Narragansett Bay CommissionNarragansett Bay CommissionCombined Sewer OverflowCombined Sewer OverflowControl Facilities ProgramControl Facilities Program

The Biggest Project You will Never The Biggest Project You will Never SeeSee

Narragansett Bay CommissionNarragansett Bay CommissionCombined Sewer OverflowCombined Sewer OverflowControl Facilities ProgramControl Facilities Program

The Biggest Project You will Never The Biggest Project You will Never SeeSee

Paul Pinault, P.E. Former Executive Director NBCPaul Pinault, P.E. Former Executive Director NBC

Client Service Leader CDM SmithClient Service Leader CDM Smith

Paul Pinault, P.E. Former Executive Director NBCPaul Pinault, P.E. Former Executive Director NBC

Client Service Leader CDM SmithClient Service Leader CDM Smith

NBC CSO NBC CSO ProgramProgram

NBC CSO NBC CSO ProgramProgram

Combined Sewer OverflowCombined Sewer OverflowControl Facilities ProgramControl Facilities ProgramCombined Sewer OverflowCombined Sewer OverflowControl Facilities ProgramControl Facilities Program

Phase I Facilities...Phase I Facilities...Phase I Facilities...Phase I Facilities...

CSO Diversion and CSO Diversion and CollectionCollection

CSO Storage - Main CSO Storage - Main Spine TunnelSpine Tunnel

Tunnel Capacity: Tunnel Capacity: – 61.8 MG Design61.8 MG Design– 66.5 MG Actual66.5 MG Actual

Tunnel Pump Tunnel Pump StationStation

CSO Diversion and CSO Diversion and CollectionCollection

CSO Storage - Main CSO Storage - Main Spine TunnelSpine Tunnel

Tunnel Capacity: Tunnel Capacity: – 61.8 MG Design61.8 MG Design– 66.5 MG Actual66.5 MG Actual

Tunnel Pump Tunnel Pump StationStation

SITE S1 AND OUTFALL 067

CSO Diversion and CollectionCSO Diversion and CollectionCSO Diversion and CollectionCSO Diversion and Collection

COMBINED SEWAGEOVERFLOW - DIVERSION AND STORAGE

TUNNEL1.PRS

DIVERSION STRUCTURE(APPROX. 22'L X 12'W)

INTERCEPTS EXISTING CSO OVERFLOW

GATE & SCREENING STRUCTURE(APPROX 35'L x 20'W)CONTROLS FLOW INTO TUNNEL

APPROACH CHANNELORGANIZES FLOW TO CREATE VORTEX

DE-AERATION CHAMBERREMOVES ENTRAINED AIR FROM FLOWS

RECIRCULATION PIPEDE-AERATED AIR IS DRAWN BACK INTO DROP SHAFT

CONNECTING ADIT(APPROX 72" DIA; LENGTH VARIES)

EXISTING SEWER SYSTEMCURRENTLY OVERFLOWS

INTO RIVERS AND BAY DURING WET WEATHER NEAR SURFACE

FACILITIES WITHIN 25' OF GROUND SURFACE

SOIL / ROCK INTERFACE- DEPTH VARIES BETWEEN 40' AND 160'

MAIN SPINE TUNNEL(APPROX 26'DIA; 16,000' LONG & 62 MG STORAGE)CONVEYS FLOW TO PUMPING FACILITIES

DROP SHAFT(5' - 9' DIA; DEPTH 250')TRANSFERS FLOW FROM SURFACE TO TUNNEL DEPTH

VENTILATION SHAFT (2'-3.5' DIA.)

ENABLES DE-AERATED AIR TO LEAVE CHAMBER

SUCTION LINE - TRANSFERSWATER FROM TUNNEL TO

PUMPS

SCREENS

GRITS AND SCREENING REMOVAL BY GANTRY

CRANE

FORCE MAIN TO FIELDS POINT

SITE S1

CONFIGURATION OFPUMP STATION OPERATING

FACILITIES

200' ±

TPS1.PRS

UPPER LEVEL - PUMP FLOOR

LOWER LEVELPUMP FLOOR

TPS OPERATION & CONTROL BUILDING

110'±

68'±

SoilDepth155'±

Rock150'±

TOTAL DEPTH TO INVERT 305'±

SUMP

SAFEROOM

32-FEET DIAMETERACCESS SHAFT

MAIN SPINE TUNNEL62 MG

11-FEET DIAMETEREQUIPMENT

HOISTING SHAFT

SAFEROOM

SITE S1CONFIGURATION OF PUMP STATION OPERATING FACILITIES

CSO StorageCSO StorageMain Spine TunnelMain Spine Tunnel

CSO StorageCSO StorageMain Spine TunnelMain Spine Tunnel

Tunnel capacity: Tunnel capacity: – 61.88 MG (Design)61.88 MG (Design)– 66.5 MG (Actual)66.5 MG (Actual)

Tunnel capacity: Tunnel capacity: – 61.88 MG (Design)61.88 MG (Design)– 66.5 MG (Actual)66.5 MG (Actual)

Seven dropshaftsSeven dropshafts

divert flow to the tunneldivert flow to the tunnel

Seven dropshaftsSeven dropshafts

divert flow to the tunneldivert flow to the tunnel

B R I N E P U M P

M O B I L E R E F R I G E R A T I O N P L A N T

E X P A N S I O N V A L V E

L I Q U I D R E F R I G E R A N T

F R E E Z E T U B E S

C O O L I N G W A T E R

L O W P R E S S U R E R E F R I G E R A N T G A S

H I G H P R E S S U R E R E F R I G E R A N T G A S

C O M P R E S S O RC H I L L E RC O N D E N S E R

D E V E L O P I N GF R E E Z E W A L L

B R I N E F R E E Z I N G S Y S T E M

Developmental Phases

1

2

3

45

6

9

78

1011

2

3

4,5

6,7,8

9,10,11

The End of the TunnelThe End of the Tunnel