<p style='text-indent:20px;'>In this work we propose a new numerical scheme for solving Richards' equation within Gardner's framework and accomplishing mass conservation. In order to do so, resort Kirchhoff transformation of in mixed form, so exploit specific Gardner model features, obtaining linear second partial differential equation. Then, leveraging the balance condition, integrate bo...

Three implicit numerical procedures for solving Richards’ equation were compared. In some tests non-linear source terms were included. The main focus is on two massconserving procedures where the highly non-linear nature of Richards’ equation is overcome by substantially different iterative techniques. In the first procedure (P1), which is well described in the literature, the time step is set ...

Howickia Richards 1951 is redefined to include all wingless or strongly brachypterous Sphaeroceridae in New Zealand as well as two newly described fully winged species, H. oliveri and H. lepidostylus. Biroina Richards 1973 is newly treated as a junior subjective synonym of Howickia. The following new flightless species are described from New Zealand: H. bicolor, H. cordata, H. exasperata, H. ha...

Accurate, reliable, efficient, and robust simulation of groundwater flow in the unsaturated zone for the problems that characterized by sharp fronts in both space and time is computationally expensive. The accurate numerical solution of these problems by standard approaches with uniform spatial and temporal discretization usually inefficient and simulation is too costly. Moreover, it is very di...

First order traffic flow models have been studied for long time, since they represent the simplest way to begin with the understanding of such a complex system. To our knowledge the Lighthill-Whitham-Richards (LWR) model was the first model to describe unidirectional, one-dimensional traffic flow in a highway [1], [2]. This model considers the continuity equation for the density of vehicles (nu...

There have been several proposals to evaluate potential runoff in center pivot irrigation, through the integration of time varying infiltration–precipitation rate curves, involving complex iterative procedures. Some methods use empirical infiltration functions, such as the Kostiakov equation. Others use physically based infiltration functions, such as the Green–Ampt equation. Another option is ...

Abstract. This paper presents WHETGEO and its 1D deployment: a new physically based model simulating the water energy budgets in soil column. The purpose of this contribution is twofold. First, we discuss mathematical numerical issues involved solving Richardson–Richards equation, conventionally known as Richards heat equation heterogeneous soils. In particular, for (R2) take advantage nested N...

A FORTRAN code for liquid water flow in unsaturated soil under the isothermal condition was developed to simulate water infiltration into Yolo light clay. The governing equation, that is, Richards' equation, was approximated by the finite-difference method. A normalized sensitivity coefficient was used in the sensitivity analysis of Richards' equation. Normalized sensitivity coefficient was cal...