Quantifying the contribution of tile drainage to basin-scale water yield using analytical and numerical models

Keith E Schilling; Philip W Gassman; Antonio Arenas-Amado; Christopher S Jones; Jeff Arnold

doi:10.1016/j.scitotenv.2018.11.340

Quantifying the contribution of tile drainage to basin-scale water yield using analytical and numerical models

Sci Total Environ. 2019 Mar 20:657:297-309. doi: 10.1016/j.scitotenv.2018.11.340. Epub 2018 Dec 3.

Authors

Keith E Schilling¹, Philip W Gassman², Antonio Arenas-Amado³, Christopher S Jones³, Jeff Arnold⁴

Affiliations

¹ Iowa Geological Survey, University of Iowa, Iowa City, IA, United States of America. Electronic address: keith-schilling@uiowa.edu.
² Center for Agricultural and Rural Development, Iowa State University, Ames, IA, United States of America.
³ IIHR-Hydroscience & Engineering, University of Iowa, Iowa City, IA, United States of America.
⁴ Grassland Soil and Water Research Laboratory, USDA-ARS, Temple, TX, United States of America.

PMID: 30543979
DOI: 10.1016/j.scitotenv.2018.11.340

Abstract

The Des Moines Lobe (DML) of north-central Iowa has been artificially drained by subsurface drains and surface ditches to provide some of the most productive agricultural land in the world. Herein we report on the use of end-member mixing analysis (EMMA) models and the numerical model Soil and Water Assessment Tool (SWAT) to quantify the contribution of tile drainage to basin-scale water yields at various scales within the 2370 km² Boone River watershed (BRW), a subbasin within the Des Moines River watershed. EMMA and SWAT methods suggested that tile drainage provided approximately 46 to 54% of annual discharge in the Boone River and during the March to June period, accounted for a majority of flow in the river. In the BRW subbasin of Lyons Creek, approximately 66% of the annual flow was sourced from tile drainage. Within the DML region, tile drainage contributes to basin-scale water yields at scales ranging from 40 to 16,000 km², with downstream effects diminishing with increasing watershed size. Developing a better understanding of water sources contributing to river discharge is needed if mitigation and control strategies are going to be successfully targeted to reduce downstream nutrient export.

Keywords: Agriculture; Artificial drainage; EMMA; End member mixing analysis; Iowa; SWAT; Tiles.