The group and its expert consultants have investigated the Manuherikia catchment’s water supply and the potential demand for water. A pre-feasibility study on how the water could be used efficiently and sustainably has been completed. The studies show the catchment is not short of water and, through upgraded and new infrastructure and more efficient irrigation methods, existing irrigators could have a more reliable water supply. The studies show there is also enough water to increase the amount of land which is irrigated, without having a negative effect on the environment. At present 25,000 hectares is irrigated in the Manuherikia Valley, during all or part of the irrigation season. The studies show this could be increased to 35,000 hectares of reliable irrigation. All of the land would be on the Manuherikia Valley floor, not the hills.
These changes, if pursued, would result in higher minimum flows for the Manuherikia River, providing a healthier habitat for aquatic life and better recreational opportunities for anglers, kayakers and other river users.
Moving from the current method of irrigation in the Manuherikia Valley, which is by surface flooding, to more efficient spray irrigation would result in significantly less water being applied per hectare, reducing the risk of runoff or seepage into the Manuherikia River. These measures are expected to maintain, or improve, the already good health of the river.
The MCWSG is working toward timeframes set by both the Otago Regional Council and the Government, around improving the water quality in rivers and lakes by preventing runoff or seepage into waterways, restricting nutrient levels and increasing the flow of rivers.
The infrastructure options the group and its consultants identified during the initial studies are outlined below. A feasibility study to fully investigate these possibilities is underway.
- Raising the existing Falls Dam, including upgrading it, as required;
- Investigating potential dam sites in the Mt Ida and Manorburn catchments;
- Improving the efficiency of the existing water schemes.
The feasibility study is assessing the agricultural and environmental benefits of these proposals and the impact they could have. The results of the study are being publicised as they become available, on this website and through meetings with various sectors of the community. The study was completed in 2015.