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| {{short description|Geographical model of river characteristics}} | |||
| {{One source|date=September 2012}} | |||
| The '''Bradshaw Model''' is a geographical model which describes how a river's characteristics vary between the ''upper course'' and ''lower course'' of a river. It shows that ], occupied channel width, channel depth and average load quantity increases downstream. Load particle size, channel bed roughness and gradient are all characteristics which decrease; it is represented by triangles, of different sizes according to their quantity, facing either towards or away from the mouth or the source of the river downstream.<ref>earthstudies.co.uk</ref> | |||
| The '''Bradshaw Model''' is an idealised ] model which suggests how a river's characteristics vary between the '']'' and '']'' of a river. It indicates how ], occupied channel width, channel depth, and average load quantity increase downstream,<ref>{{Cite web|url=https://www.geography-fieldwork.org/rivers/river-variables.aspx|title=Models of downstream change|website=Geography Fieldwork|publisher=]|archive-url=https://web.archive.org/web/20160513161314/https://www.geography-fieldwork.org/rivers/river-variables.aspx|archive-date=May 13, 2016|url-status=}}</ref> and other properties such as load particle size, ] roughness, and gradient as characteristics that decrease. These features are represented by triangles; an increase in the size of a triangle represents an increase in the variable. Generally the Bradshaw model shows the characteristics expected to be present in a river, but due to the nature of rivers and the ever-changing environment in which they exist, not all rivers assimilate to the model. Therefore, the model is often applied to compare natural rivers against ideal rivers that fit the model perfectly.<ref>earthstudies.co.uk</ref> | |||
| ==The origins of the Bradshaw model== | |||
| The model first appears as an illustration in M. J. Bradshaws's 1978 high school textbook ''The Earth's Changing Surface''. Bradshaw's illustration is a simplification of Stanley Schumm's river model which had been published a year earlier in ''The Fluvial System'', although aspects of the model had already appeared in a series of academic papers over the previous decade. Schumm based his model on an empirical analysis of a variety of North American rivers and suggested that it could be used to predict how any given river channel would respond to changes in discharge or sediment supply caused by river engineering, such as a ] or flood relief channel. | |||
| ==References== | ==References== | ||
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| {{Rivers, streams and springs}} | |||
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| {{Hydrology-stub}} | |||
| {{Topography-stub}} | |||
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Latest revision as of 06:13, 30 October 2023
Geographical model of river characteristicsThe Bradshaw Model is an idealised geographical model which suggests how a river's characteristics vary between the upper course and lower course of a river. It indicates how discharge, occupied channel width, channel depth, and average load quantity increase downstream, and other properties such as load particle size, channel bed roughness, and gradient as characteristics that decrease. These features are represented by triangles; an increase in the size of a triangle represents an increase in the variable. Generally the Bradshaw model shows the characteristics expected to be present in a river, but due to the nature of rivers and the ever-changing environment in which they exist, not all rivers assimilate to the model. Therefore, the model is often applied to compare natural rivers against ideal rivers that fit the model perfectly.
References
- "Models of downstream change". Geography Fieldwork. Field Studies Council. Archived from the original on May 13, 2016.
- earthstudies.co.uk