volume 1 - Halifax Regional Municipality

Halifax Water Integrated Resource Plan
Integrated Resource Plan Development and Evaluation
• Objective 1 – Current Wastewater Compliance (other than for projects within the
Five-Year Capital Plan).
• Objective 3 – Current Wastewater Overflow Compliance.
• Objective 4 – Future Wastewater System Compliance.
As shown in Table 5.3, two variations were considered for nutrient reduction upgrading
at the 10 WWTFs discharging to receiving waters with limited assimilative capacity. The
WWTFs considered were: Aerotech, BLT, Fall River, Frame, Middle Musquodoboit, Mill
Cove, North Preston, Springfield Lake, Uplands and Wellington. Under the option
termed “Modified RWWFP” 9 of 10 WWTFs were upgraded to the limit-of-technology
for nutrient (N and P) reduction. The BLT facility was already undergoing substantial
upgrade, which was incorporated into this option. The timing of the upgrades other
than BLT was as per the variations considered under IRP Objective 4 as shown in Table
5.4. Under the second option designated “RWWFP”, 8 of 10 WWTFs were upgraded, the
current upgrade of BLT satisfied short-term requirements while the consolidation of the
remaining two – BLT and Springfield Lake as per the concept of the RWWFP satisfied
long term requirements. The timing of the upgrades other than BLT was as per the
variations considered under IRP Objective 4. The timing of the consolidations was fixed
as per the RWWFP.
The RWWFP provided a baseline level of overflow control that offset the impacts of
growth for only the 28 modeled overflows with tributary growth. This was termed
“Baseline” overflow control. As noted previously, the timing of the Baseline was fixed by
the RWWFP. A second level of overflow control addressing 31 overflows including 9 with
baseline controls provided by the RWWFP was also developed as the Enhanced
Program.
At present there is no regulatory requirement or associated timing that corresponds to
the Enhanced Overflow Control Program. Hence, given these uncertainties, the
Enhanced Program was incorporated with a fixed 30-year timing at the end of the IRP
planning period.
A, B, C levels of asset renewal (Objective 8) were considered for both point and linear
assets in the initial and intermediate resource plans. As was explained above and in Volume
1 Appendix F, these were converted into a composite plan for the refined and shortlisted
plans.
5.6 PLAN ANALYSIS ASSUMPTIONS
The capital costs and change in operating and maintenance (O&M) costs associated with
all alternative resource plans were entered into a financial modeling tool developed for
the IRP. The IRP financial model facilitates data entry, enables calculation of the 30-year
net present value (NPV), evaluation of the impact of the variations on the 30-year NPV,
and can present capital and O&M costs by driver, objective, and asset system as well as
Revision: 2012-10-29 Integrated Resource Plan 55
October 31 2012 Page 88 of 272