Millbrook Stream Repair

Stormwater

Millbrook Exchange Park Stream Project

Stream Repairs

In 2019, a technique using in-stream stone structures was implemented to reduce stream erosion at Millbrook Exchange Park and prevent pollution from flowing into Perry Creek. After the project was completed, heavy rainfall and streamflow damaged the structures. We designed and constructed repairs to the stream that will prevent erosion.

Project Details

 
Type:
Lakes, Streams, and Dams
Budget:
$440,000 (Repair Design + Construction)
Project Lead:
Stormwater Management
Contractors:
Ecosystem Planning & Restoration (EPR), KBS Earthworks, Inc.

Contact

 

Megan Walsh, PE
Senior Engineer
megan.walsh@raleighnc.gov
919-996-4009

Lead Department:
Engineering Services
Service Unit:
Stormwater

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Design

Design of the repair project has been completed. Topographic survey data was collected in August 2022 to help inform the design.

Public Meeting

We hosted a public meeting May 2023 to discuss the status of the Millbrook Exchange Park Stream Project. At this meeting, the City answered questions and solicited feedback and concerns from the public.

May 11, 2023 Public Meeting Materials

Lead Department:
Engineering Services

Construction

This phase is complete.

Lead Department:
Engineering Services

Complete

Construction on the stream repairs were completed. Repairs included:

  • Armoring the structures with stone;
  • Raising the streambed using soil and other natural materials; and
  • Constructing a floodplain bench that will reduce erosion by allowing water to spread out along the stream bank.

The floodplain bench (ground running along the stream) will be planted with native trees and grass to stabilize the project, provide wildlife habitat, and replace trees that were removed during construction.

Lead Department:
Engineering Services

Completed Project Photos

Schedule

Date Activity
Winter 2022 Finalize design for repairs
Spring 2023 Receive Permits
January 2024 Construction Begins
Summer 2024 Construction Completed

History

This stream flows to Perry Creek and passes through Millbrook Exchange Park.

It receives stormwater runoff from a largely developed 167-acre drainage area. Stormwater runoff coming from the surrounding area caused erosion and the stream bed to drop several feet below its natural level. In this condition, the stream lacked many key ecological functions.

In 2019, a low-cost and unique technique was implemented that included fitting eleven (11) boulder structures in the stream to fill with sediment over time and help raise the streambed. This technique was intended to reduce the amount of sediment downstream, transform the energy and flow of the stream, and help prevent erosion to the streambank.

North Carolina State University conducted post-construction monitoring of the stream from Spring 2019 to December 2020. During this time, heavy rainfall and streamflow damaged structures in the stream.