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  Services » Publications » Technical reports - by year » tr200517

Ecohydrological characterisation of Opuatia wetland and recommendations for future management

Report: TR05/17
Author: Katrina Browne and Dave Campbell (University of Waikato), Edmund Brown

Abstract

Many of the Waikato Region's wetlands have been destroyed. Opuatia Wetland is situated in the lower Waikato River catchment, North Island, New Zealand. The wetland catchment is predominantly agricultural land, and livestock which graze on the surrounding hill slopes have direct access to the wetland margins. This as well as agricultural runoff, pose a harmful source of nutrients.

Monitoring and research of the ecohydrology of Opuatia Wetland was initiated as a result of Environment Waikato's resource consent condition requirements to extend the existing Lower Waikato Flood Control Scheme. A combined effort by the University of Waikato and Environment Waikato (Waikato Regional Council) enabled a wetland monitoring network to be established in early 2003. This included vegetation plots, water table and river stage monitoring sites, a climate station and a micrometeorological station. This report outlines the findings from a MSc. research project studying the ecohydrology of Opuatia Wetland.

Ecohydrological Characterisation of Opuatia Wetland and Recommendations for Future Management
(1075 kb, 153 seconds to download, 56k modem)

Table of Contents

1. Introduction 1
2. Opuatia Wetland 3
  2.1 Study site description 3
  2.2 Geological history 6
  2.3 Climatic conditions 6
  2.4 Human influences 8
  2.5 The monitoring network 9
3. Vegetation 11
  3.1 Present day distribution 11
  3.2 Invasion of willow species since 1942 15
  3.3 What is being lost by the invasion of grey willow? 18
4. Peat physical and chemical characteristics 19
5. Hydrology 22
  5.1 Monitoring network 22
  5.2 General variation in the water table regime at Opuatia Wetland 24
  5.3 Transect across the wetland 25
  5.4 Surface water contours and flow directions 29
  5.5 The hydrological regime at bog sites 32
  5.6 Opuatia Wetland water balance 34
  5.7 Opuatia River hydrology 39
  5.8 Flood events 41
6. Current ecosystem pressures 44
7. Recommendations 45
  7.1 General 45
  7.2 Restoration area 47
8. Conclusions 47
9. References 49
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