phantom tributaries

Hallo, I am using ce-qual-w2 to build up an waterqualitymodel for a shallow River. The section of the river I am modeling is about 40 km long and has a depth of 40 cm. The model is devided into 20 waterbodys with a spillway between each waterbody. The river has 12 tributaries. The model is running without any error and terminates normal. My problem is that the model crates 3 additional tributaries for itself. The additional inflow from these tributaries is substracted atomatically from the model by 3 withdrawal flow components. The main problem is that also tributary inflow temperature for these phantom tributraries is created and this results in a temperaturepeak of 70°C in the river.