Combined Sewer Overflow Long Term Control Plan Citywide/Open Waters - PowerPoint PPT Presentation

Combined Sewer Overflow Long Term Control Plan Citywide/Open Waters LTCP Staten Island Retained Alternatives Public Meeting November 6, 2019

What is a Combined Sewer Overflow (CSO)? Ø NYC’s sewer system is approximately 60% combined, which means it is used to convey both sanitary and storm flows . Stormy Weather Conditions Dry Weather Conditions Down Down Spout Spout Catch Basin Catch Basin Combined Combined Building Sewer Building Sewer Connection Sewer Outfall Sewer Outfall Connection City Sewer Main City Sewer Main to WWRF to WRRF Sewer Sewer Interceptor Sewer Interceptor Sewer Regulator Regulator Ø 65% to 90% of combined sanitary & storm flow is captured at wastewater resource recovery facilities (WRRF). Ø When the sewer system is at full capacity, a diluted mixture of rain water and sewage may be released into local waterways. This is called a combined sewer overflow (CSO). 2

What is a LTCP and CSO Consent Order? Long Term Control Plan (LTCP) identifies appropriate CSO controls to achieve applicable water quality standards consistent with the Federal CSO Policy and Clean Water Act CSO Consent Order an agreement between NYC and DEC that settles past legal disputes without prolonged litigation DEC requires DEP to develop LTCPs and mitigate CSOs 3

LTCP Milestone Status ID LTCP Approved? 3 ü 1 Alley Creek 2 5 ü 2 Westchester Creek ü 8 3 Hutchinson River 1 ü 4 4 Flushing Creek 9 5 ü Bronx River ü 6 Gowanus Canal 6 7 ü Coney Island Creek 10 ü 8 Flushing Bay 9 ü Newtown Creek 7 Jamaica Bay and 10 Under DEC review Tributaries (1) 11 11 LTCP in development Citywide/Open Waters (2) Due to DEC March 2020 (1) Jamaica Bay includes Thurston Basin, Bergen Basin, Hendrix Basin, Fresh Creek, Spring Creek, Paerdegat Basin and Jamaica Bay (2) Citywide/Open Waters LTCP includes East River, Lower Long Island Sound, Hudson River, Harlem River, Lower and Upper New York Bay, Arthur Kill and Kill Van Kull 4

Citywide/Open Waters LTCP • Waterbody-specific CSO evaluation of Open Waters: • Harlem River • Hudson River • East River/Long Island Sound • Upper and Lower New York Bay • Arthur Kill and Kill Van Kull • Citywide/Open Waters LTCP will be submitted to DEC in March 2020 5

Staten Island is Primarily MS4 The MS4 Permit regulates drainage areas (collectively called the MS4 area) where stormwater drains: To a city-owned MS4 o By overland flow from a city-owned facility o 6

Overview of Baseline Projects & Floatables Control Approach 7

Citywide/Open Waters LTCP Baseline Conditions Ø Grey Infrastructure Projects • WWFP Projects ($2.7B) • Tributary LTCPs ($5.2B) Ø Green Infrastructure Projects ($1.5B) • Right-of-way Green Infrastructure • Public Property Retrofits • Private Property Incentives • Stormwater Rules • Demand Management • Tibbetts Brook Daylighting 8

Green Infrastructure in Staten Island • Arrochar Playground • DeMatti Playground • Grandview Playground • Levy Playground • McDonald Playground 9

Citywide/Open Waters Floatables § Approaches a. Continue and enhance current floatables controls b. Coordinate with MS4 to develop citywide floatables plan and associated field program to further quantify floatables in 303(d) impaired areas c. Evaluate additional programmatic/integrated floatables control d. Evaluate purchasing an inter-pier skimmer vessel e. Eliminate existing floatables booms where feasible 10

Programmatic Controls Stewardship Programs Educational Programs Other Programs • • • 311 Water Resources Annual Art and Poetry Public Litter Baskets Contest • • Adopt-a-Bluebelt Mechanical Broom Street Sweeping • Catch Basin Marking • • Shoreline and Bluebelt Cleanups Catch Basin Inspection, Cleaning, • Environmental Education Grates and Hoods • Adopt-a-Basket • • Visitor Center at Newtown Creek Floatables Controls in Combined • Community Clean-ups Sewer System • SAFE Disposal Events • Park Stewardship • End-of-pipe Booms and Nets • Special Waste Drop-Off Sites • Adopt-a-Highway/Greenway • School Sustainability Coordinator Trainings • The Natural Classroom • Weekend, Pop-up, and Custom Adventures 11

Overview of Retained Alternatives 12

Water Quality Standards New York State Saline Surface Water Quality Standards Bacteria (1) Dissolved Class Fecal Enterococci (3)(4) Oxygen Coliform (2) > 4.8 mg/L GM ≤ 35/100mL (daily avg) SA - STV 90% ≤ 130 cfu/100mL ≥ 3.0 mg/L > 4.8 mg/L GM ≤ 35/100mL Monthly GM (daily avg) SB ≤ 200/100mL STV 90% ≤ 130 cfu/100mL ≥ 3.0 mg/L Monthly GM I - ≥ 4.0 mg/L ≤ 200/100mL Monthly GM SD - ≥ 3.0 mg/L ≤ 200/100mL Notes: (1) Total coliform criteria not shown (2) Assessed on an annual basis and recreational season (3) Assessed during primary contact recreational season or as necessary to protect human health (4) Applicable to coastal primary contact recreational waters only 13

Fecal Coliform Gap Analysis Baseline Conditions 100% CSO Control 10-yr Annual Attainment 10-yr Annual Attainment 100 100 95 Attainment (%) 95 Attainment (%) 90 90 80 80 70 70 0 0 Fecal Coliform Monthly Mean Fecal Coliform Monthly Mean ≤ 200 cfu/100mL ≤ 200 cfu/100mL 14

Enterococci GM Gap Analysis Baseline Conditions 100% CSO Control 10-yr Annual Attainment 10-yr Annual Attainment 100 100 95 Attainment (%) 95 Attainment (%) 90 90 80 80 70 70 0 0 Enterococci (1) 30-day Geomean Enterococci (1) 30-day Geomean (2) ≤ 35 cfu/100mL (2) ≤ 35 cfu/100mL Enterococci 30-day Geomean ≤ 35 cfu/100mL Notes: 1) Enterococci criteria apply only to Class SB Coastal Primary Contact Recreational waters 2) 30-day running geometric mean 15

Enterococci STV Gap Analysis Baseline Conditions 100% CSO Control 10-yr Annual Attainment 10-yr Annual Attainment 100 100 95 Attainment (%) 95 Attainment (%) 90 90 80 80 70 70 0 0 Enterococci (1) 30-day STV (2) Enterococci (1) 30-day STV (2) ≤ 130 cfu/100mL ≤ 130 cfu/100mL Enterococci 30-day 90 th Percentile ≤ 130 cfu/100mL Notes: 1) Enterococci criteria apply only to Class SB Coastal Primary Contact Recreational waters 2) 30-day running 90 th percentile statistical threshold value 16

Key Take-Aways for Alternatives Analysis 5% Over $9B in Annual CSO investments volume is have been small 95% made or percentage committed as of total part of the volume CSO Program treated at to date WRRFs Paerdegat Basin CSO Facility *Based on 2008 JFK Typical Year rainfall Annual CSO Volume Baseline Water CSO volume to be captured Quality shows high levels of increases significantly attainment with applicable WQS with increasing level of control 50% 75% 100% % Volume Capture for 2008 JFK Typical Year Rainfall 17

Citywide/Open Waters LTCP Alternatives Toolbox Source Control Green Infrastructure Storm Sewers Pump System Parallel Bending Weirs Pump Station Fixed Weir Station Optimization Interceptor / Sewer Control Gates Expansion Optimization Gravity Flow Tipping Pumping Station Flow Tipping with CSO Relocation to Other Watersheds Modification Conduit/Tunnel and Pumping Water Quality / Floatables Environmental Ecological Wetland Restoration & Daylighting Control Dredging Enhancement Treatment Outfall High Rate Clarification Retention Treatment Basin (RTB) Satellite: Disinfection (HRC) WRRF Expansion Centralized: Storage In-System Shaft Tank Tunnel Ongoing Projects Evaluated but Screened Out Retained Alternatives 18

CSO Regulator Operation Combined Sewer conveys stormwater runoff and sanitary waste to the Wastewater Resource Recovery Facility. Stormwater Catch Basins Regulator directs combined sewage to the Runoff flows into wastewater resource recovery facility. If the convey stormwater into the combined the combined sewer. facility reaches full capacity, the combined sewer. sewer flow is directed to overflow outfalls. 2 1 3 CSO Outfalls are locations where “combined sewer overflows” discharge. LEGEND 4 Stormwater Runoff Combined Sanitary and Stormwater Flow 6 Wastewater Resource 5 Recovery Facility treats the combined sewage and releases clean water into surrounding waterbodies. 19

System Optimization Analysis Summary • Each CSO outfall was assessed for distance to closest public access point • Optimization process prioritized outfalls that were near public access points • Performance of optimization alternatives was driven by system hydraulics, and limited by constraints on increasing water levels in 15.8 the sewers • Analysis demonstrated that the existing system is currently being operated essentially at its capacity • Limited opportunities to further optimize flow to the WRRFs and reduce CSOs in the existing system without increasing risk of flooding/sewer backups 20

Lower and Upper New York Bay Meets most Class SB WQ standards ü Fecal Coliform, Dissolved Oxygen, and Enterococci (GM) û Enterococci (STV) Total Number of CSO Outfalls = 39 Total CSO Discharge Volume = 3.0 BGY Top 5 CSO outfalls account for 80% of Top 5 CSO Outfalls CSO discharge volume Total Discharge Volume = 2.5 BGY 18% (0.5 BGY) 82% (2.5 BGY) 21