У роботі проаналізовані типи русел та встановлений їх зв"язок з гідроморфологічною оцінкою річок верхньої частини басейну Тиси (в межах України). Наведена характеристика типів русел річок в залежності від їх похилів, та побудовано залежності довжин ділянок від похилів річок вказаного водозбору. Встановлено, що поріжно-водоспадний тип русла, русла з нерозвинутими і розвинутими алювіальними формами відносяться до гірської частини басейну. Русла з розвинутими алювіальними формами та руслова багаторукавність є перехідними до низькогір"я. А для передгір"я характерним є меандрування (врізане). Встановлено, що поріжно-водоспадні русла відносяться до відмінного класу якості, русла з нерозвинутими алювіальними формами розміщені між першим і другим класами, а русла з розвинутими алювіальними формами в цілому відповідають третьому (задовільному) класу гідроморфологічної якості.
The classification of the river bed types in terms of nature of the bed reformations and their morphological manifestations is taken as a basis for definition of the bed types for rivers of Tisza river upper basin (within Ukraine). Having examined the conditions of bed formation of upper Tisza rivers (within Ukraine) an effort was made to assess the rivers of abovementioned basin by& corresponding slopes that meet the certain types of the beds. In total, the analysis involved five types of river beds: step-waterfall bed, with undeveloped alluvial forms, bed with developed alluvial forms, braided bed and meandering (embedded). Th&e paper analyzes the bed types and sets their connection with hydromorphological assessment of the rivers of Tisza upper basin (within Ukraine). Almost all the rivers of the upper Tisza (within Ukraine) are classified as mountainous. In total, five t&ypes of beds are defined: 1) stepwaterfall bed (43.6% of the length of all river beds); 2) bed with with undeveloped alluvial forms constitute 41.1% of the length of all beds; 3) beds with developed alluvial forms (12.8%); 4) braided beds are 1.5%; 5&) embedded meandering (1.0%). The characteristic of the river bed types is given depending on their slope and the dependences of the length of areas on river slopes of mentioned water catchment area are set. Analyzing the relationship between the len>hs of areas and slopes the clear trend is observed: the longer the river, the lower the slope. This is explained by quite steep embedded valleys in the highlands of Tisza basin rivers (within Ukraine). The greater the river slope, the larger embedm&ent of bed and smaller the length of the river. It is found that step-waterfall type of bed spreads from the head to the absolute marks of encroachment line of 770-800 m. Slope of these rivers exceeds 30 ‰ and reach 100 ‰ and more in the upper reache&s. Structureless sediment transportation is observed in these beds.
The beds with undeveloped alluvial forms are regulated by the river encroachment lines of 800-380 m above sea level. Slopes of these rivers are also significant (15-30%). Sediment t&ransportation is the combination of structureless forms with available self-paving layer. The beds with developed alluvial forms are distributed mostly at altitudes below 330 m (along the river encroachment lines). Their slopes are also decreased up &to 5-15%. The beds have evident self-paving layer of alluvium.
Step-waterfall beds, beds with undeveloped alluvial forms refer to the mountainous part of the basin. The channels with developed alluvial forms and braided beds are transitional to lowl&and. And in the foothills, the embedded meandering is typical. It is established that the step-waterfall beds relate to the highest quality class due to the absence of human loading and significant height points in mentioned water catchment area. The& beds with undeveloped alluvial forms are between the first and second classes due to the availability of bank protection structures that were built after catastrophic flood in 2008. And the beds with developed alluvial forms generally meet the third&
