×J11. Advances in large scale hydrological modelling to improve predictions and assessments of water availability and accounting

Predictions and assessments of water availability across large regions are required so that water managers and policymakers can adequately plan for current and future water availability and water use. In general, only a few catchments are gauged, thus making estimates of discharge for large ungauged areas challenging. Numerous techniques have been developed to make these estimates, with most relying on a kind of hydrologic regionalisation. For undertaking water assessment and accounting in regulated and unregulated river systems, spatiotemporal estimates of streamflow across the whole basin are required for river system modelling, which considers all the relevant hydrological processes (e.g. river routing, overbank flow, surface water – groundwater interactions, etc.) and anthropogenic water demands (e.g. irrigation diversions, storages, urban water and environmental water, etc.).

This session invites papers that:

1. examine how best to undertake regional-scale water balance modelling and regionalise hydrologic response across large gauged and ungauged areas, with a particular focus on assessing/quantifying the uncertainty in the regionalised predictions so that they can be used with confidence for river basin planning and management
2. examine the impacts of regionalisation on streamflow characteristics (e.g. high flows, low flows, number of dry days or dry flows below a certain threshold, sequencing of high and low flows, etc.) for use in aquatic ecosystems and flood risk management
3. demonstrate large scale applications of landscape and river system models for water assessment and accounting (including innovative modelling approaches in process representation, calibration, data assimilation, integration with landscape and landcover models)

Key topics: Regional hydrological modelling, Water assessment, Water accounting, Prediction in ungauged basins