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

1. District of Columbia Water and Sewer Authority George S. Hawkins, General Manager Briefingon: Rainwater Harvesting: Update on Bioretention at Wangari Gardens September 7, 2014

2. Agenda • Background: Stormwater Runoff & CSOs • Background: Plan to Mitigate Flooding • DCCR Irving Street Green Infrastructure Project • Purpose • Bioretention Locations • Benefits • Example of Plant Palette • Maintenance • DC Water’s Proposed GI Plan

3. Background:Comparing Natural vs. Built Environment Natural Environment (0% Impervious Surface) Built Environment (75-100% Impervious Surface)

4. Background:Why is stormwater runoff a problem? Stormwater: Carries trash, excess nutrients (such as nitrogen and phosphorus), sediment and other pollutants; Impacts waterbodies we use for swimming, fishing and providing drinking water.

5. Background:Separate and Combined Sewer Systems 1 pipe 2 pipes 100% of suburbs 67% of D.C. 0% of suburbs 33% of D.C. Including Bloomingdale

6. Background: Northeast Boundary Combined Sewer Drainage Area • The Northeast Boundary Drainage Area has been historically prone to combined sewer overflow (CSO) flooding issues. • The Bloomingdale Drainage Area is located in the northern portion of the Northeast Boundary Drainage Area. • Stormwater runoff from this drainage area contributes to flooding events experienced just north of the Northeast Boundary Trunk Sewer. Bloomingdale Flood Areas

7. Background:Mayor Gray’s Task Force Task Force Members Regulatory O&M Code Changes Public Outreach Engineering McMillan Storage First St Tunnel Northeast Boundary Tunnel

8. Background: Three-step Infrastructure Solution To Mitigate Flooding Irving St Bioretention (Green Infrastructure) along Irving St North Capitol Tank & Diversion Structure 1 Michigan Ave First St Diversion Chamber First St. 2 North Cap. St Connect Diversion Chamber to First St Tunnel Channing St. 3 First St Tunnel Northeast Boundary Tunnel Legend 2014 2016 Rhode Island Ave 2022 8 8

9. Irving Street Green Infrastructure Project:Purpose Flooding in Bloomingdale and LeDroit Park • To help mitigate flooding in the Bloomingdale area, the DC Clean Rivers Irving Street Green Infrastructure Project included: • Installation of 14 bioretention facilities • Located along Irving Street corridor between Michigan Avenue and North Capitol Street Recently planted bioretention

10. Irving Street Green Infrastructure Project: Bioretention Locations Old Soldiers’ Home Bioretention Locations (typical) N Park Place NW Irving St Washington Hospital Center First St

11. Irving Street Green Infrastructure Project:Bioretention Overview • What is Bioretention? • A planted filter bed of specialized soil, sand, and stone aggregate • Basins are typically slightly depressed into the surrounding landscape to facilitate runoff flow to the system • Also referred to as rain gardens • Formal or informal aesthetic (i.e., street side tree box vs. naturalized garden) • Purpose/Benefits: • Stormwater runoff is slowed, cooled, filtered and infiltrated • Reduced flooding • Plants and soil remove contaminants and excess nutrients Example Bioretention: Street Side Tree Box Example Bioretention: Naturalized Garden Photo courtesy: Dennis Carmichael Photo courtesy: Dennis Carmichael ~25’ (typ.) ~10’ (typ.) Photo courtesy: Daily Journal of Commerce Photo courtesy: Daily Journal of Commerce

12. Irving Street Green Infrastructure Project: Bioretention Overview (Cont.) • Additional Benefits: • Provide habitat • Establish shade and cooling of surrounding areas • Create community amenity and enhance green space • Improve air quality

13. Irving Street Green Infrastructure Project:Typical Bioretention Cross Section Cross section courtesy: DDOE Stormwater Management Guidebook 2013

14. Irving Street Green Infrastructure Project:Bioretention at Wangari Gardens For Bioretention at Wangari Gardens and along Irving Street: • Stormwater collected in the basins will pond to a depth of up to 12” • Stormwater then filters through a soil media layer which removes contaminants. • Stormwater is then stored in a deep layer of stone and detained there until it is released into the underdrain and ultimately back into the sewer. Recently plantedbioretention

15. Irving Street Green Infrastructure Project:Plant Selection Examples • Grasses: Provide texture and seasonal interest year round. • Perennials: Flowers provide diversity of color during the growing season. Coastal Panic Grass Little Bluestem Photo courtesy: Chhe Photo courtesy: Chhe Photo courtesy: USDA-NRCS PLANTS Database Switchgrass Photo courtesy: D. Gordon E. Robertson Photo courtesy: Denis Prevot Photo courtesy: Lorax Wild Blue Indigo Foxglove Beardtongue Black-eyed Susan

16. Irving Street Green Infrastructure Project: Selection Examples (Cont.) • Shrubs: Provide texture and form to bioretention areas. • Trees: Provide shade and canopy adjacent to the bioretention facility. Flowers and fall foliage enhance bioretention aesthetics. Photo courtesy: H. Zell Photo courtesy: USDA-NRCS PLANTS Database Photo courtesy: Derek Ramsey New Jersey Tea Redosier Dogwood Northern Bayberry Photo courtesy: Jean-Pol Grandmont Photo courtesy: Chhe Photo courtesy: Greg Hume Black Gum Eastern Redbud Fringetree

17. Irving Street Green Infrastructure Project:Bioretention Planting Establishment Example Photo courtesy: Seattle Public Utilities Bioretention Immediately Following Planting Bioretention After 1 Growing Season Bioretention During 2nd Growing Season

18. Irving Street Green Infrastructure Project: Maintenance and Monitoring DC Water will perform ongoing maintenance to ensure long-term performance of the facilities, such as: Remove trash, sediment and animal waste Weed and prune plants Inspect cleanout pipes and underdrains Inspect and treat vegetation for disease and pest problems Pre/post construction monitoring will provide data to improve future Green Infrastructure design, construction, operation and maintenance.

19. Irving Street Green Infrastructure Project:Signage Signage has been placed at each bioretention location providing contact information for inquiries.

20. Proposed Green Infrastructure Plan:What is Proposed for Potomac and Rock Creek? $60 M of Green Infrastructure in Piney Branch $30 M of Green Infrastructure in CSO 027, 028 and 029 Separate CSO 025 and 026 ($10 M) For more information on DC Water’s Green Infrastructure Plan, visit: www.dcwater.com/green

21. Irving Street Green Infrastructure Project:Contact Information For more information on the Irving Street Green Infrastructure Project, visit: www.dcwater.com/workzones/projects/irvingstreet How to reach us: Project Manager: Bethany Bezak (202) 787-4466Community Outreach: (202) 787-4723