There was improved theoretic methodological basis of hydronetwork sewerage and artificial backwater phase-ethological stability modeling. The degree of ethological blockage of Desna river geosystem’s hydronetwork was determined. The challenges concerning the changes in nature of channel processes for Desna basin geosystem were analyzed. Keywords: basin geosystem, basin territorial subsystem, ethological blocking of hydronetwork, hydronetwork sewerage and artificial backwater phase-ethological stability modeling.