Two of the four stream segments (segments 1 and 3) have headwater concentrations of 1E-5. The other two have headwater concentrations of zero.
Edit each of the objects that define stream segments. Activate the SFT package in each of them. Specify the initial concentrations and dispersions of all of them as zero. Then switch to the Head Water Conc tab and set the head water concentration to 1E-5 for segments 1 and 3 and to zero for segments 2 and 4. It would also be possible to specify the concentration of precipitation or runoff into the stream or specify a constant concentration for the stream but those capabilities are not used in this model.
