Field Validation of a Computer Model
for Forecasting Mean Weekly
in situ Moisture Condition Value

I.G.N. Smith

Department of Civil & Transportation Engineering
Napier University, Edinburgh
e-mail

J. Oliphant and S.G. Wallis

Department of Civil & Offshore Engineering
Heriot-Watt University Edinburgh

ABSTRACT

This paper presents and discusses field data collected as part of a research program directed towards the determination of soil water fluxes in the zone between the bottom of crop rooting depth and the water table. The influence of the root zone and the existence of a zero flux plane was indicated by the data. This data was used to estimate short to medium term vadose zone fluxes in the semi arid region. Other estimates of the long term average flux were obtained by using the chloride mass balance method and migration of chloride and nitrate peaks. All the different methods used provided estimates of flux within one order of magnitude. The study emphasizes that it may be advantageous to deploy a variety of techniques for obtaining reliable estimates of soil water flux in semi arid regions.

KEYWORDS: Semi - Arid,Vadose, Water, Chloride, Mass, Balance, Nitrate, Zero, Flux, Plane

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