1. Low Impact Development Training Module 1: Background Part 3: D.C. Stormwater Regulations

2. Sponsors 2 District Department of Transportation U.S. Department of Transportation Federal Highway Administration The Low Impact Development Center, Inc. University of the District of Columbia Funding for this project was provided through a grant from the Federal Highway Administration, U.S. Department of Transportation

3. Contributors 3 The Low Impact Development Center, Inc. John Shorb Landscaping, Inc. Logo Groundwork Anacostia River, D.C.

4. Copyright 4 Unless otherwise noted, Low Impact Development Training, funded by DDOT & DDOE, is licensed under a Creative Commons Attribution-NonCommerical- ShareAlike 3.0 Unported License. Content provided by cited entities remains the property of those entities and may not be used without their explicit permission.

5. Overview Development projects in the District are required to take steps to limit the amount of stormwater runoff discharged to city storm sewers and receiving waters. This module will provide an overview of DDOE stormwater regulations 5

6. Expected Outcomes Know what stormwater requirements are triggered by construction Be able to navigate the process of preparing and submitting a stormwater management plan for a construction project 6

7. Outline Design requirements Permitting process Construction and maintenance inspections Fines and corrective actions 7

8. Supplemental Information Note that slides with orange backgrounds contain supplemental details that are provided for informational purposes, but which are not required content for this course 8

9. Principal Players Owner DDOE – District Department of the Environment –Responsible for stormwater regulation –Set rules, issue permits, conduct inspections DDOT – District Department of Transportation –Own many bioretention installations in the right-of-way 9

10. Green Area Ratio Proposed change to District zoning codes Sets standards for landscape design Required Green Area Ratio (GAR) score varies by zone Encourages green space and promotes infiltration 10

11. D.C. Stormwater Regulations Stormwater is regulated by the District Department of the Environment (DDOE) A revised Stormwater Guidebook was adopted in July 2013 Increased focus on retention for stormwater quality and quantity control 11

12. DDOE Stormwater Requirements Retention requirements Detention requirements Extreme flood requirements Water quality requirements 12

13. What activities trigger these requirements? Major Land Disturbing Activities: –Soil disturbance is greater than 5,000 square feet Major Substantial Improvement Projects: –Combined footprint of building improvements and land disturbance is greater than 5,000 square feet All land disturbing activities requiring a building permit also require an erosion and sediment control plan, regardless of size 13

14. Retention requirements Require that a certain volume of stormwater runoff be captured and not discharged Retention requirements target small, every day rainstorms, which are responsible for most stormwater pollution Required retention volume is calculated using a Compliance Spreadsheet 14

15. Retention requirements 15 Photo Courtesy of Emily Ayers

16. Retention requirements For Major Land Disturbing Activities: Retain a volume equal to post-development rainfall from 90th percentile event (1.2 inches) For Major Substantial Improvement Activities: Retain a volume equal to post-development rainfall from 80th percentile event (0.8 inches) 16

17. Retention requirements Retention requirements apply to each drainage area on site Excess retention in one area may be credited toward other areas up to the 1.7 inch storm 17 Graphic Courtesy of the Low Impact Development Center, Inc.

18. Off-site retention Off-site retention may be used for up to 50% of retention requirement 18

19. Projects in the Right-of-Way Must meet retention requirements only to the Maximum Extent Practicable Details in Guidebook Appendix B 19 Photo Courtesy of DDOT

20. Stormwater Retention Credits If a project achieves retention in excess of what is required, the excess can be awarded Stormwater Retention Credits (SRCs) SRCs can then be sold for use as offsite retention for other projects 20

21. Detention Requirements Apply to larger, infrequent storm events Require that a certain quantity of stormwater runoff be held back temporarily, so that stormwater flow rates do not reach damaging levels 21

22. Flood control requirements Apply to very large, very infrequent storms (once in 100 years) Triggered when proposed development is likely to increase flooding This can happen when development involves filling in a floodplain, or dramatically increasing imperviousness of a watershed 22

23. Water quality requirements Treated effluent concentration of oil and grease must be less than 10 mg/L 60% of Total Suspended Solids (TSS) must be removed 23

24. Accepted BMPs Green roofs Rainwater harvesting Impervious surface disconnection Permeable pavement systems Bioretention Filtering systems Infiltration Open channel systems Ponds Wetlands Storage practices Proprietary practices Tree planting and preservation 24

25. Green roofs Two types: Extensive (3-6” media) Intensive (6”-4’ media)  Retention Detention  Water Quality 25 ASLA Headquarters Green Roof, Washington DC Photo Courtesy of the Low Impact Development Center, Inc.

26. Rainwater harvesting Rain barrels or cisterns Captured rainfall can be used for irrigation and non-potable applications Consult District Construction Codes (DCMR, Title 12) for allowable indoor uses 26  Retention Detention  Water Quality Photo Courtesy of Robb Lukes

27. Impervious surface disconnection Disconnect downspouts or impervious surfaces to drain toward pervious areas 27  Retention Detention  Water Quality Infiltration Planter, Navy Yard, Washington DC Photo Courtesy of the Low Impact Development Center, Inc.

28. Permeable pavement systems Porous asphalt Pervious concrete Permeable interlocking concrete pavers / concrete grid pavers Plastic grid pavers 28  Retention Detention  Water Quality Navy Yard, Washington DC Photo Courtesy of the Low Impact Development Center, Inc.

29. Bioretention Several different variations: Traditional bioretention Streetscape bioretention Engineered tree pits Stormwater planters Residential rain gardens 29  Retention Detention  Water Quality Edmonston, MD Photo Courtesy of the Low Impact Development Center, Inc.

30. Filtering systems Use sand or other media to filter stormwater 30 Retention Detention  Water Quality Photo Courtesy of DDOE

31. Infiltration Infiltration trench Infiltration basin Must be located in areas with high infiltration rates Must be set back from foundations and pavement 31  Retention Detention  Water Quality Photo Courtesy of the Low Impact Development Center, Inc.

32. Open channel systems Grass channels Dry swales Wet swales Used to convey runoff from drainage area to other BMPs Provide limited water quality and retention benefits 32  (Dry swales)Retention Detention  Water Quality Photo Courtesy of the Low Impact Development Center, Inc.

33. Ponds Used to provide detention for large events Included if necessary at end of treatment train 33 Retention  Detention  Water Quality Photo Courtesy of the Low Impact Development Center, Inc.

34. Wetlands Used to provide detention for large events Included if necessary at end of treatment train Drainage area must be large enough to sustain a permanent water level 34 Retention  Detention  Water Quality Photo Courtesy of Emily Ayers

35. Storage practices Underground vault Dry pond Rooftop storage Stone storage under permeable pavement or other BMPs Used for detention of stormwater from large events 35 Retention  Detention Water Quality Photo Courtesy of the Low Impact Development Center, Inc.

36. Proprietary practices Must be approved by DDOE Provide water quality treatment 36 Retention Detention  Water Quality Photo Courtesy of Larry Coffman.

37. Tree planting and preservation Preserve existing trees Plant and maintain new trees Reduce runoff volume Improve infiltration Use tree canopy to intercept rainfall over paved areas 37  Retention Detention  Water Quality Photo Courtesy of the Low Impact Development Center, Inc.

38. BMP Selection BMPs are selected based on a 5-step screening process: 1.Stormwater management suitability 2.Land use factors 3.Physical feasibility factors 4.Community and environmental factors 5.Location and permitting considerations 38

39. 1. Stormwater management suitability Select BMPs or combinations of BMPs that will meet retention, detention, and water quality requirements 39

40. 2. Land use factors Select BMPs most suitable for the land use: –Residential –Commercial development –Roads and highways –Hotspot land uses 40

41. 3. Physical feasibility factors Select BMPs that are feasible given the physical conditions onsite: –Underlying soils –Water table depth –Contributing drainage area –Practice surface slope –Head 41

42. 4. Community and environmental factors Consider community and environmental factors: –Maintenance burden –Cost –Safety risk –Space required –Environmental factors –Habitat value 42

43. 5. Location and permitting considerations Prohibitions Regulated areas Setbacks 43

44. Permitting Process 44

45. Permitting Process (cont’d) 45

46. 1. Submit application package Submitted to DCRA Permit Service Center Includes: –Stormwater Management Plan (SWMP) Requests for: –Public Right-of-Way MEP –Exemption for extraordinarily difficult site conditions –Use of proprietary practice –Soil Erosion and Sediment Control Plan (SESCP) 46

47. SWMP A Stormwater Management Plan (SWMP) contains: –supporting computations –drawings –sufficient information to evaluate the environmental characteristics of the affected areas –the potential impacts of the proposed development on water resources –the effectiveness and acceptability of Stormwater Best Management Practices (BMPs) for managing stormwater runoff –maintenance and construction schedules –number of gallons the applicant shall retain off-site (where applicable) 47

48. Site Plan 48 Graphic Courtesy of the Low Impact Development Center, Inc.

49. Stormwater Hotspots H-1 Vehicle Maintenance and Repair H-2 Vehicle Fueling H-3 Vehicle Washing H-4 Vehicle Storage H-5 Loading and Unloading H-6 Outdoor or Bulk Material Storage If any of the above operations are expected to occur on a planned development site, the Stormwater Hotspot Cover Sheet should be completed. Further, a stormwater pollution prevention plan (SWPPP) or the Stormwater Hotspot Checklist 49

50. Required supporting documents (1) Site Development Submittal Information Form (2) DC Water Storm Sewer Verification Form (3) DCRA Application for Construction Permit on Private Property (4) Environmental Intake Screening Form (EISF) (5) Environmental Questionnaire (6) DC Green Building Act Permit Application Intact Form (7) Contract Agreement (8) Lead Permit Screening Form (9) Zoning Data Summary Form (10) Reasonable Accommodations and Modifications for Persons with Disabilities Form Forms 1 and 2 are found in Section 5.7 of the Guidebook. Forms 3 through 10 are available at the DCRA intake counter or can be downloaded at: http://dcra.dc.gov/DC/DCRA/Permits/Building+Permit+Application+Supplement al+Documents http://dcra.dc.gov/DC/DCRA/Permits/Building+Permit+Application+Supplement al+Documents 50

51. Current fees (as of 2013) SWMP ReviewLand disturbance ≥5,000sf & ≤10,000sf Land disturbance ≥10,000sf Initial plan review due upon filing$3,300.00$6,100.00 Final plan review due before issuance of building permit $1,500.00$2,400.00 Supplemental review fee due before issuance of building permit $1,000.00$2,000.00 51

52. Current fees (as of 2013) Additional feesLand disturbance ≤10,000sf Land disturbance ≥10,000sf Field visit for soil percolation test$300 for ≤ 10 borings; $600 for > 10 Review of soil percolation test report$150.00 Soil characteristics inquiry$150.00 Review of geotechnical report$70.00/hour After-hours inspection fee$50.00/hour Stormwater pollution plan review$1,100.00 Dewatering pollution reduction plan review$1,100.00$2,100.00 Application for relief from extraordinarily difficult site conditions $500.00$1,000.00 52

53. Current fees (as of 2013) SWMP Review to create retention capacity for Department certification of stormwater retention credits Land disturbance ≤10,000sf Land disturbance ≥10,000sf Initial plan review due upon filing$575.00$850.00 Final plan review due before issuance of building permit $125.00$200.00 Supplemental review fee due before issuance of building permit $500.00 53 Review of Green Area Ratio planLand disturbance ≤10,000sf Land disturbance ≥10,000sf Initial plan review due upon filing$575.00$850.00 Final plan review due before issuance of building permit $125.00$200.00 Supplemental review fee (for reviews after first re-submission) $500.00

54. EPA filings Filing a Notice of Intent Form with US EPA is required if the project will disturb 1 or more acres of land, or part of a common plan of development or sale that will ultimately disturb 1 or more acres of land must file. Consult US EPA’s web site for details, http://cfpub.epa.gov/npdes/stormwater/app lication_coverage.cfm http://cfpub.epa.gov/npdes/stormwater/app lication_coverage.cfm 54

55. Inspection Requirements Prior to SWMP approval, applicant must submit a proposed construction and inspection control schedule Stages: –Pre-construction meeting with DDOE –Inspections during construction –Final inspection after construction –Maintenance inspections 55

56. Pre-construction meeting Required before beginning land disturbance or installing any BMPs Contact DDOE 3 days prior to starting construction Submit material certifications for aggregate, soil media, and geotextiles Site visit to confirm drainage area, inlet elevations 56

57. Construction inspections Contact DDOE 3 days before starting construction of BMPs Certifying PE must accompany inspectors at on-site inspections The following detail construction inspection schedule for bioretention See the Guidebook for inspection schedules for other BMPs 57

58. Bioretention Construction Inspection Checklist 58

59. Construction inspections During percolation/infiltration tests 59

60. Construction Inspections Upon completion of stripping, stockpiling, and construction of temporary sediment control and drainage facilities 60 Photo Courtesy of DDOT.

61. Construction inspections Upon completion of excavation to subgrade 61 Photo Courtesy of Rasma Plato

62. Construction inspections During the placement of: –perforated PVC/HDPE standpipes (for observation wells) including bypass pipes (where applicable) –geotextile materials –gravel, or crushed stone course –backfill 62

63. Construction inspection Upon completion of final grading and establishment of permanent stabilization 63 Photo Courtesy of DDOT

64. Final Inspection A final inspection must be conducted by the DDOE upon completion of the BMP to determine if the completed work is constructed in accordance with approved plans Contact DDOE to schedule a final inspection 1 week prior to the completion of a BMP construction to schedule inspection PE is required to certify “As-Built" plans that the BMP has been constructed in accordance with the approved plans and specifications 64

65. Maintenance inspections Performed by DDOE Twice per year for the first five years Once every three years thereafter Maintenance inspection forms are provided in the Guidebook 65

66. Review Construction activities disturbing more than 5,000 square feet of built or landscaped space require submission of a Stormwater Management Plan (SWMP) when applying for a building permit New rules require retention of runoff from small storms SWMPs must include construction and maintenance schedules Certification requires multiple inspections during construction and ongoing maintenance inspections 66

67. Resources 2013 District of Columbia Stormwater Management Guidebook (http://ddoe.dc.gov/swregs)http://ddoe.dc.gov/swregs District of Columbia Soil Erosion and Sediment Control Handbook (http://ddoe.dc.gov/soil-erosion-and-sediment- control-handbook)http://ddoe.dc.gov/soil-erosion-and-sediment- control-handbook 67