Federal Water Quality Association Bloomingdale Neighborhood

District of Columbia Water and Sewer Authority George S. Hawkins, General Manager

Briefing on: Bloomingdale Neighborhood Flooding Mitigation Washington, DC

Briefing for: Federal Water Quality Association

December 12, 2013 Agenda

. Background on DC Clean Rivers . Flooding in the Northeast Boundary Sewershed . 2012 Flood Events & Mayor’s Task Force . Northeast Boundary Neighborhood Protection Project

2 Background DC Combined Sewer System

. 1/3 of DC area is served by combined sewers (12,478 Bloomingdale acres)

. 53 CSO outfalls . 15 to Anacostia . 10 to Potomac . 28 to Rock Creek

. Three receiving waters . Anacostia River . Potomac River . Rock Creek

. Long Term Control Plan = “DC Clean Rivers Project”

3 Bloomingdale

First1st Street Street Anacostia River Projects: Tunnel, NE Boundary NovNov 20122013 –– Tunnel and area MarJan 20152016 projects, $606M Implementation on Schedule Mar 2016 – Mar 20222025 . 4 large storage/conveyance tunnels

. Dewatering pumping station at Blue After 2018 U.S. RFK Capitol Stadium Plains Building Before 2018 . Pumping station replacement at

Poplar Point Nationals Anacostia River Park Anacostia River Anacostia Tunnel, $$291M253M River Nov 2013 – . Schedule Sept 2017 . LTCP = 20 years (2005-2025)

. Nitrogen Removal = 2007-2015 Joint Base Anacostia- Bolling . Cost . LTCP = $2.6 billion . Nitrogen Removal = $950 M Blue Plains Potomac Tunnel, $397M . Total > $3.5 billion River Sept 2011 – Nov 2015

DC Water Blue Plains AWWTP 4 Northeast Boundary Tunnel

. CSO storage and flood conveyance tunnel . Flood relief = uniform 15-year 6-hour storm (per NOAA) . Provide flood relief to 5 chronic flooding areas

th Capacity of . Relieve NEB trunk sewer from RFK to 6 Known Chronic Current System Characteristic Street & R Street, NW Flooding Areas (Storm Frequency) . Allowances for future connections W. Virginia & Less than 2 yr Bowl . Other NEB areas may not meet 15-year Mt Olivet Rhode Island Less than 2yr Bowl design standard; can be addressed by future Metro connection to tunnel (not DCCR project) First & P St, Less than 5 yr Bowl . Configure the system to operate by gravity NW Bloomingdale Less than 5 yr Bowl (no gates or controls) 6th & R St NW Less than 5 yr Bowl . 2025 completion per Consent Decree

5 Background NEB Drainage Area

Northeast Boundary Drainage Area (NEB) serves the Bloomingdale neighborhood . Part of the District’s Combined Sewer Bloomingdale System Drainage Area . One (1) pipe in street serves both >700 acres sanitary collection and storm water runoff . Built-out in the early 1900s Bloomingdale Northeast Boundary Trunk (NEBT) Sewer . Major sewer serving the NEB Drainage area . Constructed circa 1870-1880

RFK Stadium U.S. Capitol Building

6 Background History of Flooding Bloomingdale (Thomas & Flagler) Flooding occurred soon after NEBT is the old stream Sewer construction valley . Recognition that sewer capacity was too low

Many studies have identified longstanding flooding issues in Northeast Boundary . 1955 Sewer Investigation . 1957 Board of Engineers . 1968 Burns & MacDonald . 1997 Alignment Study . 1999 NEB Flooding Study . 2002 CSO Long Term Control Plan 1860’s Map of DC . 2006 Bloomingdale Flood Study

7 Background Why was Flooding not Addressed in the Past?

Bloomingdale . Massive scale of project . Not constructible without large disruption to neighborhoods and existing infrastructure unless tunneling is used . New tunneling technologies have made soft ground tunneling practical

Existing NEBT Sewer Section Existing NEBT Sewer Section 8 (10’-0” Diameter) (22’-0” × 23’-6”) 2012 Flooding in Bloomingdale And LeDroit Park

st 1 & P St NW (2001) Rhode Island & T St NW Rhode Island & 1st St NW

Rhode Island Metro Rhode Island & T St NW

9 9 Flagler St NW Rhode Island Between 1st & 2nd St 1st & V St NW June/July 2012 Storm Events Intensity Analysis

Peak Intensity of June/July 2012 Storms

Approx. Rainfall Date Duration Precipitation (inches)* Frequency

7/10/2012 1-hour 1.96 10 year storm

7/18/2012 30-minute 1.35 5 year storm

7/19/2012 15-min 0.94 5 year storm

9/2/2012 2-hour 2.78 10 year storm

NOTES: *Bryant Street Station Rain Gauge N.B. Radar data confirmed the measured intensity of the three July storm events 10 Recent Flooding has Severely Impacted Residents

. Major flooding July 10, 18, 19 and Sept 2, 2012 . More than 200 property owners affected . Flood clean-up costs $3,000-$18,000 per household . Concerns about public health and safety

11 Bloomingdale Topography

. Flow from North to South

. McMillan Sand Filtration Site is upstream of Bloomingdale residential area

. Flow funnels to Flagler and 1st Streets NW.

Old Soldiers Home Medstar Hospital

VA Hospital McMillan Sand Filtration Site

Bloomingdale Residential Area Modeling Results – July 10th Storm Event

Choke point causing upstream flooding

Surface Flooding Predicted

Rhode Island Avenue Flooding

13 Modeling Results

. Store as much flow as possible upstream of and within Bloomingdale

. Increase capacity through Bloomingdale

. Increase capacity downstream of Bloomingdale Three-step Infrastructure Plan To Mitigate Flooding

McMillan Site, LID, Backflow Prevention 1 3.1 million gallons 1 (Existing abandoned filter cells)

First Street Tunnel – 8.9 million 2 gallons (2,800 LF, Min 18.5’ I.D.) 2

Northeast Boundary Tunnel 3 3 (23’ I.D.)

NEBT (Future) 15 Schedule

. Place McMillan tanks in service by March 2014 to be ready for spring / summer storms

Proj. Activity ‘13 ‘14 ‘15 ‘16 ‘17 ‘18 ‘19 ‘20 ‘21 ‘22

1 McMillan Stormwater Storage + Backflow Prevention Program

2 First St Tunnel (Div P)

3 Northeast Boundary Tunnel (Div J)

16 Three-step Infrastructure Plan To Mitigate Flooding

McMillan Site, LID, Backflow Prevention 1 3.1 million gallons 1 (Existing abandoned filter cells)

First Street Tunnel – 8.9 million 2 gallons (2,800 LF, Min 18.5’ I.D.) 2

Northeast Boundary Tunnel 3 3 (23’ I.D.)

NEBT (Future) 17 Filter Cell No. 14 After Sand Removed

Photo taken May 2013 18 McMillan Stormwater Storage Overall Site Plan

Storage Tank DCCR First Street Tunnel Shaft & 3-acre staging area Online by Spring 2014 •Sewer Diversions •Tank Rehab •Upstream Sewer Rehab In Service: until 2022

19 How will McMillan Storage Tank and Sewer Diversions Work? Dry Weather & Moderate Storms Major Rain Events

No flow to Cell Cell fills & 14 or Tunnel empties by gravity

10 11 12 13 14 10 11 12 13 14

North Service Court St First North Service Court

15 16 17 18 19 Tunnel fills by15 16 17 18 19 First St First gravity and is

emptied by temp. North Capitol St. Capitol North pump station St. Capitol North 20 21 22 23 24 20 21 22 23 24

South Service Court South Service Court

Tunnel 28 29 Tunnel 28 29 Shaft Shaft

Flow uses existing Storms that exceed the pipes capacity of the storage tank and tunnel continue downstream 20 Trunk Sewer Profile

HGL During Larger Storms Approaches Grade in Surrounding Service Area When Storage is Full and Weir Overtops

Diverted to Storage Tank and Tunnel by Surcharging Upstream Sewers to Fill by Gravity Two Options: • Automated Gate • Vortex Flow Control Device

21 North Capitol Street Sewer Diversion: Construction Staging

Materials staging area in McMillan site adjacent to Site occupies 2 travel N. Capitol Street lanes in North Capitol Street (6 lanes total) Outside travel lane Night work required used for offloading materials and equipment

Diversion Chamber 20’ Inside Diameter

22 North Capitol Street Sewer Diversion: Diversion Chamber Construction

New 48” Temporary flow diversion sewer maintenance to tank

Rebar for overflow weir

Existing 60” storm sewer

Timber lagging Photo taken support of September excavation 2013 23 Low Impact Development

. Rain barrel and cistern rebate program . Administered by DC Greenworks for DDOE and DC Water . Irving Street LID Project

24 Backflow Prevention Program

. BWV Rebate Program . Current Program . Area includes Bloomingdale neighborhood & 2/3 LeDroit Park neighborhood . Task Force Recommendation . Expanded boundary including all of Northeast Boundary drainage area upstream of N. Capitol St. and Florida Ave. . New Program . Alternative 1: Area defined by Legislative boundary in DC Act 19-660 – Area includes Bloomingdale, LeDroit Park, and additional Florida Ave . Alternative 2: Expanded boundary – Area includes all of Northeast Boundary drainage area upstream of N. Capitol St. and Florida Ave.

. Floodproofing Rebate Program . Current program . No rebate offered, but engineering consultations available to Bloomingdale & LeDroit Park residents . Task Force Recommendation . Expanded boundary including all of Northeast Boundary drainage area upstream of N. Capitol St. and Florida Ave. . New Program . Alternative 1: Properties in Bloomingdale & LeDroit Park neighborhoods with reported overland flooding during 2012 storms . Alternative 2: Area defined by Legislative Boundary in DC Act 19-660

25 Backflow Prevention Program Determine the nearest trunk sewer for each property

26 Backflow Prevention Program Estimate Basement Elevations and Depth of Sewage

27 Backflow Prevention Program Compare Basement Elevation to HGL

28 Three-step Infrastructure Plan To Mitigate Flooding

McMillan Site, LID, Backflow Prevention 1 3.1 million gallons 1 (Existing abandoned filter cells)

First Street Tunnel – 8.9 million 2 gallons (2,800 LF, Min 18.5’ I.D.) 2

Northeast Boundary Tunnel 3 3 (23’ I.D.)

NEBT (Future) 29 First Street Tunnel

. Min 18.5’ diameter, 2,800’ long . Acts as storage tunnel 2022, then connects to Northeast Boundary Tunnel . Contract awarded – in operation Oct 2016 . Block meetings held with residents this summer

30 Three-step Infrastructure Plan To Mitigate Flooding

McMillan Site, Local Storage, Backflow Prevention 1 3.1 million gallons 1 (Existing abandoned filter cells)

First Street Tunnel – 8.9 million 2 gallons (2,800 LF, Min 18.5’ I.D.) 2

Northeast Boundary Tunnel 3 3 (23’ I.D.)

NEBT (Future) 31 Northeast Boundary First St Tunnel Tunnel Bloomingdale

Northeast . Completion date accelerated from Boundary Tunnel 2025 (Consent Decree) to 2022 (Mayor’s Task Force) . 23’ diameter, about 5 miles long . On schedule Anacostia River Tun. . RFP under preparation (Construction) . Alignment improvements being Blue Plains Tunnel made to minimize property impacts (Construction) . Provide storage for 15-year storm before treatment

Tunnel Dewatering Pump. Station and ECF (Construction)

32 Summary

. Northeast Boundary Tunnel planned to provide protection from CSOs and flooding. . Large storms in 2012 accelerated the schedule for NEBT and other solutions in Bloomingdale. . Implementing 3-step plan to provide protection ASAP to Bloomingdale while moving forward with the NEBT. . 15-year storm protection by 2022 in Bloomingdale and other areas.

33 Contact

Essey Woldemariam . DC Water, Planning Department . [email protected] Steve Skripnik, PE . LimnoTech, DC Clean Rivers Project . [email protected]