Analysis of the fluviometric network of Rio das Velhas using Entropy

ABSTRACT In this work a comparative study was carried out, in which different methods were used in the literature that seek to evaluate the number of stations and the quality of the information generated by the hydrometric network of a watershed, using Information Theory concepts. The underlying idea is the so-called optimal network whose function, according to World Meteorological Organization (WMO) is to optimally and inexpensively meet the primary goal of hydrometry, which is to provide the necessary information with a minimum number of stations correctly positioned in the basin. Methodologies based on Information Theory ascend to fill the gap on a standard method for the design of hydrometric networks. The evaluated methods were applied to the subbasin of the Rio das Velhas belonging to the São Francisco River basin in Brazil. The results showed that the methods analyzed, which use the concept of entropy, are adequate and efficient for evaluation of existing fluviometric networks, since they allow the reduction of eventual redundancies and at the same time, seek to maximize the information generated. It was possible to compare them and indicate the most appropriate method for the application within the national context, as well as indicate new methods for use thereof.

摘要 本研究开展了一项对比分析，基于信息论（Information Theory）概念，采用现有文献中的多种方法，对某流域水文测站网络的测站数量与所生成信息的质量进行评估。其核心思路为所谓的最优水文测站网络——根据世界气象组织（WMO）的定义，该网络的功能是以最优且经济的方式达成水文测量的核心目标：在流域内合理布设最少数量的测站，以获取所需的必要信息。基于信息论的方法填补了水文测站网络设计缺乏标准方法的空白。本次评估的方法被应用于巴西圣弗朗西斯科河（São Francisco River）流域下属的韦拉斯河（Rio das Velhas）子流域。结果表明，所分析的基于熵（entropy）概念的方法，对现有河流水文测站网络的评估具备适用性与高效性：此类方法可减少潜在的冗余，同时最大化所生成的信息价值。本研究可对各方法进行对比，明确在巴西国内场景下最适用的评估方法，并提出可推广应用的新型方法。