The Global Centre for Risk and Innovation (GCRI)
Model descriptions are published here once reviewed, with their assumptions, evidence and validation. They describe models; they are not live simulations.
Water Nexus reviewed models are published descriptions of the models used in the water field, with their assumptions, data, validation and limits, built on methods such as hydrology and water science as well as water and environmental engineering. They describe models; they are not live simulations, and no output on them is a finding.
Fig.A programme from scoping to the owner's decision. Design, not a record.
Rivers, lakes and how far each division sits from mapped surface water, shown for Mexico as an example geography for this subject.
| Model class | Open examples | Question it answers | Validation |
|---|---|---|---|
| Rainfall-runoff and land-surface | GR4J, HBV, VIC, LISFLOOD | Flow at decision points from weather inputs | Split-sample tests on gauged flows |
| Hydraulic inundation | LISFLOOD-FP, HEC-RAS | Depth and extent of flooding | Comparison with surveyed and satellite flood extents |
| Groundwater flow | MODFLOW | Aquifer response to pumping and recharge | Head observations, water balance closure |
| Water allocation and reservoir operation | WEAP and similar planning models | Who gets water under each rule in a drought | Reproduction of historical allocations |
| Global hydrological models | Models in the ISIMIP water sector | Large-scale scenarios under climate change | Multi-model spread, global discharge archives |
A model description lists its version, the basin it was set up for and its validation period. A model built for one basin is not reused for another without recalibration and a new validation.
Analysis runs in Nexus Foundry; reviewed releases are listed here.
Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.
| Term | Definition |
|---|---|
| Model validation | Comparing model predictions with independent observations to judge fitness for a stated use. |
| Model card | A short document describing a model's intended use, training data, performance and limits. |
| Uncertainty quantification | Characterising and propagating the uncertainties in a model to state confidence in its outputs. |
| Surrogate model | A fast statistical model trained to approximate a slow simulation or experiment. |
The bodies and documents this page is read against. Status and editions change; each link goes to the issuing body.
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.