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This is the first of two linked programmes relating to the lakes and rivers course work. D.E. Jackson discusses stream meandering in alluvial channels, he shows, by means of flow tank experiments ...and film animation that meandering and migrating channels can be explained in terms of stream flow. Since rivers have a natural tendancy to meander there are problems to be faced with river training schemes. To illustrate how river training problems are 'solved' using scale models, Mr. John Burgess of the Hydraulics Research Station, Wallingford demonstrates their River Vistula Model, In order to recognise some of the freshwater invertebrates to be seen in Programme 4. Dr. M.E. Varley shows adaptations of some invertebrate animals so they can survive in turbulent flow. The programme closes with an introduction to the field area to be covered in Programme 4. In post broadcast notes the students are asked to complete a preparatory exercise.
Metadata describing this Open University video programme
Item code: S2-3; 03
First transmission date: 29-07-1972
Published: 1972
Rights Statement:
Restrictions on use:
Duration: 00:21:57
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Producer: Penny Crompton
Contributors: John Burgess; Dennis Jackson; Peggy Varley
Publisher: BBC Open University
Keyword(s): Alluvial channels; Flow tank; Freshwater invertebrates; Hydraulics research station; River training schemes; River vistula model; Stream meandering
Footage description: Shots of a water channel in a sand box. Commentary by Dennis Jackson who introduces the programme. Aerial still shots of River Clyde and an Alaskan river. Shots of an experiment in the Arlborne Tank which shows some of the characteristics of water flow in a straight channel. Jackson uses animated diagrams to demonstrate the nature of flow in an alluvial channel. The corkscrew effect is explained and its possible effect in producing bends in alluvial channels discussed. The hypothesis that corkscrew effect may be present in a meandering flow is tested in the flow tank. Surface and bottom flow are shown and contrasted. Jackson presents evidence for meander migration. He uses an animated diagram of the Little Missouri river bed over a 250 year period to make his point. Jackson examines the possibility that the corkscrew effect is responsible for the phenomenum of meander migration. Animated diagrams are used. To introduce the practical problem of river control, Jackson uses an animated diagram which shows the extent of meander migration of parts of the Mississippi River for the period 1820 to 1932. He then introduces John Burgess. John Burgess, Hydraulics Research Station, Wallingford, uses diagrams and a physical flow channel model of parts of the Vistula to explain the project for training the river in order to make navigation possible. Peggy Varley explains the effect of flow and turbulence on the distribution of organisms in streams. She show two tanks, one with a silted bottom, the other with a rocky bottom and the organisms found in each. Film shots show animals (greatly magnified) living in a turbulent stream. Shots of: Larval caddis (Silo pallipes); Stonefly nymph (Isoperla graranatica); Mayfly nymph (Ecdynurus insignis); Mayfly nymph (Baetis rhodani) Simulium sp. larvae; Fresh water shrimp (Gammarus pulex); Caseless caddis larva (hydropsyche angustipennis). Varley sums up. Dennis Jackson, with a topographical model of the Windermere Troutbeck area explains what points will be covered in the next T.V. broadcast. Peggy Varley joins in.
Master spool number: 6HT/70617
Production number: 00521_2148
Videofinder number: 1651
Available to public: no