Journal article
Two‐Stage Ditch Floodplains Enhance N‐Removal Capacity and Reduce Turbidity and Dissolved P in Agricultural Streams
Journal of the American Water Resources Association, Vol.51(4), pp.923-940
08/2015
Handle:
https://hdl.handle.net/2376/109179
Abstract
Two‐stage ditches represent an emerging management strategy in artificially drained agricultural landscapes that mimics natural floodplains and has the potential to improve water quality. We assessed the potential for the two‐stage ditch to reduce sediment and nutrient export by measuring water column turbidity, nitrate (NO3−), ammonium (NH4+), and soluble reactive phosphorus (SRP) concentrations, and denitrification rates. During 2009‐2010, we compared reaches with two‐stage floodplains to upstream reaches with conventional trapezoid design in six agricultural streams. At base flow, these short two‐stage reaches (<600 m) reduced SRP concentrations by 3‐53%, but did not significantly reduce NO3− concentrations due to very high NO3− loads. The two‐stage also decreased turbidity by 15‐82%, suggesting reduced suspended sediment export during floodplain inundation. Reach‐scale N‐removal increased 3‐24 fold during inundation due to increased bioreactive surface area with high floodplain denitrification rates. Inundation frequency varied with bench height, with lower benches being flooded more frequently, resulting in higher annual N‐removal. We also found both soil organic matter and denitrification rates were higher on older floodplains. Finally, influence of the two‐stage varied among streams and years due to variation in stream discharge, nutrient loads, and denitrification rates, which should be considered during implementation to optimize potential water quality benefits.
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Details
- Title
- Two‐Stage Ditch Floodplains Enhance N‐Removal Capacity and Reduce Turbidity and Dissolved P in Agricultural Streams
- Creators
- Ursula H Mahl - University of Notre DameJennifer L Tank - University of Notre DameSarah S Roley - Michigan State UniversityRobert T Davis - Whiterock Conservancy
- Publication Details
- Journal of the American Water Resources Association, Vol.51(4), pp.923-940
- Academic Unit
- Environment, School of the (CAS)
- Number of pages
- 18
- Grant note
- Great Lakes Bioenergy Research Center, Michigan State University (DE‐FC02‐07ER64494) National Institute of Food and Agriculture (NIFA) (#2008‐51130‐04766) United States Department of Agriculture's Natural Resources Conservation Service
- Identifiers
- 99900547358801842
- Language
- English
- Resource Type
- Journal article