Manchester’s CSO Program: A Look Behind and a Look Ahead Highway Commission Meeting January 6, 2014

Presentation Agenda Background on CSOs Phase I CSO Program (1999-2009) Phase II CSO Program (2012 -2032) Chestnut Street Sewer Separation Project (2012 -2014) Questions

What is a CSO? A "combined sewer" system is when one subsurface pipe is used to covey both sewer and stormwater flows. During rain events, the capacity of this single pipe is exceeded due to the large amount of stormwater entering the system. Therefore, outlets into local waterways were constructed to allow for the combined sewer overflows (CSOs) to exit the system. This results in the discharge of raw sewage into our waterways. This was standard construction practice for environmental infrastructure from the 1800s to the 1950s.

Manchester’s CSO History EPA issued national CSO Policy in 1994 Negotiations w/ EPA mid/late 1990s Manchester’s CSO Compliance Order issued 1999 Two phase approach Phase I: West Side Phase II: East Side

Requirements of Phase I CSO Abatement Program Separate 14 CSO Basins Raise 2 CSO Weirs Upgrade Wet-Weather Treatment Capacity at WWTP Flow Monitoring Program Supplemental Environmental Projects Program (SEPP)

Phase I: 1999 – 2009 Scope of Work 10-year $58 million program Fully separated 15 basins 8 construction contracts Over 53 miles of new or rehabilitated piping up to 60” diameter

Phase I CSO Abatement Program– Surpasses all Goals! Average annual CSO discharges decreases by 99% from 53.2 mgd to 0.2 mgd Goal was three-month level of CSO control, program achieved two-year level of CSO control Merrimack River water quality increases Manchester’s west side received full infrastructure upgrade; sewer, drain, water, gas, road, sidewalks, and curb Ten year program was completed on schedule and on budget

Additional Benefits and Upgrades Road reconstruction (26 miles) Other utility construction Water (9 miles) Gas (14 miles) Surface reconstruction Curbing (8 miles) Sidewalks (6 miles) Pedestrian Ramps (290)

Lessons learned from Phase I - Biggest bang for $$$ Do all infrastructure work at once How do our residents benefit? Address sewer backups Address street flooding What do our residents want? Roads, sidewalks, and curbing

Phase II Long-term Control Plan for East Side due to EPA in 2010 Evaluation of 7 CSO Basins on East Side of City 4,500 acre Cemetery Brook Basin 1,500 acre Pennacook Street Basin 640 acre Stark Brook Basin 15 Outfalls

Goals for Phase II Work Remove five brooks from system 5 mgd day weather flow 55 mgd peak wet weather flow Achieve CSO reduction w/out off-site treatment facilities Promote urban revitalization Green infrastructures Roads, sidewalks, plantings,

Proposed Plan for Future CSO Work – Submitted to EPA in 2010 Phase II - $165 million over 20 years $20 million in WWTP improvements $3 million in system optimization $65 million for removal of Cemetery Brook $73 million in sewer separation $4 million in program assessment/reporting Phase III - $177 million over next 20 years

Phase II CSO Program

Chestnut Street Sewer Separation Project 14

Chestnut Street Sewer Separation Project Design - 2012 Construction – 2013 4400 LF of new drain (15” – 60”) 1640 LF of new sewer (6” – 12”) 2670 LF of new water main (6” – 20”) Final Paving – 2014 Total Project Costs - $6.60 million

Chestnut Street Challenges New drain system designed for 50 year storm to account for climate change 60-inch drain pipe up to 26 feet deep Keep Verizon Arena/local businesses operational and happy Traffic control Work in front of MFD for over one month Unforeseen utilities/problems

60-inch Pipe Moved into Place

60-inch Pipe Lowered into Trench

Pipe Rammed “Home”

Pipe Installation 26 feet deep

Manhole Section being Lowered

Sidewalk, Curbing, Paving, and Striping

Next up - North Chestnut Street Sewer Separation Project 23

Questions? Frederick J. McNeill, PE 624-6341 FMcNeill@ManchesterNH.gov