this can result from the physical impossibility to divide the available water resources or because the water temperature for cooling water or salinity for agriculture is too high category takes precedence over all others it includes freshwater use for safety and the prevention of irreversible damage eg ensuring the stability of flood defence structures settling and subsidence of peat bogs and moorland nature dependent on soil conditions category includes drinking water supply and power supply category includes smallscale highquality uses such as temporary spraying of capitalintensive crops and process water