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Midland Avenue RTF and Conveyances: Facility Plan Amendment, June 2003
by Environmental Engineering Associates, LLP
for Onondaga County Department of Water Environment Protection
2. Supplemental facilities planning
Subsequent to the preparation of the September 2001
Facilities Plan, a number of supplemental facilities
planning activities were undertaken to further refine
and enhance the development of the most appropriate
and cost-effective CSO abatement plan for the Midland
Avenue RTF and Conveyances Project. These supplemental
facilities planning activities are described in
further detail below.
Due to the proximity of the Newell Street CSO (CSO
067) tributary drainage area to the Midland Avenue CSO
service area, the County considered it advisable to
investigate whether or not it would be more
cost-effective to install a regional treatment
facility (RTF) at the Newell Street CSO overflow
location or convey CSO 067 flows to the Midland Avenue
RTF. A memorandum describing this evaluation is
presented as Appendix 3. This evaluation demonstrated
that it would be more cost-effective to convey Newell
Street CSO (CSO 067) flow, up to the one-year design
storm event, to the Midland Avenue CSO conveyances and
subsequently to the Midland Avenue RTF for treatment.
Subsequent to developing the Newell Street CSO
Abatement Evaluation Memorandum (Appendix 3), an
analysis was conducted to determine the additional
impacts that would be associated with closing CSO 067
as part of the Midland Avenue RTF and Conveyances
Project.
This analysis (see Appendix 4) revealed that
by increasing to 42-inch diameter the proposed 36-inch
diameter Newell Street CSO conveyance pipeline (for
the one-year design storm event) to its connection
with the Midland Avenue CSO transmission pipeline at
West Brighton Avenue, CSO 067 can be completely closed
with minimal impacts to the downstream Midland Avenue
Conveyances and RTF. The closure of CSO 067 was,
therefore, determined to be appropriate to include in
the Midland Avenue RTF and Conveyances Project.
Appendix 4. Memorandum: Newell St. CSO closure evaluation
The closure of CSO 067 will require the construction
of a conveyance pipeline from CSO 067 to the
previously proposed upstream termination point of the
Midland Avenue CSO transmission pipeline at West
Brighton Avenue. A new diversion structure would be
constructed at the intersection of West Newell Street
and Vale Avenue to divert CSO into a new 42-inch
diameter conveyance pipeline. The conveyance pipeline
would be routed northeasterly along Onondaga Creek
approximately 1,500 linear feet to a point of
connection with the proposed Midland Avenue CSO
transmission pipeline at West Brighton Avenue. The
previously installed Newell Street CSO demonstration
facility located at the CSO 067 outfall would also be
decommissioned and abandoned.
Subsequent to the preparation of the Sewer Separation
Evaluation Memorandum (dated October 1998) presented
in Appendix A of the September 2001 Facilities
Plan—which evaluated the cost-effectiveness of
separating sewers in other CSO drainage basins within
the Midland Avenue CSO service area not previously
scheduled for sewer separation—the County had a
separate analysis of up-to-date sewer separation costs
completed by its ACJ Oversight Program Manager CDM/C&S
Joint Venture. This analysis, presented in a CDM/C&S
memorandum (included as Appendix 5) to the County
dated April 30, 2001 (issued September 10, 2001),
established recommended unit costs for sewer
separation for both residential and commercial areas
in the metropolitan Syracuse area.
Appendix 5. Memorandum: Recommended sewer separation unit costs
These recommended unit costs for sewer separation were
identified to be 70% (residential areas) to 215%
(commercial areas) higher than the unit cost for sewer
separation (dollars per linear feet) used for cost
comparisons in the October 1998 Sewer Separation
Evaluation memorandum. This information further
supports the conclusion of the October 1998 Sewer
Separation Evaluation that in comparing the costs of
conveying CSO flows for storage and/or treatment at
the Midland Avenue RTF, there are no cost benefits to
separating additional CSOs within the Midland Avenue
CSO service area, with the exception of a minor
Glenwood area sewer separation project as described
below.
During the development of the October 1998 Sewer
Separation Evaluation Memorandum, the County met with
representatives of the City of Syracuse to identify
potential future, cost-effective sewer separation
projects within the Midland Avenue CSO service area.
During these discussions, the City identified a small
area in the vicinity of Glenwood Avenue in the CSO 052
drainage basin where sewer separation may alleviate
local drainage problems. No facilities planning design
and/or cost effectiveness evaluation has been
conducted by the County to date nor have potential
project boundaries been established.
As discussed in Section 2.2, it has been determined to
be cost-effective to include CSO 067 in the Midland
Avenue RTF and Conveyances Project. Table 2-1,
therefore, presents an updated summary of the Midland
Avenue CSOs.
| TABLE 2-1. MIDLAND AVENUE SERVICE AREA OVERFLOWS |
|
No.
|
ID
|
Drainage area (acres)
|
Location
|
CSO abatement strategy**
|
|
1
|
038
|
10
|
Taylor Street
|
4
|
|
2
|
039
|
478
|
Tallman Street - East
|
3
|
|
3
|
040
|
12
|
Tallman Street - West
|
4
|
|
4
|
041
|
3
|
Oxford Street
|
4
|
|
5
|
042
|
248
|
Midland Avenue - West
|
3
|
|
6
|
043
|
493
|
Midland Avenue - East
|
2
|
|
7
|
044
|
115
|
West Castle Street/South Avenue
|
3
|
|
8
|
045
|
7
|
West Castle Street/Hudson Street
|
4
|
|
9
|
046A
|
15
|
Onondaga Avenue
|
4
|
|
10
|
046B
|
16
|
Onondaga Avenue
|
4
|
|
11
|
047
|
<1
|
South Avenue - North
|
4
|
|
12
|
048
|
9
|
South Avenue - South
|
4
|
|
13
|
049
|
5
|
Kirk Park - North
|
1
|
|
14
|
050
|
30
|
Rockland Avenue/Hunt Avenue
|
4
|
|
15
|
051
|
25
|
West Colvin Street/Hunt Avenue
|
4
|
|
16
|
052
|
228
|
Elmhurst Avenue/Hunt Avenue
|
2
|
|
17
|
053
|
10
|
Marguerite Avenue/Hunt Avenue
|
4
|
|
18
|
054
|
10
|
West Brighton Avenue/Hunt Avenue
|
4
|
|
19
|
060
|
28
|
West Colvin Street/Onondaga Creek
|
2
|
|
20
|
061
|
3
|
Crehange Street/Onondaga Creek
|
2
|
|
21
|
062
|
15
|
West Brighton Avenue - East
|
1
|
|
22
|
067
|
42
|
West Newell Street
|
2
|
|
23
|
076
|
86
|
West Brighton Avenue/Midland Avenue
|
2
|
|
24
|
077
|
445
|
Midland Avenue/West Colvin Street
|
(discharges to Overflow 060)
|
|
25
|
093
|
N/A*
|
Kirk Park Siphon Chamber Emergency Bypass (not a CSO)
|
1
|
|
|
|
Total
|
2,345
|
|
|
* N/A: Previous emergency bypass off MIS siphon; no associated drainage area.
|
** CSO abatement strategy:
1. Previously permanently closed
2. Closure upon project completion
3. Discharge in excess of 1-year storm only
4. Conversion to storm water only via sewer separation
Due to the inclusion of CSO 067 in the Midland Avenue
RTF and Conveyances Project (Midland Project), the
following presents an updated summary of the resultant
disposition of the existing CSOs in the Midland Avenue
tributary service area upon completion of the Project.
See Table 2-1 and Figure 2-1 which list and depict the
location of the CSO basins described below.
Click here for Figure 2-1.
| TABLE 2-2. MOST VIABLE ALTERNATIVES: ESTIMATED COSTS |
|
Alternative
|
Estimated project cost
|
Estimated annual O&M cost
|
Estimated 25-year present worth
|
|
1. 667 cfs RTF (plus 4.2 MG upstream storage)
|
$55,610,000
|
$684,000
|
$65,100,000
|
|
2. 330 cfs RTF (plus 6.7 MG upstream storage)
|
$55,240,000
|
$525,000
|
$62,500,000
|
|
3. 12 MG underground storage tank (plus additional 4.2 MG upstream storage)
|
$80,410,000
|
$413,000
|
$86,200,000
|
Notes: 1. Costs based on June 2003 Dollars (ENRCCI=6662).
2. 25-year present worth based on 5% discount rate, rounded to nearest $100,000.
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These will remain active overflow diversions that will
only activate above the one-year design storm event
upon completion of the Midland Project. This will be
achieved by implementing modifications to the existing
regulator structures for the CSOs. Flow above the
one-year design storm event will continue to discharge
to Onondaga Creek through the existing CSO outfalls.
These are active overflow diversions that will be
permanently closed upon completion of the Midland
Project (note: former overflow 077 will continue to
discharge to the CSO 060 regulator structure for
subsequent conveyance to the Midland Avenue CSO
transmission pipeline and RTF; overflow 077 at no time
has separately discharged directly to Onondaga Creek).
The method of closure for the CSOs will be site
specific, depending upon existing site and regulator
structure details. In general, closure is anticipated
to include bulkheading of the existing CSO outfall
pipe at the CSO regulator structure and construction
of a new connection pipeline from the regulator
structure to a new CSO transmission pipeline, with
subsequent conveyance of CSO to the Midland Avenue
RTF.
The ACJ listed 16 CSO basins within the Midland
service area to be abated through sewer separation.
The County contracted with the United States Army
Corps of Engineers (USACOE) in September 1998 to
design and complete an environmental assessment for
these abatement projects. Several sewer separations in
the Clinton Street CSO service area were also included
in the County-USACOE contract. The USACOE
subcontracted with O'Brien & Gere Engineers to
undertake the design work. To date, the County has
completed sewer separation of CSO basins 023/024 on
Water Street in downtown Syracuse (Clinton Street CSO
service area) and is proceeding with construction of
sewer separation in CSO basins 053/054 to be completed
in 2003.
These are active overflow diversions that will be
closed by sewer separation as part of the Midland
Project, by the County. CSO 041 will include the
installation of new storm only sewers within the
drainage basin and a new storm only discharge to
Onondaga Creek. The existing combined sewer will be
converted to a sanitary only sewer with direct
connection into the MIS. The CSO 047 drainage basin is
anticipated to be separated similarly.
These are former overflow diversions that were
previously permanently closed. The previous CSO
outfall pipes from the regulator structures have been
bulkheaded and all drainage basin flow is conveyed to
the MIS.
This was previously a siphon chamber emergency bypass
off the MIS at its crossing of Onondaga Creek. This
emergency bypass was previously permanently closed.
Overflow 093 does not have an associated drainage area
as it was an MIS emergency relief bypass.
As presented in the September 2001 Facilities Plan,
the recommended CSO abatement plan for the Midland
Avenue RTF and Conveyances Project was to include
construction of various CSO transmission pipelines and
an RTF with a 667 cubic feet per second (cfs) peak
influent pumping rate located at the recommended RTF
site as described in Section 1.3. Subsequent to the
preliminary design development for the 667 cfs RTF, a
series of mediation meetings were held with
representatives from the County, the City of Syracuse,
NYSDEC, the Partnership for Onondaga Creek, Atlantic
States Legal Foundation, and the Onondaga Nation to
discuss alternatives to the 667 cfs RTF. Non-county
mediation representatives expressed concern regarding
the size of the aboveground structure for the 667 cfs
RTF and the issue of chlorinated/dechlorinated
discharges from the RTF. Complete underground storage
of the Midland Avenue CSOs with subsequent conveyance
and treatment at Metro was identified as the preferred
CSO abatement approach by the non-County mediation
participants.
Through multiple meetings and discussions with the
mediation representatives, various reduced size RTF
and large underground storage alternatives were
evaluated. The results of these evaluations
demonstrated that the three most viable alternatives
for the Midland Avenue CSOs when considering cost,
impacts, and constructability were as follows:
-
RTF with 667 cfs peak influent design pumping rate
plus large diameter upstream conveyance providing 4.2
million gallons (MG) of upstream storage (total system
storage equals 7.6 MG).
-
RTF with 330 cfs peak influent pumping rate plus
large diameter upstream conveyances (4.2 MG) and
off-line underground storage tank (2.5 MG) providing
6.7 MG of upstream storage (see Midland RTF Size
Evaluations memorandum - Appendix 6) (total system
storage equals 8.45 MG).
-
Large (12 MG) underground storage tank (with no
RTF) plus large diameter upstream conveyances
providing 4.2 MG of storage upstream of the 12 MG
underground storage tank plus sewer separation for CSO
tributary areas 076 and 067 (total system storage
equals 16.2 MG).
Capital, operation and maintenance (O&M) and 25-year
present worth costs were developed for the above three
alternatives. These costs are presented in Table 2-2.
Based upon the cost data presented in Table 2-2, the
County determined that Alternative 2 - 330 cfs RTF
plus 6.7 MG of upstream storage (total system storage
equals 8.45 MG) is the preferred approach to abating
the Midland Avenue CSOs. In addition to having the
lowest estimated project cost and 25-year present
worth, this alternative provides a smaller above grade
structure for the RTF due to its reduced size and
maximizes the cost-effective use of upstream,
underground storage, while decreasing the number and
volume of treated discharges to Onondaga Creek.
Note:
Parties to the mediation process, excluding the
County, continue to advocate for Alternative 3. The
County had offered to proceed with that alternative on
the following conditions:
-
The City contribute $7.975 million for the sewer separation at CSO basins 067/076.
-
The City contribute the required City-owned properties for the Midland Avenue and Clinton Street CSO abatement projects.
-
The City support construction of an RTF project for the Clinton Street CSO abatement project.
See Appendix 7 for a comparison of advantages and disadvantages of Alternative 2 and Alternative 3.
Upon identifying Alternative 2 - 330 cfs RTF plus 6.7
MG of upstream storage as the preferred CSO abatement
approach for the Midland Avenue RTF and Conveyances
Project, the County evaluated various facility layouts
to accomplish this proposed approach. As noted in
Appendix 6—Midland RTF Size Evaluations—the 6.7 MG
of upstream storage would be composed of 4.2 MG of
in-line storage in the Midland Avenue Conveyances plus
2.5 MG of additional in-line/off-line storage.
During preliminary planning for the additional 2.5 MG
of in-line/off-line storage, a parallel 12-foot
diameter pipeline, 900 feet in length (0.8 MG storage)
plus a 1.7 MG off-line underground storage tank were
considered as options to achieve the total required
storage of 2.5 MG. Further review of the available
land area for locating the additional 2.5 MG of
upstream storage (northeast intersection of Midland
Avenue and West Castle Street on the east side of
Onondaga Creek) revealed that construction of the
parallel 12-foot diameter pipeline would potentially
interfere with the stability of the existing Main
Interceptor Sewer (MIS) that parallels the eastern
edge of Onondaga Creek in close proximity to the
proposed parallel pipeline.
Therefore, it was determined that a single, 2.5 MG
underground storage tank directly upstream of the
proposed Midland Avenue RTF provides the most
practical and cost-effective upstream, off-line
storage option for use in conjunction with the 330 cfs
RTF. The parallel storage pipeline was also considered
not to be desirable from an operation and maintenance
standpoint.
The County established a conceptual plan layout for the 330 cfs RTF plus 6.7 MG of in-line/off-line storage as shown on Figure 2-2.
This plan included a single, upstream 2.5 MG
underground storage tank in the vicinity of the
Midland Avenue/West Castle Street, an aboveground RTF
building in the Blaine/Oxford Street area, and an
underground disinfection tank extending into Central
New York Regional Transportation Authority (CNYRTA)
property that would be purchased by the County.
In February 2003, the County approached the CNYRTA to
consider allowing the County to purchase CNYRTA
property north of Oxford Street to locate the RTF
aboveground building further away from the existing
residences located on Blaine Street. The CNYRTA
subsequently agreed to consider the property transfer
to the County. Based upon the potential availability
of this property, a revised conceptual plan layout for
the 330 cfs RTF plus 6.7 MG of in-line/off-line
storage was developed.
This plan layout is shown on Figure 2-3.
With the availability of the CNYRTA
property described above, it was determined possible
to locate the 2.5 MG upstream underground storage tank
in the Blaine Street-Oxford Street area rather than in
the vicinity of Midland Avenue-West Castle Street. The
aboveground RTF building and underground disinfection
tank would be primarily located on property to be
purchased from the CNYRTA by the County. The 2.5 MG
upstream underground storage tank would be located on
land recently acquired by the County from the Syracuse
Urban Renewal Agency (SURA) between Blaine Street and
Oxford Street.
A preliminary cost comparison between the two
conceptual plan layouts also indicated that locating
the 2.5 MG underground storage tank in the Blaine
Street/Oxford Street area results in both construction
cost and operation and maintenance cost savings. The
revised conceptual plan layout depicted on Figure 2-3
was, therefore, selected by the County as the
recommended CSO abatement plan for the Midland Avenue
RTF and Conveyances Project.
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2. Supplement
Susan Miller, Project Deputy Director
Onondaga County Dept of Water Environment Protection