Abstract
The paper deals with the derivation of governing propagation equations of nonlinear waves in thin liquid films applying to two basic cases, namely for the perfect fluid flow with a weak mass source at the bottom and for the thin film of viscid liquid flow with a mass source and surface activity at the free moving boundary. The second case is considered on the example of a condensate film flow under the low heat transfer intensity. The conditions under which the model equation has the left-hand side of a type of the Korteweg-deVries equation with slowly evolved parameters, and perturbed right-hand side have been established for the both cases. The conditions under which the solitary wave solutions are possible have been defined too.