Geostatistical features of streambed vertical hydraulic conductivities in Frenchman Creek Watershed in Western Nebraska

Authors

Olufemi P. Abimbola, University of Nebraska - LincolnFollow
Aaron R. Mittelstet, University of Nebraska-LincolnFollow
Troy E. Gilmore, University of Nebraska - LincolnFollow

ORCID IDs

Aaron R. Mittelstet https://orcid.org/0000-0001-9857-5539

Document Type

Article

Date of this Version

2020

Citation

Published in Hydrological Processes. 2020;1–11.

DOI: 10.1002/hyp.13823

Comments

Copyright © 2020 John Wiley & Sons Ltd. Used by permission.

Abstract

This study evaluated the spatial variability of streambed vertical hydraulic conductivity (K_v) in different stream morphologies in the Frenchman Creek Watershed, Western Nebraska, using different variogram models. Streambed K_v values were determined in situ using permeameter tests at 10 sites in Frenchman, Stinking Water and Spring Creeks during the dry season at baseflow conditions. Measurements were taken both in straight and meandering stream channels during a 5 day period at similar flow conditions. Each test site comprised of at least three transects and each transect comprised of at least three K_v measurements. Linear, Gaussian, exponential and spherical variogram models were used with Kriging gridding method for the 10 sites. As a goodness-of-fit statistic for the variogram models, cross-validation results showed differences in the median absolute deviation and the standard deviation of the cross-validation residuals. Results show that using the geometric means of the 10 sites for gridding performs better than using either all the K_v values from the 93 permeameter tests or 10 K_v values from the middle transects and centre permeameters. Incorporating both the spatial variability and the uncertainty involved in the measurement at a reach segment can yield more accurate grid results that can be useful in calibrating K_v at watershed or sub-watershed scales in distributed hydrological models.