More than $6.2 billion worth of conservation practices are in place on Iowa farms and landscapes, according to a first-of-its-kind statewide mapping effort by the Iowa Department of Natural Resources and Iowa State University.
Researchers used LiDAR derived elevation data and aerial imagery to identify and inventory six types of conservation practices in 1,711 watersheds, providing the most comprehensive inventory of conservation practices in the nation. Practices identified were terraces, ponds, grassed waterways, water and sediment control basins, contour strip cropping and contour buffer strips/prairie strips.
“This mapping effort shows the scale and investment made by farmers, landowners, state and federal agencies, conservation partners and many others over several decades to reduce erosion and protect our natural resources,” said Iowa Secretary of Agriculture Mike Naig. “While the practices identified are focused on reducing soil erosion and phosphorus loss, seeing the progress that has been made illustrates how we can make similar progress with a long-term focus and investment in proven conservation practices targeted at reducing nitrogen loss.”
The conservation practices identified by the mapping project include 327,000 acres of grassed waterways, 557,700 acres of contour buffer strips and 506,100 terraces stretching nearly 89,000 miles. The analysis also found 114,400 pond dams, 246,100 water and sediment control basins stretching 12,555 miles, and 109,800 acres of contour strip cropping.
Those water quality practices, which were identified using LiDAR data and imagery taken from 2007 to 2010, would cost an estimated $6.2 billion to build in today’s dollars, according to the analysis.
“This demonstrates that the consistent and persistent effort, year after year, … can, practice by practice, change the landscape for the better,” said DNR Director Bruce Trautman. “I’m excited and encouraged to see what we can do as we continue to scale up our collective efforts in support of the Iowa Nutrient Reduction Strategy.”
Additional work is underway to utilize the science of the Iowa Nutrient Reduction Strategy to quantify the water quality impact the practices are having in terms of reduced sediment and phosphorus loads to Iowa streams.
Iowa is the first state to analyze every watershed within its borders using LiDAR and aerial imagery to create a detailed assessment of conservation practice implementation.
The data provide a much more detailed and accurate analysis of soil conservation and water quality efforts focused on phosphorus reduction because it includes all practices implemented by farmers, including those done without government cost-share, Naig said.
It also provides a benchmark for measuring progress regarding public and private conservation efforts and will help target resources where they are needed most, he said.
Additional efforts are underway to assess the status of these conservation practices going back to the 1980s and also to assess the recent status of practices from 2016-2018. Once completed, the assessments will provide a robust timeline to show the progress that has been made in Iowa over time.
The project has garnered significant interest outside of Iowa as well. ISU was recently awarded a grant from a national remote sensing consortium to develop a handbook of the processes used for the project so other states can conduct a similar inventory of conservation practices.
“Other states continue to look to Iowa as we set the standard for implementation of conservation practices and science-based progress measurement,” Naig said.
Maps and additional information about the project can be found at https://www.gis.iastate.edu/gisf/projects/conservation-practices.
For more information about techniques and practices farmers are using to improve Iowa water quality, visit https://www.iowafarmbureau.com/Conservation-Counts/Conservation-QA.