Estimating dominant runoff modes across the conterminous United States

Authors

Brian Buchanan, Seattle UniversityFollow
Daniel A. Auerbach, Washington Department of Fish and Wildlife
James Knighton, Cornell University
Darrick Evensen, University of Edinburgh
Daniel R. Fuka, Virginia Tech
Zachary Easton, Virginia Tech
Michael Wieczorek, MD‐DE‐DC Water Science Center, United States Geological Survey
Josephine A. Archibald, Seattle University
Brandon McWilliams, Seattle University
Todd Walter, Cornell University

ORCID IDs

http://orcid.org/0000-0003-0641-4450

http://orcid.org/0000-0002-3655-5206

Document Type

Article

Date of this Version

9-17-2018

Citation

2018 John Wiley & Sons, Ltd.

Comments

Hydrological Processes. 2018;32:3881–3890. wileyonlinelibrary.com/journal/hyp

Abstract

Effective natural resource planning depends on understanding the prevalence of runoff generating processes. Within a specific area of interest, this demands reproducible, straightforward information that can complement available local data and can orient and guide stakeholders with diverse training and backgrounds. To address this demand within the contiguous United States (CONUS), we characterized and mapped the predominance of two primary runoff generating processes: infiltration‐excess and saturation‐excess runoff (IE vs. SE, respectively). Specifically, we constructed a gap‐filled grid of surficial saturated hydraulic conductivity using the Soil Survey Geographic and State Soil Geographic soils databases. We then compared surficial saturated hydraulic conductivity values with 1‐hr rainfall‐frequency estimates across a range of return intervals derived from CONUS‐scale random forest models. This assessment of the prevalence of IE versus SE runoff also incorporated a simple uncertainty analysis, as well as a case study of how the approach could be used to evaluate future alterations in runoff processes resulting from climate change. We found a low likelihood of IE runoff on undisturbed soils over much of CONUS for 1‐hr storms with return intervals <5 years. Conversely, IE runoff is most likely in the Central United States (i.e., Texas, Louisiana, Kansas, Missouri, Iowa, Nebraska, and Western South Dakota), and the relative predominance of runoff types is highly sensitive to the accuracy of the estimated soil properties. Leveraging publicly available data sets and reproducible workflows, our approach offers greater understanding of predominant runoff generating processes over a continental extent and expands the technical resources available to environmental planners, regulators, and modellers.