Ottocodification as a Water Resources Management Tool: A Case Study in Hydrographic Region 8 Litoral Centro

Código

I-EBHE0144

Autores

Leandro José Isensee, EWERTHON CEZAR SCHIAVO BERNARDI, Luis Henrique Beduschi, Luiz Felipe Pereira de Brito, Gustavo Antonio Piazza, Adilson Pinheiro

Tema

WG 2.6: Water systems analysis for integrated planning & management

Resumo

The current system used in Brazil to code watersheds and their respective watercourses is called ottocoding. Ottocoding can be done by levels, where each level represents 9 sub-watersheds of a given main watershed. This coding system was designed to also serve as a tool for managing water resources. However, few studies have been conducted on the application of ottocoding as a tool for watershed management. This work aims to analyze the potential of ottocoding as a management tool, as well as to analyze ottocoding data at each level in a specific watershed. For this study, Hydrographic Region 8 (HR8) - Central Coast, one of the most populous hydrographic regions in the State of Santa Catarina, was used as a case study. HR8 includes, among other cities, the state capital, Florianópolis. This hydrographic region, being coastal, was ottocoded with the ocean as the mouth of the main river (code zero). A quantitative analysis of ottocoded data by the level of watercourses and a qualitative analysis of potentials were carried out. It was observed that there are variations in the lengths of watercourses at each level, with an average of 69 km at level 5 and 570 m at level 12, varying approximately linearly between other levels. Regarding the area of watersheds, there is approximately 960 km² at level 5 and 0.14 km² at level 12. It was also observed that the number of watercourses per level follows a normal distribution, with a median at level 9, which can be explained by the limitation of the digital terrain model. Concerning the qualitative analysis, the following management potentials were identified: 1) Unification of the coding system for federal, state, and municipal entities. 2) Ottocoding allows multi-scale analyses. 3) The coding separates watercourses from inter and intra watersheds, making it possible to infer whether a particular watershed is more affected by diffuse or point-source impacts. 4) The visualization of watercourse crossings at certain levels can support the planning of hydrometeorological monitoring stations. 5) Being an aggregative numerical system, other information can also be integrated into ottocoding, such as the predominant land use in a given sub-watershed. It is clear that ottocoding, although a simple coding process, has the potential to be used to extract basic information about the behavior of watercourses. Through adaptations such as the aggregation of letters at each coding level, this system has the potential to enable qualitative analyzes of water resources.