The importance of a small ephemeral tributary for fine sediment dynamics in a main-stem river

B. Marteau*, R. J. Batalla, D. Vericat, C. Gibbins

*Corresponding author for this work

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Studies of ephemeral streams have focused mainly in arid and semi-arid regions. Such streams also occur widely in temperate regions, but much less is known about their influence on fluvial processes in main-stem rivers here. In this paper, we present evidence of the importance of a small ephemeral temperate stream for main-stem fine sediment dynamics. The paper focuses on a restoration project (River Ehen, North West England) which involved the reconnection of a headwater tributary to the main-stem river. We present data on suspended sediment transport 2 years prior to and 2 years following the reconnection. Despite the small size and non-perennial flow of the tributary, its reconnection resulted in an increase of 65% in the main-stem sediment yield. During both the pre-reconnection and post-reconnection periods, a higher proportion of the annual yield was conveyed during short events with relatively high suspended sediment concentrations. Following the reconnection, the magnitude and frequency of such events increased, primarily due to sediment being delivered from the tributary at times when main-stem flows were not elevated. Overall, the main-stem remains supply limited and so is highly dependent on sediment delivered from the tributary. The study helps stress that even non-perennial tributaries yielding only a small increase in catchment size (+1.2% in this case) can have a major influence on main-stem fluvial dynamics. Their role as sediment sources may be especially important where, as in the case of the Ehen, the main-stem is regulated and the system is otherwise starved of sediment.

Original languageEnglish
Pages (from-to)1564-1574
Number of pages11
JournalRiver Research and Applications
Volume33
Issue number10
Early online date21 Jul 2017
DOIs
Publication statusPublished - 1 Dec 2017

Keywords

  • channel reconnection
  • ephemeral stream
  • regulated river
  • river restoration
  • suspended fine sediment
  • temperate region

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology
  • Environmental Science(all)

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