
Mitigation
Ratio
(X:1)
Credits Comments
Stream
Sassarixa
Creek R1‐R3 2,631 2,631 Warm EII 2.5 1,052.400 Ford Crossing, Fencing Out
Livestock
T1 R1 570 570 Warm EII 2.5 228.000 Bank Stabilization, Fencing
Out Livestock
T1 R2 824 810 Warm R 1.0 824.000 Full Channel Restoration,
Fencing Out Livestock
T1 R3 509 507 Warm R 1.0 509.000 Full Channel Restoration,
Fencing Out Livestock
T1 R4 252 252 Warm EII 2.5 100.800 Fencing Out Livestock
T1A 358 356 Warm EII 2.5 143.200 Fencing Out Livestock
T1B 275 276 Warm EII 2.5 110.000 Fencing Out Livestock
T1C 307 307 Warm EII 2.5 122.800 Fencing Out Livestock
T2 1,010 1,006 Warm R 1.0 1,010.000 Pond Removal, Fencing Out
Livestock
T3 R1 1,053 1,041 Warm R 1.0 1,053.000 Full Channel Restoration,
Fencing Out Livestock
T3 R2 61 61 Warm P 10.0 6.100 Conservation Easement
T4 R1 206 206 Warm EII 2.5 82.400 Ford Crossing, Fencing Out
Livestock
T4 R2 398 399 Warm EII 2.5 159.200 Bank Stabilization, Fencing
Out Livestock
T4 R3 1,509 1,510 Warm P 10.0 150.900 Culvert Crossing,
Conservation Easement
T5 R1 670 642 Warm EII 2.5 268.000 Bank Stabilization
T5 R2 885 874 Warm R 1.0 885.000 Full Channel Restoration,
Fencing Out Livestock
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final 1‐2
PROJECT MITIGATION QUANTITIES
Project
Segment
Mitigation
Plan
Footage
As‐Built
Footage
Mitigation
Category
Restoration
Level
Mitigation
Ratio
(X:1)
Credits Comments
Stream
T5 R3 965 961 Warm EII 4.0 241.250 Culvert Crossing, Bank
Stabilization
T5A 1,026 1,018 Warm EII 2.5 410.400 Bank Stabilization, Fencing
Out Livestock
T5B 580 580 Warm EII 2.5 232.000 Fencing Out Livestock
T5C1 588 588 Warm EII 2.5 235.200 Fencing Out Livestock
T6 R1 381 383 Warm R 1.0 381.000 Full Channel Restoration,
Fencing Out Livestock
T6 R2 1,035 1,037 Warm EII 2.5 414.000
Culvert Crossing, Bank
Stabilization. Fencing Out
Livestock
Total: 8,618.650
1. T5C Credited using the Headwater Stream guidance method of the valley length.
Blue = Restoration Orange = Enhancement II Green = Preservation
1.2 Project Goals and Objectives
The project is intended to provide numerous ecological benefits. Table 2 below describes expected
outcomes to water quality and ecological processes and provides project goals and objectives.
Restoration Level Stream
Warm Cool Cold
Restoration 4,662.000
Enhancement I ‐‐
Enhancement II 3,799.650
Preservation 157.000
Totals 8,618.650
Total Stream Credit 8,618.650
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final 1‐3
Table 2: Goals, Performance Criteria, and Functional Improvements
Goal Objective/ Treatment Likely Functional
Uplift
Performance
Criteria Measurement
Cumulative
Monitoring
Results
Improve the
stability of
stream
channels.
Construct stream
channels that will
maintain stable cross‐
sections, patterns,
and profiles over
time.
Reduce sediment
inputs from bank
erosion. Reduce
shear stress on
channel boundary.
ER stays over 2.2
and BHR below
1.2 with visual
assessments
showing
progression
towards stability.
Cross‐section
monitoring will be
assessed during
MY1, MY2, MY3,
MY5, and MY7
and visual
inspections will
be assessed
annually.
Cross‐section
surveys show the
channels are
stable. Visual
observations
indicate the
majority of
channels are
performing as
intended. An
additional cross‐
section was added
to determine if
the upper third of
T2 is transitioning
into a linear
wetland
Improve
in‐stream
habitat.
Install habitat
features such as
constructed riffles,
lunker logs, and brush
toes into
restored/enhanced
streams. Add woody
materials to channel
beds. Construct pools
of varying depth.
Increase and
diversify available
habitats for
macroinvertebrates,
fish, and
amphibians leading
to colonization and
increase in
biodiversity over
time.
There is no
required
performance
standard for this
metric.
N/A N/A
Reconnect
channels
with
floodplains
to allow a
natural
flooding
regime.
Reconstruct stream
channels with
designed bankfull
dimensions and depth
based on reference
reach data. Remove
pond above T2.
Allow more
frequent flood
flows to disperse on
the floodplain.
Four bankfull
events in
separate years
within
monitoring
period.
30 consecutive
days of flow for
intermittent
channels.
Crest gauges
and/or pressure
transducers
recording flow
elevations.
Bankfull event
documented on
T1 R3, T2, and T5
R2 during MY3; T3
R1 did not meet
during MY3.
Greater than 30
consecutive days
of flow recorded
on all intermittent
streams during
MY3.
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final 1‐4
Goal Objective/ Treatment Likely Functional
Uplift
Performance
Criteria Measurement
Cumulative
Monitoring
Results
Restore and
enhance
native
floodplain
and
streambank
vegetation.
Plant native tree and
understory species in
riparian zones and
plant native shrub and
herbaceous species
on streambanks.
Reduce sediment
inputs from bank
erosion and runoff.
Increase nutrient
cycling and storage
in floodplain.
Provide riparian
habitat. Add a
source of LWD and
organic material to
stream.
Survival rate of
320 stems per
acre at MY3, 260
planted stems
per acre at MY5,
and 210 stems
per acre at MY7.
Height
requirement is 7
feet at MY5 and
10 feet at MY7.
One hundred
square meter
vegetation plots
are placed on 2%
of the planted
area of the Site
and monitored
during MY1, MY2,
MY3, MY5, and
MY7.
9 out of 11
vegetation plots
have a planted
stem density
greater than 320
stems per acre. A
small
supplemental
planting occurred
along T1 in
February 2023.
Permanently
protect the
project Site
from
harmful
uses.
Establish conservation
easements on the
Site.
Protect the Site
from encroachment
on the riparian
corridor and direct
impact to streams
and wetlands.
Prevent
easement
encroachment.
Visually inspect
the perimeter of
the Site to ensure
no easement
encroachment is
occurring.
No easement
encroachments.
1.3 Project Attributes
The project includes several adjacent properties that have been owned and operated as a livestock farm
by a single family since 1850, where livestock were continually rotated through all fields with access to
the project streams. Based on aerial photos from 1950 to 2012 onsite streams have existed in their
approximate locations with very little change to riparian buffer extents since 1950. Two alterations to
the Site visible from historical aerial photography were the addition of the pond on T2 between 1964
and 1973, and the addition of the large pond below T5A, T5B, and T5C between 1950 and 1961.
According to the landowners, in the 1960’s and early 1970’s a hog yard was located at the upstream end
of T4 and T5, where the streams were diverted to make a hog wallow area. The hogs were moved to a
hog house in the early 1970’s, however goats, horses, and cattle had continuous access to this portion of
the site until Hurricane Matthew struck in September 2016. The floods from the storm destroyed much
of the fencing around T4 and T5 and livestock have been rotated in other fields since that time while
fencing was being repaired. Other portions of the site had not seen significant changes in land use with
livestock or crop rotations from existing activities. Table 3 below and Table 9 in Appendix C present
additional information on pre‐restoration conditions.
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final 1‐5
Table 3: Project Attributes
PROJECT INFORMATION
Project Name Sassarixa Swamp
Mitigation Site County Johnston County
Project Area (acres) 65.06 Project Coordinates 35.472153, ‐78.436000
PROJECT WATERSHED SUMMARY INFORMATION
Physiographic Province Rolling Coastal Plain River Basin Neuse River
USGS HUC 8‐digit 03020201 USGS HUC 14‐digit 03020201130030
DWR Sub‐basin 03‐04‐04 Land Use Classification 66% agriculture, 27%
forested, 7% developed
Project Drainage Area (acres) 5,024 Percentage of Impervious Area 0.9%
RESTORATION TRIBUTARY SUMMARY INFORMATION
Parameters T1 T2 T3 T5 T6
Pre‐project length (feet) 2,202 348 1,098 2,544 1,342
Post‐project (feet) 2,155 1,010 1,114 2,553 1,451
Valley confinement (Confined, moderately confined,
unconfined) Unconfined Moderately Confined to Unconfined
Drainage area (acres) 45 25 26 41.25 38.25
Perennial, Intermittent, Ephemeral Intermittent Perennial
DWR Water Quality Classification C, NSW B, NSW
Dominant Stream Classification (existing) G5 G5 B5/G5 E5 G5/E5
Dominant Stream Classification (proposed) C5b/E5b C5b/E5b C5b/E5b C5/E5 C5/E5
Dominant Evolutionary class (Simon) if applicable Stage III Stage IV Stage III Stage IV
REGULATORY CONSIDERATIONS
Parameters Applicable? Resolved? Supporting Documentation
Water of the United States ‐ Section 404 Yes Yes USACE Nationwide Permit No. 27
and DWQ 401 Water Quality
Certification No. 4134. Water of the United States ‐ Section 401 Yes Yes
Endangered Species Act Yes Yes Categorical Exclusion in Mitigation
Plan (Wildlands, 2019) Historic Preservation Act Yes Yes
Coastal Zone Management Act (CZMA or CAMA) N/A N/A N/A
Essential Fisheries Habitat N/A N/A N/A
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final 2‐1
Section 2: MONITORING YEAR 3 DATA ASSESSNENT
Annual monitoring and site visits were conducted during MY3 to assess the condition of the project. The
vegetation and stream success criteria for the Site follow the approved success criteria presented in the
Mitigation Plan (Wildlands, 2019). Performance criteria for vegetation, stream, and hydrologic
assessment are located in Section 1.2 Table 2: Goals, Performance Criteria, and Functional
Improvements. Methodology for annual monitoring is presented in the MY0 Annual Report (Wildlands,
2021).
2.1 Vegetative Assessment
The MY3 vegetative survey was completed in September 2023. Vegetation monitoring resulted in a stem
density range of 243 to 567 planted stems per acre and the average stem density was 427 planted stems
per acre. Out of the eleven vegetation plots, nine met the success criteria of 320 stems per acres, while
vegetation plots 1 and 2 have 283 and 243 stems per acres, respectively. Mortality is contributed to
competition from dense herbaceous grass and a dry spring when the trees were originally planted in
2021. Refer to Appendix A for Vegetation Plot Photographs and the Vegetation Condition Assessment
Table and Appendix B for Vegetation Plot Data.
There were a significant number of mature hardwood trees that were left untouched from construction.
A visual site assessment in September 2022 indicated that some mature trees are starting to decline
after construction. Further observations throughout 2023 did not show a significant change in the
condition of the mature hardwoods left onsite. Planted trees and volunteer species are growing
throughout the Site and starting to fill in an understory that will eventually become a mature hardwood
forest.
2.2 Vegetation Areas of Concern and Management
Approximately 0.55 acres along T1 was identified as an area of low stem density in MY2. A supplemental
planting of the area was approved in MY2 and conducted in February 2023 (Figure 1a). The
supplementally planted species were the same from the approved Mitigation Plan (Table 7b). Ring
sprays were completed throughout the supplementally planted area and soil amendments were applied
locally to replanted trees to reduce competition and aid in planted stem success. Ring sprays and soil
amendments will be competed in MY4 in the supplementally planted areas as well as any areas where
the herbaceous vegetation is affecting tree growth.
An invasive species treatment was completed in May 2023 to address a dense population of Chinese
privet (Ligustrum sinense) along Sassarixa Creek Reach 3 and scattered stems throughout the remainder
of the Site. A combination of methods included foliar and cut stump applications. Approximately 4.97
acres at the downstream reach of Sassarixa Creek was treated and may require additional treatment in
MY4 if resprouting occurs. The Site will continue to be monitored for invasive species and follow up
treatments will occur if necessary.
A dense stand of sweetgum (Liquidambar styraciflua) and loblolly pine (Pinus taeda) covering
approximately 0.70 acres became established along T1 and T1B. This area was treated, and individuals
of both species were thinned in May 2023 by brush cutting. The Site will continue to be monitored for
additional dense populations of sweetgum and loblolly pine and follow up treatments will occur if
necessary.
2.3 Stream Assessment
Morphological surveys for MY3 were conducted in March 2023. All streams within the Site are stable
and functioning as designed. All 10 cross‐sections at the Site show little to no change in the bankfull area
and width‐to‐depth ratio, and bank height ratios are less than 1.2. Refer to Appendix A for the Visual
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final 2‐2
Stream Morphology Stability Assessment Table and Stream Photographs. Refer to Appendix C for Stream
Geomorphology Data.
2.4 Stream Areas of Concern and Management
Due to concern over the upper third of T2 appearing to be turning into a linear wetland, the NCIRT
requested that an additional cross‐section be installed at the upstream end of T2. During and
immediately following construction of the Site, sediment entered the top of T2 and began accumulating
in the channel. This allowed in‐stream vegetation to become established, which resulted in channel
constriction and flow restriction. The additional cross‐section (XS 11) was installed in May 2023 and a
cross‐section survey was taken to document geomorphology of the channel before being raked out. At
the end of June 2023, approximately 545 linear feet of channel was raked out to remove in‐stream
vegetation and sediment (Figure 1a). An additional cross‐section survey was completed immediately
after the stream was raked out, and then again four months later. While the cross‐sectional area
experienced little change between the initial survey on May 31, 2023, and when it was resurveyed on
July 20, 2023 after the raking, the max depth increased. The third survey on November 14, 2023,
indicated minimal changes in cross‐sectional area, bankfull elevations, thalweg elevation, and max
depth. This indicates that the stream stable and moving sediment through the system. The upper third
of T2 will continue to be monitored for further sediment accumulation or vegetation growth in the
channel.
2.5 Hydrology Assessment
By the end of MY7, four bankfull events must have occurred in separate years within the restoration
reaches. At least one bankfull event was recorded on all stream restoration reaches except T3 Reach 1.
While a bankfull event was not recorded on the T2 flow gauge, evidence of a bankfull event was visually
observed and documented. The hydrologic success criterion for bankfull events has been partially met in
MY3.
In addition, the presence of baseflow must be documented on restored intermittent reaches (T1 Reach
2, T2 and T3 Reach 1) for a minimum of 30 consecutive days during a normal precipitation year. In‐
stream flow gauges equipped with pressure transducers were installed to monitor continuity of
baseflow. All intermittent reaches in MY3 exceeded baseflow success criteria. The maximum
consecutive days ranged from 45 days to 75 days. Refer to Appendix 5 for hydrologic data.
2.6 Wetland Assessment
One groundwater gauge was installed and monitored within an existing wetland zone along T3 at a
location requested by North Carolina Division of Water Resources. The purpose of the gauge is to assess
potential effects to wetland hydrology from the construction of the restored stream channel through
this area. The results of this monitoring are not tied to any success criteria. Results from the
groundwater gauge, during MY3, show that the existing wetland maintained free groundwater within 12
inches of the ground surface for 39.1% of the defined growing season (March 1 to November 16).
2.7 Monitoring Year 3 Summary
Overall, the Site has met the success criteria for MY3. Nine out of eleven veg plots are on track to meet
the MY3 interim success criteria. A supplemental planting on 0.55 acres was completed in February 2023
to accommodate for tree mortality along T1. Some mature trees that were avoided during construction
were starting to decline in 2022, however their condition was stable in 2023 and a new understory layer
is continuing to establish. An approximately 4.97 acre dense stand of Chinese privet along Sassarixa
Creek Reach 3, as well as scattered stems throughout the remainder of the Site were treated in May
2023. Chinese privet throughout the Site will continue to be monitored and treated as necessary. The
upper reach of T2 was raked to clear excessive sedimentation and vegetation from the channel and
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final 2‐3
continue to be monitored for changes in channel condition and dimension. Bankfull events were
documented on all stream restoration reaches except T1 Reach 3, partially fulfilling the final bankfull
hydrologic success requirement. Greater than 30 days of consecutive flow were recorded on monitored
intermittent stream reaches T1 Reach 2, T2, and T3 Reach 1 fulfilling MY3 success requirement. The Site
boundary was walked, and fences are in good condition and are keeping livestock out, and all crossings
are stable and in good condition. Overall, the Site is meeting its goals of preventing excess nutrients and
sediment from entering the Neuse River tributaries and is on track to meet final success criteria.
Summary information and data related to the performance of various project and monitoring elements
can be found in the tables and figures in the report appendices. All raw data supporting the tables and
figures in the appendices are available from DMS upon request.
Sassarixa Swamp Mitigation Site
Monitoring Year 3 Annual Report ‐ Final 3‐1
Section 3: REFERENCES
Breeding, R. 2010. Neuse River Basin Restoration Priorities 2010. NCEEP, NC
Doll, B.A., Grabow, G.L., Hall, K.A., Halley, J., Harman, W.A., Jennings, G.D., and Wise, D.E. 2003. Stream
Restoration A Natural Channel Design Handbook.
Harrelson, C.C., Rawlins, C.L., Potyondy, J.P. 1994. Stream Channel Reference Sites: An Illustrated Guide
to Field Technique. Gen. Tech. Rep. RM‐245. Fort Collins, CO: U.S. Department of Agriculture, Forest
Service, Rocky Mountain Forest and Range Experiment Station. 61 p.
Rosgen, D. L. 1994. A classification of natural rivers. Catena 22:169‐199.
Rosgen, D.L. 1996. Applied River Morphology. Pagosa Springs, CO: Wildland Hydrology Books.
Rosgen, D.L. 1997. A Geomorphological Approach to Restoration of Incised Rivers. Proceedings of the
Conference on Management of Landscapes Disturbed by Channel Incision. Center For
Computational Hydroscience and Bioengineering, Oxford Campus, University of Mississippi, Pages
12‐22.
North Carolina Division of Water Resources (DWR). 2015. Neuse 01 CU Update. River Basin Restoration
Priorities Transition Approach.
North Carolina Interagency Review Team (NCIRT). 2016. Wilmington District Stream and Wetland
Compensatory Mitigation Update. Accessed at: https://saw‐
reg.usace.army.mil/PN/2016/Wilmington‐District‐Mitigation‐Update.pdf
United States Army Corps of Engineers. 2003. Stream Mitigation Guidelines. USACE, NCDENR‐DWQ,
USEPA, NCWRC.
United States Geological Survey. 1998. North Carolina Geology.
Wildlands Engineering, Inc. (2019). Sassarixa Swamp Mitigation Project Mitigation Plan. DMS, Raleigh,
NC.
T2
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5
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Reach 1
Reach 2
Reach 3
Reach 2
Reach 3
Reach 3Reach 4
Reach 2
Reach 3
Reach 2
Reach 1
Reach 1
Reach 2
Figure 1. Current Condition Plan View Key
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 - 2023
2019 Aerial Photography
0 1,200600 Feet
Johnston County, NC
Conservation Easement
Internal Crossing
Existing Wetlands
Utility Easement
Vegetation Plot Condition - MY3
Criteria Met - Fixed
Criteria Not Met - Fixed
Criteria Met - Random
Vegetation Area of Concern -
MY3
Chinese Privet Removal
Supplemental Planting
(February 2023)
Sweetgum & Loblolly
Thinning
Cross-Sections
Stream Restoration
Stream Enhancement II
Stream Preservation
Not for Credit
Non-Project Streams
Stream Area of Concern - MY3
Stream Raking & Vegetation
Removal
Fencing
Gates
Photo Points
Reach Break
Figure 1a.
Figure 1b.
Figure 1c.
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Reach 1
Reach 1
Reach 2
Reach 3Reach 4
Reach 2
Reach 3
Reach 2
Reach 1
X
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XS1
XS
7
XS2
X
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2
0
P
P
1
9
PP10
PP18
PP17
PP16
PP15
PP12
PP14
PP13
PP11
P
P
2
1
PP6
3
6
4
2
7
5
1
11
Figure 1a. Current Condition Plan View
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 - 2023
2021 Aerial Photography
0 400200 Feet
Johnston County, NC
Conservation Easement
Internal Crossing
Existing Wetlands
Vegetation Plot Condition -
MY3
Criteria Met - Fixed
Criteria Not Met - Fixed
Criteria Met - Random
Vegetation Area of Concern -
MY3
Chinese Privet Removal
Supplemental Planting
(February 2023)
Sweetgum & Loblolly
Thinning
Stream Restoration
Stream Enhancement II
Stream Preservation
Not for Credit
Non-Project Streams
As-Built Top of Bank
Structures
Fencing
Cross-Sections
Stream Area of Concern - MY3
Stream Raking &
Vegetation Removal
Gates
Barotroll
Crest Gauge
Flow Gauge
Groundwater Well
Photo Points
Reach Break
T4
T6
T5
710+
0
0
70
4
+
0
0
700+
0
0
620+00
615+00
610+00
605+00
600+
0
0
520+00
515+00
510+00
505+00
501
+
0
0
6
2
5
+
0
0
Reach 1
Reach 1
Reach 2
Reach 3
Reach 2
Reach 3
Reach 1
Reach 2
XS
8
XS9
X
S
1
0
PP40
PP38
PP36
PP54
PP53
PP50
PP43
PP34
PP42
PP41
PP33 PP39
PP37
PP35
PP32
PP31
PP30
PP51 PP52
8
10
Figure 1b. Current Condition Plan View
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 - 2023
2021 Aerial Photography
0 600300 Feet
Johnston County, NC
Conservation Easement
Internal Crossing
Utility Easement
Existing Wetlands
Vegetation Plot Condition - MY3
Criteria Met - Fixed
Stream Restoration
Stream Enhancement II
Stream Preservation
Not for Credit
Non-Project Streams
As-Built Top of Bank
Structures
Fencing
Cross-Sections
Gates
Crest Gauge
Photo Points
Reach Break
T
5
A
T5C
T
5
B
6
6
4
+
0
0
66
0
+
0
0
645+00
640+0
0
63
0
+
2
6
625+00
620+00
PP45
PP48PP49
PP47
PP46
PP44
9
Figure 1c. Current Condition Plan View
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 - 2023
0 200100 Feet
Johnston County, NC
2021 Aerial Photography
Conservation Easement
Existing Wetlands
Vegetation Plot Condition - MY3
Criteria Met - Fixed
Stream Enhancement II
Not for Credit
Non-Project Streams
As-Built Top of Bank
Structures
Fencing
Gates
Photo Points
APPENDIX A. VISUAL ASSESSMENT DATA
Table 4. Visual Stream Morphology Stability Assessment Table
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 - 2023
T1 R2
810
1,620
Surface Scour/
Bare Bank
Bank lacking vegetative cover resulting simply from
poor growth and/or surface scour.0 100%
Toe Erosion
Bank toe eroding to the extent that bank failure
appears likely. Does NOT include undercuts that are
modest, appear sustainable and are providing
habitat.
0 100%
Bank Failure Fluvial and geotechnical - rotational, slumping,
calving, or collapse.0 100%
0 100%
Grade Control Grade control structures exhibiting maintenance of
grade across the sill. 00 N/A
Bank Protection Bank erosion within the structures extent of
influence does not exceed 15%. 27 27 100%
T1 R3
507
1,014
Surface Scour/
Bare Bank
Bank lacking vegetative cover resulting simply from
poor growth and/or surface scour.0 100%
Toe Erosion
Bank toe eroding to the extent that bank failure
appears likely. Does NOT include undercuts that are
modest, appear sustainable and are providing
habitat.
0 100%
Bank Failure Fluvial and geotechnical - rotational, slumping,
calving, or collapse.0 100%
0 100%
Grade Control Grade control structures exhibiting maintenance of
grade across the sill. 00 N/A
Bank Protection Bank erosion within the structures extent of
influence does not exceed 15%. 14 14 100%
Visual assessment was completed on 11/14/2023.
Structure
Major Channel Category Metric
Number
Stable,
Performing
as Intended
Total
Number in
As-built
Amount of
Unstable
Footage
Assessed Stream Length
Assessed Bank Length
Bank
Totals:
% Stable,
Performing as
Intended
Assessed Stream Length
Assessed Bank Length
Bank
Totals:
Structure
Visual assessment was completed on 11/14/2023.
% Stable,
Performing as
Intended
Major Channel Category Metric
Number
Stable,
Performing
as Intended
Total
Number in
As-built
Amount of
Unstable
Footage
Table 4. Visual Stream Morphology Stability Assessment Table
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 - 2023
T2
1,006
2,012
Surface Scour/
Bare Bank
Bank lacking vegetative cover resulting simply from
poor growth and/or surface scour.0 100%
Toe Erosion
Bank toe eroding to the extent that bank failure
appears likely. Does NOT include undercuts that are
modest, appear sustainable and are providing
habitat.
0 100%
Bank Failure Fluvial and geotechnical - rotational, slumping,
calving, or collapse.0 100%
0 100%
Grade Control Grade control structures exhibiting maintenance of
grade across the sill. 34 34 100%
Bank Protection Bank erosion within the structures extent of
influence does not exceed 15%. 18 18 100%
T3 R1
1,041
2,082
Surface Scour/
Bare Bank
Bank lacking vegetative cover resulting simply from
poor growth and/or surface scour.0 100%
Toe Erosion
Bank toe eroding to the extent that bank failure
appears likely. Does NOT include undercuts that are
modest, appear sustainable and are providing
habitat.
0 100%
Bank Failure Fluvial and geotechnical - rotational, slumping,
calving, or collapse.0 100%
0 100%
Grade Control Grade control structures exhibiting maintenance of
grade across the sill. 00 N/A
Bank Protection Bank erosion within the structures extent of
influence does not exceed 15%. 30 30 100%
Visual assessment was completed on 11/14/2023.
Structure
Major Channel Category Metric
Number
Stable,
Performing
as Intended
Total
Number in
As-built
Amount of
Unstable
Footage
Assessed Stream Length
Assessed Bank Length
Bank
Totals:
% Stable,
Performing as
Intended
Assessed Stream Length
Assessed Bank Length
Bank
Totals:
Structure
Visual assessment was completed on 11/14/2023.
% Stable,
Performing as
Intended
Major Channel Category Metric
Number
Stable,
Performing
as Intended
Total
Number in
As-built
Amount of
Unstable
Footage
Table 4. Visual Stream Morphology Stability Assessment Table
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 - 2023
T5 R2
874
1,748
Surface Scour/
Bare Bank
Bank lacking vegetative cover resulting simply from
poor growth and/or surface scour.0 100%
Toe Erosion
Bank toe eroding to the extent that bank failure
appears likely. Does NOT include undercuts that are
modest, appear sustainable and are providing
habitat.
0 100%
Bank Failure Fluvial and geotechnical - rotational, slumping,
calving, or collapse.0 100%
0 100%
Grade Control Grade control structures exhibiting maintenance of
grade across the sill. 00 N/A
Bank Protection Bank erosion within the structures extent of
influence does not exceed 15%. 20 20 100%
T6 R1
383
766
Surface Scour/
Bare Bank
Bank lacking vegetative cover resulting simply from
poor growth and/or surface scour.0 100%
Toe Erosion
Bank toe eroding to the extent that bank failure
appears likely. Does NOT include undercuts that are
modest, appear sustainable and are providing
habitat.
0 100%
Bank Failure Fluvial and geotechnical - rotational, slumping,
calving, or collapse.0 100%
0 100%
Grade Control Grade control structures exhibiting maintenance of
grade across the sill. 00 N/A
Bank Protection Bank erosion within the structures extent of
influence does not exceed 15%. 5 5 100%
Visual assessment was completed on 11/14/2023.
Visual assessment was completed on 11/14/2023.
Totals:
Structure
% Stable,
Performing as
Intended
Assessed Stream Length
Assessed Bank Length
Bank
Major Channel Category Metric
Number
Stable,
Performing
as Intended
Total
Number in
As-built
Amount of
Unstable
Footage
Assessed Stream Length
Assessed Bank Length
Totals:
Bank
Structure
% Stable,
Performing as
Intended
Major Channel Category Metric
Number
Stable,
Performing
as Intended
Total
Number in
As-built
Amount of
Unstable
Footage
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 ‐ 2023
Planted Acreage 13.03
Vegetation Category Definitions
Mapping
Threshold
(ac)
Combined
Acreage
% of Planted
Acreage
Bare Areas Very limited cover of both woody and herbaceous material.0.10 0 0%
Low Stem Density
Areas
Woody stem densities clearly below target levels based on current MY stem count
criteria.0.10 0.55 4%
0.55 4%
Areas of Poor Growth
Rates
Planted areas where average height is not meeting current MY Performance
Standard.0.10 0 0%
0.55 4%
Easement Acreage 65.06
Vegetation Category Definitions
Mapping
Threshold
(ac)
Combined
Acreage
% of
Easement
Acreage
Invasive Areas of
Concern
Invasives may occur outside of planted areas and within the easement and will
therefore be calculated against the total easement acreage. Include species with the
potential to directly outcompete native, young, woody stems in the short‐term or
community structure for existing communities. Invasive species included in
summation above should be identified in report summary.
0.10 4.97* 8%
Easement
Encroachment Areas
Encroachment may be point, line, or polygon. Encroachment to be mapped consists
of any violation of restrictions specified in the conservation easement. Common
encroachments are mowing, cattle access, vehicular access. Encroachment has no
threshold value as will need to be addressed regardless of impact area.
none
*Chinese privet (Ligustrum sinense ) resprouted throughout an existing mautre canopy forest along Sassarixa Creek and was treated March 2023.
Table 5. Vegetation Condition Assessment Table
Total
Cumulative Total
0 Encroachments Noted/
0 Ac
*Supplemental planting occurred in February 2023.
STREAM PHOTOGRAPHS
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 1 T1 R1 – upstream (2/7/2023) PHOTO POINT 1 T1 R1 – downstream (2/7/2023)
PHOTO POINT 2 T1 R2 – upstream (2/7/2023) PHOTO POINT 2 T1 R2 – downstream (2/7/2023)
PHOTO POINT 3 T1 R2 – upstream (2/7/2023) PHOTO POINT 3 T1 R2 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 4 T1 R2 – upstream (2/7/2023) PHOTO POINT 4 T1 R2 – downstream (2/7/2023)
PHOTO POINT 5 T1 R3 – upstream (2/7/2023) PHOTO POINT 5 T1 R3 – downstream (2/7/2023)
PHOTO POINT 6 T1 R3 – upstream (2/7/2023) PHOTO POINT 6 T1 R3 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 7 T1 R3 – upstream (2/7/2023) PHOTO POINT 7 T1 R4 – downstream (2/7/2023)
PHOTO POINT 8 T1 R4 – upstream (2/7/2023) PHOTO POINT 8 T1 R4 – downstream (2/7/2023)
PHOTO POINT 9 T1A – upstream (2/7/2023) PHOTO POINT 9 T1A – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 10 T1B – upstream (2/7/2023) PHOTO POINT 10 T1B – downstream (2/7/2023)
PHOTO POINT 11 T1B – upstream (2/7/2023) PHOTO POINT 11 T1B – downstream (2/7/2023)
PHOTO POINT 12 T1C – upstream (2/7/2023) PHOTO POINT 12 T1C – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 13 Sassarixa Creek R2 – upstream (2/7/2023) PHOTO POINT 13 Sassarixa Creek R2 – downstream (2/7/2023)
PHOTO POINT 14 Sassarixa Creek R2 – upstream (2/7/2023) PHOTO POINT 14 Sassarixa Creek R2 – downstream (2/7/2023)
PHOTO POINT 15 Sassarixa Creek R2 – upstream (2/7/2023) PHOTO POINT 15 Sassarixa Creek R2 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 16 Sassarixa Creek R2 – upstream (5/31/2023) PHOTO POINT 16 Sassarixa Creek R2 – downstream (5/31/2023)
PHOTO POINT 17 Sassarixa Creek R3 – upstream (2/7/2023) PHOTO POINT 17 Sassarixa Creek R3 – downstream (2/7/2023)
PHOTO POINT 18 Sassarixa Creek R3 – upstream (5/31/2023) PHOTO POINT 18 Sassarixa Creek R3 – downstream (5/31/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 19 T2 – upstream (2/7/2023) PHOTO POINT 19 T2 – downstream (2/7/2023)
PHOTO POINT 20 T2 – upstream (2/7/2023) PHOTO POINT 20 T2 – downstream (2/7/2023)
PHOTO POINT 21 T2 – upstream (2/7/2023) PHOTO POINT 21 T2 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 22 T2 – upstream (2/7/2023) PHOTO POINT 22 T2 – downstream (2/7/2023)
PHOTO POINT 23 T2 – upstream (2/7/2023) PHOTO POINT 23 T2 – downstream (2/7/2023)
PHOTO POINT 24 T3 R1 – upstream (2/7/2023) PHOTO POINT 24 T3 R1 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 25 T3 R1 – upstream (2/7/2023) PHOTO POINT 25 T3 R1 – downstream (2/7/2023)
PHOTO POINT 26 T3 R1 – upstream (2/7/2023) PHOTO POINT 26 T3 R1 – downstream (2/7/2023)
PHOTO POINT 27 T3 R1 – upstream (2/7/2023) PHOTO POINT 27 T3 R1 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 28 T3 R1 – upstream (2/7/2023) PHOTO POINT 28 T3 R1 – downstream (2/7/2023)
PHOTO POINT 29 T3 R2 – upstream (2/7/2023) PHOTO POINT 29 T3 R2 – downstream (2/7/2023)
PHOTO POINT 30 T4 R1 – upstream (2/7/2023) PHOTO POINT 30 T4 R1 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 31 T4 R2 – upstream (2/7/2023) PHOTO POINT 31 T4 R2 – downstream (2/7/2023)
PHOTO POINT 32 T4 R3 – upstream (2/7/2023) PHOTO POINT 32 T4 R3 – downstream (2/7/2023)
PHOTO POINT 33 T4 R3 – upstream (2/7/2023) PHOTO POINT 33 T4 R3 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 34 T4 R3 – upstream (2/7/2023) PHOTO POINT 34 T4 R3 – downstream (2/7/2023)
PHOTO POINT 35 T5 R1 – upstream (2/7/2023) PHOTO POINT 35 T5 R1 – downstream (2/7/2023)
PHOTO POINT 36 T5 R1 – upstream (2/7/2023) PHOTO POINT 36 T5 R1 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 37 T5 R2 – upstream (2/7/2023) PHOTO POINT 37 T5 R2 – downstream (2/7/2023)
PHOTO POINT 38 T5 R2 – upstream (2/7/2023) PHOTO POINT 38 T5 R2 – downstream (2/7/2023)
PHOTO POINT 39 T5 R2 – upstream (2/7/2023) PHOTO POINT 39 T5 R2 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 40 T5 R2 – upstream (2/7/2023) PHOTO POINT 40 T5 R3 – downstream (2/7/2023)
PHOTO POINT 41 T5 R3 – upstream (2/7/2023) PHOTO POINT 41 T5 R3 – downstream (2/7/2023)
PHOTO POINT 42 T5 R3 – upstream (2/7/2023) PHOTO POINT 42 T5 R3 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 43 T5 R3 – upstream (2/7/2023) PHOTO POINT 43 T5 R3 – downstream (2/7/2023)
PHOTO POINT 44 T5A – upstream (2/7/2023) PHOTO POINT 44 T5A – downstream (2/7/2023)
PHOTO POINT 45 T5A – upstream (2/7/2023) PHOTO POINT 45 T5A – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 46 T5B – upstream (2/7/2023) PHOTO POINT 46 T5B – downstream (2/7/2023)
PHOTO POINT 47 T5B – upstream (2/7/2023) PHOTO POINT 47 T5B – downstream (2/7/2023)
PHOTO POINT 48 T5C – upstream (2/7/2023) PHOTO POINT 48 T5C – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 49 T5C – upstream (2/7/2023) PHOTO POINT 49 T5C – downstream (2/7/2023)
PHOTO POINT 50 T6 R1 – upstream (2/7/2023) PHOTO POINT 50 T6 R1 – downstream (2/7/2023)
PHOTO POINT 51 T6 R2 – upstream (2/7/2023) PHOTO POINT 51 T6 R2 – downstream (2/7/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Photographs
PHOTO POINT 52 T6 R2 – upstream (2/7/2023) PHOTO POINT 52 T6 R2 – downstream (2/7/2023)
PHOTO POINT 53 T6 R2 – upstream (2/7/2023) PHOTO POINT 53 T6 R2 – downstream (2/7/2023)
PHOTO POINT 54 T6 R2 – upstream (2/7/2023) PHOTO POINT 54 T6 R2 – downstream (2/7/2023)
STREAM CROSSING PHOTOGRAPHS
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Crossing Photographs
Sassarixa Creek Reach 2 – Looking Upstream (11/14/2023) Sassarixa Creek Reach 2 – Looking Downstream (11/14/2023)
T1 Reach 1 – Looking Upstream (11/14/2023) T1 Reach 1 – Looking Downstream (11/14/2023)
T4 Reach 3 – Looking Upstream (11/14/2023) T4 Reach 3 – Looking Downstream (11/14/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Stream Crossing Photographs
T5 Reach 3 – Looking Upstream (11/14/2023) T5 Reach 3 – Looking Downstream (11/14/2023)
T6 Reach 2 – Looking Upstream (11/14/2023) T6 Reach 2 – Looking Downstream (11/14/2023)
VEGETATION PLOT PHOTOGRAPHS
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Vegetation Plot Photographs
FIXED VEG PLOT 1 (9/14/2023) FIXED VEG PLOT 2 (9/14/2023)
FIXED VEG PLOT 3 (9/19/2023) FIXED VEG PLOT 4 (9/19/2023)
FIXED VEG PLOT 5 (9/19/2023) FIXED VEG PLOT 6 (9/19/2023)
Sassarixa Swamp Mitigation Site
Appendix A: Visual Assessment Data – Vegetation Plot Photographs
FIXED VEG PLOT 7 (9/19/2023) FIXED VEG PLOT 8 (9/19/2023)
FIXED VEG PLOT 9 (9/19/2023) FIXED VEG PLOT 10 (9/20/2023)
RANDOM VEG PLOT 11 (9/20/2023)
APPENDIX B. VEGETATION PLOT DATA
Table 6. Vegetation Plot Data
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 ‐ 2023
13.03
2021‐03‐05
2023‐02‐13
2023‐09‐21
0.0247
Scientific Name Common Name
Planted Total Planted Total Planted Total Planted Total Planted Total
Acer negundo boxelderTreeFAC11 111111
Betula nigra river birchTreeFACW22 441122
Magnolia virginiana sweetbayTreeFACW 11 1111
Platanus occidentalis American sycamoreTreeFACW1111442233
Populus deltoides eastern cottonwoodTreeFAC 33 1111
Quercus michauxii swamp chestnut oakTreeFACW11 223311
Quercus nigra water oakTreeFAC1111 11
Quercus phellos willow oakTreeFACW11 333322
Sum 7766141413131111
Liquidambar styraciflua sweetgum Tree FAC
Sum 7766141413131111
7 6 14 13 11
283 243 567 526 445
64587
29 50 29 23 27
23313
00000
7 6 14 13 11
283 243 567 526 445
64587
29 50 29 23 27
23313
00000
Post Mitigation
Plan
Performance
Standard
Current Year Stem Count
Stems/Acre
Species Count
Dominant Species Composition (%)
Average Plot Height (ft.)
% Invasives
Species Included
in Approved
Mitigation Plan
Post Mitigation
Plan Species
Mitigation Plan
Performance
Standard
Performance Standard
Proposed Standard
Veg Plot 5 FIndicator
Status
Veg Plot 1 FVeg Plot 2 FVeg Plot 3 FVeg Plot 4 F
Date of Current Survey
Plot size (ACRES)
Tree/S
hrub
Planted Acreage
Date of Initial Plant
Date(s) of Supplemental Plant(s)
Current Year Stem Count
Stems/Acre
Species Count
Dominant Species Composition (%)
Average Plot Height (ft.)
% Invasives
Table 6. Vegetation Plot Data
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 ‐ 2023
13.03
2021‐03‐05
2023‐02‐13
2023‐09‐21
0.0247
Scientific Name Common Name
Acer negundo boxelder Tree FAC
Betula nigra river birch Tree FACW
Magnolia virginiana sweetbay Tree FACW
Platanus occidentalis American sycamore Tree FACW
Populus deltoides eastern cottonwood Tree FAC
Quercus michauxii swamp chestnut oak Tree FACW
Quercus nigra water oak Tree FAC
Quercus phellos willow oak Tree FACW
Sum
Liquidambar styraciflua sweetgum Tree FAC
Sum
Post Mitigation
Plan
Performance
Standard
Current Year Stem Count
Stems/Acre
Species Count
Dominant Species Composition (%)
Average Plot Height (ft.)
% Invasives
Species Included
in Approved
Mitigation Plan
Post Mitigation
Plan Species
Mitigation Plan
Performance
Standard
Performance Standard
Proposed Standard
Indicator
Status
Date of Current Survey
Plot size (ACRES)
Tree/S
hrub
Planted Acreage
Date of Initial Plant
Date(s) of Supplemental Plant(s)
Current Year Stem Count
Stems/Acre
Species Count
Dominant Species Composition (%)
Average Plot Height (ft.)
% Invasives
Veg Plot
11 R
Planted Total Planted Total Planted Total Planted Total Planted Total Total
22111111 1
2222112211
111111 221
22332244226
11 2
3333221133
11 4
331111 11
1313131388889914
1
1313131388889914
13 13 8 8 9 14
526 526 324 324 364 567
686455
23 23 25 50 33 40
122211
000000
13 13 8 8 9 14
526 526 324 324 364 567
686455
23 23 25 50 33 40
122211
000000
Veg Plot 10 FVeg Plot 6 FVeg Plot 7 FVeg Plot 8 FVeg Plot 9 F
Table 7a. Vegetation Performance Standards Summary Table
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 ‐ 2023
Stems/Ac. Av. Ht. (ft) # Species % Invasives Stems/Ac. Av. Ht. (ft) # Species % Invasives Stems/Ac. Av. Ht. (ft) # Species % Invasives
283 2 6 0 243 3 4 0 567 3 5 0
324 1 6 0 283 1 5 0 567 2 5 0
364 1 6 0 243 1 3 0 607 1 6 0
567 1 8 0 445 1 5 0 607 1 6 0
Stems/Ac. Av. Ht. (ft) # Species % Invasives Stems/Ac. Av. Ht. (ft) # Species % Invasives Stems/Ac. Av. Ht. (ft) # Species % Invasives
526 1 8 0 445 3 7 0 526 1 6 0
526 1 8 0 486 2 7 0 526 1 6 0
567 1 8 0 486 1 7 0 526 1 6 0
607 1 8 0 486 1 7 0 567 1 6 0
Stems/Ac. Av. Ht. (ft) # Species % Invasives Stems/Ac. Av. Ht. (ft) # Species % Invasives Stems/Ac. Av. Ht. (ft) # Species % Invasives
526 2 8 0 324 2 6 0 324 2 4 0
526 1 8 0 364 1 6 0 364 1 5 0
567 1 8 0 567 1 7 0 607 1 7 0
567 1 8 0 567 1 7 0 648 1 7 0
Stems/Ac. Av. Ht. (ft) # Species % Invasives Stems/Ac. Av. Ht. (ft) # Species % Invasives
364 1 5 0 567 1 5 0
567 1 6 0 486 1 7 0
891 1 8 0 486 1 8 0
607 1 8 0 648 1 8 0
*Each monitoring year represents a different plot for the random vegetation plot "groups". Random plots are denoted with an R, and fixed plots with an F.
Veg Plot 3 F
Veg Plot 4 F Veg Plot 5 F Veg Plot 6 F
Veg Plot 7 F Veg Plot 8 F Veg Plot 9 F
Monitoring Year 2
Monitoring Year 1
Monitoring Year 0
Veg Plot 1 F Veg Plot 2 F
Veg Plot 10 F Veg Plot Group 11 R
Monitoring Year 1
Monitoring Year 0
Monitoring Year 7
Monitoring Year 5
Monitoring Year 3
Monitoring Year 0
Monitoring Year 7
Monitoring Year 5
Monitoring Year 3
Monitoring Year 2
Monitoring Year 7
Monitoring Year 5
Monitoring Year 3
Monitoring Year 2
Monitoring Year 1
Monitoring Year 0
Monitoring Year 7
Monitoring Year 5
Monitoring Year 3
Monitoring Year 2
Monitoring Year 1
Table 7b. Supplementally Planted Tree Species and Quantities
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 ‐ 2023
Scientific Name Common Name Number Planted % of Total Type
Quercus phellos Willow Oak 367 15%Bare Root
Platanus occidentalis Sycamore 490 20%Bare Root
Betula nigra River Birch 490 20%Bare Root
Quercus michauxii Swamp Chestnut Oak 367 15%Bare Root
Quercus nigra Water Oak 172 7%Bare Root
Acer negundo Box Elder 245 10%Bare Root
Populus deltoides Eastern Cottonwood 172 7%Bare Root
Magnolia virginiana Sweetbay Mangolina 147 6%Bare Root
2,450 100%
* A total area of 8.51 acres were supplemented with trees in February 2023 along T1, the ditch above T3, T4, T5A, and T5C. Of that,
0.55 acres were within the Sassarixa Swamp Mitigation Site along T1.
Total
APPENDIX C. Stream Geomorphology Data
Cross‐Section Plots
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross‐Section Plots
Downstream (03/07/2023)
MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation ‐ Based
on AB‐Bankfull Area 149.35 149.41 149.28 149.27
Bank Height Ratio ‐ Based
on AB‐Bankfull Area 1.00 0.93 1.03 1.01
Thalweg Elevation 148.45 148.62 148.34 148.28
LTOB Elevation 149.35 149.36 149.31 149.28
LTOB Max Depth 0.90 0.74 0.97 1.00
LTOB Cross‐Sectional Area 2.47 2.16 2.63 2.51
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross‐Section Plots
Downstream (03/07/2023)
MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation ‐ Based
on AB‐Bankfull Area N/A N/A N/A N/A
Bank Height Ratio ‐ Based
on AB‐Bankfull Area N/A N/A N/A N/A
Thalweg Elevation 147.78 147.58 147.67 147.87
LTOB Elevation 148.82 148.77 148.83 148.79
LTOB Max Depth 1.04 1.19 1.16 0.92
LTOB Cross‐Sectional Area 3.20 2.84 2.91 2.79
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross‐Section Plots
Downstream (03/07/2023)
MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation ‐ Based
on AB‐Bankfull Area 130.69 130.77 130.75 130.68
Bank Height Ratio ‐ Based
on AB‐Bankfull Area 1.00 0.91 0.94 1.08
Thalweg Elevation 130.04 130.24 130.12 130.02
LTOB Elevation 130.69 130.72 130.71 130.73
LTOB Max Depth 0.64 0.48 0.59 0.71
LTOB Cross‐Sectional Area 1.67 1.45 1.50 1.93
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross‐Section Plots
Downstream (03/07/2023)
MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation ‐ Based
on AB‐Bankfull Area 141.46 141.52 141.49 141.51
Bank Height Ratio ‐ Based
on AB‐Bankfull Area 1.00 0.94 0.95 0.91
Thalweg Elevation 140.66 140.78 140.77 140.77
LTOB Elevation 141.46 141.47 141.46 141.45
LTOB Max Depth 0.80 0.69 0.69 0.68
LTOB Cross‐Sectional Area 1.99 1.76 1.80 1.65
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross‐Section Plots
Downstream (03/07/2023)
MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation ‐ Based
on AB‐Bankfull Area N/A N/A N/A N/A
Bank Height Ratio ‐ Based
on AB‐Bankfull Area N/A N/A N/A N/A
Thalweg Elevation 139.53 139.50 139.51 139.67
LTOB Elevation 141.12 141.10 141.07 141.06
LTOB Max Depth 1.58 1.60 1.56 1.39
LTOB Cross‐Sectional Area 4.88 4.82 4.57 4.65
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross‐Section Plots
Downstream (03/07/2023)
MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation ‐ Based
on AB‐Bankfull Area N/A N/A N/A N/A
Bank Height Ratio ‐ Based
on AB‐Bankfull Area N/A N/A N/A N/A
Thalweg Elevation 126.70 127.32 127.31 127.31
LTOB Elevation 128.16 128.35 128.31 128.33
LTOB Max Depth 1.46 1.03 1.00 1.02
LTOB Cross‐Sectional Area 3.25 2.57 2.40 2.27
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross‐Section Plots
Downstream (03/07/2023)
MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation ‐ Based
on AB‐Bankfull Area 127.58 127.56 127.54 127.57
Bank Height Ratio ‐ Based
on AB‐Bankfull Area 1.00 1.10 1.09 0.99
Thalweg Elevation 127.06 126.89 126.89 126.91
LTOB Elevation 127.58 127.63 127.59 127.56
LTOB Max Depth 0.52 0.74 0.70 0.65
LTOB Cross‐Sectional Area 1.50 1.82 1.77 1.48
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross‐Section Plots
Downstream (03/07/2023)
MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation ‐ Based
on AB‐Bankfull Area 133.06 133.12 133.08 133.10
Bank Height Ratio ‐ Based
on AB‐Bankfull Area 1.00 0.85 1.02 1.00
Thalweg Elevation 132.36 132.42 132.40 132.36
LTOB Elevation 133.06 133.02 133.10 133.10
LTOB Max Depth 0.70 0.60 0.70 0.74
LTOB Cross‐Sectional Area 2.49 1.95 2.60 2.48
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross‐Section Plots
Downstream (03/07/2023)
MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation ‐ Based
on AB‐Bankfull Area N/A N/A N/A N/A
Bank Height Ratio ‐ Based
on AB‐Bankfull Area N/A N/A N/A N/A
Thalweg Elevation 131.03 131.50 131.69 131.69
LTOB Elevation 132.53 132.46 132.55 132.50
LTOB Max Depth 1.50 0.96 0.86 0.81
LTOB Cross‐Sectional Area 6.97 3.86 4.66 4.02
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross‐Section Plots
Downstream (03/07/2023)
MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation ‐ Based
on AB‐Bankfull Area 156.43 156.50 156.48 156.49
Bank Height Ratio ‐ Based
on AB‐Bankfull Area 1.00 0.88 0.96 0.99
Thalweg Elevation 155.62 155.69 155.67 155.67
LTOB Elevation 156.43 156.40 156.45 156.48
LTOB Max Depth 0.81 0.71 0.78 0.81
LTOB Cross‐Sectional Area 2.69 2.20 2.51 2.64
Sassarixa Swamp Mitigation Site
Appendix C: Stream Geomorphology Data – Cross-Section Plots
Downstream (07/20/2023)
MY3
(5/31/2023)
MY3
(7/20/2023)
MY3
(11/14/2023) MY4 MY5 MY7
Bankfull Elevation - Based
on AB-Bankfull Area 94.62 94.52 94.57
Bank Height Ratio - Based
on AB-Bankfull Area 1.00 1.00 1.00
Thalweg Elevation 94.13 93.88 93.98
LTOB Elevation 94.62 94.52 94.57
LTOB Max Depth 0.49 0.64 0.60
LTOB Cross-Sectional Area 1.69 1.68 1.69
Table 8. Baseline Stream Data Summary
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 ‐ 2023
Parameter
Riffle Only Min Max n Min Max Min Max n
Bankfull Width (ft)1 1
Floodprone Width (ft)1 1
Bankfull Mean Depth (ft)1 1
Bankfull Max Depth (ft)1 0.4 0.5 1
Bankfull Cross Sectional Area (ft2)11
Width/Depth Ratio 1 1
Entrenchment Ratio 1 1
Bank Height Ratio 1 1.0 1.2 1
Max particle size (mm) mobilized at bankfull
Rosgen Classification
Bankfull Discharge (cfs)
Sinuosity
Water Surface Slope (ft/ft) 0.0190 0.0300 2 0.0250 0.0410
Other
Parameter
Riffle Only Min Max n Min Max Min Max n
Bankfull Width (ft)1 1
Floodprone Width (ft)1 1
Bankfull Mean Depth (ft)1 1
Bankfull Max Depth (ft)1 0.4 0.6 1
Bankfull Cross Sectional Area (ft2)11
Width/Depth Ratio 1 1
Entrenchment Ratio 1 1
Bank Height Ratio 1 1.0 1.2 1
Max particle size (mm) mobilized at bankfull
Rosgen Classification
Bankfull Discharge (cfs)
Sinuosity
Water Surface Slope (ft/ft) 0.0190 0.0300 2 0.0092 0.0250
Other
12.0
0.4
0.6
1.7
9.0
1.20
90
0.4
4.2
‐‐‐
0.0322
11.0
1.0
‐‐‐
34.6
4.9
2.2
C5b/E5b
‐‐‐
3.08.8
1.20 1.20
‐‐‐
‐‐‐‐‐‐‐‐‐
3.4
8
1
0.7
2.5
1.20 1.20 1.20
0.0181
G5 C5/E5 C5/E5
8.8 3.5 4.3
‐‐‐‐‐‐‐‐‐
4.9
2.2
3.0
>2.2
11.1
21.9
1.0
1.5
0.7
2.5
‐‐‐
T1 R3
3.4
8
1
>9.2
4.3
MONITORING BASELINE
(MY0)
3.6
11.0
1.2
0.3
200
0.4
0.9
2.5
PRE‐EXISTING
CONDITIONS
‐‐‐
G5 C5b/E5b
3.0
T1 R2
>7.9
>2.2
5.2
DESIGN
Table 8. Baseline Stream Data Summary
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 ‐ 2023
Parameter
Riffle Only Min Max n Min Max Min Max n
Bankfull Width (ft)1 1
Floodprone Width (ft)1 1
Bankfull Mean Depth (ft)1 1
Bankfull Max Depth (ft)1 1
Bankfull Cross Sectional Area (ft2)11
Width/Depth Ratio 1 1
Entrenchment Ratio 1 1
Bank Height Ratio 1 1.0 1.2 1
Max particle size (mm) mobilized at bankfull
Rosgen Classification
Bankfull Discharge (cfs)
Sinuosity
Water Surface Slope (ft/ft)1 0.0051 0.0064
Other
Parameter
Riffle Only Min Max n Min Max Min Max n
Bankfull Width (ft) 3.2 4.2 2 1
Floodprone Width (ft) 5 24 2 1
Bankfull Mean Depth (ft) 0.42 0.5 2 1
Bankfull Max Depth (ft) 0.7 0.56 2 0.4 0.5 1
Bankfull Cross Sectional Area (ft2)21
Width/Depth Ratio 6.4 10 2 1
Entrenchment Ratio 1.1 7.1 2 1
Bank Height Ratio 2.7 7.0 2 1.0 1.2 1
Max particle size (mm) mobilized at bankfull
Rosgen Classification
Bankfull Discharge (cfs) 6.2 6.9 2
Sinuosity
Water Surface Slope (ft/ft)1 0.0280 0.0330
Other
1.5
14.8
7.4
1.0
75
0.4
0.8
2.0
15.7
13.4
0.0312
‐‐‐‐‐‐‐‐‐
0.0340
0.0290
2.5 4.5
1.16 1.20 1.20
‐‐‐‐‐‐‐‐‐
B5/G5 C5/E5b C5/E5b
12.0
>2.2
>7.9
0.3
1.7 1.0
35
0.3
0.5
0.0147
‐‐‐‐‐‐‐‐‐
T3 R1
3.6 4.7
5.4 2.0 4.3
1.14 1.40 1.40
‐‐‐‐‐‐‐‐‐
G5 C5b/E5b C5b/E5b
6 12.0
1.2 >2.2
6.5 1.0
4 >9.2
0.5 0.4
0.6
1.5 1.5
0.5
PRE‐EXISTING
CONDITIONS DESIGN MONITORING BASELINE
(MY0)
T2
3 4.2 5.6
Table 8. Baseline Stream Data Summary
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 ‐ 2023
Parameter
Riffle Only Min Max n Min Max Min Max n
Bankfull Width (ft)1 1
Floodprone Width (ft)1 1
Bankfull Mean Depth (ft)1 1
Bankfull Max Depth (ft)1 0.6 0.8 1
Bankfull Cross Sectional Area (ft2)11
Width/Depth Ratio 1 1
Entrenchment Ratio 1 1
Bank Height Ratio 1 1.0 1.2 1
Max particle size (mm) mobilized at bankfull
Rosgen Classification
Bankfull Discharge (cfs)
Sinuosity
Water Surface Slope (ft/ft)1 0.0086 0.0170
Other
Parameter
Riffle Only Min Max n Min Max Min Max n
Bankfull Width (ft)1 1
Floodprone Width (ft)1 1
Bankfull Mean Depth (ft)1 1
Bankfull Max Depth (ft)1 0.5 0.7 1
Bankfull Cross Sectional Area (ft2)11
Width/Depth Ratio 1 1
Entrenchment Ratio 1 1
Bank Height Ratio 1 1.0 1.2 1
Max particle size (mm) mobilized at bankfull
Rosgen Classification
Bankfull Discharge (cfs)
Sinuosity
Water Surface Slope (ft/ft)1 0.0049 0.0150
Other
90
0.4
0.8
2.7
13.3
15.1
170
0.4
0.7
2.5
14.0
16.9
0.0107
‐‐‐‐‐‐‐‐‐
0.0120
0.0086
12.8 5.5 5.9
1.10 1.20 1.20
‐‐‐‐‐‐‐‐‐
G5 C5/E5 C5/E5
3.7 12.0
1.7 >2.2
2.0 1.0
7 >14
1.1 0.41
1.5
4.4 3.3
0.0111
‐‐‐‐‐‐‐‐‐
T6 R1
4.1 6.4 6.0
10.9 6.0 5.4
1.20 1.40 1.40
‐‐‐‐‐‐‐‐‐
E5 C5/E5 C5/E5
2.8 12.0
8.7 >2.2
1.6 1.0
27 >11
1.1 0.5
1.4
3.5 2.7
PRE‐EXISTING
CONDITIONS DESIGN MONITORING BASELINE
(MY0)
T5 R2
3.1 5.6 5.9
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
MY0 MY1 MY2 MY3 MY5 MY7 MY0 MY1 MY2 MY3 MY5 MY7 MY0 MY1 MY2 MY3 MY5 MY7 MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation (ft) ‐ Based on AB‐Bankfull1 Area 149.35 149.41 149.28 149.27 N/A N/A N/A N/A 130.69 130.77 130.75 130.68 141.46 141.52 141.49 141.51
Bank Height Ratio ‐ Based on AB Bankfull1 Area 1.00 0.93 1.03 1.01 N/A N/A N/A N/A 1.00 0.91 0.94 1.08 1.00 0.94 0.95 0.91
Thalweg Elevation 148.45 148.62 148.34 148.28 147.78 147.58 147.67 147.87 130.04 130.24 130.12 130.02 140.66 140.79 140.77 140.77
LTOB2 Elevation 149.35 149.36 149.31 149.28 148.82 148.77 148.83 148.79 130.69 130.72 130.71 130.73 141.46 141.48 141.46 141.45
LTOB2 Max Depth (ft)0.90 0.74 0.97 1.00 1.04 1.19 1.16 0.92 0.64 0.48 0.59 0.71 0.80 0.69 0.69 0.68
LTOB2 Cross Sectional Area (ft 2)2.47 2.16 2.63 2.51 3.20 2.84 2.91 2.79 1.67 1.45 1.50 1.93 1.99 1.76 1.80 1.65
MY0 MY1 MY2 MY3 MY5 MY7 MY0 MY1 MY2 MY3 MY5 MY7 MY0 MY1 MY2 MY3 MY5 MY7 MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation (ft) ‐ Based on AB‐Bankfull1 Area N/A N/A N/A N/A N/A N/A N/A N/A 127.58 127.56 127.54 127.57 133.06 133.12 133.08 133.10
Bank Height Ratio ‐ Based on AB Bankfull1 Area N/A N/A N/A N/A N/A N/A N/A N/A 1.00 1.10 1.09 0.99 1.00 0.85 1.02 1.00
Thalweg Elevation 139.53 139.51 139.51 139.67 126.70 127.32 127.31 127.31 127.06 126.89 126.89 126.91 132.36 132.42 132.40 132.36
LTOB2 Elevation 141.12 141.11 141.07 141.06 128.16 128.35 128.31 128.33 127.58 127.63 127.59 127.56 133.06 133.02 133.10 133.10
LTOB2 Max Depth (ft)1.58 1.60 1.56 1.39 1.46 1.03 1.00 1.02 0.52 0.74 0.70 0.65 0.70 0.60 0.70 0.74
LTOB2 Cross Sectional Area (ft 2)4.88 4.82 4.57 4.65 3.25 2.57 2.40 2.27 1.50 1.82 1.77 1.48 2.49 1.95 2.60 2.48
MY0 MY1 MY2 MY3 MY5 MY7 MY0 MY1 MY2 MY3 MY5 MY7
Bankfull Elevation (ft) ‐ Based on AB‐Bankfull1 Area N/A N/A N/A N/A 156.43 156.50 156.48 156.49
Bank Height Ratio ‐ Based on AB Bankfull1 Area N/A N/A N/A N/A 1.00 0.88 0.96 0.99
Thalweg Elevation 131.03 131.50 131.69 131.69 155.62 155.69 155.67 155.67
LTOB2 Elevation 132.53 132.46 132.55 132.50 156.43 156.40 156.45 156.48
LTOB2 Max Depth (ft)1.50 0.96 0.86 0.81 0.81 0.71 0.78 0.81
LTOB2 Cross Sectional Area (ft 2)6.97 3.86 4.66 4.02 2.69 2.20 2.51 2.64
1Bank Height Ratio (BHR) takes the As‐built bankful area as the basis for adjusting each subsequent years bankfull elevation.
Table 9. Cross‐Section Morphology Monitoring Summary
Cross‐Section 1 (Riffle)Cross‐Section 2 (Pool)Cross‐Section 3 (Riffle)
Cross‐Section 7 (Riffle)
T6 Reach 1
T2
Cross‐Section 8 (Riffle)
T1 Reach 3
Monitoring Year 3 ‐ 2023
T1 Reach 2
Cross‐Section 5 (Pool)
2LTOB Area and Max depth ‐ These are based on the LTOB elevation for each years survey (The same elevation used for the LTOB in the BHR calculation). Area below the LTOB elevation will be used and tracked for each year as above. The difference between the LTOB elevation and the
thalweg elevation (same as in the BHR calculation) will be recroded and tracked above as LTOB max depth.
T5 Reach 2
Cross‐Section 4 (Riffle)
T2 T3 Reach 1
Cross‐Section 6 (Pool)
T5 Reach 2
Cross‐Section 10 (Riffle)Cross‐Section 9 (Pool)
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
MY3*
(5/31/2023)
MY3*
(7/20/2023)
MY3*
(11/14/2023)MY4 MY5 MY7
Bankfull Elevation (ft) - Based on AB-Bankfull1 Area 94.61 94.52 94.62
Bank Height Ratio - Based on AB Bankfull1 Area 1.00 1.00 1.00
Thalweg Elevation 94.13 93.88 93.98
LTOB2 Elevation 94.62 94.52 94.62
LTOB2 Max Depth (ft)0.50 0.64 0.60
LTOB2 Cross Sectional Area (ft2)2.00 1.68 1.50
1Bank Height Ratio (BHR) takes the As-built bankful area as the basis for adjusting each subsequent years bankfull elevation.
T2
Cross-Section 11 (Riffle)
Table 9. Cross-Section Morphology Monitoring Summary
Monitoring Year 3 - 2023
2LTOB Area and Max depth - These are based on the LTOB elevation for each years survey (The same elevation used for the LTOB in the BHR calculation). Area below the LTOB
elevation will be used and tracked for each year as above. The difference between the LTOB elevation and the thalweg elevation (same as in the BHR calculation) will be
recroded and tracked above as LTOB max depth.
* An additional cross-section on the upper reach of T2 was requested by the NCIRT to monitor sedimentation and vegetation accumulating within the channel. The cross-
section was installed in May 2023. The cross-section was surveyed to establish baseline conditions before vegetation and sedimentation were raked out to clear the stream.
The cross-section was then surveyed after raking was completed, and then surveyed again 6 months later to observe any changes in channel stability.
APPENDIX D. Hydrology Data
Reach MY1 (2021) MY2 (2022) MY3 (2023)* MY4 (2024) MY5 (2025) MY6 (2026) MY7 (2027)
T1 Reach 3 2/16/2021
7/28/2021
3/12/2022
5/23/2022
9/10/2022
12/27/2022
6/22/2023
T2 7/27/2021
10/9/2021 N/A 6/30/20231
T3 Reach 1 7/28/2021 1/18/2022
12/27/2022 N/A
T5 Reach 2 1/24/2021
7/28/2021 9/10/2022 8/15/2023
MY1 (2021) MY2 (2022) MY3 (2023) MY4 (2024) MY5 (2025) MY6 (2026) MY7 (2027)
Annual Precip
Total 34.14 28.44 38.24*
WETS 30th
Percentile 44.35 44.67 44.91
WETS 70th
Percentile 52.31 52.62 52.91
Normal LL*
Annual Precipitation Source: Smithfield Station, Johnston County, NC, State Climate Office (Approximately 6 miles northeast of the Site).
30 Year Average Precipitation Source: Smithfield Station, Johnston County, NC, AgCIS (Approximately 6 miles northeast of the Site).
*Annual precipitation total was collected up until 11/14/2023. Data will be updated in MY4.
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 ‐ 2023
Table 10. Bankfull Events
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
Monitoring Year 3 ‐ 2023
Table 11. Rainfall Summary
* Data was collected 1/1/2023 to 11/14/2023. Data from the remainder of MY3 will be updated in MY4.
1. Bankfull event recorded based on visual observations
BANKFULL EVENTS
VISUAL OBSERVATIONS
Sassarixa Swamp Mitigation Site
Appendix D: Hydrology Data – Bankfull Events Visual Observations
T2 (6/30/2023) T2 (6/30/2023)
Table 12. Groundwater Gauge Summary
Sassarixa Swamp Mitigation Site
Monitoring Year 3 - 2023
MY1 (2021) MY2 (2022) MY3 (2023)* MY4 (2024) MY5 (2025) MY6 (2026) MY7 (2027)
1 124 Days
(47.5%)
96 Days
(36.8%)
102 Days
(39.1%)
*Data was collected from 3/1/2023 to 11/14/2023 (258 Days).
Gauge Max. Consecutive Hydroperiod (Percentage)
DMS Project No. 100040
WETS Station: Smithfield 2 North
Growing Season: 3/1/2023 to 11/16/2023 (260 Days)
Performance Standard: None
Groundwater Gauge Plot
Monitoring Year 3 - 2023
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
St
a
r
t
o
f
G
r
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i
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g
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e
a
s
o
n
3/
1
/
2
0
2
3
En
d
o
f
G
r
o
w
i
n
g
S
e
a
s
o
n
11
/
1
6
/
2
0
2
3
102 max consecutive days
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
0
2
4
6
8
10
-60
-50
-40
-30
-20
-10
0
10
Pr
e
c
i
p
i
t
a
t
i
o
n
(
i
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)
Wa
t
e
r
L
e
v
e
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(
i
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)
Monitoring Year 3 - 2023
Daily Precipitation Gauge #1 Criteria Level Soil Surface 30-Day Rolling Precip Total 30th & 70th Percentile
Sassarixa Swamp Groundwater Gauge #1 Possible gauge malfunction early
morning of 7/25/23. Transducer
replaced mid-day on 7/25/23.
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
MY1 (2021) MY2 (2022) MY3 (2023)** MY4 (2024) MY5 (2025) MY6 (2026) MY7 (2027)
T1 Reach 2 44 Days/
122 Days
86 Days/
147Days
45 Days/
152 Days
T2 103 Days/
192 Days
87 Days/
156 Days
75 Days/
169 Days
T3 Reach 1 108 Days/
190 Days
63 Days/
130 Days
54 Days/
158 Days
**Data was colleted through 11/14/2023. Data will be updated in MY4.
*Success criteria is 30 consecutive days of flow.
Table 13. Recorded In-Stream Flow Events Summary
Monitoring Year 3 - 2023
Reach Max Consecutive Days/Total Days Meeting Success Criteria*
Recorded In-Stream Flow Events Plot
Monitoring Year 3 - 2023
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
45 days of consecutive stream flow
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
0
2
4
6
8
10
159
160
161
162
163
164
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Monitoring Year 3 - 2023
Daily Precipitation Water Level Thalweg Bankfull 30-Day Rolling Precip Total 30th & 70th Percentile
Sassarixa Swamp: T1 Reach 2
Recorded In-Stream Flow Events Plot
Monitoring Year 3 - 2023
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
75 days of consecutive stream flow
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
0
2
4
6
8
10
137
138
139
140
141
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Monitoring Year 3 - 2023
Daily Precipitation Water Level Thalweg Bankfull 30-Day Rolling Precip Total 30th & 70th Percentile
Sassarixa Swamp: T2
Recorded In-Stream Flow Events Plot
Monitoring Year 3 - 2023
Sassarixa Swamp Mitigation Site
DMS Project No. 100040
54 days of consecutive stream flow
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov
0
2
4
6
8
10
149
150
151
152
153
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Monitoring Year 3 - 2023
Daily Precipitation Water Level Thalweg Bankfull 30-Day Rolling Precip Total 30th & 70th Percentile
Sassarixa Swamp: T3 Reach 1
APPENDIX E. Project Timeline and Contact Info
DMS Project No. 100040
DMS Project No. 100040
Table 14. Project Activity and Reporting History
Sassarixa Swamp Mitigation Site
Monitoring Year 3 - 2023
Activity or Deliverable Data Collection Complete
Task Completion or Deliverable
Submission
Project Instituted NA January 2018
Mitigation Plan Approved NA November 2019
As-Built Survey Completed NA Febuary 2021
Construction (Grading) Completed NA January 2021
Planting Completed NA March 2021
March 2023
Vegetation Survey September 2023
December 2022
Easement Encroachment
December 2021
April 2021
Supplemental Planting February 2022
Invasive Species Treatment May 2023
Sweetgum & Loblolly Thinning May 2023
Year 5 Monitoring Stream Survey 2025 December 2025Vegetation Survey 2025
Year 6 Monitoring December 2026
Year 7 Monitoring Stream Survey 2027 December 2027Vegetation Survey 2027
Construction Contractor
Land Mechanic Designs, Inc.
126 Circle G Lane
Willow Spring, NC 27592
Table 15. Project Contact Table
Sassarixa Swamp Mitigation Site
Monitoring Year 3 - 2023
Designer
Angela Allen, PE
Wildlands Engineering, Inc.
312 West Millbrook Road, Suite 225
Raleigh, NC 27609
919.851.9986
Monitoring, POC Jason Lorch
919.851.9986
Monitoring Performers Wildlands Engineering, Inc.
July 2021
September 2021
Stream Survey March 2022
Year 1 Monitoring Stream Survey July 2021
Vegetation Survey September 2021
Baseline Monitoring Document (Year 0)
In-Stream Vegetation Treatment
Stream Survey January 2021
Vegetation Survey March 2021
December 2024
Instaled XS 11 May 2023
Year 2 Monitoring
September 2022
March - July 2022Invasive Species Treatment
Vegetation Survey
Year 3 Monitoring
Supplemental Planting February 2023
Year 4 Monitoring
Sediment Removal Along T2 June 2023
December 2023
Stream Survey
APPENDIX F. Additional Documentation
Wildlands Engineering, Inc. page 1
Sassarixa Swamp Mitigation Site
MEETING MINUTES
MEETING: MY2 IRT Site Visit
Sassarixa Swamp Mitigation Site
Neuse River Basin 03020201; Johnston County, NC
NCDMS Project No. 100040
USACE ID: SAW‐2018‐00432
NCDEQ Contract No. 7425
DATE: On‐site Meeting: Thursday, May 18, 2023
Meeting Notes Distributed: Friday, May 19, 2023
Attendees
Kim Browning, USACE
Casey Haywood, USACE
Jeremiah Dow, NC Division of Mitigation Services
Emily Dunnigan, NC Division of Mitigation Services
Angela Allen, Wildlands Engineering
Carolyn Lanza, Wildlands Engineering
Andrew Radecki, Wildlands Engineering
Meeting Notes
T2
o The upper third of T2 has sediment accumulated in the channel due to erosion from the valely
side slopes during construction. The IRT is concerned this segment will eventually trend towards
a linear wetland. Wildlands will install one riffle cross‐section along the upper third of T2 to
show signs of stream stability. After the cross‐section is installed and surveyed, Wildlands will
remove the instream vegetation and sediment deposition from the erosion and then continue to
monitor the cross‐section in subsequent monitoring years. Wildlands will also plant several
container trees in the current bare areas around the BMP to prevent further erosion.
o The IRT gave suggestions that in future areas where rock is utilized to stabilize an erosive slope
that it’s preferable that rock be more embedded into the ground.
o The IRT is not concerned with flow along T2 and a flow gauge is not needed in the upper third of
the stream.
T3
o Wildlands will manually repair the one log sill that was piping.
o Overall, the IRT was happy with the stability of T3.
Vegetation
Wildlands Engineering, Inc. page 2
Sassarixa Swamp Mitigation Site
o Overall, the IRT was happy with the vegetation being established across the Site. The IRT would
like Wildlands to be mindful of the area surrounding Vegetation Plot 2, since that was the only
plot not meeting MY3 success criteria.