The Iowa Department of Natural Resources announced Tuesday completion of the first phase of a statewide project to map use of conservation practices designed to prevent erosion and reduce phosphorus runoff.
The public now can view online maps showing the locations of terraces, ponds, grassed waterways, water and sediment control basins, contour strip cropping and contour buffer strips/prairie strips in about one-third of the state. The rest of the maps, made from aerial photos and light detection and ranging, or LIDAR, should be available in the spring.
Adam Schnieders, the DNR’s water quality resource coordinator, talked with The Gazette about what the mapping shows (and doesn’t show) and how it might be used for research and modeling to improve water quality.
Q: What is the primary value of these maps?
A: “The LIDAR was flown from 2007 to 2010, so these practices were all before the (Nutrient Reduction) Strategy, which was in 2013,” Schnieders said of the state’s plan for reducing by 45 percent nitrogen and phosphorus runoff from farm fields into waterways. “This (mapping) could help inform the baseline for the future, showing our baseline practices.”
Q: Why quantify the number of conservation practices?
A: We know we have the 45 percent reduction goal for nitrogen and phosphorus with point sources and nonpoint source working together. It costs a lot of money and when you look at it at first blush, it’s daunting. What you can see here, from this information, if you can build 114,000 ponds, we should be able to build 4,000 wetlands. It makes you hopeful we can hit these marks over time.
Q: Counting up the number of ponds and terraces doesn’t necessarily equate to cleaner water. To what degree does the state plan to use this data in connection with water monitoring?
A: This helps inform what we’re doing on the input side and also on the water monitoring side. It’s not one or the other. Both are critical. This could be something where the Nutrient Research Center says, “Do we know this has had any impact on water quality?” “Has this big investment over time yielded water quality benefits statewide or locally or in a specific watershed?”
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Q: Many water quality experts advocate for the “watershed approach,” or concentrating funding to specific areas where improvement can be measured. How can this data be used in that approach?
A: Knowing where the conservation practices are at allows us to look at targeting and where we apply these practices. We can subtract what’s existing from the potential to see what practices we can put in this watershed.
Q: How were these conservation practices chosen over others?
A: The ones that went forward had more obvious protocols. It’s what could you see from the LIDAR imagery? They are looking at ways of doing that (measuring cover crops). Sometimes it’s difficult to know the differences between a cover crop, alfalfa or a pasture. There’s been some experimentation of a green index and ways of using satellite imagery rather than aerial photography.
Q: The DNR reports the value of these conservation strategies at $6.2 billion in today’s dollars. How much of that is public money?
A: It’s blind about whether it’s public or private investment. Could be another research project out of it.
Q: You said this three-year, $300,000 project was crowdfunded. What do you mean?
A: We started with available money here and there, piecemeal. Ultimately (Iowa Department of Agriculture and Land Stewardship) IDALS, (Iowa State University) ISU, Nutrient Education Council as well contributed. We couldn’t have done it alone at our department, but everyone working together saw the value of how it could be used.”
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