General Permitting DuPage County Stormwater Ordinance

DuPage County Overview Year Formed- 1839 Area- 332.1 mi2 Population- 929,192 (2007 Census) 9 Townships 40 Communities

Why was the Stormwater Management Program Initiated?

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.

History of the Ordinance Stormwater Management Plan adopted September 1989 Stormwater Ordinance adopted September 24, 1991 Effective February 15, 1992 Revised: 1994 1996 1997 1999 2000 2003 2004 2005 2006 2008

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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.

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

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

Wetland Mitigation

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

Wetland Buffer Mitigation Replace lost functions due to unavoidable buffer impacts

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

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

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

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

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

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

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.

Types of Permanent BMPs 11/21/2018

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)

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

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

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

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

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

Stormwater Permit Submittal Flow Chart

http://www.dupageco.org/stormwater/

Questions? 11/21/2018