Economic Assessment of Braided Rivers Management

Braided rivers provide the majority of groundwater recharge to Aotearoa’s main aquifer systems, and yet we do not know the amount of water they provide because of their size and complexity. The team at Lincoln Agritech Ltd will characterise the subsurface saturation and structure of these complex rivers in order to provide conceptual understanding of braided river hydrology.

This research will impact on the way water is managed by informing management practices, security of supply for irrigators, and the setting of nutrient and allocation limits.

The AERU team is leading the economics component of the research programme that aims to place estimates of economic values alongside the management implications and recommendations developed by the broader research team. This will contribute to understanding the benefits and costs to affected communities from the different braided river management options developed. The tradeoffs identified can then be assessed overall within a Benefit Cost Analysis. Our approach is to form an integrated framework that captures both market and non-market benefit and cost values inherent in different management strategies. Farm Systems models will be used to assess the market effects on agricultural production such as forgone productive land along river margins, increased water security to irrigators, and levels of resource extraction such as gravel. Non-market valuation techniques including Choice Modelling will be applied to value changes in environmental assets such as habitat for native biodiversity and aquatic species, and recreational use and access.

The work programme runs through to the end of 2024.