millbrook park stream

Stormwater

Millbrook Exchange Park Stream Project

Stream Improvements

We used an innovative technique to reduce erosion in a stream at Millbrook Exchange Park.  The project prevents pollution, like sediment, from flowing into Perry Creek. 

The project is supported through a grant from NC Land and Water Fund (formerly Clean Water Management Trust Fund). 

Project Details

 
Type:
Lakes, Streams, and Dams
Budget:
$300,000
Project Lead:
Stormwater Management
Contractors:
NCSU Stream Restoration Program; Ecosystem Planning & Restoration (EPR)

Contact

 

Heather Dutra
Senior Engineer
919-996-4012

Lead Department:
Engineering Services
Service Unit:
Stormwater

Subscribe

 

Planning

This phase is complete.

Phase Contacts

 

Heather Dutra
Senior Engineer
919-996-4012

Lead Department:
Engineering Services

Design

This phase is complete.

Phase Contacts

 

Heather Dutra
Senior Engineer
919-996-4012

Lead Department:
Engineering Services

Construction

This phase is complete.

Phase Contacts

 

Heather Dutra
Senior Engineer
919-996-4012

Lead Department:
Engineering Services

Complete

This project is complete. We installed 11 stone dams and a vertical control structure to prevent streambank erosion. We also planted trees and shrubs in the project area. 

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. 

Now, we've contracted with Ecosystem Planning & Restoration (EPR) to do an analysis that'll help us explore different design options for repairs required at the stream. The analysis will be completed at the end of September.

Phase Contacts

 

Heather Dutra
Senior Engineer
919-996-4012

Lead Department:
Engineering Services

Schedule

Date Activity
Spring 2018 Project design and permitting/bid process complete
Fall 2018 Project construction begins
Spring 2019 Project construction complete
Spring 2019 - Late Fall 2020 Monitoring underway
Fall 2021 Analysis underway for repair options
TBD Design created for repairs; repairs made

History

This stream flows to Perry Creek and passes through Millbrook Exchange Park. It receives stormwater runoff from a 167-acre largely developed drainage area.  Erosion from stormwater runoff coming from the surrounding area caused the stream’s bed to drop several feet below its natural level. The stream was between 5-12 feet with high banks.

In this condition - The stream lacks many key functions that preserve it and protect wildlife in the area. With the design, the streambed will go from 12 feet deep to 3 feet deep (in some places along the stream). 

This stream is also unique because it only fills up with water during rainy seasons or heavy rainstorms. So, it may take several years for the streambed to be completely repaired. 

The Technique

We used a low-cost and unique design that includes fitting 11 boulder structures in the stream that will fill in with sediment (i.e. silt, sand, and gravel) over time and raise the streambed. This stream technique reduces the amount of sediment downstream, transforms the energy and flow of the stream, and prevents any further erosion to the streambank.