Nonpoint source pollution

Nonpoint Source Pollution in Indiana

Nonpoint source (NPS) pollution is the leading cause of water quality problems in the state, affecting Hoosiers’ drinking water supplies, recreation, fisheries, and wildlife. NPS pollution does not come from a single, identifiable source but occurs when surface runoff carries natural and human-made contaminants into wetlands, lakes, rivers, and ground waters.

While some NPS pollution is caused by natural sources, human activity is responsible for the majority of NPS pollution. Common contaminants include:

Fertilizer, pesticides, and herbicides from farms and yards
Toxic chemicals from urban runoff
Sediment from construction sites and crop lands
Road salt carried in snowmelt
Acid drainage from abandoned mines
Bacteria from livestock, pet waste, and septic systems

What strategies can be used to manage NPS pollution?

Although the many sources of NPS pollution complicate the problem of controlling it, a number of strategies exist to prevent pollutants from reaching waterways:

Reduced use of chemical pollutants
No-till or reduced-till farming to prevent soil erosion
Use of grass “buffer strips” to absorb pollutants before they reach water
Use of porous paving materials in parking lots and sidewalks to reduce water runoff
Planting trees and native plants

Facts about NPS pollution in Indiana

2,500Indiana streams impacted by NPS pollution in 2020

7,000acres of Indiana lakes and reservoirs contain nitrogen or phosphorous from excess fertilizers

100percent of Indiana’s Great Lakes shoreline contains bacteria from human and animal waste

$3,900,000 awarded to Indiana NPS pollution control projects by the Clean Water Act in 2019

Source: Indiana Department of Environmental Management

How can Hoosiers help address NPS pollution?

Preventing nonpoint source pollution from contaminating Indiana waterways requires the cooperation of many groups and agencies at the federal, state, and local level. Every Hoosier who cares about the condition of their local watershed can also make a difference by following a few key practices:

Keep litter, pet wastes, leaves, and debris out of street gutters and storm drains.
Apply lawn and garden chemicals sparingly and according to directions.
Dispose of used oil, antifreeze, paints, and other household chemicals properly.
Clean up spilled brake fluid, oil, grease, and antifreeze.
Control soil erosion on your property by planting ground cover and stabilizing erosion-prone areas.
Encourage local government officials to develop construction erosion and sediment control ordinances in your community.
Have your septic system inspected and pumped, at a minimum every three to five years, so that it operates properly.
Purchase household detergents and cleaners that are low in phosphorous.

ERI Projects

ERI supports a number of initiatives to raise awareness about NPS pollution and monitor the health of waterways in the state of Indiana.

A tractor applying nutrients to a crop field

Modeling Farm Management Practices

IU Associate Professor Adam Ward and his collaborators partnered with an Indiana based farming cooperative to investigate variables that affect farm productivity and environmental impact. Researchers collected data on soil quality, fertilizer and pesticide application, crop yield, and more, and used it to create a high-resolution model to better understand agriculture’s environmental footprint.

Researchers in a field digging up small samples of soil

Improving Waterways

Researchers from IUPUI and IU Bloomington and the City of Indianapolis assessed the environmental, social, and health impacts of changes along Pleasant Run Creek, a 27-mile urban watershed on the east side of Indianapolis. The research team worked to quantify the impacts of greenways on human and environmental health and tested for positive feedbacks between urban biodiversity restoration, citizen engagement, and ecosystem resilience.

Water Quality on Farms

IU Assistant Professor Landon Yoder and his team collaborated with Indiana farmers to monitor nutrient runoff from their fields. The team analyzed water samples collected from participating farms and providing farmers with reports on how much nitrogen they may be losing from their fields. The data could help inform strategies that maximize nutrient efficiency and limit NPS pollution.

Environmental Resilience Institute

Nonpoint source pollution