Floodplain construction by recent, rapid vertical accretion: Waipaoa River, New Zealand

The rate of vertical accretion (typically 14–18 mm h−1) during eight floods in the Waipaoa River basin, with recurrence intervals of 5 to 60 years, was determined by relating the floodplain stratigraphy at McPhail's bend to the 1948–1995 flood history. Overbank deposits remaining after a flood...

Full description

Saved in:

Bibliographic Details
Published in:	Earth surface processes and landforms Vol. 23; no. 5; pp. 405 - 413
Main Authors:	Gomez, Basil, Eden, Dennis N., Peacock, David H., Pinkney, Edward J.
Format:	Journal Article
Language:	English
Published:	Sussex John Wiley & Sons, Ltd 01-05-1998 Wiley
Subjects:	Bgi / Prodig channel capacity deforestation Earth sciences Earth, ocean, space Exact sciences and technology floodplain sedimentation Fluvial forms and processes Freshwater Geomorphology Geomorphology, landform evolution Physical geography Surficial geology vertical accretion New Zealand North Island Deforestation Flood Suspended load Floodplain Stratigraphy Fluvial processes Alluvium floodplains accretion fluvial sedimentation Australasia
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	The rate of vertical accretion (typically 14–18 mm h−1) during eight floods in the Waipaoa River basin, with recurrence intervals of 5 to 60 years, was determined by relating the floodplain stratigraphy at McPhail's bend to the 1948–1995 flood history. Overbank deposits remaining after a flood that occurred in March 1996 suggest a rate of vertical accretion of 15 mm h−1. By contrast, because the flow velocity across the floodplain was too high to permit deposition from suspension, during the record flood of March 1988 the rate of vertical accretion was only 6 mm h−1. The sequence of deposition is highly discontinuous, and the rapid vertical accretion is a response to a late 19th to early 20th century phase of deforestation in the headwaters that probably initiated a far greater change in suspended sediment yield than in discharge. Cross‐section surveys conducted since 1948 indicate that the high suspended sediment load of the Waipaoa River also promoted in‐channel deposition, which effected a progressive reduction in bankfull channel width although, due to the overbank deposition, channel capacity remained constant. © 1998 John Wiley & Sons, Ltd.
Bibliography:	ArticleID:ESP854 istex:FB5735508B9BFC2C1A0F3ACC14E0CD5E8C0F7630 New Zealand Foundation for Research, Science and Technology - No. 009306 ark:/67375/WNG-3XNRHLFG-5 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0197-9337 1096-9837
DOI:	10.1002/(SICI)1096-9837(199805)23:5<405::AID-ESP854>3.0.CO;2-X