Characteristics on flow rate of change

Average flow events

ra1	Average rise rate.
ra2	Variability in rise rate.
ra3	Average fall rate.
ra4	Variability in fall rate.
ra5	Ratio of days with flow rise.
ra6	Change of flow rises.
ra7	Change of flow falls.
ra8	Average annual number of reversals.
ra9	Variability in annual number of reversals.