The gullies of the Canterbury Bight : Rakaia to the Rangitata.

Type of content
Theses / Dissertations
Publisher's DOI/URI
Thesis discipline
Geography
Degree name
Master of Science
Publisher
University of Canterbury
Journal Title
Journal ISSN
Volume Title
Language
English
Date
1998
Authors
Pearce, Megan
Abstract

This thesis is an investigation into some erosional gully features of the landscape along the coastal margin of the Canterbury Bight, east coast of the South Island, New Zealand. These gullies range in size from only a few meters up to 6km in length and are a significant aspect of the landscape between the Rakaia and Rangitata Rivers.

An examination of vertical aerial photographs revealed numbers in the order of 300 gullies, although a substantial number of these can be identified as aspects of coastal cliff retreat. A number of gullies have been surveyed and ground truthed using standard surveying techniques in order to make out any distinguishing characteristics. Oblique aerial photographs were taken so as to enhance the vertical aerial photographic interpretation.

Cliff retreat along this coastline is averaged at 0.5m/yr and has been found to have considerable impact on the gullies as they are relict features and consequently, their development is not in keeping with the rate of cliff retreat. It has been found that there are at least three groupings of the gullies in relation to their size, those being small, intermediate and large.

The formation of the larger gullies has been initially attributed to subsurface processes, producing surface irregularities in which continued erosion can concentrate. It has also been estimated that the gullies were initiated between the period of 150 to 600 years BP, but that it is most likely that all gullies were not formed at the same time. The most probable explanation found that the three different gully sizes identified can be attributed to having developed in three different time periods.

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Citation
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Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
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All Rights Reserved