Storm Drainage Manual Update

The city of Aurora has drafted an update to the Storm Drainage Design and Technical Criteria (SDDTC), that became effective on Nov. 9, 2023. It is anticipated that updates will be made on an annual basis, or as otherwise needed.

This update captures feedback received from the development community and issues found by AW staff since last year's revision. Changes made include the following:

• Extended concepts traditionally applied to detention ponds to other drainage facilities, including Stormwater Control Measures (SCMs) and MHFD Maintenance Eligible Program (MEP) streams, for the purposes of construction certification, ownership and maintenance responsibilities.
• Expanded listings of stormwater facilities that are owned and maintained by other City of Aurora departments and other governmental entities to clarify ownership and maintenance responsibilities.
• Recognized that all detention ponds that have executed Inspection and Maintenance (I&M) agreements are considered to have adequate assurances, and the peak flow reductions should be included in hydrologic calculations. Doing so reduces the construction and maintenance burden of oversized infrastructure.
• Expanded policies on grandfathering of previously approved stormwater infrastructure and provided a figure and examples.
• Updated imperviousness values for 3 land uses/surface covers.
• Expanded discussion of storm inlet placement, allowing more extensive use of cross pans on local streets.
• Separated discussion of detention requirements from water quality requirements, to avoid confusion.

A detailed list of changes is shown in Section 1.6.1 of the draft.

Two versions of the draft are available:

• SDDTC Draft Update-Clean - Document with all changes incorporated.
• SDDTC Draft Update-Redline - Document with all changes shown in red.

Comments on this draft can be sent to Craig Perl, Senior Engineer at cperl@auroragov.org by Monday, Aug. 5.