1. Conservation Drainage: Drainage for the 21st Century

2. 1890s The Nitrate Saga Scientists sound alarm about
need for new source of nitrates

5. Carl Bosch
Fritz Haber

8. Nutrient contributions to the Gulf, by State

9. Distribution of Subsurface Tile Drainage in Illinois
3-4 million ha (6-10 million
acres) drained with
subsurface tile in
Illinois
This comprises some
of the most productive
agricultural land in the
US.

10. HYDROLOGIC CYCLE (with tiles)
While the water drains into the drain pipes, its is simultaneously discharged to the stream through a network of pipes. This section here, shows some important hydrologic processes where the drain meets the stream or the ditch. There is also a significant amount of water drained through the ditch sides through interflow process, all along the ditch. And of course the water that remains undrained, flows as surface runoff towards the streams as well.

11. 7.2
km/km2

12. The solutions that you seek will not be found in the streak of a pen,
or even one thousand words of mine.
Mutabaruka

13. Nitrate Reduction Techniques
Altering Nitrogen Application Amounts
Altering Nitrogen Application Timing
Edge-of-Field Treatment
Optimizing Drainage System

14. Conservation Drainage Minnesota Department of Agriculture
The incorporation of environmentally friendly practices and structures into existing drainage infrastructure
Conservation Drainage has been defined as “The incorporation of environmentally friendly practices and structures into existing drainage infrastructure.” In essence this means the optimization of drainage practices for both production and water quality objectives.
Minnesota Department of Agriculture

15. Conservation Drainage
The optimization of drainage systems for crop production, water quality and water harvesting benefits

16. No Decrease in Drainage Efficiency No Adverse Effects on Neighbors
Water
Management
No Decrease in Drainage Efficiency
No Adverse Effects on Neighbors
Conservation
Drainage
Subsurface Bioreactors
With drainage being such an important part of agriculture in Illinois, we have been at the forefront of conservation drainage research. The focus has been on three practices with increasing potential in terms of applicable acreage:
Drainage Water Management,
Passive Subsurface Bioreactors, and
Depth/Spacing Modifications
It is important to note that we have been conducting our research under self- imposed constraints. Conservation practices
should not lead to a decrease in drainage efficiency,
There should be no adverse effects of surrounding farmers and other neighbors, and
The practices should be convenient and cost effective.
We believe that these constraints will lead to more widespread adoption of these practices. I would like to share with you the results of some of the work that we are doing in these three areas.
Depth/Spacing Modifications
Convenient and Cost-Effective

17. Golden Rule of Drainage
Only release the amount water necessary to insure trafficable conditions for field operations and to provide an aerated crop root zone
any drainage in excess of this rule likely carries away nitrate and water that is no longer available for crop uptake

18. Drainage Water Management

19. Manual
Gate Structure
Automated
Gate Structure
Float Structure

20. Drainage Water Management Guidelines
– in an unusually dry season, control can be 3 to 6 inches higher; – in an unusually wet season, control should be 3 to 6 inches lower; – in coarse-textured soils, trafficability can be provided with the water table approximately 6 inches higher.

21. Managed Drainage - Winter Conservation Mode for Fallow Season

22. Managed Drainage - Spring Full Drainage Mode for Planting Season

23. Managed Drainage -Summer Shallow Drainage Mode for Growing Season

24. Managed Drainage - Fall Full Drainage Mode for Harvest Season

25. Potential Water Available from Drainage Management
~ 1.5 inches
Source: Based on DRAINMOD Simulations

26. Water Deficit Stress

27. DWM Benefits Reduces Nitrate Concentrations in Effluent
30-95% reductions annually
Increased Yield
76% higher yield in a dry year
Lower Concentrations of Other Pollutants

28. Required Information for Economic Analysis of DWM System
Drainage Costs
Added Revenue
Capital Costs
Timeliness Benefits
Schematic of proposed field-scale bio-filters. The bio-filter is teed off of an existing tile. It consists of one or more cells placed below the level of the tile. The water flows up through the bio-filter and out the outlet pipes. The outlet tile is below the level of the existing tile, thus water preferentially flows through the outlet. However, if the capacity of the bio-filter is exceeded, water will flow through the existing tile. Thus the drainage effectiveness is not reduced by the addition of a bio-filter.
In the systems that we have installed, the bottom of the bio-filter trench is 12 to 24 inches below the tile invert. The important thing is that the volume of the bio-filter should be enough to achieve an 8-hour retention time.

29. Drainage Water Management29

30. Hume 2004 30

31. Flow Depths (cm) From a Paired Drainage Site
Free Drainage
Managed Drainage 31

32. Hume 2006 32

33. Long Term Nitrate Trends: 2005
High levels of variation throughout year.
Managed Drainage and free drainage systems show similar response and variability.

34. Long Term Nitrate Trends: 2008
Nitrate concentrations continue to be lower on average for the managed drainage case.
They can still be above the MCL.

35. Free Drainage
11.3 acres
50-70 ft Spacing
Managed Drainage
13.1 acres
50-70 ft Spacing

36. Kinderhook Site
Nitrate-N (mg/L)

37. System Layout for Drainage Water Management

38. Cost Differential: $50/acre
Layout Costs
Cost Differential: $50/acre