Обобщение опыта оценивания составляющих речного стока на основе ЕММА-моделирования

The challenges of identification and assessing the river runoff components are becoming increasingly relevant due to the need to develop in-depth understanding of runoff generation mechanisms. Their solution would contribute to the understanding of many related issues concerning the formation of the chemical composition of river waters, the nature of the interaction of surface and groundwater, and enhancement of resource estimates of river runoff components. The structure of water masses in river catchments is multiplicity and is not fully reflected in the classical classifications - river runoff water sources dividing by genesis, classification of groundwater flow types to rivers, which make it necessary their addition and detail. The aim of this work is to summarize the accumulated experience in Russian for testing diagnostic procedures of EMMA-modeling in identifying sources of river runoff components and their assessment with using data of hydrological and hydrochemical measurements. The objects under study are experimental watersheds of small and medium-sized rivers, which are located in different physical and geographical conditions and have fundamental distinctive feature in the nature of water sources. The geographic scope of testing and adaptation of the model includes watersheds located in the Far East (the Ussuri River basin), in the permafrost zone in the far north (the Yanranaivaam River basin, Chukotka), on its southern border – the Mogot hydrological test site (the Gilyuy River basin, zone of Baikal-Amur Mainline Railway), on the territory of the Sarma geoecological test site in the Baikal region (the Sarma river basin), in the zone of mixed forests of the East European Plain (the Zapadnay Dvina river basin), in the area of the distribution of karst in the Crimean Mountains (the Belbek and the Biyuk-Karasu river basins). The discussed approach of diagnostic modeling of runoff formation based on EMMA includes the integration of two types of models: 1) a physical mixing model in the form of a system of balance equations for water and chemical tracers and 2) the projection method of principal component analysis from the class of formal mathematical models. This work systematizes the final results of EMMA modeling previously obtained by the authors: sets of chemical tracers used in adapting the mixing model, and identified types of river runoff components in experimental catchments. Chemical tracers which most often exhibit conservative hypothesis: water mineralization (or specific electrical conductivity), bicarbonate ion, sulfate ion. Calcium, magnesium, sodium, and dissolved silicon ions exhibited conservative properties a smaller number of times. Dissolved organic carbon exhibits high indicative properties in the separation of subsurface soil-slope runoff into runoff components from organic soil and mineral horizons. The identified various types of subsurface flow show the effectiveness of diagnostic EMMA-modeling in research the structure of river flow, establishing its regional specificity, due to different landscape situations in the basins. The demonstrated possibilities of assessing the components of river flow of any time dynamics (daily, seasonal, flood) opens up prospects for an in-depth understanding of the mechanisms of runoff formation.