Halcrow Group

The School of Geography at The University of Nottingham is renowned nationally and internationally. Its status is reflected by its position as a UK top six geography department in “The Times” University Guide 2005, along with a rating of ‘excellent’ in teaching and 5 grading for international excellence in the Research Assessment Exercise 2001.

As the Chair of Physical Geography, former Head of School and past Dean of his Faculty, Professor Colin Thorne has a world-class reputation in research, teaching and consultancy related to river management and geomorphology, particularly of big rivers. “Let’s say I’m in demand a lot,” he modestly states.

Professor Thorne’s reputation was forged in the floodplains of Bangladesh, following the 1988 flood disaster which claimed the lives of thousands and the homes of millions. Having researched and published papers on managing tributaries of the Mississippi River, Professor Thorne’s big river credentials led to his invitation by the Halcrow Group to study the Brahmaputra in 1990. “If you can understand a river’s history, you can often predict its future.”

Professor Thorne and the Halcrow team studied the historical forms of the river, past records of water and sediment flows, and old maps to establish the river’s evolution. 17km wide in places, with an awesome flood discharge of over 105,000 cubic metres per second (compared to 1,000 cubic metres per second in the biggest UK rivers), their work was arduous. “We came up with a master plan for managing the river that worked with nature, rather than against it. It was pretty innovative in 1990” declares Professor Thorne. This included the realignment of strategic flood defences and the construction of ‘hard points’ to prevent bank retreat at key locations. Today, their work enables faster mobilisation of flood fighting teams and sustainable stabilisation of the banklines at key points along the river.

Today, Professor Thorne continues to apply his expertise throughout the UK and the world. His particular expertise is in accounting for river sediment. “Rivers are not just water. Their flow includes of mobile sediment that may consist of clay, silt, sand, pebbles, gravel or even boulders. This has an effect on the nature of the river.” Current projects in conjunction with Royal Haskoning, Cascade Consulting, Hydraulics Research Wallingford and Jacobs-Babtie are benefiting from his knowledge. These include the Morayshire Flood Alleviation Scheme and, particularly, the Burn of Rothes project, which is designed to protect 3 frequently flooded distilleries. “The plan has to be sustainable, aesthetic, low maintenance and effective. Success has come from taking our cues from nature,” says Professor Thorne.

“The fact is, no-one wants to maintain rivers any more. It’s too expensive. Also the Water Framework Directive has changed the priorities of river management. Now the number one priority is achieving good ecological status.” Professor Thorne is unperturbed, however. “The fact is, floods are inevitable and necessary. You can build walls and defences, but that tends to move the problem elsewhere. Future innovation lies less in flood management, and more in managed flooding.”

Professor Thorne also continues to work on big rivers. As well as studying the Brahmaputra, Ganges, Padma, Yangtze, Awash and Thames at present, he and the Halcrow Group are just beginning a new analysis of long term sediment records for the Lower Mississippi River for the US Army Corps of Engineers. “They’ve got lots of data, but it takes our expertise to take meaning from it.” Professor Thorne declares. “We’ve built a powerful team over the last 16 years.”