It is only right to give you, as reader, some indication of the reasons for my enthusiasm for water in the environment and its management. To do this, I describe here some particular experiences from my childhood, and subsequently from my student years and professional life. Like many children, my first enjoyable memories of water were at the seaside, attempting to build sandcastles that would defy the persistent encroaching waves, or of being turned upside down by breakers on the sandy beach. I welcomed the challenge of trying to dam streams in the Welsh hills or to skim flat stones across the river at Hay-on-Wye, where my paternal grandparents lived. But water at the seaside was not just an enjoyable experience. I became aware of the awesome power of water when news came of serious flooding from a disastrous surge in the North Sea along the East Anglian coast in 1953, and the unacceptable and devastating floods from the River Lugg invaded the lower part of Leominster, the small country town where I was brought up. Little did I realise then that these events would be seminal in forming the focus of my future career.

In my last year at the local grammar school, I bought a book on physics that discussed the flow of fluids. This made me aware that there was some interesting mathematics undergirding the subject, but it seemed complicated and abstruse, depending on partial differential equations, which were then a considerable mystery to me. I was accepted to study maths at Cambridge, but it was not until my third year that I was able to begin to unlock the mysteries of fluid dynamics. My fourth year doing Part III of the Maths Tripos (the Cambridge equivalent of an MSc) was given over to a range of topics in fluids: aeronautics, magneto-hydrodynamics, meteorology, turbulence, open channel flow, oceanography, cosmology, etc. After some uncertainty, I resolved to do a PhD in fluid dynamics. One of the lecturers in the subject at Cambridge, Dr Ian Proudman, was appointed professor of mathematics at the completely new University of Essex, so I jumped at the chance of joining him as one of his graduate students in the autumn of 1964.

For the first year, I explored the delights of Ekman layers in deep oceans and other strange phenomena, but these had been researched by others and I could not find a research problem that was potentially tractable. Then Prof Proudman suggested the topic of breaking waves. The die was cast, and I enthusiastically set to work. For the next four years, I looked at the problem from a range of different (mathematical) points of view. I spent hours on holiday at beaches fascinated and entranced by the waves curling over at the top and then ‘breaking’. I would like to think that I made a significant contribution to the subject, but the problem is highly non-linear, and mathematical techniques for this sort of problem are very limited. Although I had done enough for a PhD, I needed a new approach to the problem. Solving the non-linear mathematical equations for fluid flow analytically, even under very simplified conditions, was virtually impossible. But there was another way of tackling the problem—using computers. These had become commercially available during the early 1960s, and the new University of Essex had an ICL 1900 series machine. My fellow research students and I began to see the possibilities of the electronic computer in helping us to solve our nonlinear equations numerically. So in 1967, with the aid of a fellowship, I began to solve my breaking wave equations on the computer. I managed to get to the stage where the wave was beginning to curl over: I had begun to conquer the process.

But I was restless. Detailed numerical calculations of one breaking wave were interesting from a theoretical point of view, indeed, the calculations were fascinating. But what were the practical implications of this solution? I could not break my virtual wave against a virtual wall and look at the consequent pressures as would interest an engineer, or look at the effect on a breaking wave of the returning surge back down the beach from the previous wave. I was focussed so much on the detailed dynamics that what I was doing was of little practical use. I needed a change of attitude. Five years of analytical mathematics was enough. I decided to get involved in computer based hydraulic engineering.

The opportunity came to do research for a year at the Coastal and Oceanographic Engineering Department at the University of Florida in Gainesville. There, accompanied by my wife, Thea, I became involved in exploring hurricane surges (analytically!) and modelling heated outfall discharges from proposed nuclear power stations in shallow coastal waters (numerically!). Although I enjoyed the challenge of this research, I felt called to be more involved in Christian ministry.

So far, I have said little about my awareness of the Christian faith and its place in my early life. My first memory of church was being taken to Brecon cathedral as a child on Easter day and being entranced with the Easter garden made entirely out of spring flowers. Then at the age of seven I became a chorister in the large parish church of St Peter and St Paul in Leominster. I was fortunate to have a wonderful choirmaster who taught me the rudiments of music, and when I was older, the organ. I remained a member of the choir until I went to university at Cambridge to read mathematics. During my mid-teenager years, whereas I enjoyed my singing in the church choir, I felt that I was missing out on something deeper in being a Christian than I had experienced. This was particularly highlighted by the strong personal faith centred in Jesus Christ which was exhibited by my non-conformist friends. Their vibrant faith persuaded me that when I went to Cambridge, I would find out more about Jesus. So it was in October 1960, I was invited by some members of the Christian Union to the ‘Freshers’ sermon’ which was being given by David Shepherd, the former England batsman who became a vicar in the Church of England, and eventually Bishop of Liverpool. His preaching challenged me to commit my life to Christ, and I did that night. I have spent my life since then working out what this means for me, and the journey has been one that has largely focussed on being part of and helping to develop strong local church communities with underlying charismatic gifts in a village south of Oxford in England, and in The Hague in the Netherlands.

The stirrings towards Christian ministry that I experienced in Gainesville, Florida, led Thea and me to return to England where I spent some time exploring ordination to priesthood in the Church of England. This did not happen then, and instead I joined a UK government laboratory: the Hydraulics Research Station in Wallingford. I now became a mathematician in a truly engineering environment; at long last I could hopefully put my skills to better practical use.

In view of my experiences in Florida, I expected to work on coastal problems; but I was asked to investigate methods for flood propagation in rivers as part of a UK Flood Studies project. This enabled me to do some analytical mathematics as well as computational hydraulics. Later, I became involved in the computer simulation of flows in urban drainage systems consisting of networks of pipes under the ground. The objective was to assess the performance of networks that had been designed on the computer for alleviating flooding. As so often happens, success in one area leads to new opportunities of addressing problems in another. In particular, I became involved in applying the computer simulations to determine how best to rehabilitate drainage networks that were deteriorating with age and usage. The tools I was developing were also being made available (at a price) to river and urban drainage engineers in the UK.

From 1982, following the privatisation of the laboratory where I worked, my colleagues and I were free to develop the commercial potential of the modelling software products. So I spent the next 12 years building up a subsidiary business to market and further develop such products. But although I enjoyed the challenge of building up a successful commercial business from scratch, I wanted to return to research: others could do a better job of managing the commercial aspects of the business than I could. The opportunity came following a significant disappointment. I had become enamoured by the use of expert systems and artificial intelligence to analyse scientific texts, and I wanted to use related techniques to improve the knowledge provided on-line to engineers using modelling software products. Khurshid Ahmad, a colleague at Surrey University, and I, set up a second business venture in HR Wallingford that in the first instance provided translation tools to translators of technical texts. It turned out, however, that this was too far outside the core business of my parent company, and the main board decided not to go any further with the business. The day after receiving the news that the second business venture was to be closed down, I was invited to apply for the post of Professor of Hydroinformatics at IHE in Delft.

Crossing boundaries, whether physical or mental, is something that most of us have to face at one stage or another in our lives. I was happy working at HR Wallingford in the commercial software house that I had helped to establish. In deciding to put my name forward for the post of Professor of Hydroinformatics at IHE Delft (an important UNESCO Category 1 post-graduate institute, 2007-2015), I knew I was crossing a real physical sea boundary that separated England from the Netherlands, and that Thea and I would have to face up to living in another country. We had been married for almost thirty years and our youngest children were well into their teens. Up to then we had no expectation of moving from the village where we lived. But God had other ideas, and the post in Delft was offered to me. There were not a few tears shed in making the decision to move, not least because we were leaving behind many dear friends who had been a key part of our life in the village. Although we knew that many people go and live in countries other than the one they were born in, this did not minimise the fact that for us it was still a major adventure. Being aware that God was with us in the move helped us make the transition. The last fifteen years have been ones that I would not have missed, especially as they have brought me in touch with many wonderful people from all over the world. I have learned much about the practical aspects of water and its management, and have had the privilege of working with students from many different countries doing research in hydroinformatics (the management of water in the environment using information and communication technology).

This academic post gave me opportunities for research in water management that I had only dreamt of, particularly in developing countries. Coming from industry rather than academia, it took time for me to build up a research group and accrue a sufficient number of peer-reviewed publications, but by the time of my retirement I had promoted and worked with 17 PhD students doing research into: uncertainty in model predictions, data driven modelling, chaos, anticipatory water management, information theory for monitoring, urban flood modelling, inclusion of real time control in urban drainage design, providing water services for urbanising areas, digital terrain models from remote sensing, and eutrophication in deep reservoirs and shallow lakes, supported by colleagues from all over the world. Doing this research, and establishing a regular Masters course in hydroinformatics for 15–20 mature students annually from developing countries, was my privilege during the 10 years I was in full-time employment at UNESCO-IHE (we became a UNESCO Institute in 2007 but this decision was reversed in 2015, although the Institute still maintains close links with UNESCO). I could not have asked for a better way to conclude my professional career. Even in retirement, I have continued developing software for flooding in rivers and urban areas and writing textbooks for researchers.

So now you know something of my professional background. On the spiritual front, I was a lay reader in the Church of England from 1968 to 1995, at which time I was ordained deacon in Christchurch, Oxford, and priested in 1996. All the while I have been intrigued by the references to water in the Bible and how faith communities can contribute to the achievement of the Millennium Development Goals. My aim in this book is to take you on a journey so that I can share with you some of the challenges and opportunities there are for deepening our understanding of water in creation and of God’s plan for our redemption, and to encourage you to develop a personal relationship with Jesus Christ. I invite you to put on your spiritual life jackets!