HISTORICAL PERSPECTIVE
The ACRU model has its hydrological origins in a distributed catchment evapotranspiration based
study carried out in the Natal Drakensberg in the early 1970s (Schulze, 1975). The acronym ACRU is
derived from the Agricultural Catchments Research Unit within the Department of Agricultural
Engineering of the University of Natal in Pietermaritzburg. The agrohydrological component of ACRU
first came to the fore during research on an agrohydrological and agroclimatological atlas for Natal
(Schulze, 1983). Since then the model has developed, through co-operation with many colleagues and
graduate students, and through generous funding from the Water Research Commission (WRC), to its
present status.
User documentation on ACRU was first published in 1984 (Schulze, 1984) and updated in 1989 (Schulze,
George, Lynch and Angus, 1989). A series of papers and reports applying constantly updated and more
sophisticated versions of the model has been published in the international and southern African
literature, the major papers on developmental aspects being an overview by Schulze (1986), a paper
on its application as a dynamic simulator of afforestation effects on runoff (Schulze and George,
1987a), a synthesis on its status as of 1988 by Schulze (1988a) and an unpublished report to the WRC
in 1992 on new development to the model up to then, mainly in regard to flow routing, wetlands,
shallow groundwater routines, a forest Decision Support System and model linkage to GIS. This
present text, viz. "Hydrology and Agrohydrology: A Text to Accompany the ACRU 3.00 Modelling
System", supersedes and replaces the 1989 "ACRU: Background, Concepts and Theory" (Schulze, 1989a).
The companion volume to this present text is the "ACRU 3.00 User Manual" under editorship of Smithers and
Schulze (1994), which in turn supersedes the "ACRU-2 : User Manual" by Schulze, George, Lynch and
Angus (1989).
Other than in southern Africa (South Africa, Botswana, Namibia, Lesotho, Swaziland and Zimbabwe),
lectures on the ACRU system have been given in Australia, Austria, Canada, Chile, Czech Republic,
France, Germany, Hungary, Kenya, Portugal, Switzerland, the UK and the USA. The model has been
verified widely on data from southern Africa and the USA (Schulze, 1994, Chapter 22), used
extensively in decision making in southern Africa and by 1994 the model had been applied
internationally in research in Botswana, Chile, Germany, Lesotho, Namibia, Swaziland and the USA.
ACRU - homepage:
http://www.beeh.unp.ac.za/pike/acru/acruhomepage/index.htm