Surface water supply and use index from National Water Availability Assessment Data Companion

The surface water supply and use index (SUI) expresses the fraction of the median long-term water supply at a HUC12 that is unavailable either because of climatic variability (e.g. an unusually dry year) or because the water is used consumptively for crop irrigation, thermoelectric power, or public supply. Higher values indicate a higher potential water limitation because a higher proportion of the typical water supply is unavailable. The SUI varies between 0 (no apparent limitation) and 1 (total depletion of the local water supply). Image from the National Water Availability Data Companion.