recurrence frequency of once in 10 years. 7Q10 The Chronic lowest toxicity to seven day aquatic life average flow with a recurrence frequency of once in 10 years. 30Q5 The Impacts to lowest 30 human day health from average toxics flow with classified a as recurrence carcinogens frequency of once in 5 years. Harmonic Long term Impacts to mean mean flow human health from calculated toxics by classified dividing as the number of daily flows by the sum of the reciprocals of those daily flows. The equation is: n = number of daily flows and Q = flow 1Impacts are evaluated with respect to pollutants for which DEQ has developed water quality criteria. More information may be found at
recurrence frequency of once in 10 years. 7Q10 The lowest seven day average flow with a recurrence frequency of once in 10 years. Chronic toxicity to aquatic life 30Q5 The lowest 30 day average flow with a recurrence frequency of once in 5 years. Impacts to human health from toxics classified as Harmonic mean Long term mean flow calculated by dividing the number of daily flows by the sum of the reciprocals of those daily flows. The equation is: n = number of daily flows and Q = flow Impacts to human health from toxics classified as carcinogens 1Impacts are evaluated with respect to pollutants for which DEQ has developed water quality criteria. More information may be found at