Iowa Farmers Tackle Erosion to Protect Flood-Fighting Ponds

Iowa scientists just cracked the code on keeping farm ponds healthy longer, and their discovery could protect communities from flooding for decades to come.

Researchers at the Iowa Geological Survey found that farm ponds across southeast Iowa were filling with sediment 25% faster than their designed 50-year lifespan. These ponds act like natural sponges, soaking up floodwaters and catching soil before it flows downstream into rivers and lakes.

The unexpected part? Most of the sediment wasn't coming from cropland like scientists thought.

Keith Schilling, director of the Iowa Geological Survey, discovered that gully erosion from nearby woodlands and forests was dumping major amounts of soil into the ponds. Dense forest canopies shade out grassy ground cover, leaving bare soil vulnerable when heavy rains hit.

"Even forests in some areas can contribute a lot of sediment," said Matthew Streeter, a soil scientist who worked on the study. The team found that many forested areas still carry the "legacy" of past farming, with eroded landscapes that never fully recovered.

But here's where the discovery gets exciting. Now that scientists understand the problem, they can fix it before building new ponds.

Schilling recommends that farmers and land managers examine nearby areas for gully erosion before installing a pond. Simple fixes like adding terraces, water control structures, or buffer zones can stop erosion at its source and help ponds live up to their full 50-year potential.

The Bright Side

This research doesn't mean farm ponds have failed. It means they're about to get much better.

The study gives conservation teams a clear roadmap for making these flood-fighting systems more effective. By addressing gully erosion during the planning phase rather than after a pond fills up, communities can stretch their conservation dollars further and protect more land from flooding.

The findings also apply beyond Iowa's borders. Any region with steep slopes and farm ponds, from Missouri to Minnesota, can use these insights to build smarter conservation projects.

Schilling stressed that installing farm ponds remains crucial for reducing sediment in waterways and protecting downstream communities. The researchers are now working to measure sedimentation rates across different types of watersheds to create even more precise guidelines.

Iowa's farmers and conservation teams now have the knowledge to make every new pond count for its full five decades.