NC0056561_Environmental Assessment_19980827

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NORTH CAROLINA DEPARTMENT OF
ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF WATER RESOURCES
August 27, 1998 Lill V1
MEMORANDUM
TO: Melba McGee
THROUGH: John Sutherland
FROM: Jim Mead I ;e
SUBJECT: Maggie Valley Sanitary District, Haywood County
Water Treatment Plant Expansion to 3.0 MGD
Environmental Assessment and Addendum No. I
DENR Project No. 936 (Reference No. 882)
The Division of Water Resources (DWR) has reviewed the EA for the water
treatment plant expansion proposed by the Maggie Valley Sanitary District
(MVSD). With the attachment of Addendum No. 1, we are in agreement with a
Finding of No Significant Impact (FONSI) for this project. The following
requirements, as described in the addendum to the EA, must be implemented
when the water supply intake and treatment plant are expanded.
Conscientious monitoring and management oft.he withdrawal at the
Jonathan Creek intake will be necessary to maintain a minimum flow of 8
efs immediately downstream of the intake. During some periods, the
withdrawal at the Jonathan Creek intake will need to be reduced to
maintain this minimum flow. However, a withdrawal of 1.5 mgd (the
present capacity) can be made regardless of the resulting downstream
flow. When the withdrawal is reduced below 3.0 mgd, "make-up" water
up to 1.5 mgd can be withdrawn at the Campbell Creek intake. The
existing interconnection with Waynesville also offers an additional back-
up during extreme droughts or other emergencies.
P.O. Box 27687, RALEIGH, NORTH CAROLINA 27611-7687
PHONE [phone] FAX[phone]
AN EQUAL OPPORTUNITY /AFFIRMATIVE ACTION EMPLOYER - 50% RECYCLED/10% POST -CONSUMER PAPER

Memo from Jim Mead to Melba McGee
Re: MVSD, August 27,1998 Page2
A staff gage must be installed to insure that the minimum flow of 8.0 cfs is maintained
downstream of the Jonathan Creek intake whenever withdrawals are in excess of 1.5 mgd.
If the gage is installed downstream of the intake, it should be calibrated to determine the
water level corresponding to 8.0 cfs. If it is installed upstream of the intake, it should be
calibrated to measure flows between 10.3 cfs (8.0 cfs minimum flow plus 1.5 mgd
minimum withdrawal) and 12.6 cfs (8.0 cfs minimum flow plus 3.0 mgd maximum
withdrawal). The selection of the gage location will depend on suitable channel
geometry. It also will be influenced by whether MVSD wants to closely monitor inflows
in order to withdraw amounts between 1.5 and 3.0 mgd when inflows are not sufficient to
allow the full 3.0 mgd withdrawal, or if they instead will just reduce withdrawals to 1.5
mgd when inflows are low and get any additional water from Campbell Creek.
The staff gage should be installed and calibrated following procedures described in U.S.
Geological Survey Water Supply Paper 2175, "Measurement and Computation of
Streamflow." Plans for the gage should be submitted to DVVR for approval prior to
installation. Staff gages must be calibrated to indicate the water surface elevation(s)
corresponding to the flow(s) of interest, with calibration verified at least every two years.
All initial calibration and re -calibration measurements, including field data, must be
provided to DWR within 30 days of completion.
In addition to these requirements, we recommend that MVSD consult with the Division of Water
Quality regarding any potential concerns for the effect of the expanded withdrawal on
downstream assimilative capacity and point source discharges.
Any additional expansion in the future will require a consideration of the effect on instream
flows and aquatic habitat. Based on the study conducted for the proposed expansion, combined
withdrawals from the Jonathan Creek/Campbell Creek intakes in excess of 3.0 mgd would have
an unacceptable adverse impact on aquatic habitat during some periods of the year. If the water
treatment plant capacity is expanded beyond 3.0 mgd, the additional water supply would have to
be provided by an alternate source, interconnection, offstrearn storage, water conservation, or a
combination of alternatives during some parts of the year. We encourage MVSD to continue
efforts to reduce the amount of water loss in their system to increase the length of time that this
expansion to 3.0 mgd will meet their water supply demand.
cc: Steve Reed and Tony Young, DWR
Mark Davis, WRC
Ruth Swanek, DWQ
Harold Saylor, DEH

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