Аннотация:The analysis of river runoff change limits in the mouth areas of the rivers is made. The main attention is paid to transformation of sediments yield. Theoretical differences of mineral particles transit and accumulation processes for mouth sites with domination of river and sea factors, and also for mouths of the rivers of different type are studied. Natural data on the Russian rivers with the characteristic of sediments yield transformation in deltas of the rivers and on mouths beach are generalized. Features of deposits accumulation influence and change of reception reservoir level on change of deposits volume in the Volga river mouth are considered. Regularities of sediments yield change at different stages of the Kargalinsky cycle of delta Terek evolution are studied.