June's report on freshwater models by the Parliamentary Commissioner for the Environment (https://pce.parliament.nz/publications/a-review-of-freshwater-models-used-to-support-the-regulation-and-management-of-water) highlighted the poor and fragmentary state of modelling Aotearoa's freshwater systems to support regulation and management.
Planted and indigenous forests are typically located in headwaters. They are important for NZ's hydrological landscape. Existing models poorly predict forest water use, storage and release due to forests' unique hydrological processes. The Forest Flows Endeavour Research programme has created a new Forest Flows Hydrological Model that accurately simulates planted forested catchments, both low and storm stream flows, and tree water use. The process-based model was developed by Scion, NIWA and CSIRO using data from NZ, Australia and Chile. It can be used for a wide range of catchments under current and future climates.
More information about the Forest Flows Combined Hydrological Model can be found here:
https://www.scionresearch.com/__data/assets/pdf_file/0005/119417/Predicting-Stream-Flow.pdf
The Forest Flows programme is funded by the Ministry of Business, Innovation and Employment Endeavour fund.