Drainage Water Management

What Is Drainage Water Management? By adding a water control structure to existing tile networks drainage water management (DWM) can raise or lower the water table to a desired elevation depending on crop needs. NRCS image Illustrations courtesy of USDA NRCS.

Why Use Drainage Water Management? Drainage water management helps to control the amount and timing of water leaving agricultural fields through tile lines. After harvest, farmers can add riser boards to retain water and limit nutrient runoff. Illustrations are credit of Dr. Jane Frankenberger Before planting or harvest, farmers can remove riser boards to ensure that the soil is dry enough. Illustrations courtesy of Jane Frankenberger.

What Can Drainage Water Management Do for Water Quality? According to the Iowa Nutrient Reduction Strategy, DWM can reduce nitrate-nitrogen loss through tile lines by an average of 33%. DWM site in Sac County, Iowa. NRCS/SWCS photo by Lynn Betts.

Benefits of Drainage Water Management Manage soil moisture Decrease nutrient leaching Increase soil carbon (reduced oxidation of soil organic matter) Increase yield (estimated 50 to 70 bushels per acre of corn and 20 to 25 bushels per acre of soybeans) DWM site in Sac County, Iowa. Top of water control structure – all that’s seen after installation. NRCS/SWCS photo by Lynn Betts.

What Is the Cost of Drainage Water Management? Estimated to cost $40 to $110 per acre (assuming land is flat enough for one structure to control 20 acres). Funds are available through the Natural Resources Conservation Service’s (NRCS): Environmental Quality Incentives Program (EQIP) Conservation Security Program (CSP) Conservation Reserve Program (CRP) Conservation Reserve Enhancement Program (CREP) Installation of the water control structure in Sac County, Iowa. NRCS/SWCS photo by Lynn Betts.

Drainage Water Management Works Best when…. Drainage water management works best on very flat land, less than 0.5% slope. It also works best on fields that have been pattern tiled (rather than a random system). Before (above) and during (below) the installation of a DWM system in Sac County, Iowa. NRCS/SWCS photo by Lynn Betts.

Drainage Water Management Video from the USDA NRCS

Other Resources https://www.flickr.com/photos/151012306@N08/albums/72157695593730612: A step by step visual guide to drainage water management. These photos were taken on real farms across Iowa and are part of the Conservation Media Library. https://vimeo.com/291575807: A video about drainage water management in Iowa that is part of the Conservation Media Library. https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/water/manage/: General information from the Natural Resources Conservation Service on drainage water management, including information on cost share and information videos. https://transformingdrainage.org/: A storing house for drainage water management research from a collaborative research group across eight states. https://www.iowalearningfarms.org/page/webinars: On October 19, 2016 Iowa Learning Farms gave a webinar on controlled drainage from researchers Gary Sands, Tony Thompson, and Matt Helmers. https://vimeo.com/101558889: A video on conservation drainage created by the Leopold Center for Sustainable Agriculture at Iowa State University.

This presentation is part of the Conservation Media Library This presentation is part of the Conservation Media Library. To learn more about it and access other resources, go to www.swcs.org. The Library was supported by an Iowa NRCS funded Conservation Innovation Grant to the Soil and Water Conservation Society and Conservation Districts of Iowa.