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  Services » Publications » Technical reports - by year » tr201025

Soil Stability and Disturbance in the Kawhia Catchment - Changes from 2002 to 2007

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Report: TR 2010/25
Author: A B Thompson (Thelton Environmental Ltd) and D L Hicks


 The Waikato Regional Council has requested an assessment of the extent of erosion, and coverage by soil conservation measures in a catchment that is representative of the region’s west coast management zone. This zone encompasses all catchments west of the Waikato and Waipa watersheds.   The assessment is intended to assist with upcoming discussions with the community as to the future promotion of catchment protection programmes in the zone.

The Waikato Regional Council contracted Mr. A.B. Thompson (Thelton Environmental) to undertake the assessment, with involvement of Dr. D. Hicks as needed for analysis procedure and comparisons.   Following discussion with Waikato Regional Council staff, Kawhia was selected as a representative catchment.   The assessment was undertaken as a point sample from aerial photographs. This is now a standard method for assessing erosion and erosion control measures, used by EW as well as other regional councils.

The report starts with an overview of soil stability, soil disturbance and bare soil.   It then gives results from the 2007 assessment of soil conservation measures for Kawhia, and compares them with results from a previous assessment in 2002. Results and comparisons are split according to whether land is farmed, planted in forest, or under natural vegetation, then grouped as a single catchment-wide summary.

Soil Stability and Disturbance in the Kawhia Catchment - Changes from 2002 to 2007

Table of contents

  Acknowledgements i
  Executive summary v
1 Introduction 1
2 Method 1
3 Contents of the report 2
4 Soil stability, soil disturbance and bare soil 2
4.1 Soil stability 2
4.2 Bare soil 3
5 Soil stability under different land uses 4
6 Extent of soil conservation 5
6.1 Farmland 5
6.2 Forest plantations 6
6.3 Natural vegetation 7
7 Effectiveness of soil conservation 8
7.1 Farmland 8
7.2 Forest plantations 9
7.3 Natural vegetation 10
7.4 Cautionary comment 11
8 Land uses' extent and effect catchment-wide 11
9 Soil conservation cover's extent and effect catchment-wide 12
10 Conclusions 13
  References 14
  Appendices 15
Appendix A Data summary spreadsheets for Kawhia Catchment 15
Appendix B Data summary tables for West Coast Management Zone, 2007 25
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