What is WAIORA?
WAIORA stands for Water Allocation Impacts on River Attributes. It’s a decision support system designed to help regional councils assess the effects of flow changes on streams and rivers. WAIORA was designed by NIWA and is available free over the web.
WAIORA can be used to predict how instream habitat, water temperature, dissolved oxygen, and total ammonia concentrations change with flow. These changes are then compared to environmental guidelines to assess whether the effects are acceptable. The assessments are recorded in a database leaving a clear audit trail, including all data and parameter estimations used in the process.
For example, the graph shows a hypothetical reduction in summer low flow from 80 litres per second to 25 litres per second. In this case, the lower flow would increase daily maximum water temperatures from 21.7°C (vertical green line) to 23°C (vertical red line). Water temperature guidelines suggest that the maximum daily water temperature should not exceed 23°C, so WAIORA displays a red warning cross on the graph.
WAIORA can also be used to predict how changing the water flow could affect the instream habitat of 26 freshwater fish and invertebrate species.
Download the programme and associated manuals from www.niwa.co.nz/ncwr/tools/waiora