Harbor Brook CSO Abatement Project Facility Plan (Aug 2005)
by Brown and Caldwell
for Onondaga County Dept of Water Environment Protection

1. Basis for CSO Abatement

1.1 Introduction

Onondaga County entered into an Amended Consent Judgment (ACJ) on January 20, 1998. Under Section 14 of the ACJ, entitled [Combined Sewer Overflow] CSO Control and Upgrade Compliance Schedule, it states:

The County shall design, construct, maintain and modify and/or supplement, as necessary, a CSO control and upgrade program in accordance with [NYS Department of Environmental Conservation] DEC CSO guidance, as set forth in [Technical and Operations Guidance Series] TOGS 1.6.3 (CSO Control Strategy), which implements the “presumptive approach” in [US Environmental Protection Agency] EPA's CSO control policy, as set forth in 59 F.R. 18688 (April 18, 1994). The County's program shall achieve the following:
 
A. elimination or the capture for treatment of no less than 85% by volume of the combined sewage collected in the combined sewer system during precipitation events on a system-wide annual average basis
B. elimination or minimization of floating substances in Onondaga Lake attributed to the County's CSOs
C. achievement of water quality standards for bacteria for all portions of Onondaga Lake that are classified as “Class B” pursuant to 6 NYCRR Part 895.

The Harbor Brook In-Water System (HB IWS) is listed in the ACJ as an Interim CSO Project. The ACJ references the HB IWS as follows:

The CSO abatement proposed on Harbor Brook will use an in-lake technology called the EquiFlow system. The intent of this project is to be a demonstration project to determine the technical applicability of its use in this location. The maximum term of the initial project is 15 years. This system will provide an opportunity to demonstrate abatement of CSO, urban stormwater, and non-point pollution through a combination of floatable solids entrapment, in-water storage, pumpback, and treatment at Metro [Metropolitan Syracuse Wastewater Treatment Plant]. The in-water system will also include the construction of a floatable solids netting device to remove CSO and stormwater floatables from Harbor Brook before they reach the Equiflow system. (ACJ Appendix B, p. 10)
 
The Harbor Brook floatables netting device will be located in the downstream reach of the brook between Hiawatha Boulevard and the outlet to Onondaga Lake. By placing the facility as close to the lake as possible, floatables capture will be most effective for the entire brook. The purpose of this facility is to capture most of the floatable material that is discharged to the lake from Harbor Brook. A secondary purpose of this facility is to capture floatables in the brook before they enter the proposed Equiflow? facility.” (ACJ Appendix B, p. 12)
 
Complete construction and begin operation of each and every CSO Interim Project by July 1, 2002.” (ACJ Appendix B, p. 13)
 
If the [HB IWS] project is not deemed technically acceptable, the County will proceed with the design and construction of the Delaware and State Fair RTFs [regional treatment facilities] at a schedule to be proposed by the County to DEC. (ACJ Appendix B, p. 10)
 
The County, with input as provided by the City of Syracuse, will review infrastructure needs, maintenance considerations, and potential opportunities for sewer separation before the start of the following activity for the identified projects:
a. Design of the Midland Avenue Conveyances Project
b. Design of the Clinton Conveyances Project
c. Design of each of the RTF facilities within the Harbor Brook drainage area, should RTFs be necessary. (ACJ Appendix B, p. 9)

The regional facility may be designed to store and/or treat CSO. Regional facilities will be referred to as Regional Treatment Facilities (RTF) or Floatables Control Facilities (FCF).

The purpose of the Harbor Brook CSO Facilities Plan is to evaluate the HB IWS in comparison to other alternatives for abatement of CSOs in the Harbor Brook basin, including regional facilities and sewer separation based upon engineering and operational considerations, environmental and community impacts, and cost effectiveness.

In-water treatment of the County's CSOs was first proposed in an August 1983 report entitled, “In-Water Combined Sewer Overflow Abatement Study,” as an alternative to constructing a number of the regional treatment facilities that were recommended in the 1979 CSO Facilities Plan. At that time, two in-water treatment facilities were considered, one for Onondaga Creek and one for Harbor Brook. During development of the draft Municipal Compliance Plan in the early to mid-1990s the Onondaga Creek facility was dropped from consideration leaving only the Harbor Brook in-water facility included in the ACJ.

1.2 Harbor Brook watershed

Harbor Brook is one of the primary tributaries to Onondaga Lake, and has three water quality designations, as listed in 6 NYCRR Part 895.4: Class C from the source waters to the City of Syracuse line (i.e. the vicinity of Velasko road and CSO 078); Class B from the City line to the covered section (i.e. the vicinity of Delaware Street and CSO 014); and Class C through the covered section to Onondaga Lake. These areas are shown in Figure 1.1.

Figure 1.1. Harbor Brook watershed

These Classes are defined in 6 NYCRR Part 701, as follows:

• "§701.7 Class B fresh surface waters. The best usages of Class B waters are primary and secondary contact recreation and fishing. These waters shall be suitable for fish propagation and survival.”
• "§701.8 Class C fresh surface waters. The best usage for Class C waters is fishing. These waters shall be suitable for fish propagation and survival. The water quality shall be suitable for primary and secondary contact recreation, although other factors may limit the use for these purposes.”

The Harbor Brook watershed has a surface area of 8,234 acres. The land use in the southern, or upper, section of the watershed consists predominately of suburban and residential areas and agricultural lands that have different hydrologic responses than the northern, or lower, urbanized section. The urbanized areas of the Harbor Brook basin are located within the farthest downstream reaches of the watershed and are closest to Onondaga Lake. The 1,221-acre combined sewered area within the urbanized portion of the Harbor Brook basin, as shown on Figure 1.1, constitutes approximately 20% of the combined sewer area tributary to Metro.

The reach of Harbor Brook that flows through the urban portion was channelized during the 1930s as part of the U.S. Army Corps of Engineers (USACOE) city-wide flood control program from Velasko Road to the Lake. In 1980 Onondaga County constructed a flood detention basin between Velasko Road and DePalma Avenue, which was improved in 1999.

South of the detention basin, Harbor Brook is characterized as an open, trapezoidal section from DePalma Ave. to Delaware Street; a section from Delaware St. to State Fair Blvd., which with the exception of a short reach near Fowler High School is covered; and another open, trapezoidal section from State Fair Boulevard to Onondaga Lake.

For the purposes of this facilities plan, the urbanized (combined sewer-service) portion of the watershed will be broken up into three general areas with the following designations:
Upper Basin, which begins near Velasko Road
Middle Basin, which is the predominantly covered section
Lower Basin, which is the northernmost open section that ends at the Lake.

The Onondaga County Harbor Brook Drainage District is administered by the Onondaga County Department of Water Environment Protection (OCDWEP), which is responsible for the operation of the Velasko Road Detention Basin. This detention basin was constructed in 1980, and includes a dam and flow-regulating device located at the end of DePalma Ave. The detention basin was expanded near the east end so that it would retain stream flows up to and including the 25-year design storm. The basin expansion, channel and culvert improvements were completed in 1999. The flow-regulating structure was modified to increase the maximum basin discharge to 480 cfs (the previous discharge rate was 300 cfs).

1.3 Harbor Brook combined sewer collection system

A total of 18 CSOs from the Harbor Brook watershed discharge into the Brook from 18 combined sewer drainage areas. The characteristics of each CSO have been summarized in Table 1.1.
 

Table 1.1 Lower Basin
CSO	Location	Basin area (acre)	Overflow location	Peak rate (cfs)*	Volume (MG)
063	Emerson Ave., SW	122	West side	57	0.55
003	Hiawatha Blvd.	112	West side	95	1.15
064	State Fair Blvd.	350	West side	131	2.10
Total volume: 3.8 MG

The locations of all CSO outfalls and drainage areas are shown in Figure 1.2.
These areas are shown on an aerial photo in Figure 1.3.

Sanitary sewage and storm water from these areas collects in a network of pipes that discharge into the Harbor Brook Interceptor Sewer (HBIS). The HBIS starts near Velasko Road as a 15-inch pipe located on the south side of the Brook, which it generally parallels as it flows north toward the lake.

Click to enlarge

See Figure 1.4.

The HBIS gradually increases in size and capacity until it becomes a 50-inch diameter pipe that terminates at the Harbor Brook Pumping Station, which is located along Hiawatha Blvd. adjacent to the Metro headworks. The Harbor Brook Pumping Station is equipped with three Archimedes screw pumps (two duty and one standby) that discharge to the Main Interceptor Sewer (MIS), which flows to the New Screenings and Grit (NSG) side of the Metro headworks. The maximum capacity of this pumping station is 30 MGD with two pumps running. Flows in excess of the capacity of the HBIS are relieved through Combined Sewer Overflows (CSOs), which discharge to Harbor Brook.

The regulator manholes (also known as diversion or overflow manholes) and sewer pipes were typically constructed at the same time as the HBIS, circa 1920. The regulator and interceptor sewers are typically sized to accommodate the anticipated dry-weather flow and a small component of wet-weather flow from a drainage area. Wet-weather conditions can cause flow in the combined sewer to increase above the capacity of the pump station, regulator and/or interceptor sewers. During such conditions, the combined sewage backs up and is stored in the system until the level of the combined sewage reaches the crest of the overflow weir. The excess flow passes over the weir to the combined sewer overflow pipes that discharge to the Brook.

The oldest portions of the HBIS are those from Hoeffler Street north to Fayette Street. In this stretch the HBIS is a 30-inch slab top sewer that is in poor condition. In addition, in the vicinity of Fowler High School the HBIS appears to have a significant defect that has reduced its capacity by more than 50 percent.

Another known area of concern is associated with CSO 018. The overflow chamber has high flows during springtime conditions and may be causing dry-weather overflows during these periods. During the late spring of 2004, it was observed that significant flow was being discharged to the combined sewers at the Glenwood Avenue drainage boundary from the Bellevue Golf Course. While there was no dry-weather overflow occurring at the time, the flow was very close to overflowing at the overflow chamber. This flow appears to be drainage from the golf course's pond. Additional investigation will be necessary during spring time conditions to evaluate the potential for dry-weather overflows.

Hydraulic modeling has shown that the existing conveyance capacity (the sum of regulator-interceptor flows and overflows) of the Harbor Brook combined sewer system is generally limited to flow rates resulting from events less than, or equal to, the 5-year recurrence interval storm. Wet-weather flow that cannot enter the combined sewer system is either stored at street level or passes along the surface until it can either enter the system, or it reaches Harbor Brook.

The Storm Water Management Model (SWMM) has been used to develop the flows and volumes used throughout this report. The model development, calibration and projections are documented in a report entitled “Harbor Brook SWMM Modeling Report” and is included in Appendix A.
Click here for Appendix A. Harbor Brook SWMM Modeling Report.
Note: Please add the following to p. 19 of Appendix A: The average annual volumes developed with the long-term simulation used a historical rain record from 1963 to 1993. The average annual volume represents the volume generated by the model, divided by 30 years.

1.4 Impacts of CSO discharges

With the exception of CSOs 063 and 018, all of the overflows discharge directly to Harbor Brook. Overflows from CSO 018 flow through a short, grass-lined swale located in the detention basin before discharging to Harbor Brook. Overflows from CSO 063 currently flow through a “retention basin” created by the flow restriction of a culvert under the rail lines just east of Erie Blvd. Just downstream of the rail lines flow passes through a natural wetland before passing under the Ontrack rail line and then discharges to Harbor Brook.

The discharge of untreated sewage through combined sewer overflows to Harbor Brook contributes to conditions where the bacterial levels in Onondaga Lake exceed the coliform standards set in 6 NYCRR Part 703.4. However, computer modeling has been used to demonstrate that the disinfection of all CSOs is not required to achieve water quality standards for bacteria in those portions of Onondaga Lake designated as Class B. See Appendix B for a summary of the Bacteria Model developed for Onondaga Lake.
Click here for Appendix B. Memorandum: Bacterial model update for Onondaga Lake.

CSOs also contribute to the release of floating solids in violation of 6 NYCRR Part 703.2. The term floating solids or “floatables” is used to describe those materials that float at or near the water surface, and can include neutrally buoyant materials that are carried along within the flow. Besides being unsightly in the water bodies, floatables may also be a source of pathogens and biochemical oxygen demand (BOD). CSO-related pollutants have a negative impact on the ecology of natural waters and contribute to problems in other areas of the environment. The nature of floatable material can vary widely, and can include:

• Street litter such as plastics, paper and cigarette butts
• Natural material such as leaves, branches and twigs
• Sewage-related material such as condoms, tampons, toilet paper, fecal matter and other material flushed down toilets.

The quantity of floatable material that is discharged can also vary widely depending on the:

• Degree to which the watershed is littered
• Number of antecedent dry-weather days during which litter can accumulate
• Implementation and maintenance of upstream source controls
• Land use
• Season
• Intensity of rainfall
• Frequency at which best management practices are performed.

Currently there are no numerical regulatory requirements for the capture of floatable material. However, the ACJ states:

The County's program shall achieve:
B. elimination or minimization of floating substances in Onondaga Lake attributed to the County's CSOs . . . .

The goal for floatables removal is that floatables from CSOs are to be eliminated for up to and including a 1-year, 2-hour, design storm through the use of floatables control technologies where applicable. However, on occasion, higher intensity and/or duration storms will cause flow rates that exceed those generated by the 1-year design storm event. During such events, lower floatables capture efficiency is expected.

In an effort to demonstrate compliance with the “85% capture” requirement, the calibrated SWMM models were executed for the various compliance projects included in the ACJ. The models were run using a long-term simulation approach based upon 30 years of precipitation data for the Syracuse metropolitan area.

For pre-abatement conditions, without implementation of any CSO abatement projects, the County Sanitary District trunk and interceptor sewer system transports 74% of the average annual volume of combined sewage collected within the City of Syracuse collector and combined sewer system to Metro for treatment. A summary of this volume capture information is presented in Table 1 found in Appendix C.
Click here for Appendix C. CSO volume capture table.

For comparison purposes, it is estimated that with the implementation of CSO projects as of December 2004 the sewer system transports approximately 81% of the average annual volume of combined sewage to Metro for treatment. Upon implementation of all the ACJ CSO Abatement projects, as described above, the average annual volume of combined sewage collected within the combined sewer system for transport to Metro is projected to be 88%. A summary of this volume capture information is presented in Table 2 found in Appendix C. These data indicate that the fully implemented ACJ CSO compliance projects will satisfy the 85% capture requirements of the ACJ. The Harbor Brook project represents the recommended abatement alternative as developed in this document. Table 3 in Appendix C presents the CSO volume capture information for the combined treatment of CSO both at Metro and the proposed ACJ CSO compliance projects.

1.5 Environmental information document

A separate Environmental Information Document (EID) has been developed as a companion document for the Harbor Brook CSO Abatement Facilities Plan. In addition, a Phase I Cultural Resource Survey has been completed by Hartgen Archeological Associates, Inc. as a subconsultant to Brown & Caldwell on potential sites for CSO facilities. This document also serves as a companion document to the Facilities Plan.

1.6 Public participation

During the compilation of this draft Facilities Plan, County staff and design engineers met with and gave presentations to various individuals and groups to provide information on the purpose and status of the Facility Plan and to obtain public input on potential issues and concerns. Individuals included interested county and city officials, area business people, local school and church officials and residents of the City's west side. Meetings were held with Tomorrow's Neighborhood Today (TNT) Westside Sector, Neighborhood Watch at Frazier School and representatives of Sacred Heart Seniors and the Knights of Columbus.

With completion of the Facilities Plan, which provides the data on the CSO abatement needs and proposes alternative solutions, the County will continue its public participation activities to solicit and receive further input from the community. Public participation activities will include direct mailings to area residents, holding availability sessions in the neighborhoods near Harbor Brook, presentations to local groups and organizations, public information meetings, and other activities.

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Susan Miller, Project Deputy Director
Phone 315-435-2260   Fax 315-435-5023
 Onondaga County Dept of Water Environment Protection