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Green Infrastructure Design Manual

By: Montaze Trumbo

MSD modified the Wastewater/ Stormwater Discharge Regulations (WDRs) for compliance with the EPA’s Municipal Separate Storm Sewer System (MS4) permit with changes effective August 1, 2013.  The amendments require the use of green infrastructure to manage stormwater from new development construction.  Communicating expectations, procedures and standards via the Design Manual was central to the regulatory updates.

Updates Based In Experience

Green Infrastructure Design Manual (i.e., MSD’s Design Manual, Chapter 18) was developed in August 2011 coinciding with a green infrastructure financial incentives program composed of a short-term construction cost reimbursement based incentive (i.e., stipend) and long-term reduction in drainage service charges based incentive (i.e., a credit).  Many lessons were learned through the wide variety of projects that went through the incentives program.  These lessons were captured in the 2013 Design Manual updates.  Similarly, the Plant Guide (i.e., MSD’s Design Manual, Chapter 13) was significantly updated to better communicate the wide variety of vegetative options.

2013 Major Updates Summary

  • Overall standard s and BMP selection process streamlined and increased flexibility for varied site soil conditions 
  • New and revised drawings, illustrations and examples for design and field use
  • New  specific calculation sheets making plan preparation and review quicker (including automated tools)
  • New checklists for plan preparers / reviewer and inspectors
  • Expanded operation and maintenance guidance
  • Financial incentives and Fee-In-Lieu programs and processes
  • Standardized maintenance agreements

The Green Infrastructure Design Manual and Plant Guide can be downloaded here:

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