1. General Permitting DuPage County Stormwater Ordinance

2. DuPage County Overview
Year Formed- 1839
Area mi2
Population- 929,192 (2007 Census)
9 Townships
40 Communities

3. Why was the Stormwater Management Program Initiated?

9. Floods of the 1980s
1987 Flood resulted from more than 9.4 inches of rain over a 24 hour period of time, and 13 inches over a 4 day period.
1987 Flood caused more than $200 million in damage.

10. History of the Ordinance
Stormwater Management Plan adopted September 1989
Stormwater Ordinance adopted September 24, 1991
Effective February 15, 1992
Revised:

11. The principal of the Stormwater Ordinance is to promote effective, equitable, acceptable, and legal stormwater management measures

12. DuPage County Countywide Stormwater and Flood Plain Ordinance
Political Support
Written through regular meetings between County staff, DuPage municipal engineers, Northeastern Illinois Planning Commission, State and Federal agencies.
Consensus

13. Major Components Administrative structure
Site runoff and storage (detention)
Floodplain/floodway
Erosion and sediment control
Wetland
Riparian
BMPs for water quality

14. Ordinance Highlights
Detention at 0.1cfs/ac- no minimum restrictor size
100 yr flood design standard
1.5:1.0 compensatory flood plain storage
1 foot of freeboard on all buildings
Mitigation for all wetland and wetland buffer impacts
Riparian mitigation
Water quality BMP’s

15. Administrative
There are 40 communities within DuPage County. Each has one of three types of waiver status:
Non Waiver- DuPage County reviews all permit applications, 7 communities
Partial Waiver- DuPage County reviews only those permit applications involving special management areas, 21 communities
Complete Waiver- The community reviews all permit applications, 10 communities
2 communities have opted out to other counties- no permits from DuPage County are required
The Forest Preserve, DuPage County, and Township Highway Departments must also obtain permits

16. Site Runoff and Storage
Where detention is required:
Release rate is restricted to 0.1 cfs/acre of development for the 100-year (1.0% chance) storm

17. Site Runoff and Storage
Where detention is not required (development is under the detention threshold):
Development should not adversely impact any surrounding properties.

18. Site Runoff and Storage
Exceptions (have to meet specific conditions)
Grading of pervious areas
Reconstruction of an existing parking lot
Regional Stormwater Management Project or Flood Control Project
Stream Bank Stabilization
Construction or reconstruction of a pedestrian walkway/bike path
SERZ

19. Floodplain/Floodway FEMA Regulatory Flood Plain Maps (RFMs)
Digital Flood Insurance Rate Maps (DFIRMs)
County FEQ maps
1.5:1.0 compensatory flood plain storage
1 foot of freeboard on all buildings

20. Floodplain/Floodway
Illinois Department of Natural Resources, Office of Water Resources (IDNR/OWR)
IDNR/OWR delegated its floodway permitting authority for certain construction activities to DuPage County DEC in 1997.
The majority of the permit applications have been delegated to DEC.
Delegation of floodway review authority to DEC includes complete waiver communities

21. Erosion and Sediment Control
Apply to all developments, whether a permit is required or not.

22. Erosion and Sediment Control
Shall be appropriate with regard to the amount of tributary drainage area:
< 1 acre: filter barrier – straw bales are prohibited
1 – 5 acres: sediment trap
> 5 acres: sediment basin

23. Erosion and Sediment Control
Pumping (dewatering) must be filtered prior to discharge
Discharge locations must be protected from erosion
All discharges must be designed for non-erosive velocity corresponding to soil and vegetative cover

24. Erosion and Sediment Control
Temporary and permanent stormwater conveyance channels (including ditches, swales, and diversions) and all outlets must be designed and constructed to withstand the 25-year frequency storm velocity

25. Erosion and Sediment Control
Storm drain inlets must be protected by appropriate sediment control measure
Silt fence can be used to intercept sheet flow only
Reinforced silt fence can be used to intercept sediment-laden water from disturbed areas less than 1 acre
Special Management areas and ‘Waters’ must be protected by dual silt fence

26. Wetland Protection Under the Stormwater Ordinance
If wetlands are suspected or known to be on or near a property proposed for development, a wetland determination and/or delineation is required.
Because of size, configurations, vegetation, soils, or other characteristics, play crucial roles in storing or conveying flood waters, controlling erosion, maintaining or enhancing water quality, and providing habitat for T&E Species
If wetlands are identified, a Stormwater Permit under the DCSFPO is necessary.
In many cases, a permit from the U.S. Army Corps of Engineers is also required.

27. Corps General Permit No. 25
Through the issuance of a Programmatic General Permit (G.P. 25), the Corps has given DEC authority to evaluate permit applications for activities requiring permits under Section 404 of the Clean Water Act.
Because of size, configurations, vegetation, soils, or other characteristics, play crucial roles in storing or conveying flood waters, controlling erosion, maintaining or enhancing water quality, and providing habitat for T&E Species
If a Stormwater Management Permit is issued by DEC, and the Corps concurs with its findings, a Department of the Army authorization will be issued at that time.
Pre-discharge notification (5-day comment period) to Federal and State resource agencies required under G.P. 25.

28. Corps General Permit No. 25
G.P. 25 Reauthorization by Corps of Engineers is due out at any time
The reauthorized G.P. 25 will include 401 Water Quality Certification
Because of size, configurations, vegetation, soils, or other characteristics, play crucial roles in storing or conveying flood waters, controlling erosion, maintaining or enhancing water quality, and providing habitat for T&E Species

29. Wetland Protection Under the Stormwater Ordinance
50-foot buffer protection around regulatory wetlands
100-foot buffer protection around critical wetlands
Limits/restricts development activity within the buffer
Requires identification of buffer functions
Minimization of buffer impacts

30. Wetland Mitigation

31. Wetland Mitigation
If development impacts to a wetland meet all the conditions for mitigation in the Ordinance (sequencing arguments acceptable):
On-site mitigation
Off-site mitigation
Wetland banking
Fee-in-lieu program

32. Wetland Buffer Mitigation
Replace lost functions due to unavoidable buffer impacts

33. Riparian Environment
Vegetated areas along waterways within the limits of the regulatory flood plain.
Identify riparian functions
Minimize impacts due to development
Mitigate for lost functions due to unavoidable impact

34. Best Management Practices (BMPs)
Water Quality
Best Management Practices (BMPs)

35. DuPage County Stormwater and Flood Plain Ordinance
Appendix E: Part I- Technical
Guidance Water Quality Best Management Practices (BMPs)
11/21/2018

36. generated by nonpoint sources to a level compatible with water quality
What is a BMP?
Blackberry Creek Watershed Alternatives Analysis Project
Best Management Practices (BMPs) are a means of preventing or reducing the amount of pollution
generated by nonpoint sources to a level compatible with water quality
11/21/2018

37. BMPs lower the quantities of pollutants from ending up in our waterways and drinking water.
11/21/2018

38. Temporary BMPs
Installed only during construction to control the erosion of soils and the transport of sediment.
Please refer to the Illinois Urban Manual for examples and specifications

39. Permanent BMPs are the focus of the Technical Guidance Document.
Storm water treatment BMPs designed to remain in place. Permanent BMPs usually require MAINTANENCE.
Illinois Urban Manual
Multnomah Arts Center, WA
Planning By Design
Permanent BMPs are the focus of the Technical Guidance Document.

40. Types of Permanent BMPs
11/21/2018

41. Conveyance BMPs Vegetated filter strips Vegetated swales
Infiltration practices
Permeable pavers
Manufactured BMPs
3:1
Permeable pavers used for driveway
(The Journal for Surface Water Quality Professionals, Storm water Features 2002)

42. Storm Water Detention BMPs
Dry Detention
Wet Detention
Wet/Wetland Detention
Constructed Wetland Detention
Manufactured-Underground Detention
Detention Retro-fit
Subsurface Stormwater Management
US Fish and Wildlife
Blackberry Creek Watershed Alternatives Analysis Project

43. Easements
Easements are required over major and minor stormwater facilities. BMPs will be considered a stormwater facility and required to be put into an easement.
11/21/2018

44. Maintenance
It is imperative that permanent BMPs are maintained appropriately. All applicants will be required to provide a maintenance and monitoring plan.

45. Types of Permits
7 types of permit applications exist, ranging from the construction of a shed to the construction of a subdivision
Of these, 4 types are stormwater permit applications, which are required for all development:
Over 5,000 ft2
Affecting special management areas
Pre-application meetings are available for all permit types

46. County Review Process Pre-application meetings Two days per week
Coordinate with waiver community.

48. Stormwater Permit Submittal Flow Chart

51. Questions?
11/21/2018