River/Stream Decay Model Examples

Point Source (Nonconservative Substances)

This applet modeling is based on a first-order, at steady state, linear differential equation:

where:

S = Substance Concentration at x = x(t) (mg/L)
S₀ = Substance Concentration at x = 0 (mg//L)
K = Decay Constant (1/day)
t = Travel Time (day) = x / U
U = Stream Velocity (mi/day; mpd)

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