20080868 Ver 2_DWQ Response to USACE after Reviewing MP_20080903

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Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
Coleen H. Sullins. Director
Division of Water Quality
September 3, 2008
David M. Lekson, PWS
U.S. Army Corps of Engineers
Washington Regulatory Field Office
P.O. Box 1000
Washington, NC 27889-1000
Re: PCS Phosphate - Proposed Mitigation Sites
DWQ Comments on Restoration Plans and Site Visits
NCDWQ# 08-0868 (associated with impact)
Dear. Mr. Lekson:
We have reviewed the Restoration Plans for the above-referenced proposed mitigation sites. In
addition, the proposed sites were visited by DWQ staff on July 29, August 19, and August 26, 2008.
Our comments are as follows:
Sage Gut Swamp Mitigation Site (DWQ# 08-1318)
Wetland Restoration
Hydrology: A number of items were discussed during the site visit on August 26, 2008, including:
Revision of the boundaries between riparian and non-riparian wetlands based on the topographic
and hydrologic conditions of the site,
Development of appropriate hydrology success criteria based on scientific data and community
descriptions, reference ecosystems, and expected site-specific conditions,
Development of a sampling strategy that will accurately demonstrate the extent of influence of the
marginal ditches.
DWQ believes that the provider is aware of these issues and expects they will be addressed in the final
mitigation plan.
Noce hCarolina
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401 OversightfExpress Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone [phone] / Fax [phone]
Internet: http://h2o.enr.state.nc.us/ncwetlands
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
Mr. Lekson
USACE Washington Regulatory Field Office
PCS Phosphate - Proposed Mitigation Sites
Page 2 of 6
Vegetation: Planting plans generally include appropriate species (see note regarding Tag alder below)
and densities. Success evaluation should take into account both density (the proposed criteria for stem
counts are acceptable) and diversity of the targeted ecosystem types.
DWQ recognizes that Alnus serrulata can be a useful plant for soil and stream bank stabilization.
However, the USDA notes that it is "not recommended for planting in areas where additional
nitrogen might add to water quality problems" (http://plants.usda.gov/factsheet/pdf`/fs alse2.pdf)
due to its nitrogen-fixing action. Due to the nutrient-sensitive nature of the Pamlico River, DWQ
suggests that Alnus serrulata be removed from the planting plan and/or be replaced with another
shrub that is characteristic of the targeted ecosystems.
Dense stands of Phragmites were observed during the site visit. DWQ appreciates the
commitment to eradicate and then proactively prevent reestablishment of invasive and aggressive
plant species throughout the monitoring period.
Stream and Riparian Buffer Restoration
The site appears to be a good candidate for headwater stream valley restoration. That said, document-
tation of flow in these systems, in particular the most upstream extent of flow, will be critical in
assessing the success of these headwater valley systems, and the amount of both stream and buffer credit
generated.
Regarding the proposed stream preservation, it was noted that the quality of the riparian buffer adjacent
to the preservation reach is marginal. Exotic species control and possibly supplemental plantings may
be warranted.
Bay City Farm Mitigation Site (DWQ# 07-1012)
The mitigation plan approved in 2007 contained relatively little detail; therefore, our comments are
based on the April 2008 mitigation plan and observations made during the site visit on August 26, 2008.
Wetland Restoration and Preservation
Mitigation Types: The presence of a perennial stream, combined with LIDAR data showing a similar
landscape position to proposed riparian wetland restoration, indicates that there may be riparian
wetlands present around Gum Swamp Run in the northeastern corner of the project. The soils map is
inconclusive in this regard. The final mitigation plan should discuss the process for determining riparian
vs. non-riparian acreage in more detail. Also, Figure 13 should separately show riparian enhancement
and riparian preservation, rather than combining the two.
One
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401 Oversight/Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone [phone] / Fax [phone]
Internet: httr)://h2o.enr.state.nc.us/ncwetlands
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
Mr. Lekson
'USACE Washington Regulatory Field Office
PCS Phosphate - Proposed Mitigation Sites
Page 3 of 6
Vegetation: Planting has already occurred on the site and tree survival appeared adequate during the
site visit. Individual trees were difficult to find due to the dense herbaceous vegetation on the site.
However, survival appeared good and diversity appeared adequate.
Hydrology: DWQ appreciates that the influence of the ditch to remain along Bay City Road has been
factored into the projected mitigation area on the site. A sampling strategy should be included that will
accurately demonstrate the actual influence of the ditch throughout the monitoring period.
Stream and Riparian Buffer Restoration
A headwater valley restoration was constructed on the western side of the site, flowing northwest toward
South Creek. The valley was discernible in the field, and some evidence of flow patterns were observed
in the lower (downstream) portion of the stream valley.
Berms constructed parallel to surface contours were in the process of being reduced in height, and gaps
were being dug through the berms to allow better surface flow downstream and toward the valley.
Success of the system and generation of appropriate mitigation credit are subject to flow issues
presented above in the Sage Gut discussion.
P Lands Mitigation Site (DWQ# 08-1312)
Wetland Restoration
This site currently consists of drained and ditched land with loblolly pines and small hardwoods which
have been actively managed for forestry. No significant comments were generated by the site visit; the
comments below are based on review of the mitigation plans submitted to date.
Soils and Landscape: Based on soils and LIDAR mapping, this appears to be an appropriate site for the
targeted non-riparian mitigation.
Vegetation: The vegetation plan in the April 2008 mitigation plan is "under development". Further
details will be necessary in the final plan. The mapped organic muck soils over much of the site indicate
that some areas may better support pocosin vegetation than exclusively hardwoods. Vegetative
communities proposed in the final plan should reflect those in high-quality reference ecosystems with
similar soils and landscape positions, and should take into account site characteristics as well as the
surrounding communities within the mitigation corridor.
Hydrology: Based on the project location, it appears that ditches will need to be left in place in order to
prevent hydrologic trespass around the northeast corner and along the northern edge of the site. As
mentioned above, the hydrologic sampling plan should include well placement that will demonstrate the
influence of any remaining marginal ditches.
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North Carolina
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401 Oversight/Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone [phone] / Fax [phone]
Internet: http://h2o.enr.state.ne.us/ncwetlands
An Equal Opportunity/Affirmative Action Employer- 50% Recycled/10% Post Consumer Paper
Mr. Lekson
USACE Washington Regulatory Field Office
PCS Phosphate - Proposed Mitigation Sites
Page 4 of 6
U Lands Mitigation Site (DWQ# 08-1313)
Wetland Restoration: Please see the P Lands comments.
Parker Farm, Sections H, I, and J (DWQ# 98-1139)
Wetland Restoration
Vegetation: Vegetation across most of Sections H, I and J consisted of bottomland hardwood trees and
understory, with the exceptions of the filled ditch areas which were mostly herbaceous with occasional
trees. According to the mitigation information provided, a portion of Section J consists of a marsh area
dominated by Phragmites sp. and Baccharis sp. This is not generally what we look for in a preservation
site. Phragmites control and some additional planting in this area may be warranted.
Hydrology:
DWQ prefers that mitigation occur within the same 8-digit hydrologic unit as the related impact.
Much of Parker Farm Sections I and J lie outside of 03020104, so they are expected to be less
effective at offsetting water quality impacts associated with the proposed mine expansion. Since
these areas drain to the Pamlico Sound, their restoration is projected to provide some uplift to the
impacted aquatic ecosystem; therefore, DWQ is willing to discuss with the Interagency Review
Team (IRT) the possibility of their inclusion in the mitigation package. However, we would
recommend an increased mitigation ratio for out-of-CU mitigation.
Monitoring data from some wells in Section H met neither the success criteria (saturation for at
least 12.5% of the growing season) nor USACE jurisdictional criteria (saturation for at least 5% of
the growing season). The amount of mitigation credit generated by the Parker Farm sites should
be based on the area shown by the monitoring results to be successfully restored.
Stream Preservation
The proposed stream preservation appears adequate, and DWQ has no comments regarding this portion
of the site.
Gum Run Projects Mitigation Site (DWQ# 08-1314)
Wetland Restoration
The applicant may submit monitoring data from all years such data were collected at the Gum Run sites,
along with discussion of the targeted ecosystems and functions. DWQ will examine these data and
401 Oversight/Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone [phone] / Fax [phone]
Internet: http://h2o.enr.state.nc.us/ncwetlands
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An Equal Opportunity/Affirmative Action Employer- 50% Recycled/10% Post Consumer Paper
Mr. Lekson
VSACE Washington Regulatory Field Office
PCS Phosphate - Proposed Mitigation Sites
Page 5 of 6
determine, in cooperation with the IRT, the appropriateness of utilizing these sites as mitigation for the
proposed mine expansion.
South Creek Corridor Preservation Parcels Mitigation Site (DWQ# 08-1315)
Wetland Preservation
DWQ supports the inclusion of the South Creek Corridor preservation in the mitigation package for the
proposed mine expansion. Credit determination by the agencies should take into account the current
wetland types and quality ratings.
Stream and Riparian Buffer Preservation
Based on the portions of the proposed preservation corridor visited, South Creek appears to represent an
excellent candidate for preservation. Vegetation in the riparian zone in the areas visited appeared to
consist of fairly mature riverine swamp forest vegetation (gum and cypress) with appropriate understory
and herbaceous layers.
Jacobs Creek Mitigation Site
Wetland Restoration
The proposed site appears to be appropriate for brackish marsh restoration and enhancement. In the
long term, these activities are expected to have a positive impact on the local water quality and
environment. Further details regarding the proposed fill removal, grading, planting, and Phragmites
control activities should be included in the final mitigation plan. Plan review and a site visit will need to
be conducted by DWQ personnel before the plan can be approved.
Vegetation:
¦ "Seedling availability" should play a relatively minor role in the selection of plantings compared
with the other variables (soil characteristics, hydrology, grading, elevation, and field observations)
listed in the FEIS mitigation plan. Plants in coastal marsh settings are especially sensitive to
minor changes in elevation and exposure to water and salts. Planning and coordination with local
nurseries should ensure that adequate quantities of appropriate species are available at the time of
planting.
¦ In regards to Phragmites control, more details should be included in the final mitigation plan,
including types and concentrations of chemicals, their applicability in aquatic settings, timeline
and frequency of application, and other methods (e.g. mechanical removal) that will be employed.
¦ Given the small size of the site, it is expected that vegetation monitoring plots will cover nearly
the entire 0.2-acre restoration area, and that the Phragmites control areas will be evaluated
regularly to assess the percent cover of desirable vs. aggressive weedy species.
Nye Carolina
Naturally
401 Oversight/Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone [phone] / Fax [phone]
Internet: http://h2o.enr.state.nc.us/ncwetlands
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
Mr. Lekson
USACE Washington Regulatory Field Office
PCS Phosphate - Proposed Mitigation Sites
Page 6 of 6
Please feel free to contact Tammy Hill or Eric Kulz at [phone] if you have any questions
regarding these projects.
Sincerely,

Cyndi B. Karoly, Program Manager
401 Oversight and Express Review Program
cc: File Copy (Eric Kulz)
Kyle Barnes - DWQ Washington Regional Office
Tom Walker - USACE Asheville Regulatory Field Office
401 Oversight/Express Review Permitting Unit
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone [phone] / Fax [phone]
Internet: http://h2o.enr.state.nc.us/ncwetlands
None Carolina
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An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper