HomeMy WebLinkAboutFINAL_CaryApex_IBT_ComplianceMonitoring Plan_2015
F INAL
2015 Interbasin Transfer Certificate
Compliance and Monitoring Plan
Prepared for
Town of Cary Town of Apex
Submitted to
North Carolina Division of Water Resources
July 2015
CH2M HILL North Carolina, Inc.
3120 Highwoods Boulevard
Suite 214 - Magnolia Building
Raleigh, NC 27604
(919) 875-4311
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Contents
Section Page
I
1 Introduction ...................................................................................................................................... 1-1
2 Interbasin Transfer Calculation .......................................................................................................... 2-1
2.1 Definitions ........................................................................................................................................ 2-1
2.2 Data Compilation ............................................................................................................................. 2-2
2.3 Data Assumptions ............................................................................................................................ 2-2
2.4 Interbasin Transfer Calculation........................................................................................................ 2-3
3 Reporting Methodologies and Schedules ........................................................................................... 3-1
3.1 Compliance Reporting ..................................................................................................................... 3-1
3.1.1 Quarterly Reporting ............................................................................................................ 3-1
3.1.2 Annual Reporting ................................................................................................................ 3-1
3.2 Compliance Schedule ....................................................................................................................... 3-1
4 References ........................................................................................................................................ 4-1
Tables
1 Sample of Daily IBT and Average Day of Calendar Month IBT Calculation ................................................... 2-5
2 IBT Compliance Monitoring and Reporting .................................................................................................. 3-2
ii
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1-1
SECTION 1 Introduction
On March 12, 2015, the North Carolina Environmental Management Commission (EMC) granted an interbasin
transfer (IBT) certificate modification to the Towns of Cary and Apex (Towns) with transfer limits of 31 million
gallons per day (mgd) from the Haw River basin to the Neuse River basin, and 2 mgd from the Haw River basin to
the Cape Fear River basin, calculated as a daily average of a calendar month.
In addition to the permitted transfer volume, the IBT certificate includes eight conditions:
1. Water Conservation Plan – Within 90 days of receipt of the IBT certificate, the Towns are required to submit a
water conservation plan subject to approval by the North Carolina Division of Water Resources (NCDWR) that
specifies the water conservation measures that will be implemented by the Towns to ensure the efficient use
of the transferred water.
2. Drought Management Plan – Within 90 days of receipt of the IBT certificate, the Towns are required to
submit a drought management plan subject to approval by the NCDWR that specifies how the transfer will be
managed to protect the source river basin (Haw River basin) during drought conditions or other emergencies
that occur within the source river basin.
3. Compliance and Monitoring Plan – Within 90 days of receipt of the IBT certificate, the Towns are required to
submit a quarterly compliance and monitoring plan subject to approval by the NCDWR.
4. EMC Consideration of Alternative Sources – The EMC may reopen and amend the maximum amount of the
IBT authorized if it appears that an alternative source of water is available to the Towns within the receiving
basin (Neuse River basin).
5. EMC Consideration of Future Water Demands – The EMC may reopen and amend the certificate if it is
determined that the Towns’ actual future water needs are significantly less than the projected water needs at
the time the certificate was granted.
6. Resale of Transferred Water – The Towns shall not resell the water that would be transferred pursuant to the
IBT certificate to another public water system.
7. EMC Consideration of Impacts – The EMC may reopen the certificate and amend existing or require new
conditions to ensure detrimental impacts are mitigated if environmental impacts are found to be substantially
different from those on which the EMC’s Findings of Fact were based.
8. Intake Access – The Towns shall be required to provide access at their existing intake site to other Jordan Lake
water allocation holders that need access to utilize their allocations to the extent that this additional use is
determined to be feasible by the NCDWR.
To meet Condition 3, the following sections of this Compliance and Monitoring Plan include a description of how
the Towns will monitor the amount of IBT, and also as required by the certificate, methodologies, and schedules
for reporting the following information:
Monthly average day transfer amounts (calculated)
Compliance with IBT certificate conditions
Progress on mitigation measures (there are no mitigation measures required by this IBT certificate)
Reporting
1 INTRODUCTION
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2-1
SECTION 2 Interbasin Transfer Calculation
The combined IBT amount from the communities served will be calculated on a daily basis. The methodology for
calculating the daily IBT amount was developed in cooperation with NCDWR staff for the Towns’ 2001 IBT
Certificate Compliance and Monitoring Plan and is consistent with NCDWR guidelines (2009) for estimating IBT
amounts as part of the local water supply planning process.
Because of the complexity of the Towns’ water systems, which straddle the ridge line between IBT basins, water is
transferred via wastewater discharge, potable water consumptive use, or reclaimed water consumptive use. Daily
IBT is calculated based on a combination of meter data and assumptions. Daily IBT data are then used to calculate
the IBT certificate compliance metric – IBT calculated as the daily average of a calendar month.
2.1 Definitions
The following definitions are used to assign collected water system data and conduct calculations for IBT
compliance and monitoring, as shown by column in Table 1.
Water Withdrawal/Purchase (Table 1, Columns 1-4) could occur in two ways: water withdrawal from Jordan
Lake (Haw River basin) and purchases from the Neuse River basin. Currently, emergency purchases can be
made via interconnections with the City of Durham and City of Raleigh water systems (Neuse River basin
sources), and reclaimed water is purchased from Durham County (Neuse River basin source) to provide
reclaimed water supply on a daily basis to the Town of Cary’s reclaimed water system in the Haw River basin.
Total System Use (Table 1, Column 5) is the sum of water withdrawn from the Haw River basin and bulk
purchases from the City of Raleigh, City of Durham, and Durham County in the Neuse River basin.
Consumptive Use (Table 1, Column 6-11) is the water used by customers that does not end up in the
wastewater collection system; irrigation is the most common consumptive use. Potable and reclaimed water
consumptive use are estimated separately.
Water Use Discharged as Wastewater (Table 1, Column 12-15) is the proportion of non-consumptive water
use discharged as wastewater in each basin, based on effluent flow meter data and Total System Use. The
following facilities discharge in each basin:
- Neuse River basin (Table 1, Column 15):
North Cary Water Reclamation Facility (NCWRF)
South Cary Water Reclamation Facility (SCWRF)
Apex Middle Creek Water Reclamation Facility (MCWRF)
Wastewater sent from the Town of Apex to the City of Raleigh (emergency use only)
- Cape Fear River basin (Table 1, Column 14):
Western Wake Regional Water Reclamation Facility (WWRWRF) – While this discharge is physically in
the Cape Fear River basin, for IBT purposes, it is considered a return to the source basin (Haw River
basin) because the water is returned to a point downstream of the withdrawal that it would have
reached anyway if it had not been withdrawn (referred to by NCDWR as the “cork rule”).
- Haw River basin (Table 1, Columns 1-13):
Process water use at Cary/Apex Water Treatment Facility (WTF), discharged to Jordan Lake
Wastewater sent by the Town of Cary to Durham County Triangle Wastewater Treatment Plant
2 INTERBASIN TRANSFER CALCULATION
2-2
Total Returned/Used in Each Basin (Table 1, Columns 16-18) is the sum of Consumptive Use and Water Use
Discharged as Wastewater for each basin.
Interbasin Transfer (Table 1, Columns 20-21) is defined as the withdrawal from the source basin (Haw River
basin) minus the return to the source basin. IBT is calculated for each of the two receiving basins (Neuse and
Cape Fear River basins):
- Cape Fear River basin: The transfer to the Cape Fear River basin is made up solely of the consumptive use
by the Town of Apex in this portion of its service area.
- Neuse River basin: The total amount of water transferred out of the Haw River basin, minus the transfer
to the Cape Fear River basin. This value includes both wastewater discharge and consumptive use.
2.2 Data Compilation
Metered daily data are used to calculate IBT. The following data are collected and input into the Towns’ IBT
tracking spreadsheet:
Water Withdrawal and Purchase, comprising:
- Cary/Apex WTF, including:
Jordan Lake withdrawal
Process water use (discharged back to Jordan Lake per National Pollution Discharge Elimination
Permit permit)
Finished water produced
- Finished water purchase from others (emergency use only)
- Reclaimed water purchase from others
Consumptive Use
- Reclaimed Water
- NCWRF and SCWRF, including:
In-facility use of reclaimed water
Distributed reclaimed water
Bulk reclaimed water
- WWRWRF’s bulk reclaimed water
Water Use Discharged as Wastewater, including:
- Discharges from the NCWRF, SCWRF, WWRWRF, and MCWRF
- Wastewater sent from the Town of Cary to Durham County (emergency use only)
- Wastewater sent from the Town of Apex to City of Raleigh (emergency use only)
2.3 Data Assumptions
The calculation of IBT is essentially similar to performing a water balance – estimating how much of the water
withdrawn from the source basin ends up in each IBT basin as either treated wastewater discharge, potable
consumptive use, or reclaimed water consumptive use. The following assumptions are used to estimate
consumptive use and to account for factors such as wastewater system infiltration and inflow (I/I):
Potable consumptive use is estimated daily as the greater of (a) water produced minus wastewater generated
or (b) 5 percent of water used (typically in the winter or very rainy periods).
2 INTERBASIN TRANSFER CALCULATION
2-3
The percentages of consumptive use that occurs in the source basin and each IBT receiving basin are
estimated based on a review of actual water consumption data for customers in each IBT basin during
previous years. Based on this review, the assumed percentage of consumptive use in each basin is set at the
beginning of each year.
When wastewater discharge is greater than water used (including consumptive use), it is likely the result of
wastewater system I/I during very rainy periods. In these instances, the proportion of water use discharged as
wastewater in each IBT basin is assumed to be the same as the proportion of measured wastewater
discharged in each basin.
2.4 Interbasin Transfer Calculation
Generally, the sequence of the daily IBT calculations is as follows:
1. Estimate potable consumptive use from total potable water use and wastewater discharges, and calculate
total consumptive use by adding reclaimed water usage, as follows:
a. Potable consumptive use is estimated based on assumptions described in Section 2.3.
b. Reclaimed water usage is based on meter data.
2. Calculate amount of water use discharged as wastewater, calculated as the difference between the total
water withdrawal and total consumptive use.
3. Distribute consumptive use and water use discharged as wastewater by IBT basin: Haw, Cape Fear, and Neuse
River basins, as follows:
a. Consumptive use distribution by IBT basin is based on assumptions described in Section 2.3.
b. Water use discharged as wastewater distribution by IBT basin is based on the calculated proportion of
each water reclamation facility’s (WRF’s) metered discharge of the total WRF discharge multiplied by the
difference between total finished water produced and consumptive use.
4. Calculate the total returned and used in each basin, calculated as the total amount of consumptive use and
water use discharged as wastewater within the Haw, Cape Fear, and Neuse River basins.
5. Determine IBT from the Haw to the Cape Fear River basins, which is equal to consumptive use in the Cape
Fear River basin.
6. Calculate IBT from the Haw to the Neuse River basin as the sum of the Neuse River basin consumptive use and
water use discharged as wastewater, minus any Neuse River basin water withdrawal and purchase.
The average day IBT values will be calculated for each month in a calendar year from the daily IBT values
developed following the calculation steps outlined herein.
Table 1 provides a summary example of the calculations used for determining daily IBT amounts and the IBT
compliance metric: IBT calculated as an average day of a calendar month.
2 INTERBASIN TRANSFER CALCULATION
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2 INTERBASIN TRANSFER CALCULATION
2-5
TABLE 1
Sample of Daily Interbasin Transfer and Average Day of Calendar Month Interbasin Transfer Calculation
Column
Number: (1) (2) (3) (4) (5)=1+2+3+4 (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16)=6+7+12+13 (17)=8+9+14 (18)=10+11+15 (19)=16+17+18 (20)=8+9
(21)=18-
2-3-4
Water Withdrawal / Purchase (mgd) Consumptive Use (mgd) Water Use Discharged as Wastewater
(mgd) Total Return / Used (mgd) Interbasin Transfer
(mgd)
Haw
Withdrawal Neuse Basin Purchase Total
System Use Haw Cape Fear Neuse Haw Cape
Fear Neuse Haw Cape Fear Neuse Total Return/
Used
Haw to
Cape
Fear
Haw to
Neuse
Date Jordan Lake Raleigh Durham
Durham
County
Reclaimed
Potable WRF
Reuse Potable WRF
Reuse Potable WRF
Reuse
WTF
Process
Water
WRF WRF Total
WRFs
3/1/2015 18.52 0.00 0.00 0.03 18.55 0.25 0.03 0.01 0.00 0.58 0.19 1.98 0.00 3.98 11.54 2.26 3.99 12.31 18.55 0.01 12.3
3/2/2015 20.20 0.00 0.00 0.05 20.25 0.25 0.03 0.01 0.00 0.59 0.22 3.19 0.00 3.90 12.04 3.49 3.91 12.85 20.25 0.01 12.8
3/3/2015 16.60 0.00 0.00 0.04 16.64 0.23 0.03 0.01 0.00 0.53 0.23 1.43 0.00 3.49 10.68 1.69 3.50 11.44 16.64 0.01 11.4
3/4/2015 16.53 0.00 0.00 0.10 16.63 0.27 0.03 0.01 0.00 0.53 0.28 1.45 0.00 3.65 10.39 1.77 3.66 11.20 16.63 0.01 11.1
3/5/2015 18.49 0.00 0.00 0.04 18.53 0.25 0.03 0.01 0.00 0.58 0.26 1.83 0.00 3.82 11.75 2.11 3.83 12.58 18.53 0.01 12.6
3/6/2015 19.20 0.00 0.00 0.04 19.24 0.25 0.02 0.01 0.00 0.59 0.24 2.19 0.00 3.97 11.95 2.48 3.98 12.78 19.24 0.01 12.7
3/7/2015 19.43 0.00 0.00 0.04 19.47 0.23 0.03 0.01 0.00 0.55 0.25 3.74 0.00 3.89 10.76 4.01 3.90 11.56 19.47 0.01 11.5
3/8/2015 16.38 0.00 0.00 0.05 16.43 0.22 0.03 0.01 0.00 0.53 0.25 1.27 0.00 4.03 10.07 1.54 4.04 10.84 16.43 0.01 10.8
3/9/2015 23.16 0.00 0.00 0.04 23.20 0.37 0.03 0.02 0.00 0.67 0.30 3.8 0.00 4.88 13.21 4.13 4.89 14.18 23.20 0.01 14.1
3/10/2015 14.92 0.00 0.00 0.17 15.09 0.20 0.03 0.01 0.00 0.48 0.24 1.18 0.00 3.36 9.44 1.56 3.37 10.17 15.09 0.01 10.0
3/11/2015 19.88 0.00 0.00 0.04 19.92 0.34 0.05 0.02 0.00 0.60 0.28 2.72 0.00 4.08 11.94 3.02 4.09 12.82 19.92 0.01 12.8
3/12/2015 17.87 0.00 0.00 0.05 17.92 0.30 0.04 0.02 0.00 0.53 0.26 2.5 0.00 3.69 10.64 2.77 3.70 11.44 17.92 0.01 11.4
3/13/2015 16.74 0.00 0.00 0.04 16.78 0.50 0.10 0.04 0.00 0.54 0.25 1.33 0.00 2.13 12.26 1.60 2.14 13.04 16.78 0.01 13.0
3/14/2015 16.15 0.00 0.00 0.04 16.19 0.20 0.04 0.01 0.00 0.46 0.26 2.88 0.00 3.73 8.62 3.12 3.73 9.34 16.19 0.01 9.3
3/15/2015 18.54 0.00 0.00 0.05 18.59 0.24 0.04 0.01 0.00 0.57 0.26 2.03 0.00 4.85 10.58 2.32 4.86 11.41 18.59 0.01 11.7
3/16/2015 19.81 0.00 0.00 0.05 19.86 0.33 0.04 0.02 0.00 0.61 0.44 2.35 0.00 4.15 11.99 2.66 4.16 13.04 19.86 0.01 13.0
3/17/2015 19.91 0.00 0.00 0.05 19.96 0.32 0.05 0.02 0.00 0.55 0.38 4.2 0.00 3.75 10.80 4.48 3.75 11.72 19.96 0.01 11.7
3/18/2015 16.61 0.00 0.00 0.04 16.65 0.22 0.04 0.01 0.00 0.50 0.33 2.178 0.00 3.45 9.93 2.43 3.46 10.76 16.65 0.01 10.7
3/19/2015 18.67 0.00 0.00 0.04 18.71 0.23 0.17 0.01 0.00 0.54 0.36 3.18 0.00 3.69 10.66 3.45 3.70 11.56 18.71 0.01 11.5
3/20/2015 18.84 0.00 0.00 0.03 18.87 0.25 0.04 0.01 0.00 0.58 0.24 2.03 0.00 3.82 11.91 2.31 3.83 12.73 18.87 0.01 12.7
3/21/2015 17.95 0.00 0.00 0.04 17.99 0.21 0.05 0.01 0.00 0.50 0.29 3.46 0.00 3.46 10.01 3.71 3.47 10.81 17.99 0.01 10.8
3/22/2015 17.94 0.00 0.00 0.03 17.97 0.23 0.04 0.01 0.00 0.53 0.29 2.67 0.00 3.79 10.43 2.93 3.80 11.24 17.97 0.01 11.2
3/23/2015 16.58 0.00 0.00 0.03 16.61 0.68 0.04 0.06 0.00 0.51 0.31 1.8 0.00 2.49 11.25 2.04 2.50 12.07 16.61 0.01 12.0
3/24/2015 17.13 0.00 0.00 0.02 17.15 0.22 0.05 0.01 0.00 0.52 0.29 2.26 0.00 4.35 9.48 2.50 4.36 10.29 17.15 0.01 10.3
3/25/2015 19.20 0.00 0.00 0.05 19.25 0.25 0.05 0.01 0.00 0.59 0.34 2.23 0.00 4.06 11.71 2.53 4.07 12.65 19.25 0.01 12.6
3/26/2015 18.88 0.00 0.00 0.05 18.93 0.23 0.05 0.01 0.00 0.53 0.32 3.59 0.00 3.76 10.45 3.86 3.77 11.30 18.93 0.01 11.3
3/27/2015 18.15 0.00 0.00 0.04 18.19 0.23 0.04 0.01 0.00 0.54 0.30 2.68 0.00 3.54 10.85 2.95 3.55 11.69 18.19 0.01 11.7
3/28/2015 15.85 0.00 0.00 0.04 15.89 0.22 0.04 0.01 0.00 0.48 0.29 2.08 0.00 3.33 9.47 2.32 3.34 10.23 15.89 0.01 10.2
3/29/2015 18.13 0.00 0.00 0.04 18.17 0.23 0.03 0.01 0.00 0.53 0.28 2.86 0.00 3.86 10.36 3.12 3.87 11.17 18.17 0.01 11.1
3/30/2015 18.34 0.00 0.00 0.04 18.38 0.24 0.04 0.01 0.00 0.56 0.31 2.12 0.00 3.89 11.21 2.40 3.90 12.08 18.38 0.01 12.0
3/31/2015 19.36 0.00 0.00 0.05 19.41 0.24 0.03 0.01 0.00 0.56 0.31 3.38 0.00 3.83 11.04 3.67 3.84 11.90 19.41 0.01 11.9
Average
Day 18.19 0.00 0.00 0.05 18.24 0.27 0.04 0.01 0.00 0.55 0.28 2.47 0.00 3.76 10.88 2.75 3.77 11.72 18.24 0.01 11.7
2 INTERBASIN TRANSFER CALCULATION
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3-1
SECTION 3 Reporting Methodologies and Schedules
Compliance with the permitted IBT limits from the Haw River basin to the Neuse River basin, and from the Haw
River basin to the Cape Fear River basin, is required in the IBT certificate to be reported quarterly. The status of
the additional eight conditions that the Towns must meet in order to maintain compliance with the IBT certificate
will be reported annually.
3.1 Compliance Reporting
3.1.1 Quarterly Reporting
At the end of each quarter, the Towns will calculate the daily average IBT amount for each month in the quarter
and post this information on the Town of Cary website within 30 days after the end of the quarter. NCDWR will be
able to review and download the information from this website, as will the public.
The schedule for quarterly reporting is as follows:
Quarter 1 (Q1) – report due by April 30 (Q1 includes January, February, and March)
Quarter 2 (Q2) – report due by July 30 (Q2 includes April, May, and June)
Quarter 3 (Q3) – report due by October 30 (Q3 includes July, August, and September)
Quarter 4 (Q4) – report due by January 30 (Q4 includes October, November, and December)
3.1.2 Annual Reporting
At the end of each calendar year, by May 1 of the following year, the Towns will submit an Annual IBT Report to
NCDWR with the following information:
1. Summary of historical water withdrawals, reclaimed water usage, wastewater discharges, and IBT, beginning
with the 2015 award date of this IBT certificate for the 2015 Annual Report and reported for the January to
December calendar year thereafter.
2. Table of calculated daily IBT amounts for January 1 to December 31 of the reporting year.
3. Table of calculated daily average of calendar month IBT amounts for the reporting year.
4. Summary of amount of water used during previous years by customers in the Neuse River, Haw River, and
Cape Fear River basins for use in determining the distribution of consumptive uses among the basins. Based
on the amount of water used in each basin for the previous year, the distribution of consumptive use by basin
in the following calendar year will be determined and documented.
5. Status of compliance with IBT certificate limits and conditions.
3.2 Compliance Schedule
The schedule for monitoring and reporting on IBT certificate compliance is provided in Table 2.
3 REPORTING METHODOLOGIES AND SCHEDULES
3-2
TABLE 2 Interbasin Transfer Compliance Monitoring and Reporting
Description a Comments
IBT Limits
Daily average of a calendar month:
- 31 mgd Haw to Neuse
- 2 mgd Haw to Cape Fear
Daily average IBT is calculated daily and reported in the Annual IBT Report.
IBT calculated as the daily average of a calendar month reported on the Town of
Cary website quarterly and in the Annual IBT Report.
The percentages of water use in each basin, summarized historically, and set for
calculating daily IBT for the next year will be reported in the Annual IBT Report.
Condition 1 Water Conservation Plan
Initial submittal to NCDWR by June 10, 2015, and then revised as needed to
obtain NCDWR approval. Updates, if necessary, will be provided to NCDWR in
the Towns’ respective Secondary and Cumulative Impacts Master Management
Plan biennial updates.
Water Conservation Plan will always be available on the Town of Cary website.
Status of the plan will be included in the Annual IBT Report.
Condition 2 Drought Management Plan
Initial submittal to NCDWR by June 10, 2015, and then revised as needed to
obtain NCDWR approval. Updates will be provided to NCDWR as needed.
Drought Management Plan will always be available on the Town of Cary website.
Status of the plan will be included in the Annual IBT Report.
Condition 3 IBT Compliance and Monitoring
Plan
Initial submittal to NCDWR by June 10, 2015, and then revised as needed to
obtain NCDWR approval.
IBT Compliance and Monitoring Plan will always be available on the Town of
Cary website.
Status of the plan will be included in the Annual IBT Report.
Condition 4 EMC Consideration of Alternative
Sources No reporting necessary.
Condition 5 EMC Consideration of Future
Water Demand No reporting necessary.
Condition 6 Resale of Transferred Water Included in the Annual IBT Report.
Condition 7 EMC Consideration of Impacts No reporting necessary.
Condition 8 Intake Access Included in the Annual IBT Report.
a Certificate conditions are described in Section 1.
4-1
SECTION 4 References
CH2M HILL. 2001. Compliance and Monitoring Plan. Prepared for RTP South and the Towns of Cary, Apex, and
Morrisville.
North Carolina Division of Water Resources (NCDWR). 2009. Regulation of Surface Water Transfers Statutory
Guidance. http://www.ncwater.org/files/IBT_guidance_v1.pdf. Accessed April 10, 2015.
North Carolina Environmental Management Commission (EMC). 2015. Certificate Authorizing the Towns of Cary
and Apex to Transfer Water from the Haw River Basin to the Neuse and Cape Fear River Basins.
http://www.ncwater.org/files/ibt/CaryApex/IBT_Modification_Certificate_signed.pdf.
4 REFERENCES
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