A Physically Based Two-Dimensional Infiltration Model for Furrow Irrigation

2002 ◽  
Author(s):  
Cristopher J. SkonardDerrel L. Martin
Keyword(s):  
Furrow Irrigation ◽  
Two Dimensional ◽  
Infiltration Model ◽  
Physically Based

scholarly journals Testing the effect of water in crevasses on a physically based calving model

2012 ◽  
Vol 53 (60) ◽  
pp. 90-96 ◽  
Author(s):  
S. Cook ◽  
T. Zwinger ◽  
I.C. Rutt ◽  
S. O'Neel ◽  
T. Murray
Keyword(s):  
Finite Element ◽  
Water Depth ◽  
Surface Mass Balance ◽  
Two Dimensional ◽  
Finite Element Code ◽  
Surface Mass ◽  
Starting Point ◽  
Physically Based ◽  
Calving Rate

AbstractA new implementation of a calving model, using the finite-element code Elmer, is presented and used to investigate the effects of surface water within crevasses on calving rate. For this work, we use a two-dimensional flowline model of Columbia Glacier, Alaska. Using the glacier’s 1993 geometry as a starting point, we apply a crevasse-depth calving criterion, which predicts calving at the location where surface crevasses cross the waterline. Crevasse depth is calculated using the Nye formulation. We find that calving rate in such a regime is highly dependent on the depth of water in surface crevasses, with a change of just a few metres in water depth causing the glacier to change from advancing at a rate of 3.5 kma–1 to retreating at a rate of 1.9 km a–1. These results highlight the potential for atmospheric warming and surface meltwater to trigger glacier retreat, but also the difficulty of modelling calving rates, as crevasse water depth is difficult to determine either by measurement in situ or surface mass-balance modelling.

Infiltration Model for Furrow Irrigation

1998 ◽  
Vol 124 (2) ◽  
pp. 73-80 ◽  
Author(s):  
Juan Enciso-Medina ◽  
Derrel Martin ◽  
Dean Eisenhauer
Keyword(s):  
Furrow Irrigation ◽  
Infiltration Model

scholarly journals Optimal parameters for the Green-Ampt infiltration model under rainfall conditions

2015 ◽  
Vol 63 (2) ◽  
pp. 93-101 ◽  
Author(s):  
Li Chen ◽  
Long Xiang ◽  
Michael H. Young ◽  
Jun Yin ◽  
Zhongbo Yu ◽  
...  
Keyword(s):  
Model Performance ◽  
Sensitivity Analyses ◽  
Richards Equation ◽  
Optimal Parameters ◽  
Rainfall Events ◽  
Infiltration Model ◽  
Physically Based ◽  
Close Fit ◽  
Infiltration Processes ◽  
Meansquare Error

Abstract The Green-Ampt (GA) model is widely used in hydrologic studies as a simple, physically-based method to estimate infiltration processes. The accuracy of the model for applications under rainfall conditions (as opposed to initially ponded situations) has not been studied extensively. We compared calculated rainfall infiltration results for various soils obtained using existing GA parameterizations with those obtained by solving the Richards equation for variably saturated flow. Results provided an overview of GA model performance evaluated by means of a root-meansquare- error-based objective function across a large region in GA parameter space as compared to the Richards equation, which showed a need for seeking optimal GA parameters. Subsequent analysis enabled the identification of optimal GA parameters that provided a close fit with the Richards equation. The optimal parameters were found to substantially outperform the standard theoretical parameters, thus improving the utility and accuracy of the GA model for infiltration simulations under rainfall conditions. A sensitivity analyses indicated that the optimal parameters may change for some rainfall scenarios, but are relatively stable for high-intensity rainfall events.

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