Hydrologic Indices of South America Rivers - HISAR

Rivers provide important environmental services related to the preservation and support of aquatic ecosystems, play an important role in the hydrological cycle of watersheds and support socioeconomic activities such as city water supply, industrial supply, agriculture, navigation and electricity generation. Understanding the behavior of rivers is of paramount importance, as changes in their characteristics can cause impacts, and the analysis of river behavior gives us an overview of water availability. The behavior of rivers can be understood and adequate through the study of the flow regime, which is described by the pattern of flow characteristics of a river, such as magnitude, predictability and variability of flows. This work aimed to characterize the natural flow regime of rivers in South America, analyzing their average parameters of hydrological indices, performing an analysis of the accuracy of hydrological indices estimated from data flows by hydrological modeling and to develop a database with these indexes. To obtain the hydrological indices, series of daily natural flows estimated by hydrological modeling were used, using the Large Basin Hydrological Model (MGB), in a series of flows from 1980 to 2014 (35 years), and were subsequently calculated 73 hydrological indices. For the analysis of the accuracy of the hydrological modeling, the indices were calculated with series of observed flows, which were compared with the indices estimated through relative error, absolute error and correlation. The observed hydrological indices were obtained using flow rates from fluviometric stations in South America, after passing through a quality filtering, resulting in a total of 1329 stations. The database was built through the elaboration of maps with the main hydrological indices analyzed and the river indices were made available on an online platform in the ESRI shapefile file format. The results obtained for the analysis of hydrological indices allowed us to observe patterns of behavior of the river flow regime, related, for example, to climate and hydrogeology, as well as relationships between the indices themselves. The relative error was calculated for 1329 points (corresponding to fluviometric stations) for 56 indices selected for this analysis, with this we obtained that the average of the medians of the calculated errors of the hydrological indices is 33.2%. With the database we can obtain a spatial view of the behavior of rivers, including rivers that still do not have information on the flow regime. Thus, we can conclude that the series of flows estimated by hydrological modeling have satisfactory representations of the presented hydrological indices. Among the contributions of this work, we can highlight the presentation of hydrological indices and their database, which can be used as a tool for understanding hydrological processes in South America.