Water Stress (Aqueduct 4.0)
This layer measures baseline water stress: how much of the renewable water available in an area is already being claimed by competing users.
Source: WRI Aqueduct 4.0 Year: 2023 Category: Physical risks · Provisioning services · Water availability Coverage: Global Format: Boundary polygons (hydrological catchments) Used in risk analysis: Yes — gates Provisioning services
What it shows
This layer measures baseline water stress: how much of the renewable water available in an area is already being claimed by competing users. It matters because operations and supply chains in high-stress areas face greater exposure to shortages, rising water costs, allocation restrictions and conflict with other users.
How it is built
Baseline water stress is the ratio of total water demand to the renewable surface and groundwater supplies available in each catchment. Demand combines domestic, industrial, irrigation and livestock uses. Available supply accounts for how upstream consumption and large dams reduce the water reaching downstream areas. The figures are taken from the WRI Aqueduct 4.0 dataset and provided as values for hydrological catchment areas worldwide. Higher ratios mean a larger share of the available water is already spoken for.
How to read it
Higher values indicate more competition among users and therefore greater water-supply risk; lower values indicate comparatively abundant supply relative to demand. Values are tied to catchment areas, so a site is assessed by the stress level of the basin it sits in.
Class thresholds
The underlying quantity is a physical ratio: baseline water stress — total annual water demand divided by available renewable surface and groundwater supply, expressed as a percentage (%). Darwin symbolises Aqueduct's pre-computed ordinal category (bws_cat), so each catchment falls in one of the standard Aqueduct classes:
Class (bws_cat) | Baseline water stress (demand / supply) |
|---|---|
| Arid and Low Water Use | very low water availability and use |
| Low | < 10% |
| Low – Medium | 10 – 20% |
| Medium – High | 20 – 40% |
| High | 40 – 80% |
| Extremely High | > 80% |
A site is flagged on the Provisioning services dimension (Water supply) when its catchment category is above 3 — i.e. it reaches Extremely High (baseline water stress above 80%).
How these thresholds were set. The class split follows the WRI Aqueduct 4.0 methodology — the standard Aqueduct baseline-water-stress bins (<10% / 10–20% / 20–40% / 40–80% / >80%). It is not a Darwin in-house classification.
Reference: WRI Aqueduct 4.0 — wri.org/aqueduct.
Source
WRI Aqueduct 4.0 baseline water stress (World Resources Institute). See doi.org/10.46830/writn.23.00061.
Comparison with the WWF Risk Filter Suite
This layer maps to BRF S1_1 Water Availability and WRF B1_2 Baseline Water Stress, and is aligned. WWF builds water availability from a basin composite (depletion, baseline stress, freshwater-quantity target and groundwater); Darwin uses the Aqueduct baseline water-stress signal. Groundwater stress is not separately covered here.
Risk analysis
A site is flagged on a dimension by combining a proximity trigger (this layer) with an activity trigger (the entity's ENCORE pressure/service). Proximity only → Potentially material; proximity and the matching ENCORE pressure/service is material → Very material; neither → Not material.
| Dimension | ENCORE service / pressure | Proximity trigger (this layer) | Activity trigger (entity) |
|---|---|---|---|
| Provisioning services | Water supply | Layer value above 3 | “Water supply” pressure ≥ 4; impact ratio ≥ 5%; impact ratio ≥ 5% |
Legend
Symbolised field: Baseline water stress category
| Value (Baseline water stress category) | Label | Colour |
|---|---|---|
| -1 | No Data | #d3d3d3 |
| 0 | Arid and Low Water Use | #74afd1 |
| 1 | Low (<10%) | #aac7d8 |
| 2 | Low - Medium (10-20%) | #dededd |
| 3 | Medium - High (20-40%) | #f8ab95 |
| 4 | Extremely High (>80%) | #f27454 |
Generated from darwin/layers/layer-water-stress-aqueduct-4-0.toml and risk_indicator_pairs.toml (develop).