Stormwater Design Standards for Development
Walker adopted the new Stormwater Ordinance and design standards set forth by the Michigan Department of Environment, Great Lakes, and Energy (EGLE) on February 1, 2022, in compliance with the NPDES MS4 permit.
Visit the links below or Walker's MS4 page via LGROW.org for the most up-to-date Stormwater Standards and design tools.
If a new development alters the grade or drainage capabilities of the proposed site, a stormwater permit may be required. The purpose of the stormwater permit is to ensure the site design meets both water quality and flood control requirements. These design standards protect our waterways from pollutants and erosion while also protecting our lands from flooding.
The City of Walker has updated Chapter 67: Stormwater Management that incorporates the new design standards set forth by EGLE consistent with urbanized communities throughout Michigan. Highlights of the changes are summarized below:
Updated Stormwater Ordinance Design Standards: Main Points
- Treat the runoff from the 90% annual non-exceedance storm (approximately 1")
- Reduce TSS to 80 mg/L or
- Reduce TSS by 80%
- Maintain post-development project site runoff volume and peak flow rate at or below pre-development for all storms up to the 2-year, 24-hour event.
Other Required Changes
- Water quality and quantity regulations apply to road and sidewalk work if impervious surface increase is 1 acre or more.
- Increased oversight of private stormwater facility maintenance.
- No variance procedures for water quality or channel protection requirements.
- No changes in flood control. We are maintaining our 100-year flood control design standard.
Together with the Lower Grand River Organization of Watersheds (LGROW), all Kent County MS4 communities along with collaboration with Muskegon, Ottawa, and Allegan counties, Walker helped to develop resources and tools to assist in site design under the updated standards. These are listed below along with the updated Stormwater Permit Application.
Stormwater Design Tools
- Stormwater Standards Manual (PDF) revised March 26, 2021
- LGROW Design Spreadsheet (XLSM) V 3.5. Must design for 100 year flood control. V3.5 added macro instructions. No changes to formulas.
- LGROW Design Calculator Tutorial (PDF)
- Volume Restriction Alternative Approach Flow Chart (PDF)
- BMP Manual (PDF)
Stormwater Permit Documents
Last updated 10-07-2021
- Stormwater Permit Packet (PDF) active after February 1, 2022
- Stormwater Maintenance Agreement active after February 1, 2022
- MACC BMP O&M Guide for Maintenance Agreement Development
- Kent County Development Drainage Rules
Stormwater Permitting Contact
City of Walker Engineering Department - Email Rachell Nagorsen she can also be reached by phone at 616-791-6327.