20080868 Ver 2_USACE Draft Creeks Report Comments_20081019

DEPARTMENT OF THE ARMY
WILMINGTON DISTRICT, CORPS OF ENGINEERS
69 DARLINGTON AVENUE
WILMINGTON, NORTH CAROLINA 28403-1343
1. Has mining altered the amount or timing of water flows within the creeks?
2. Has mining altered the geomorphic or vegetative character of the creeks?
3. Has mining altered the forage base of the creeks?
4. Has mining altered the use of the creeks by managed fish?
5. Has mining increased contaminate levels within -creek sediments to levels that could
impact fish or invertebrates?
6. Has mining altered overall water quality within creeks?

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REPLY TO
ATTENTION OF: October 7, 2010
Regulatory Division
Action ID. SAW-2001-10096
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Potash Corporation of Saskatchewan Phosphate Division, Aurora Mine
Attn: Mr. Steve Beckel
1530 NC Highway 306 S?
Aurora, North Carolina 27806
Dear Mr. Beckel:
Please reference the Department of the Army permit issued Potash Corporation of
Saskatchewan (PCS) Phosphate Division authorizing the discharge of dredged and fill material
into 3,927 acres of waters of the U.S. adjacent to the Pamlico River and several of its tributaries
located north of the town of Aurora, Beaufort County, North Carolina. These impacts were
authorized as part of a continuation of mining activities at the existing Aurora Mine facility.
As a condition of this authorization PCS is required to carry out chemical and biological
monitoring to assess the effects of the reduction in headwater wetlands on the utilization of
Porters Creek, Tooley Creek, Jacobs Creek, Drinkwater Creek, and Jacks Creek as nursery areas
by resident fish and appropriate invertebrate species. To this end, PCS submitted a draft plan of
study for agency review and comment in December 2009. The plan, titled "Draft Plan of Study
to Monitor Potential Effects of Reduction in Headwater Wetlands on the Downstream Aquatic
Functions and Utilization of Tributaries of South Creek, Porter Creek, and Durham Creek
Beaufort County North Carolina" included proposed methods for testing the six (6) questions
identified in Special Condition "S" of the permit. Those questions are:
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To aid in this effort, PCS worked with the Corps, the North Carolina Division of Water
Quality (NCDWQ) and other interested parties to establish an independent multidisciplinary
panel of researchers qualified in the subject matter to be examined. The major purpose of this
panel is to review reports for proper experimental design and validity of data analysis and
conclusions, identify potential trends, and comment on potential areas of further study or
changes to existing protocols. This panel was invited to review the proposed sampling
procedures and monitoring reports from previous work and provide feedback to the Corps,
NCDWQ, the N.C. Division of Coastal Management (NCDCM) and PCS. On June 16, 2010, the
panel met with representatives from the Corps, NCDWQ, NCDCM and PCS to discuss the plan
further and provide feedback.
A general suggestion offered by members of the panel was to separate each tributary into a
"stream" section and a "creek" section. Stream sections would be those segments usually
experiencing unidirectional flow from upstream runoff and groundwater input. Creek sections
would be those segments usually experiencing bidirectional flow as a result of the overriding
influence of wind and/or lunar tides. All agreed that this distinction could be useful in
experimental design and result interpretation. Therefore, for purposes of this monitoring
program, these terms will be adopted as described. The term tributary will be used when
referring to the entire system of any given named water course.
The panel also provided input on the proposed reference creeks. It was suggested that some
preliminary sampling be done in the proposed reference creeks to determine how similar they
actually are to the study creeks. The group also suggested that Long Creek, Short Creek, Little
Creek and PA2 be considered for use as reference creeks. While these creeks would not be
appropriately defined as "unaltered" systems, they could serve as potential controls. The goal of
much of the monitoring efforts is to determine what, if any changes in the measured parameters
can be attributed to the actions of the permittee. Since inflow from South Creek and the Pamlico
River influence the conditions within the study tributaries, monitoring within these other
tributaries of South Creek would provide valid data on changes that can be attributed to
alterations in the conditions of the larger waters. Additionally, due to the historic impacts to the
drainage basins of these creeks the monitoring may yield some evidence as to the predictable
long-term conditions of the study creeks.
The Panel provided input on specific details of the monitoring plan as well. In regard to
water table/water level monitoring, members of the panel suggested that data should, at least
periodically, be collected at a greater frequency (approx. 15 min. intervals) within and
surrounding the stream reaches in order to capture episodic pulse events. The panel agreed that
the value of monitoring water table/water level within the creek reaches of these tributaries
would be limited due to bidirectional flow and the overwhelming influence of wind tides.
In regard to monitoring of the geomorphic or vegetative character of the tributaries, panel
members agreed that the proposed parameters would be telling but suggested some modification
in the methods and/or frequency of data collection. The group suggested that due to the low
energy and stability of these tributaries, it is very unlikely that rapid changes in channel
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morphology will occur. Therefore, parameters such as stream/creek position, length, width and
sinuosity could be measured at a frequency greater than 1 year. The group further suggested that
changes in the cross-sectional dimensions of the creek reaches as a result of changes in flow
would not be expected and any change observed would not likely be discernable from predicted
sea-level rise. Therefore, cross sectional surveying should be limited to the stream reaches. The
group discussed the benefits of annual vegetation surveys along the tributary corridors and
decided that less frequent surveying would likely be appropriate.
The group discussed monitoring fish and invertebrate utilization within the subject
tributaries as an indicator of forage base. Members of the panel suggested concentrating benthic
invertebrate collection efforts during winter and early spring when species richness and diversity
are greatest. The group suggested that these efforts should be adequate to capture all benthic
invertebrate species thereby eliminating the need for specific efforts to capture bivalves. The
group also discussed sampling of more motile and pelagic species. Members of the panel
suggested that any sampling regime should be designed to target the variety of species expected
to occur within these systems. This could require adjustment of sampling gear and timing to
reflect ontogenetic shifts in creek usage. Proper experimental design here again should be
adequate to capture all expected species including those managed under the Magnuson-Stevens
Fishery Conservation Management Act. The group discussed Biomass Size Spectra (BSS) as a
method of assessing fisheries utilization of the area. Members of the panel opined that BSS may
be a useful tool but more information is needed on the method and the level of sampling required
to produce meaningful results. Further discussion of BSS is planned.
Finally, the group discussed water quality sampling. Members of the panel felt it
appropriate to add water quality sampling stations at the lower end of the Creek reaches near the
confluence with the receiving waters. Members of the panel also suggested adding measurement
of dissolved (DOC) and total (TOC) organic carbon, using measurement of total suspended
solids (TSS) and color as indicators of turbidity, and adopting more sophisticated techniques for
measuring light attenuation. The group discussed the fact that in these tributaries, particularly
those areas most influenced by the water quality of the receiving waters (creek reaches), no
change would be predicted in some of these parameters (e.g. Salinity). Therefore, monitoring of
these parameters may be continued on a less frequent basis or discontinued altogether once data
from the first several years can be analyzed for potential trending.
After review of the Draft monitoring plan and consideration of the above referenced
discussion, the Corps has determined that to the extent practicable and appropriate,
procedures and monitoring locations established under the 1998 monitoring plan should
be continued. Additionally, the monitoring requirements under special condition "S" of
the 2009 permit are refined as follows:
1) Has mining altered the amount or timing of water flows within the tributaries?
Data collection may include:
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i) Continuous water level recorders to measure/model average and event driven
(pulse) flow within the stream reaches.
ii) Rain gauges to measure local water input.
iii) Groundwater wells to measure input to the tributaries.
2) Has mining altered the geomorphic or vegetative character of the tributaries? Data
collection may include:
i) Periodic (3-5yr) aerial photography/lidar to determine tributary position,
length, width and sinuosity.
ii) Conduct baseline and periodic (3-5yr) cross sectional surveys of each tributary
at established locations within the stream reaches. Frequency of the surveys
may vary based on relative change observed (>stability = < frequency).
iii) Periodic (3-5yr) sediment characterization including total sediment organic
matter and porosity.
iv) Periodic (3-5yr) surveys of live vegetation and organic matter accumulation
along tributaries. Frequency of the surveys may vary based on relative change
observed.
3) Has mining altered the forage base (fish and invertebrate utilization) or use by
managed fisheries species within tributaries? Data collection may include:
i) Sampling of benthic invertebrate populations by core or grab collection.
Sampling efforts should be concentrated during winter and early spring.
ii) Periodic sampling for pelagic species such as grass shrimp, blue crabs, and
small forage fish. Sampling gears would be chosen to reflect ontogenetic
shifts in creek usage
iii) Biomass size spectra may be used as an approach to addressing this question.
4) Has mining increased contaminant levels within tributary sediments to levels that
could impact fish or invertebrates? Data collection may include:
i) Sediment and water column sampling annually or at prescribed intervals for
metals, including cadmium, mercury, silver, copper, and arsenic.
ii) If elevated levels are detected, the availability and uptake by appropriate
aquatic species (e.g., Rangia sp., blue crabs) should be measured using
appropriate bioassay techniques.
5) Has mining altered overall water quality within creeks? Water quality parameters
analyzed will include: Salinity, Temperature, Dissolved Oxygen, pH, Secchi
depth/light attenuation, Turbidity (TSS, color), Chlorophyll a, Dissolved
orthophosphate phosphorus, Total dissolved phosphorus, Particulate phosphorus,
Nitrate nitrogen, Ammonia nitrogen, particulate nitrogen, and Dissolved Kjeldahl
nitrogen, DOC/TOC
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Once all necessary modification and/or amendments to the monitoring plan are
complete, you must submit a final version to the Corps and the N.C. Division of Water
Quality. The Corps will consider requiring PCS to implement any future suggestions to
improve and/or modify data collection to better address these questions. Although the
Corps may choose not to require PCS to implement suggestions to study further
hypotheses or other areas, PCS may elect to implement these voluntarily.
Thank you for your attention to this matter. Please do not hesitate to contact me
should you have any questions. I can be reached at [phone] or by
e-mail at [e-mail].
Sincerely,
William T. Walker, Chief
Wilmington Regulatory Field Office
Copies Furnished:
Ms. Becky Fox
U.S. Environmental Protection Agency - Region 4
1307 Firefly Road
Whittier, North Carolina 28789
Mr. Mike Wicker
U.S. Fish and Wildlife Service
Fish and Wildlife Enhancement
Post Office Box 33726
Raleigh, North Carolina 27636-3726
Mr. Ron Sechler
National Marine Fisheries, NOAA
Habitat Conservation Division
Pivers Island
Beaufort, North Carolina 28516
Mr. John Dorney
Division of Water Quality
J North Carolina Department of
Environment and Natural Resources
1621 Mail Service Center
Raleigh, North Carolina 27699-1621
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Mr. David Moye
Division of Coastal Management
North Carolina Department of
Environment and Natural Resources
943 Washington Square Mall
Washington, North Carolina 27889
Mr. Richard Peed
Division of Land Resources
North Carolina Department of
Environment and Natural Resources
943 Washington Square Mall
Washington, North Carolina 27889