The initial number of practices identified include 114,400 pond dams, 327,900 acres of grassed waterways, 506,100 terraces stretching 88,874 miles, 246,100 water and sediment control basins stretching 12,555 miles, 557,700 acres of contour buffer strips and 109,800 acres of strip cropping, according to researchers. For comparison, the total area of Iowa is 56,273 square miles or 35.7 million acres. Approximately 30.6 million acres are farmed. The value of public and private investment in these practices in Iowa is valued at $6.2 billion in today’s dollars.

“This mapping effort shows the scale and investment made by farmers, landowners, state and federal landowners, conservation partners and many others over several decades to reduce erosion and protect our natural resources,” said Iowa Secretary of Agriculture Mike Naig July 31 in a statement.

The state has been engaged with many partners in recent years to reduce nitrate and phosphorous levels in Iowa streams, which ultimately flow to the Missouri and Mississippi Rivers, then on to the Gulf of Mexico. Iowa is one of several states that provides water to the Mississippi River, and is important because of the amount of agriculture within the state. This study establishes an important benchmark for measuring progress and informing where additional investment can provide benefits to nutrient reduction strategies.

View maps and additional information about the project.