A rendering of what the gravel wetland will look like when it rains and when it doesn't


Walnut Creek Gravel Wetland

Green Stormwater Infrastructure

We installed a gravel wetland at Walnut Creek Wetland Park. The wetland includes:

  • An underground gravel reservoir that'll hold and filter stormwater runoff;
  • Plant roots that will soak up and clean the water; and, 
  • Slowing down the flow of stormwater before it reaches Walnut Creek.

This project was partly funded by a grant from the NC Department of Environmental Quality. The grant covered some construction costs and educational art at the gravel wetland. 

Project Details

$350,000 (design & construction)
Project Lead:
Stormwater Management
Hazen and Sawyer (Design); Lanier Construction Company (Contractor)



Heather Dutra
Water Quality Supervisor

Lead Department:
Engineering Services
Participating Department:
Parks, Recreation and Cultural Resources
Service Unit:



This project supports

Raleigh's Climate Plan in Action


This phase is complete. 

Lead Department:
Engineering Services


This phase is complete.

Next Steps



Lead Department:
Engineering Services


This phase is complete. 

Lead Department:
Engineering Services


Crews finished this green stormwater infrastructure project in October. Work for the gravel wetland included: 

  • Installing the pipes and drainage system; 
  • Excavating the area; 
  • Adding gravel to the wetland; and, 
  • Seeding and adding a fence to the area. 

During the warranty period, crews will make required repairs or maintenance for the project. This period ends in fall 2022. 

Creative Educational Installation

There will be an interactive installation on site to educate the community about this project.

Repairs September 2023

Construction to the gravel wetland was completed and involved lining an underground pipe which is accessed through a manhole on Peterson St. and the project’s riser structure.

Lead Department:
Engineering Services

A rendering of the plants, soil, pipes of the wetland on Peterson Street

A rendering of the Walnut Creek Gravel Wetland.


Date Activity
Fall 2018 Project design began
Winter 2020 Project design complete
Spring - Fall 2020 Construction bid process
Winter 2021 Project construction phase begins
Fall 2021 Project construction complete


The 5,300-square-foot wetland will capture stormwater runoff coming from Peterson Street and other nearby streets, sidewalks, and buildings (about one acre of impervious surface). Wetlands are a very effective way to treat stormwater runoff. The area is expected to prevent excess nitrogen and suspended solids from polluting waterways each year. 

  • 8 pounds of nitrogen 
  • 135 pounds of suspended solids

This is a great example of how planted stormwater devices help the environment. The features remove pollution and reduce impacts to stormwater pipes and streams.

Learn more about green stormwater infrastructure.