Comparison of the Flood Response of a Braided and a Meandering River, Conditioned by Anthropogenic and Climatic Changes

  1. I. Peter Martini2,
  2. Victor R. Baker3 and
  3. Guillermina Garzón4
  1. G. Garzón4 and
  2. A. Alonso1

Published Online: 17 MAR 2009

DOI: 10.1002/9781444304299.ch13

Flood and Megaflood Processes and Deposits: Recent and Ancient Examples

Flood and Megaflood Processes and Deposits: Recent and Ancient Examples

How to Cite

Garzón, G. and Alonso, A. (2009) Comparison of the Flood Response of a Braided and a Meandering River, Conditioned by Anthropogenic and Climatic Changes, in Flood and Megaflood Processes and Deposits: Recent and Ancient Examples (eds I. P. Martini, V. R. Baker and G. Garzón), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304299.ch13

Editor Information

  1. 2

    Department of Land Resource Science, University of Guelph, Guelph, Ontario, Canada

  2. 3

    Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ 85721–0011, USA

  3. 4

    Dpto de Geodinámica, Fac. de Geología, Universidad of Complutense, 28040 Madrid, Spain

Author Information

  1. 1

    Sección de Ciencias de la Tierra, Fac. de Ciencias, 15071 La Coruña, Spain

  2. 4

    Dpto de Geodinámica, Fac. de Geología, Universidad of Complutense, 28040 Madrid, Spain

Publication History

  1. Published Online: 17 MAR 2009
  2. Published Print: 10 FEB 2002

ISBN Information

Print ISBN: 9780632064045

Online ISBN: 9781444304299

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Keywords:

  • comparison of flood response of braided and meandering river conditioned by anthropogenic and climatic changes;
  • the braiding Guadarrama River;
  • chute cut-off in slightly entrenched lobe (Tesoro meander);
  • flood effects and modified channel response;
  • chute cut-off in lobe with significant entrenchment (Barruelos Bridge);
  • historical variability of Guadarrama River;
  • the meandering Jarama River

Summary

The effects of floods in the last decade have been studied in two tributaries of the Tajo River in the Tertiary basin of Madrid (central Spain). Although the streams flow parallel to each other, one, the Jarama River, has a meandering pattern with gravel bedload, and the other, the Guadarrama, is braided with sandy bedload. In spite of their planform differences, the main effects of flooding on both rivers have been channel incision, widening and straightening, with meander cut-offs. Both rivers show similar recent behaviour, mainly because of the loss of discharge and bedload.

The decrease in the discharge is related to dam construction and water pumping for irrigation, whereas the bedload has been reduced as a result of gravel mining, either directly from the channel bed, or from areas on the floodplain connected to the channel. These effects have been identified in aerial photographs from 1956 onwards, although it is since the 1970s that these processes have become acute. The study of historical maps and older aerial photographs reveals that some of the effects may have started even before1956. Furthermore, the sedimentary record of the floodplain shows intense aggradation since the beginning of last century, indicating that channel incision is not just a recent anthropogenic effect but a natural tendency of the rivers, which may be related to long-term adjustment to changing climate conditions. After a significant period of alluviation and aggradation, the rivers are now going through a new entrenchment stage, with the anthropogenic activity enhancing the natural trend.