The specific applicable technical requirements and the extent of documentation required to be submitted may vary depending on existing conditions of the development site. The applicant shall combine the separate "submittals" referenced in this title into a single application package of materials. Unless superseded by application under either a general certification or a letter of permission, or the director or administrator specifically allows a modification of the submittal requirements in writing, the following shall guide the determination that an application for stormwater certification is complete.
A. Stormwater Submittal: All developments requiring a stormwater certification are required to submit the information required for minimum submittal (subsection 9-5-1A of this title). The requirement for record drawings (subsection 9-5-1B of this title) applies to all developments that construct stormwater facilities, or include wetland, buffer or floodplain on site. Unless the development fits the definition of minor development, the plans and calculations listed in subsection 9-5-1D of this title will also be required (as relevant to the specific development).
B. Maintenance Plan: When the development includes construction of a site runoff storage facility or postconstruction best management practices, a maintenance plan specifying tasks and frequency shall be submitted.
C. Exceptions: The provisions of section 9-6-2 of this title shall apply to all developments except:
1. Developments classified as "minor developments"; or
2. Developments which do not include site stormwater storage facilities and which do not include any best management practices with a design drainage area greater than one acre.
D. Performance Security: Performance security in accordance with section 9-6-1 of this title may be combined into a single instrument and is required as follows:
1. Development security in accordance with subsection 9-6-1B of this title is required for all developments which are not minor developments, and which include construction of a stormwater facility (chapter 9 of this title), or more than two hundred feet (200') of storm sewer, or a postconstruction best management practice (chapter 8 of this title) designed to serve more than one acre of drainage area.
2. Erosion and sediment control security in accordance with subsection 9-6-1C of this title is required for any development disturbing more than one acre, or which disturbs the bed and banks of a channel draining more than one hundred (100) acres, or when an erosion and sediment control plan is required because of impact to wetlands, buffers or floodplain.
3. A natural area, wetland and buffer mitigation area security shall be posted per subsection 9-6-1D of this title. Whenever a natural area is being restored or a wetland or buffer is impacted and mitigated, unless mitigation is provided by fee in lieu.
E. Soil Erosion And Sediment Control: All developments must provide both temporary and permanent soil erosion and sediment control; however, plans for these measures must be submitted for review only where the development is required to obtain a stormwater management certification (section 9-4-1 of this chapter). Developments required to make application may obtain a letter of permission (section 9-4-2 of this chapter), even if it is not a minor development, as long as no other aspect of the development requires review under chapter 8, 9, 10 or 11 of this title. All other applications shall include the following based on area of land disturbance of the proposed development:
1. If the land disturbance is less than one acre and does not disturb the bed and banks of a channel draining more than one hundred (100) acres, and the development does not involve impact to buffer, wetland, or floodplain, and is not part of a larger common plan, then the submittal shall be per subsection 9-5-4B of this title.
2. If the land disturbance is one acre or greater or disturbs the bed or banks of a channel draining more than one hundred (100) acres, or the development includes impact to buffers, wetlands, or floodplain, then the requirements of subsections 9-5-4C and D of this title shall apply.
F. Postconstruction Best Management Practices: When the impervious coverage of the development site is increased by two thousand five hundred (2,500) square feet or more compared to the predevelopment site then PCBMPs designed in accordance with chapter 8 of this title are required and submittals in accordance with section 9-5-3 of this title are required with the application, unless one of the exceptions or exclusions listed in section 9-8-1 of this title applies.
G. Floodplains And Floodways: All developments shall check the requirements of section 9-10-1 of this title to determine if floodplain exists on a development site. Chart 3 is included in chapter 21 of this title as a guide. If floodplain does exist on the development site, a BFE shall be established as outlined in subsection 9-10-1A of this title and shall be drawn on the site topographic map. If the datum for the BFE determination is different from the site topographic map datum, the appropriate conversion factor shall be used. The DuPage County developed conversion factors from NGVD 29 to NAVD 88 per watershed shall be used when appropriate. If the proposed work is outside of the BFE, there shall be no additional requirements from chapter 10 of this title that need to be met. Applicants shall determine if floodway exists following subsection 9-10-1F of this title. For developments that involve work within the floodplain or, where there is floodway within the disturbed area, the floodplain and floodway shall be delineated on the site plan.
1. For developments within the floodplain, document that requirements of section 9-10-2 of this title are being met with a narrative and appropriate calculations, modeling, cross sections and plans.
H. Wetlands: A flow chart is included in chapter 21 of this title as a guide. Stormwater management certifications are required for developments where the area being disturbed, or developed, is within one hundred feet (100') of a wetland located either on site or off site. The application shall include the following:
1. A wetland delineation and report will be required unless the wetland is determined to be greater than one hundred feet (100') away from the development's limit of disturbance, and subsection 9-2-7A1a of this title is applied with the concurrence of the administrator.
2. If the development's proposed limit of disturbance is within one hundred feet (100') of a wetland, then:
b. If there are direct impacts to the wetland, then the wetland submittal in accordance with section 9-5-2 of this title will be required.
c. If the development will cause an indirect impact to a wetland, an indirect impact analysis shall be included in the wetland submittal.
d. If the development has a direct or indirect permanent wetland impact a hydrologic analysis of the mitigation area (subsection 9-11-4L of this title) and a maintenance and monitoring plan (subsection 9-11-4M of this title) are required to be submitted, unless fee in lieu of mitigation is provided.