Summary of Submitted Works

The integrated and sustainable management of water resources depends firstly on appropriate scientific understanding of the hydrology that determines the availability of surface and groundwater resources, and secondly on the use of appropriate modelling tools to support assessment of water resource sustainability and the development and evaluation of strategies for integrated management. The ability to manage water resources effectively in arid and semi arid areas has been severely limited by: a) poor knowledge and understanding of the special hydrological characteristics of these areas, and b) the lack of modelling tools to represent these special characteristics adequately. Professor Wheater has been working for 25 years to improve the understanding of the hydrology of these areas, to develop suitable modelling tools for management, to apply these in practice for improved water resources management, and to disseminate state-of-the-art information to students and practitioners. The works presented for the Prince Sultan International Water Prize are selected to represent his contributions in each of these areas, and the development of his contributions over time.

Northern Oman Flood Study
In 1981, Professor Wheater undertook the first Flood Study of Northern Oman for the government of the Sultanate of Oman, responding to a flood emergency. He collated the available data on rainfall and flows, and produced analyses of rainfall depth-duration-frequency relationships that were subsequently used as the basis of hydrological design for the following 15-20 years. He also introduced, for the first time in the Arab region, the use of distributed, physically-based modelling of rainfall-runoff processes. As part of his work, he designed flood protection for various strategic installations in Oman, including the Royal Palace in Muscat. His paper, published in the Proceedings of the UK Institution of Civil Engineers, won national recognition and was awarded the ICE Overseas Premium.

A Multivariate Spatial-Temporal Model of Rainfall in S. W. Saudi Arabia
Professor Wheater was appointed as consultant scientific adviser to a pioneering water resources study of five basins in S.W. Saudi Arabia, undertaken on behalf of the Ministry of Agriculture and Water of the Kingdom of Saudi Arabia. The single most important element in water resources assessment is the precipitation input, and the uniquely-dense monitoring networks of this study allowed, for the first time, the quantitative characterisation of the extreme spatial variability of rainfall in the region. Professor Wheater has published a number of papers on various aspects of rainfall in Saudi Arabia. In this one, the basic characteristics are quantified, and a new approach to modelling spatial variability of rainfall for water resources assessment was pioneered.

Effects of Wadi Flood Hydrograph Characteristics on Infiltration
A key issue for the integrated management of surface and groundwater resources in arid and semi arid areas is the recharge of alluvial groundwater from ephemeral surface flows in wadi channels. Building on his Saudi Arabian five wadis project experience, Prof. Wheater developed some of the first two-dimensional numerical models of unsaturated/saturated subsurface flow and applied them for the first time to the problem of estimation of groundwater recharge from flash floods. This paper is one of several he published in the international literature on this subject, and these analyses provided important new insights into the effects of heterogeneous subsurface properties on the infiltration process, and the associated feedbacks that can strongly influence the process of transmission loss in surface flows.

A Water Resources Simulation Model for Groundwater Recharge Studies
Professor Wheater returned to the Sultanate of Oman to work on the sustainable and  integrated management of water resources in Wadi Ghulaji. The Sultanate of Oman had been pioneering the use of recharge dams to enhance groundwater recharge and hence the sustainable yield from groundwater resources. However, most applications has been to relatively simple systems on the Batinah coastal plain. In contrast, Wadi Ghulaji was an interior basin with complex hydrogeology and a well-developed afalaj system and associated system of water rights and water allocation. It was clear that a new modelling approach was needed to met the difficult challenge of defining sustainable use and the potential for enhanced recharge through recharge dam construction. Professor Wheater developed a pioneering new modelling approach. This a) represented the complex spatial structure of rainfall using a specially designed rainfall simulator, b) represented the spatial complexity of runoff generation using a spatially-distributed rainfall-runoff model, and c) represented the spatially-distributed contributions to groundwater recharge from rainfall infiltration and the focussed recharge from infiltration of wadi flows. The model was successfully used to explore the potential of recharge dams in a variety of locations, and the sustainability of yield from alternative climate sequences.

Hydrological Modelling in Arid and Semi-Arid Areas
The final work presented is an early product of a UNESCO initiative, G-WADI (Global network for Water and Development Information in arid lands). Professor Wheater has been co-chair of G-WADI, working as part of a small team to develop the G-WADI concept and secure funding from UNESCO and the UK Government. G-WADI recognises the importance of integrated and sustainable management of water resources in arid and semi arid areas, and has identified the need for access to state-of-the-art information on science and modelling tools for arid areas from institutions and individuals world-wide. G-WADI has therefore developed a global information system, based on the web-site www.g-wadi.org, and has identified needs for specialist information and support in key areas. Professor Wheater convened a Workhop in which the world’s leading authorities on hydrological modlling in arid and semi arid areas came together, with an invited audience, in Roorkee, India, and presented state-of-the-art lectures, tutorials and software instruction. This material is available on the G-WADI web-site, and will be published as a book by Cambridge University Press in 2007.