19910326 Ver 1_Scoping Comments_19940725 (2)

State of North Carolina
Department of Environment,
Health and Natural Resources --
Division of Environmental Management
James B. Hunt, Jr., Governor
Jonathan B. Howes, Secretary
A. Preston Howard, Jr., P.E., Direct
r
25, 1994
TO: Melba McGee, Leg' ive and Intergovernmental Affairs
THROUGH: Steve W. Tedde??,,r ater Quality Section Chief
FROM: Monica Swihartr,4Water Quality Planning
SUBJECT: Project No. 95-0011; EIS Scoping - Application for Non-
Project Use of Project Lands and Waters at Gaston and
Roanoke Rapids Project (FERC No. 2009)
The Division's Water Quality Section has reviewed the scoping
document (FEA) for the subject project. Our Section is primarily
concerned with the potential effects of the proposed withdrawal
on downstream water quality in the Roanoke River. We would like
to request that the following information be presented in the EIS
that the FERC prepares for this project:
1) Flow and Water Use in the Lower Roanoke River Basin -
Although Virginia Beach is proposing to mitigate the proposed 60
mgd withdrawal with flow releases from Kerr Reservoir, increased
water consumption in the lower Roanoke River Basin may
significantly reduce flows below the project in the future.
Therefore, the EIS should provide a discussion of the projected
water use needs in the lower Roanoke River Basin to supply future
industry, population growth and assimilative capacity. The
document should present an analysis of the critical flows for
protecting aquatic habitat and water quality downstream of the
proposed project in terms of these future water use scenarios.`
In addition, the water quality impacts from reduced water levels
in Kerr Reservoir should be discussed in the EIS.
2) Estuarine Water OualitX - The FEA concluded that unavoidable
adverse impacts.to the environment associated with the Lake
Gaston pipeline would result from an overall reduction in flows
to the Roanoke River Basin downstream from Lake Gaston. This
overall reduction in flows may have significant impacts on the
phytoplankton growth in the estuarine portions of the Roanoke
River, into the Albemarle Sound. Reduced flows may translate
into a longer detention time for algae to be in contact with
nutrients which may result in extensive algal blooms and
depressed dissolved oxygen concentrations. In addition, the FEA
recognizes a need to simulate the estuary. The FEA indicates
that any net reduction in downstream flows from future
consumptive demands may result 'in measurable increases in
salinity concentrations in the estuary.
P.O. Box 29535, Raleigh, North Carolina 27626-0535 Telephone [phone] FAX [phone]
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Consequently, DEM recommends that a model for the estuarine
portion of the Roanoke River be developed. This model should
extend in the Roanoke River from the Town of Hamilton to include
the estuarine portion of the Chowan and Pasquotank River Basins
into the Albemarle Sound. The model should be able to predict
instream dissolved oxygen, nutrients, salinity, and phytoplankton
concentrations. The model should be able to determine the
response of the estuary to various flow regimes, nutrient and BOD
loads originating in the upper portions of the watershed.
Specifically, at all flow regime scenarios, predictive modeling
should determine the critical levels for dissolved oxygen and
nutrient concentrations, the duration of contraventions,
phytoplankton and salinity peaks. Lake levels should also be
specified for all flow regime scenarios.
This modeling cannot be undertaken by NCDEM in the near future.
.However, it could be conducted as part of the EIS provided the
analysis was developed under very close technical review by DEM at
all stages of development, including selection of the modeling
tool, study plan and product delivery options. In addition, the
development of a QUAL2E model should be explored to simulate the
impact of BOD loads in the estuary originating from the Northwest
River and from North Landing River in Virginia, if significant
discharges exist in the freshwater portions of these rivers.
3) waste Assimilation/Dissolved Oxygen - DEM concurs with the.
FEA that potential wasteload assimilation impacts should be
evaluated further, particularly given the uncertainty of future
water availability in the lower Roanoke River Basin. As discussed
on page 63 of the FEA, the existing DO model developed by DEM is
not field calibrated.. Recognizing there is a need for a better
predictive modeling tool, DEM plans to develop a field calibrated
QUAL2E model by the end of 1995. This QUAL2E model extends from
Roanoke Rapids to Hamilton and will simulate instream DO
concentrations.
This model should be validated as part of the EIS process. This
analysis should be developed under very close technical review by
DEM at all stages of development. Concerning model prediction
error, the model that DEM will develop will only explore: 1) the
probability of violating the stream DO water quality standard at
key locations; and 2) the confidence in the model by examining the
sensitivity of the model output to the model assumptions or input
parameters. This will be achieved through Sensitivity Analysis,
Monte Carlo Simulations and First Order Analysis.
Due to time constraints and staff resources, DEM will not be able
to validate this model in the near future. Model validation is
the process of testing a mathematical model in a scenario
different from the calibration scenario to ascertain that the
predictive error is acceptable. Statistical tests are used in
model validations. Based on preliminary analyses, the QUAL2E
model of the Roanoke River is expected to demonstrate that the

oxygen-consuming assimilative capacity of the river is
compromised. Flow augmentation in the Lower Roanoke River may be
necessary to allow future increased demands on the assimilative
capacity of the river. The model could be used under several
"hypothetical" scenarios which simulate these increased demands.
The model could help to establish the required minimum releases
that would "support" certain wastewater flows downstream of the
dam. Due to the importance of the Lake Gaston pipeline, DEM
believes that this model should be validated before management
decisions can be made based on the modeling analyses.
4. Secondary and Cumulative Impacts - The availability of a new
60 MGD water supply source would dramatically increase the
potential for population growth in Virginia Beach and its
surrounding areas. The development associated with this growth
could, in turn, adversely impact water quality in areas of the
Chowan-Pasquotank watershed, including the Currituck Sound. The
EIS should assess the secondary impacts of the proposed project on
water quality in North Carolina. The EIS should also discuss the
proposed mitigation measures required to ensure that secondary
growth will be managed to prevent degradation of water uses in
North Carolina. We recommend that a permanent monitoring
agreement be developed during the EIS process. This agreement
should include establishing and maintaining a minimum of six
permanent ambient monitoring stations in the Currituck Sound and
increasing monitoring frequencies at existing ambient stations in
the Chowan-Pasquotank River Basin.
Currently, DEM only has one ambient monitoring station in the
lower Currituck Sound. DEM does not have staff to add ambient
monitoring stations or increase frequencies in the existing
network of the Chowan-Pasquotank Basin. One third of all the
ambient monitoring stations in the State are located with the
Washington Regional Office (WARO) jurisdiction. The WARO will
lose one of the two existing ambient monitoring positions. This
position has been funded through the Albemarle-Pamlico Estuarine
Study. Funding for this position is expected to end on July 31,
1994. Therefore, DEM recommends a permanent monitoring agreement
be developed and documented in the EIS in a similar manner as the
plan in which Virginia Beach will compensate Virginia Power for
energy losses resulting from this project.
5. Gaston and Roanoke Rapids FERC Relicensing - The EIS should
discuss the proposed project's relationship to the future
relicensing of the Gaston and Roanoke Rapids project in terms of
the projected cumulative downstream water quality impacts from
future water withdrawals in the lower Roanoke River Basin. The
relicensing action could present an opportunity to mitigate
downstream water quality impacts associated with the Lake Gaston
project through additional minimum releases.
6. Wetland Impacts - The potential project impacts on wetlands
along portions of the Roanoke River Basin should be addressed in

the EIS. The attached memo from John Dorney summarizes
information which is needed to address wetland impacts.
7. Protection of Water Ouality Standards - Possibly the most
critical question that should be addressed in an EIS is whether
state water quality standards will be protected if the project is
approved. In the past, environmental decisions on protecting
water quality standards were based on only a few parameters. if
simple dilution calculations and simple models indicated that
metals, temperature, and dissolved oxygen would be protected, then
the projects were usually allowed. Today, projects cannot be
approved until assurance is given that all standards will be
protected. These include biological diversity, antidegradation,
and assurances that all existing uses of the waters are protected.
Uses cannot be diminished without meeting the conditions provided
in the state's antidegradation policy contained in 15A NCAC 2B
.0201. (Copy Attached.) In making decisions regarding wetlands
alteration for 401 certifications, the Division considers whether
existing uses such as pollutant removal, wildlife habitat, bank
stabilization, and aquatic life habit are present and must make
the final decision considering if any of these uses would be
removed by the action. We similarly believe that the EIS should
determine if existing uses along the riparian areas of lakes and
streams in the Roanoke River basin would similarly be affected by
the project.
8. Basinwide Planning - In preparation of the Environmental
Impact Statement, the FERC should be cognizant of the fact that
North Carolina is in the process of preparing a basinwide water
quality management plan for the Roanoke River basin. This plan is
being prepared under North Carolina's basinwide approach to water
quality management which began in 1990. A program description
document (54 pages) and an eight-page paper describing the
basinwide approach are enclosed.
Under this approach, basinwide water quality management plans are
being prepared for each of the 17 major river basins in North
Carolina by the year 1999. The plans are being prepared pursuant
to a basinwide permitting schedule established in January 1990.
Water quality and aquatic resources will be assessed
simultaneously throughout an entire river basin, leading to the
development of basinwide water quality management plans and
strategies.
Determination and distribution of waste assimilative capacity in a
basin, and development of innovative management strategies that
protect surface water quality in the basin while allowing for
economic growth are very important objectives of this approach
(see page of Program Description document). North Carolina does
not have the resources, at this time to model all 37,000 miles of
rivers and streams in the state and determine their waste
assimilative capacity. Instead, the state is using the basinwide
approach to prioritize water quality issues and focus its
A,
attention and resources on those priority issues and water bodies.
In the Roanoke River basin, determining waste assimilative
capacity to support downstream uses and future growth and
development in the basin are key topics of the upcoming plan. A
critical factor in these determinations includes river flow. It
is unclear to what extent flow will be a limiting factor to long-
term growth and protection of downstream uses. The quantity of
water that may be removed from the river at any one time is
unclear, and no determination has been made of what amount of
water is needed to maintain enough assimilative capacity to
protect downstream uses and provide for future economic growth in
the basin. In preparing its basin plan, DEM would utilize the
best available information and attempt to make these
determinations. The resultant plan would then be used to guide
DEM's water quality program duties and responsibilities in the
basin including monitoring, permitting, planning and compliance.
work is already under way for completion of the Roanoke River
Basinwide Management Plan. According to the NPDES permitting
schedule set in 1990, all NPDES permits in the Roanoke River basin
are due to expire and be renewed in 1997 starting in January of
that year. DEM has also completed intensive water quality
monitoring in the basin for inclusion in the basin plan and to
support limited water quality modeling efforts. A draft basinwide
management plan is due for completion in July 1995. Present plans
call for taking the plan to public meetings in January 1996. The
plan is due to be finalized in July 1996.
With limited resources, the extent of waste assimilative modeling
would be restricted, and many of the strategies to be presented in
the plan would be based on best professional judgment. However,
the basin plan for Roanoke Basin could be enhanced considerably by
data generated by the proposed EIS, particularly the information
requested in items 1 through 3, above. If the EIS were conducted
so as to address the long-term objectives of North Carolina's
basinwide approach, the basin plan would be much more meaningful
and effective.
cc: Steve W. Tedder
Roger Thorpe
Greg Thorpe
Boyd DeVane
John Dorney
Alan Clark
Ken Eagleson
Don Safrit
Ruth Swanek
Juan Mangles