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Sampled suspended sediment yields from the Waikato region

TR 2012/01
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Report: TR 2012/01

Author: J Hoyle, M Hicks, H Roulston (NIWA)

Abstract

Sustainable management of the Waikato region’s land and aquatic environment requires ongoing monitoring of various environmental parameters.

Sediment in receiving water bodies is of concern, so monitoring of sediment loads and yields is required to identify and quantify its sources, manage its effects, and to measure trends and the effectiveness of management measures.

Since it is a prohibitive undertaking to continuously monitor sediment in every basin across the region, an alternative is to develop an understanding of how sediment yields vary with differing land use and basin hydrological and physical characteristics. From this, sediment yield on a regional basis can be proxied by monitoring land use and hydrological parameters such as rainfall or runoff.

Towards this understanding, this report presents results from sediment yield studies at 23 catchments under various land uses in the Waikato region.

Sampled suspended sediment yields from the Waikato region [PDF, 1.4 MB]

Contents
  Executive summary 4
1 Introduction 6
1.1 Background and purpose 6
1.2 Objectives 7
1.3 Catchment characteristics 7
1.4 Catchment locations 8
1.5 Data availability for sediment yield analysis 13
2 Analysis methods 16
2.1 The sediment concentration rating approach 16
2.2 The storm even sediment yield rating approach 17
2.3 Determining magnitude-frequency relationships for event sediment yields 19
3 Results 20
3.1 Rating relationships 20
3.2 Sediment yields 20
3.3 Annual yield variability 27
3.4 Event yield magnitude-frequency relations 27
3.5 Sediment yield vs catchment characteristics 28
3.6 Comparison of results with other studies form Waikato-Auckland region 32
4 Recommended further work 34
5 Conclusions 35
6 References 36
  Appendix A - Sediment concentration rating plots 37
  Appendix B - Event sediment yield ratings 49