Proposed Stormwater Management Criteria Update
The City of Manhattan amended our Stormwater Design Criteria to adopt the new Stormwater Management Criteria, 2023 edition.
The new criteria were published October 10, 2023, and take effect on November 1, 2023. This new document replaces the previous technical design standards contained in the Stormwater Management Master Plan (SWMMP) that had been in place since 1994.
An amendment to the City’s Post-Construction Best Management Practices Manual has also been issued with the same effective dates.
Submittals based on these designs must use the new Design Submittals Workbooks.
In addition, the City is proposing to adopt updated Standard Drawings and Construction Specifications which, when finalized, would supersede those currently in effect. Work is continuing on these documents and they will be issued at a later date.
A public comment period was held in the fall of 2022. This comment period included two public meetings held on October 18, 2022.
A second public comment period was held from August 12, 2023, through September 7, 2023, and is now closed. A presentation was given to the City Commission on the new standards at its work session held August 22, 2023.
New Criteria and Standards, As Adopted to Date
The following documents have been formally adopted and are available from the Public Works Standard Specifications page:
- Amendment 12, Adopting the Stormwater Management Criteria (PDF)
- Amendment 13, Revising the Post-Construction BMP Manual (PDF)
- Stormwater Management Criteria, 2023 (PDF; finalized October 10, 2023)
- Drainage Submittals Workbook, current edition (XLSX)
Propose Criteria and Standards, Still Under Development
- Proposed Standard Drawings for Stormwater, 2nd Public Comment Edition (PDF; posted August 12, 2023; comments closed)
- Proposed Construction Specifications for Stormwater, 2nd Public Comment Edition (PDF; posted August 12, 2023; comments closed)
- Results of Stormwater Design Survey Conducted June 2020 (PDF)
- Technical Memo for Hydrology Methods, September 2022 (PDF)
- City Commission Work Session Presentation Slides (PDF; presented August 22, 2023)