From: Spyros Beltaos To: 'Roger Bettess' ; Subject: RE: Rivers-List: River engineering problems for 21st Century Date: 29 June 2000 22:35 Dear Dr. Bettess: One problem that I hope will be solved in the 21st century is the complete prediction of river ice processes, especially the processes of the breakup of the ice cover, ice-jam formation and failure, and their interdependency. These phenomena impinge on many purely hydraulic processes, such as flooding, sediment transport, bed scour, bank erosion, etc... Our present knowledge in this field is imperfect, to say the least. Ice is a major feature of "northern" rivers, including many in moderate latitudes. It has a variety of important socio-economic/ecological implications. The predictions of meteorological scientists about our changing climate add more urgency to the need for science-based understanding of ice processes. You have already listed 12 very important problems, so I have difficulty choosing one that might be replaced by the above topic. Perhaps it is more general and less-well understood than item 3 (Determination of the discharge coefficient for a structure). Alternatively, it may be considered under item 12 since it is one of the topics discussed in the book "Issues and directions in hydraulics". Sincerely, Dr. Spyros Beltaos, P.Eng., FCSE Research Scientist, Climate Impacts on Hydrology and Aquatic Ecosystems Project Aquatic Ecosystem Impacts Branch National Water Research Institute 867 Lakeshore Road Burlington, Ontario L7R 4A6 telephone: 905-336-4898 fax: 905-336-4420 email: spyros.beltaos@cciw.ca > -----Original Message----- > From: owner-rivers-list@wldelft.nl > [mailto:owner-rivers-list@wldelft.nl]On Behalf Of Roger Bettess > Sent: June 25, 2000 2:24 AM > To: rivers-list@iahr.org > Subject: Rivers-List: River engineering problems for 21st Century > > > Introduction > > At the opening of the 20th century the mathematician David > Hilbert published > a list of problems. They were what he considered to be the > major problems > facing mathematicians at that time, covering all fields of > mathematics. He > also thought that all the problems were soluble within the > time span of the > century. By the end of the 20th century all but one of these > problems had > been solved. Recently a group of mathematicians have > published a new list > of problems for the 21st century. I thought that it would be > an interesting > exercise to produce a list of major problems for river > engineering for the > 21st century. > > The rules are only that there should be no more than 12 > problems, so any > proposal which would bring the number of problems to more > than 12 must > include a proposal for which of the other problems should be > removed from > the list. As we all have up to 100 years to answer them, > they should be > suitably challenging and general. To initiate the discussion > Professor > Knight from the University of Birmingham and myself have combined our > suggestions which are given below. Members of Rivers-list > are invited to > respond with their own proposals. The hope is that the > process should be a > converging one rather than diverging. > > Problems > > 1 Determination of the conveyance of a section of arbitrary shape. > As plan form may be significant this may have to be re-posed > using 'reach' > rather than 'section' > > 2 Representation of turbulence > An adequate description of turbulence is required > > 3 Determination of the discharge coefficient for a structure > of arbitrary > shape > > 4 An accurate sediment transport theory > In the 20th century it seemed that no theory could reliably break the > barrier of providing predictions within a factor of 2 about > 70% of the time. > We need more accurate theories or an explanation of why they > cannot be > achieved. > > 5 Prediction of local and general scour > > 6 A theoretical justification for Regime theory > > 7 Determination of the dominant physical processes > responsible for the plan > form of rivers > > 8 Analytical solutions to the Navier-Stokes equations > > 9 Effect of cross-sectional shape on resistance coefficients in > open channel flow > > 10 Suitable strategies for modelling overbank flow in > natural rivers with floodplains. > > 11 Strategies for raising the awareness of society to the value of > hydraulics engineers. > > 12 Any comments on the book "Issues and directions in hydraulics" > [Eds Nakato & Ettema, Balkema, 1996]? > > Roger Bettess > HR Wallingford > > > "Faxes and emails are used by HR Wallingford as a > convenience for confidential, and often legally > privileged, business communications both within > the firm and with Clients. Disclosure to parties > other than addressees through for example > forwarding, copying, printing, distribution etc > requires HR Wallingford's specific consent. HR > Wallingford is not liable for unauthorised > disclosures nor for subsequent actions or > omissions in reliance upon them. If you have > received this message in error please notify us > immediately and destroy all copies of it." > > > > >