Draining the Upper Midwest: Changes in Water Yield due to Agricultural Tiling
Abstract
Tile drainage has been widely implemented across the Upper Midwest of the United States to increase the amount of arable land and crop production through subsurface drainage of soils. While there has been extensive research on how tile drainage affects nutrient loads in rivers and lakes, large scale analyses of how tile drainage influences water quantity are rare. This study examines the effect of tile drainage on daily streamflow in 246 watersheds across the Upper Midwest between 2010 and 2019. Watersheds were separated into low (<= 15%), medium (15-40%), and high (>= 40%) percentages of tile drained areas within the watershed. Water yield (estimated from watershed area) was calculated from daily streamflow and used to calculate a variety of water yield metrics that included low (7-day minimum), median, and high (3-day maximum) for each watershed. Low drainage categories experienced 7-day minimum water yields that were larger than those of the medium (11% lower than low drainage) and high (51% lower than low drainage) drainage watersheds. Median water yield for the high drainage was 11% larger than that of the low and medium drainage categories. The medium and high drainage categories also exhibited larger peak flows, with 3-day maximum water yields that were 19% and 27% larger than the low drainage group, respectively. These findings indicate that tile drains alter the tails of the water yield distribution and create flashier regimes that experience larger high flows and smaller low flows, which result in increased flood peaks while simultaneously reducing water for use during drought periods due to lower baseflow. This not only affects water that is available for anthropogenic use but also negatively impacts the ability of these streams and rivers to support a healthy ecosystem in terms of both water quality and quantity.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.H15C..01A