Volume of inflows, losses, storage, outflows
Unit
Indicator
Metric type
Framework alignment notes
GRI 303-5 Change in water storage in megaliters, if water storage has been identified as having a significant water-related impact.
AWS 1.3.2 Site water balance, including inflows, losses, storage, and outflows shall be identified and mapped
ISO 14046 - quantities of water used (including water withdrawal and release)
types of water resources used (including for water withdrawal and water receiving body)
changes in drainage, stream flow, groundwater flow or water evaporation that arise from land use change, land management activities and other forms of water interception, where relevant to the scope and boundary of the study being undertaken
Target example
[Company name] will ensure that its inflows, losses, storage and outflows are all within sustainable limits by [target year].
Target source: WBCSD target template
Metric assessment
Relevance:
High
Feasibility:
Medium
Additional Metric Notes
ACT-D stage
Assess
Maturity stage
Developing
Metric Contribution to Action
This metric is both the means and outcome of the ‘Assess’ step—it provides the foundational water balance necessary for informed water stewardship planning.
Observations, Successes and Challenges
- Both a Pressure and State metric type. Pressure at site-level, State at basin-level.
- Captures the full picture of water availability and movement within a basin, useful for effective water management.
- Can be measured using hydrological models, remote sensing, and monitoring stations.
- Individual companies may not have access to all inflow, storage, and outflow data, requiring collaboration with regulators and other water users.
- Water losses can result from evaporation, leakage, or inefficiencies, and accurately tracking them at a basin level can be difficult.
- Seasonal fluctuations, climate change impacts, and infrastructure changes (e.g., new dams or reservoirs) may distort trends in water balance.x
- While technically straightforward, comprehensive mapping may be hindered by external data gaps, stakeholder coordination challenges, or changes in infrastructure or climate affecting trends in water balance.