~Information courtesy of Iowa State University

 

What is Conservation Drainage?

Conservation Drainage is the use of water control structure to raise or lower water elevations during crucial times of the year.  The purpose of a conservation drainage system is to manage the water table; to minimize drainage outflows during times of the year when drainage requirements are reduced, and provide for adequate drainage when needed most.

With conservation drainage, landowners can artificially raise the drainage outlet “elevation,” using a conservation drainage structure, and thus actively manage the outlets. Water control structures are installed in strategic locations on a field drainage system.  Management of these systems during the winter can typically be accomplished without much difficulty or interference with agricultural operations by adjusting the outlet to a constant, shallow depth. Beginning in the spring, periodic adjustment of a deeper drainage outlet control depth may be required for planting and fertilizer applications, and as new crop roots develop; this will vary with local crop, soils, and climatic conditions, and the management practice.  In the summer, the water “elevation” will need to be increased to “feed” the growing crops.       And in the fall, the water control structure could be set to a lower constant flow to enhance early harvesting of the crops.

 

Benefits of Conservation Drainage

Conservation drainage has great potential to help improve water quality, and possibly increase crop yields.  Management of water can provide environmental benefits by reducing the quantity of nitrogen, sediment, and phosphorus leaving fields, and can provide production benefits by extending the period of time when soil water is available to plants. Imagine what an extra inch or two of water in the crop root zone could do for yields in mid- to late-growing season. Studies have shown that conservation drainage reduces the amount of nitrogen, phosphorus and sediment loss during runoff events by holding the nutrients in the tile systems and allowing for the crops to use the nutrients.  Conservation drainage helps by reducing the amount of money spend on fertilizers, time spent in the field applying chemicals and the amount of nitrogen and phosphorus reaching our watercourses!

 

Below (Fig. 1) are pictures of how the conservation drainage structure works throughout the year.  The structure can be worked with to ensure proper water consumption and release depending on the cropping type.

(Figure courtesy of Agri-Drain, Iowa)

 

Conservation Drainage-Ideal Concept for Seasonally Dry Years!

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Figure 1