Sampled suspended sediment yields from the Waikato region

TR 2012/01

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