PhD Thesis Emmanuel Obeng Bekoe - Cranfield University

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However, other weather variables for some of the other methods are
discussed in Chapter 4.
6. In southern Africa where to date the ACRU model has been used most
frequently, crop coefficients, relating consumptive water use of the
plant/soil continuum under different growth stages to a reference
evaporation, have been tried and tested most widely against the A-pan. It
has been used in forested catchments e.g. Marite sub catchments in
Southern Africa (Jewitt and Schulze, 1999) with annual rainfall between
900-1400mm which is similar to that for the Densu Basin. The Marite sub
catchments lies within latitude 24 o 49’S-24 o 52’S and longitudes 31 o 00’E-
31 o 02’E and lies in the humid tropics zone defined by McGregor and
Nieuwolt. (1998). According to Jewitt and Schultz (1999) the Nash and
Sutcliffe coefficient for the simulation was 0.61 which is good. As ACRU
has been successfully applied to a Tropical catchment it suggests the
ACRU model could be used in the Densu basin.
3.4 Description of the Model Selected, ACRU
3.4.1 Model Configuration and computing requirement
The ACRU modelling system is made up of a number of discrete, but
interlinked, components. As shown in Figure 3.5 the ACRU model requires an
input MENU file (ACRU input utilities and decision support system), a file to
indicate to the model which variables are to be stored for subsequent output
and analysis; a file containing hydrometeorological data and an optional
"dynamic" file. A suite of independent programs, the ACRU input utilities, have
been written to assist in the preparation of the input data and information files.
Similarly, the ACRU Output Utilities are used to obtain output from the model
and to perform statistical analysis.
ACRU, which is written in FORTRAN 77, consists of a modularly structured
main program which calls over 150 subroutines. ACRU was originally
Emmanuel Obeng Bekoe Phd Thesis Chapter 3 Catchment-Hydrol,& Model Selection