Western North Ridge Stormwater Improvements Phase I

Last updated Jul. 13, 2017 - 4:10 pm
  • Planning
  • Design
  • Construction
  • Completed
  • Storm Drainage System
  • $2.3 million
  • Stormwater Management (Lead)
  • Dewberry (Engineering Consultant)

Current Activity

Formal design of improvements to the existing, undersized storm drainage systems along Tanbark Way, Harps Mill Road, and Grist Mill Road as well as downstream open channel stabilization and restoration are approximately 60% complete for Phase I of this two-part project.


Preliminary design includes the upgrade and installation of new closed system piping along Tanbark Way (near the intersection with Pinebark Court), at crossings on Harps Mill Road (between Tanbark and Plateau Lane as well as between Plateau and Fiesta Way) and at the pipe crossings along the 7300 block of Grist Mill Road. In addition, open channel improvements will be made along this corridor for areas where the channel is restricted and in areas where there is severe erosion. Improvements to the downstream receiving channel are also planned, including floodplain benching, and, stream stabilization and enhancement techniques to address flooding and stream erosion concerns.

Lastly, the potential for water quality improvements will be examined at several upstream locations to address regulatory requirements and water quality concerns within the Perry Creek Watershed. This includes the potential for created wetlands and possible expansion of existing best management practices (BMP)* facilities upstream. The system will outlet into the western end of the lake at the North Ridge Country Club. 

The goal of the project is to reduce street and structural flooding and provide Tanbark Way, Harps Mill Road, and Grist Mill Road with a 10-year level of service. This means that the streets will not overtop in the storm event of a magnitude expected to be equaled or exceeded once on average in a 10-year period. A secondary goal of the project will be to improve water quality to assist the City in complying with regulatory requirements for the Perry Creek Watershed.


*Best management practices include stormwater ponds, wetlands, rain gardens, etc. installed to help improve water quality in our streams.


  • *Roadway overtopping of Grist Mill Road. Roadway overtopping of Grist Mill Road.
  • *Grist Mill Road and right of way flooding. Grist Mill Road and right of way flooding.
  • *Private property flooding. Private property flooding.
  • *Yard and channel flooding. Yard and channel flooding.
  • *Dated and undersized stormwater infrastructure off Harps Mill Road. Dated and undersized stormwater infrastructure off Harps Mill Road.


Project schedule with dates and descriptions
Spring 2017Project design for phase I complete
Summer 2017Phase I easement acquisition complete
Fall 2017 Phase I project bid pending approval of FY18 budget
Summer 2018Phase I construction begins


These projects are located along the western tributary and drainage basin to the North Ridge Country Club Lake within the North Ridge community, which is in the Perry Creek Watershed. A history of flooding events in the area resulted in public meetings in April and June 2006, which initiated these stormwater projects.

An engineering study was completed in December 2006, which recommended improvements to the existing storm drainage systems at Tanbark Way, two locations on Harps Mill Road and the system crossings at Grist Mill Road. Roadway overtopping, severe channel erosion, and private property and structural flooding have all been exhibited in the past during large storm events.

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