The Iowa Agricultural Drainage Well Research and Demonstration Project was established by the Iowa Groundwater Protection Act. That legislation charged the Department to conduct a research and demonstration project to address concerns about contamination of groundwater through use of agricultural drainage wells (ADWs).
All registered ADWs in Iowa have now been studied to characterize the costs of ADW closure and development of alternative outlets to surface watercourses. The studies were performed by drainage engineering firms under contract with the Division. Through these studies, preliminary engineering concept designs have now been developed for alternative outlets for all of the registered ADWs. These studies and preliminary concept designs are now being used by the Division and involved ADW owners in the Agricultural Drainage Well Closure Assistance Program. Research to develop improved in-field management of fertilizers and herbicides for areas draining to ADWs has been conducted by Iowa State University under contract with the Division. A research installation was developed for this project in Pocahontas County, consisting of 78 research plots, two-cell wetland complex, and a controlled-drainage cropping area. The research plots are equipped with individual tile drains from which continuous flow-composited water samples are collected 24 hours/day throughout the growing season by automated sampling equipment.
Practices have been developed through this research to achieve environmental needs, for those ADWs that will be continued in use. Based upon this research, the Iowa Department of Natural Resources has issued continued-use permits to most ADWs in Iowa. New nitrogen management practices are being developed which show promise of reducing nitrate movement from cropped lands by 25-50%. Monitoring of new-generation herbicides shows no movement of herbicide in tile drainage water which exceeds the drinking water limits.
Additional research sites have been developed in Story County to develop technologies to utilize wetlands to remove nitrate and herbicides from tile drainage water. Strategically-located and designed wetlands will remove 40-90% of the nitrate and 90+% of the herbicide in tile drainage water from upper-lying croplands. This technology is now being implemented through the Iowa Conservation Reserve Enhancement Program, which will provide up to $38 million in funding over the next three years to construct and restore up to 9000 acres of wetlands and buffers.
The Agricultural Drainage Well Research and Education effort, while conducted to address the concerns about ADWs, has statewide application in dealing with the water quality concerns about nitrogen and herbicide movement from cropped lands to Iowa’s streams and lakes. Research and outreach efforts are continuing to develop and implement new strategies to address these environmental concerns.