Pleasant Run Waterway Project

Improving waterway conditions

Researchers in a field digging up small samples of soil
researchers collecting water samples

To better control the health risks associated with stormwater overflow, IU and IUPUI researchers collected water samples at Pleasant Run, on the east side of Indianapolis, over a two-year period to identify areas that would benefit most from contamination-absorbing green infrasctructure.

The Problem

Indianapolis is one of 800 communities across the United States with a combined sewer system, which handles both stormwater and wastewater. During rainfall events of a quarter inch or more, it’s common for these pipes to overflow, leaking contaminated water into area waterways. This can cause E. coli infections in pets or people who ingest the water or sicken those who swim in it.

To address this problem, the City of Indianapolis broke ground on a 15-year project to construct 28 miles of tunnels below the city and green infrastructure to absorb excess stormwater. To best ensure the success of this $2 billion project, called DigIndy, it is vital to understand which areas are most affected by overflow contamination.

The Project

Partnering with the City of Indianapolis, Citizens Utilities, and a range of Indianapolis non-profit and corporate organizations, a team led by IU and IUI researchers established six sampling locations along Pleasant Run, a 27-mile watershed on the east side of Indianapolis. Between 2020 and 2021 students collected water samples and field data every two weeks. The samples were then analyzed in a lab and tested for E. coli concentrations.

The results are being used to identify parts of the waterway that would most benefit from contamination-absorbing green infrastructure, such as bioswales and rain gardens.

Research indicates that E. coli contamination within Pleasant Run stems from the bacteria’s colonization of waterway sediments, where it can quickly grow in response to excess nutrients in stormwater. In addition, endemic E. coli populations are naturally present in the watershed, complicating the challenge of mitigating health risks.

The Path Forward

Identifying areas within the waterway catchments that tend to have higher E. coli will help land use planners more effectively pinpoint high-priority areas for green infrastructure projects. This will enhance natural stormwater infiltration and reduce discharge into vulnerable portions of the waterways.

Researchers plan to use data from this project to assist other Midwestern communities facing waterway contamination.

Updated Oct. 7, 2022

Project Data

Plans to publish data from this project in a journal are underway.