2010 IBT Annual Report

  
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Charlotte-Mecklenburg Utilities
Annual Report on Interbasin Transfer
Calendar Year 2010

The North Carolina Environmental Management Commission (EMC) approved Charlotte
Mecklenburg Utilities’ (Utilities’) petition to increase the amount of water transferred from the
Catawba basin to the Rocky River basin and an interbasin transfer (IBT) Certificate was issued
on March 14, 2002. The Certificate authorizes Utilities to transfer up to 33 million gallons per
day (mgd) from the Catawba River basin to the Rocky River basin.

The IBT Certificate requires Utilities to report maximum daily IBT amounts annually to the
North Carolina Division of Water Resources (NC DWR) until such time as the transfer amount
exceeds 80% of the authorized amount. Once that amount is exceeded, Utilities is required to
report monthly. To date, Charlotte-Mecklenburg Utilities has not exceeded 80% of the
authorized IBT amount.

System Overview
The Utilities operates the water and wastewater systems that serve Charlotte, Cornelius,
Davidson, Huntersville, Mint Hill, Matthews, Pineville, and much of the unincorporated areas of
Mecklenburg County. This system is divided between two river basins designated by NC
General Statutes for regulation of IBT water. The western portion of the system is within the
Catawba River basin and the eastern portion is within the Rocky River basin. Water transferred
from the Catawba River basin to the Rocky River basin that is not returned to the Catawba is
regulated IBT.

Water for distribution to Utilities’ customers is withdrawn from the Catawba River basin at two
locations. An intake at Lake Norman sends water to the Lee S. Dukes Water Treatment Plant. A
second intake at Mountain Island Lake sends water to the Walter M. Franklin Water Treatment
Plant and to the Vest Water Treatment Plant. Potable water from these three plants is delivered
through an interconnected distribution system to retail customers throughout Utilities’ service
area in Mecklenburg County and in small areas of Iredell, Cabarrus, and Union Counties. The
Utilities also provides wholesale water to municipal systems for Resale including: City of
Concord (NC), Town of Harrisburg (NC), Union County (NC), York County Water & Sewer
Authority (SC), and Lancaster County Water and Sewer District (SC).

Utilities treats wastewater at five advanced wastewater treatment plants (WWTP’s) which
discharge into small streams in Mecklenburg County. Four of the streams are tributary to the
Catawba River basin and one (Mallard Creek) is tributary to the Rocky River basin. Utilities also
conveys wastewater generated in portions of Mecklenburg County to the Rocky River Regional
Wastewater Treatment Plant (RRRWWTP) operated by the Water and Sewer Authority of
Cabarrus County (WSACC). The RRRWWTP discharges treated effluent to the Rocky River.

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IBT Monitoring
Water supplied to Utilities’ retail customers in the Rocky River Basin, that is not returned to the
Catawba basin, is included in the reported IBT amounts. Water provided to municipalities with
service areas in the Rocky River basin include the City of Concord and the Town of Harrisburg.

Utilities can transfer treated potable water to the City of Concord through three metered
connections to their water system. All of Concord’s service area is within the Rocky River
basin, so any water purchased by them becomes an IBT. Water service is only provided as an
emergency back-up to Concord’s routine supply which is Lake Howell and several smaller
reservoirs. All of these reservoirs are within the Rocky River basin. Wastewater from Concord
is treated at the RRRWWTP. Utilities’ agreement with Concord is that water will be supplied to
them subject to availability and subject to regulatory constraints including IBT and Federal
Energy Regulatory Commission (FERC) limitations.

Concord received an IBT Certificate in January 2007, for the transfer of up to 10 mgd from the
Catawba River basin to the Rocky River basin. NC DWR advised Utilities that water sold to
Concord should not be applied to Utilities’ IBT amount. Concord did not purchase any potable
water from Utilities in calendar year 2010, so the IBT amounts reported do not include sales to
Concord.

Utilities can transfer treated potable water to the Town of Harrisburg through two metered
connections to their water system. All of Harrisburg’s service area is within the Rocky River
basin and is included in the Utilities’ IBT amounts.

Table 1 below summarizes actual IBT amounts for calendar years 2002 through 2010 (all
calculated using the methodology approved by NC DWR in June of 2006). The table considers
the daily amounts of water transferred from the Catawba basin to customers within the Rocky
River basin that is not returned to the Catawba basin.

The data indicates that the maximum amount of IBT for year 2010 occurred in August, and was
18.22 mgd, less than 56% of the authorized maximum day value of 33 mgd. The average IBT for
2010 was 13.45 mgd, which is approximately 41% of the authorized maximum day value. In
addition to the amount of actual IBT reported in Table 1, Utilities has committed to provide
additional IBT to development that has been proposed but not yet activated in the Rocky River
basin. As of December 31, 2010, 1.16 mgd was committed to permitted donated projects
(subdivisions) that had not been activated and 0.50 mgd was committed to master meter
connections (generally commercial or multi-family developments) that had not been activated,
both based on maximum day estimates. This brings the total of the actual and outstanding IBT in
2010 to 19.88 mgd, or less than 61% of the authorized maximum day value.

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Table 1. Actual IBT Summary
Calendar Year Avg. Annual IBT (mgd) Max. Day IBT (mgd)
2002 6.74 11.97
2003 6.91 9.82
2004 7.79 12.56
2005 8.66 13.79
2006 9.56 14.35
2007 9.96 17.22
2008 11.39 17.42
2009 12.04 16.00
2010 13.45 18.22

Compliance with Certificate Conditions
Condition 1 of Utilities’ IBT certificate requires Mecklenburg County to summarize progress in
implementation of watershed management approaches of the Surface Water Improvement and
Management Program (S.W.I.M. program). This summary follows:

The watershed management approaches of the Surface Water Improvement and Management
(SWIM) Program continued to be implemented during calendar year 2010. Efforts continued
to focus on McDowell and Goose Creeks as in 2007, 2008 and 2009 as well as the South
Prong and West Branch of the Rocky River in Davidson as initiated in 2009. During
calendar year 2010, the following work was completed in the three (3) watersheds:
a) Survey and design were initiated on the restoration of 1,000 feet of stream and the
retrofit of 5 rain gardens within the North Mecklenburg Park Property in the McDowell
Creek watershed. In addition to the water quality benefits of the project, it will act as an
educational destination for property owners potentially affected by future stream
restoration and BMP retrofit projects.

b) Since 2002 Goose Creek has been listed by the N.C. Department of Environment and
Natural Resources (NCDENR) as impaired due to elevated levels of fecal coliform
bacteria. The predominant sewer treatment system in the watershed is private septic
systems; therefore, it was assumed that malfunctioning septic systems were a primary
source of the elevated bacteria levels. In 2008, Mecklenburg County initiated a program
to complete an inspection of all the septic systems in the watershed in order to identify
deficiencies and take the necessary actions to ensure correction. This effort was
completed in 2010 with the inspection of 1,422 septic systems resulting in the correction
of 13 deficiencies that could contribute to elevated bacteria levels in Goose Creek.
Following the completion of this project, NCDENR data documented a reduction in fecal
coliform bacteria levels and Goose Creek was removed from the list of impaired waters.

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c) Mecklenburg County continues to partner with Creek ReLeaf, environmental
organizations and local schools to plant trees along the banks of streams in Mecklenburg
County. The purpose of this effort is to restore the water quality buffer and floodplain.
During 2010, over 2,200 trees were planted by more 400 volunteers along the floodplain
of Little Sugar Creek.

d) Construction of the restoration of 10,000 linear feet of Torrence and Torrence Tributary
#2 was nearly completed in 2010. This project is expected to reduce the overall sediment
load in the McDowell Creek watershed by as much as 7%.

e) In 2010, Mecklenburg County requested that the Army Corps of Engineers include the
Rocky River watershed in Mecklenburg County into their 206 Program for restoration.
As a result, the Corps selected the watershed for inclusion in Program. 

f) Mecklenburg County applied for two Clean Water Management Trust Fund Grants for
the restoration of an additional 10,000 feet of stream in the McDowell Creek Watershed. 

Condition 2 of Utilities’ IBT certificate required a stakeholder process to investigate, develop,
adopt, and implement storm water ordinances that control water quantity from single-family
development and water quality for all development until completed. The requirements of
Condition 2 were completed in 2007.

Condition 3 of the IBT Certificate removes the Goose Creek subbasin from the area to be served
by the IBT, and imposes a moratorium on the installation of new IBT water lines (water lines
crossing the ridgeline) into Goose Creek subbasin until the impacts of additional growth on the
endangered species are fully evaluated.
The Utilities has requested the NC Division of Water Resources (DWR) to prepare an
Environmental Assessment (EA) of new development in the Goose Creek basin (Mint Hill
area), impacts to water quality, and measures required to protect the Carolina
Heelsplitter.

Condition 4 of the IBT Certificate provides that the Environmental Management Commission
may reopen the Certificate under certain circumstances. This did not occur in 2010.

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Condition 5 of the IBT Certificate requires Utilities to develop a compliance and monitoring plan
for reporting maximum daily transfer amounts, compliance with certificate conditions, and
progress on mitigation measures, and drought management activities. Utilities’ monitoring plan
and reporting format were approved in June of 2006 by NC DWR and continue to be used for
2010.

Charlotte Mecklenburg Utilities monitored water treatment plant pump rates, streamflow
and lake storage indicators, the US Drought Monitor, and other factors in accordance
with the Utilities Water Shortage Response Plan. Measurements were assessed monthly
to identify designated triggers that could indicate developing drought conditions. All
appropriate planning, communication and preparation were in place to respond as
needed to changing conditions.
In coordination with 15 other utilities in the Catawba-Wateree river basin, Charlotte-
Mecklenburg participated in regional drought response planning and response activities
as directed by the FERC- approved Low Inflow Protocol.

Summary
The actual maximum day amount of water transferred from the Catawba River basin to the
Rocky River basin was 18.22 mgd, less than 56% of the authorized maximum day value of 33
mgd. The total of actual and outstanding IBT was 19.88 mgd, less than 61% of the authorized
maximum day value. Utilities is in full compliance with IBT authorizations and compliance
conditions for calendar year 2010.