process of collecting and storing rainwater (3)

water that has not yet been treated (1)

sample that has all the characteristics of the matter that it was taken from (12)

(in water treatment) the amount of chlorine left in water after all the pollutants have reacted with it (5)

ability to withstand shock, stress or a natural hazard (5)

(in wastewater treatment) the time that effluent spends in a given environment, e.g. in a sedimentation tank or a stabilisation pond (11)

the chance of a hazard occurring (8)

process by which the likelihood of harm from a potential hazard is assessed (8)

rainwater that ‘runs off’ the land i.e. flows over the land surface (3)