The Deep Stream Hydro Scheme channels water flowing from an existing Deep Stream Diversion, impounds that water in a storage reservoir, and then allows the water to be released through canals containing two 2.5 MW generating units to Lake Mahinerangi.

After the granting of Resource Consents in July 2005, construction began in mid 2006 and the scheme was commissioned in the second quarter of 2008. 

The scheme has no significant environmental impacts, the reservoir being partly built on land owned by the Dunedin City Council, which had been purchased and retired from farming to prevent contamination of water supplies. In addition to supplying power for the equivalent of 3,100 homes, an agreement between TrustPower and the Dunedin City Council provides a positive spin-off thanks to the retention of sufficient water in the scheme to provide an emergency water supply for Dunedin City in the event of a prolonged drought.

Lake Mahinerangi Catchment 
Environmental Enhancement Trust

 As a result of the resource consent granted for the Deep Stream Enhancement, TrustPower has set up a fund of $100,000 for the purpose of restorative and / or conservation works within the general catchment area of the Waipori Hydro Electric Power Scheme.

 The Trust Fund is for charitable purposes and the intent that the Trust Fund shall be expended on projects within the Lake Mahinerangi catchment area (which may include improved access to reserve areas, environmental education, animal and plant pest control, resource investigation and scientific study, restoration planting and recreation planning) and the surrounding wetlands and tussock lands.         

 The application form and guidelines are below:

A requirement of the Trust Deed is to publish an Annual Report and Financial Statement giving details of the operations and activities of the Trust during the financial year, these can be found below. The inaugural AGM was held during September 2010.