The invention discloses a tidal-reach ecological-
environment water demand amount calculation method. Requirements of a tidal reach for maintaining basic river ecological-environment functions and satisfying water-salt balance, percolating recharging and river
dilution and self-purification functions are considered on the basis of clarifying a tidal-reach ecological-
environment water demand amountconcept, and composition of tidal-reach ecological-
environment water demand amounts is clearly defined; an ecological-environment
water demand amount model of the tidal reach on the basis of
water quality consideration is constructed, and an ecological-environment
water demand amount of the tidal reach on the basis of
water quality consideration is calculated; an ecological-environment
water demand amount model of the tidal reach on the basis of
silt scouring and harbor protection consideration is constructed, and an ecological-environment water demand amount on the basis of
silt scouring andharbor protection consideration is calculated; a basic riverway
ecology water demand amount demanded by the tidal reach is determined on the basis of long-series flow data; and finally, a riverway ecological-environment water demand amount of the tidal reach of a coastal area is determined through comparing the ecological-environment water demand amount demanded by the tidal riverway in consideration of a
water quality factor and the ecological-environment water demand amount demanded in consideration of
silt scouring and harbor protection.