Water Resources Research Act Program

Details for Project ID 2004IN158B

Potential of Controlled Drainage to Reduce Nitrate Contamination at the Watershed Scale

Institute: Indiana
Year Established: 2004 Start Date: 2004-03-01 End Date: 2005-02-28
Total Federal Funds: $40,000 Total Non-Federal Funds: $80,000

Principal Investigators: Jane Frankenberger, Eileen Kladivko

Project Summary: About 50% of all cropland in Indiana is artificially drained with subsurface tile drainage systems. While artificial drainage is necessary for insuring field operations and crop production, it has environmental costs, increasing nitrate-N load to surface water. Controlled drainage has been shown in plot- and field-scale studies to reduce nitrate losses from subsurface-drained soils. Control structures are used to hold the water table at a higher level during the non-growing season in November to March when most of the drainage and nitrate loss occur. Controlled drainage could have an important impact on annual nitrate load in streams and rivers that drain heavily-drained watersheds. Although field and modeling studies provide good estimates of potential nitrate loss reduction at the field scale, no studies exist that estimate how much nitrate reduction is possible from implementation of controlled drainage at the mid-size watershed scale. The goal of this study is to quantify the potential benefit of controlled drainage in reducing nitrate-N load to surface water in a mid-sized watershed, under the weather and soil conditions in Indiana. The watershed version of DRAINMOD-N will be used for analysis and prediction, and Monte Carlo simulations will be used for uncertainty analysis. The results will include the potential percent reduction in nitrate-N load that would occur if all cropland that is suitable for controlled drainage has that practice in fallow season and the confidence intervals for the estimates. This information can be delivered to producers, policy-makers, and rural communities to encourage improved drainage water management in Indiana.