Iby Street Gravel Wetland


The Potash Brook watershed is one of five stormwater impaired waterbodies in South Burlington. The City recently developed a Flow Restoration Plan (FRP) for this watershed. This plan identifies projects with the potential to reduce flow in Potash Brook, restore the brook to health, and satisfy requirements in the City’s MS4 permit. Included in the project list for the Potash Brook FRP is the construction of a gravel wetland at the end of Iby Street. This gravel wetland is also a part of the City Center Park project.

Prior to the project, stormwater runoff from Iby Street discharged untreated to the west end of Iby Street, through an eroded channel down to a Class II Wetland.


The project proposes to construct a stormwater gravel wetland, along with an improved pedestrian bridge to provide access to Dumont Park. The overall drainage area to the proposed gravel wetlands is 3.31 AC. The drainage area to the gravel wetland is comprised of Iby Street pavement and the residential development along Iby Street.


The project collects and provides treatment for runoff from a 3.3 acre drainage area, consisting of residential roads, rooftops and driveways. The subsurface gravel wetland reduces the amount of sediment and nutrients flowing to Lake Champlain. In addition, the stormwater runoff is detained and slowly released to prevent erosion of streambanks and reduce the risk of downstream flooding.

Best Management Practices

Stormwater Gravel Wetland

Pretreatment Tank


Construction of the gravel wetland and drainage system was completed in 2018.

Construction Cost


Funding Sources

Ecosystem Restoration Program, Stormwater Utility Fund.

Last Updated: 10/29/2018