Title: Dynamic domain kinematic modelling for predicting interflow over leaky impeding layers

Abstract

Traditional Boussinesq or kinematic simulations of interflow (i.e., lateral subsurface flow) assume no leakage through the impeding layer and require a no-flow boundary condition at the ridge top. However, recent analyses of many interflow-producing landscapes indicate that leaky impeding layers are common, that most interflow percolates well before reaching the toe slope, and therefore, the downslope contributing length is shorter than the hillslope length. In watersheds characterised by perched interflow over a low conductivity layer through permeable topsoil, interflow with percolation may be modelled with a kinematic wave model using a mobile upslope boundary condition defining the hillslope portion contributing interflow to valleys. Here, we developed and applied a dynamic interflow model to simulate interflow using a downslope travel distance concept such that only the active contributing length is modelled at any time. The model defines a variable active area based on the depth of the perched layer, the topographic slope and the ratio of the hydraulic conductivity of topsoil to that of the impeding layer. It incorporates a two-layer soil moisture accounting water balance analysis, a pedo-transfer function, and percolation and evaporation routines to predict interflow rates in continuous and event-based scenarios. We tested the modelling concept on twomore » sets of data (2-year dataset of rainfall observations for the continuous simulation and a multi-day irrigation experiment for the event simulation) from a 121-m-long open interflow collection trench on an experimental hillslope at the Savannah River Site, South Carolina. The continuous model simulation partially represented the observed interflow hydrograph and perched water depth in the experimental hillslope with correlation coefficients of 0.85 and 0.35, respectively. Model performance improved significantly at event-scale analysis. The modelling approach realistically represents interflow dynamics in hillslopes with leaky impeding layers and can be integrated into catchment-scale hydrology models for more detailed hillslope process modelling.« less

Authors:

Bitew, Menberu Meles  ^[1];

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Jackson, C. Rhett ^[2]; Goodrich, David C. ^[3]; Younger, Seth E. ^[2]; Griffiths, Natalie A. ^[4]; Vaché, Kellie B. ^[5]; Rau, Benjamin ^[6]

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+ Show Author Affiliations

1. US Dept. of Agriculture (USDA), Tucson, AZ (United States). Agricultural Research Service; Univ. of Georgia, Athens, GA (United States)
2. Univ. of Georgia, Athens, GA (United States)
3. US Dept. of Agriculture (USDA), Tucson, AZ (United States). Agricultural Research Service
4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
5. Oregon State Univ., Corvallis, OR (United States)
6. USDA Forest Service, Aiken, SC (United States)

Publication Date:

Sun Apr 12 00:00:00 EDT 2020

Research Org.:

USDA Forest Service-Savannah River, New Ellenton, SC (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Environment, Health, Safety and Security (AU), Office of Environmental Protection and ES&H Reporting; USDOE Office of Energy Efficiency and Renewable Energy (EERE)

Contributing Org.:

USDA Forest Service-Savannah River, New Ellenton, SC

OSTI Identifier:

1693410

Alternate Identifier(s):

OSTI ID: 1617779; OSTI ID: 1633467

Report Number(s):

20-05-P
Journal ID: ISSN 0885-6087; 20-05-P; TRN: US2204174

Grant/Contract Number:  

EM0003622; AC05-00OR22725; AC05‐00OR22725

Resource Type:

Accepted Manuscript

Journal Name:

Hydrological Processes

Additional Journal Information:

Journal Volume: 34; Journal Issue: 13; Journal ID: ISSN 0885-6087

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

60 APPLIED LIFE SCIENCES; 54 ENVIRONMENTAL SCIENCES; Boussinesq; downslope travel distance; hillslope; interflow modelling; kinematic; leaky impeding layer; open trench