Environmental flow tools
Tools and software to assist with determining and managing environmental flows.
The programme has produced a series of tools and software to assist with assessing ecological flow requirements in rivers.
New Zealand River Maps is an interactive web-based application for exploring national scale predictions of a suite of river environmental variables, including water quality, hydrology, bed sediment size, invertebrate metrics, fish presence, bed sediment cover and water allocation.
The eFlows Explorer webtool is designed to aid broad-scale river flow management planning across New Zealand. is intended to aid understanding of how minimum flow and total allocation can be set for all river reaches across a catchment or region, by demonstrating how they interact with reliability of water supply and example environmental metrics representing losses in total area of aquatic habitat.
This a water planning and management tool designed to assist with setting regional or large scale water resource use limits. It predicts how limits on water take and minimum residual river flows can be designed to optimise reliability of water use and effects on instream environments.
The Cumulative Hydrological Effects Simulator software predicts how water flows at a catchment scale will change under a combination of water uses and what these flow changes mean in terms of reliability of water supply and effects on instream environmental values. CHES operates on a daily flow time-series basis and is underpinned by outputs from hydrological models (e.g. TOPNET, ELFMOD).
This is a statistical tool for estimating flows at multiple points along rivers subject to surface/ground-water exchanges, using both measured flow at selected sites and other predictor variables such as rainfall and groundwater levels. ELFMOD can visually represent how river flow changes with time and distance.
Water Allocation Impacts on River Attributes is a decision-support system designed to provide guidance on whether a water take or discharge could have adverse impacts on selected environmental variables, including dissolved oxygen, water temperature, ammonia and aquatic habitat.
The River Environment Classification is a spatial framework for regional (or larger) scale environmental monitoring and reporting, environmental assessment and management. The REC maps a host of information about the physical characteristics of New Zealand’s rivers, including catchment climate, topography, geology and land cover. Information is mapped by individual river segment for the entire national river network. The current version available is version 2 (REC2).
Intensifying competition for water is increasing pressure on finite water resources (surface and groundwater), which manifests itself as depleted stream flows. As the concerns over water resources and the environment increase, the importance of combined water management, which acknowledges the integrated nature of groundwater and surface water, and manages them as a single resource, is critical to sustaining both human society and aquatic and terrestrial ecosystems. This tool can be used by regional and district councils, central government agencies, water managers, catchment groups, hydroelectric generators, researchers, and consultants.