1. Introduction
Sinclair Knight Merz (SKM) was commissioned by the Ministry for the Environment in October 2004 to provide a preliminary hydrogeological assessment of groundwater quantity in the Waitaki River Catchment. The demand for irrigation water, and particularly groundwater in areas underlain by high permeability gravel aquifers is increasing. In addition, the Waitaki Catchment faces unprecedented conflict over water allocation due to the various competing interests, such as hydroelectricity, irrigation schemes, farmers, and the interests of groups wishing to preserve the cultural and environmental values associated with water within the catchment.
The information obtained from this study, while preliminary in nature, will assist the Waitaki Catchment Water Allocation Board to understand groundwater resources and the interaction with surface waters.
The specific objectives of the study included:
- an assessment of groundwater flow directions and quantity
- reporting on groundwater interaction with surface water bodies and its significance
- providing the level of confidence in interpretations of groundwater flow directions and quantity.
The Waitaki Catchment
The Waitaki River Catchment comprises over 11,000 square kilometres extending from the Southern Alp headwaters to the South Island's East Coast north of Oamaru (Figure 1). The Waitaki River is the fourth largest river in New Zealand with a mean historical flow at the Waitaki Dam of 358m3/s recorded between 1927-2000 (Opus, 2003). The four major tributary basins of the Waitaki Catchment are the Tekapo, Pukaki, Ohau and Ahuriri. The catchment includes the natural lakes of Tekapo, Pukaki and Ohau, and the artificial lakes of Benmore, Aviemore and Waitaki.
Groundwater information in the upper Waitaki Catchment is limited, whilst in the lower catchment, there has been extensive study of groundwater resources for regional councils and Project Aqua. Based on the existing knowledge of groundwater resources in the Waitaki Catchment, the current report focuses on groundwater zones, direction of groundwater flow and the relationship of groundwater to physical boundaries; for example, rivers, lakes, and topography.
Figure 1. Waitaki Catchment locality plan and aquifer boundaries
A3 full version of image is available in paper format
and PDF
(1.7 MB).
