The Amazon region has rivers of great contribution to the biodiversity balance and regional landscape. Among them, the stand out are the Negro River -the most extensive, the Amazon River -with the largest volume, the Purus River -a fish supplier, and the Madeira River -the most modified. Flooding in the Amazon is often widespread and sometimes severe for those who live very close to rivers, yet urban areas are often more socially impacted than rural areas, as flooding is part of the riverside population's daily life. Flood forecasting models are important for composing extreme event alerts as well as for knowledge of decision-makers, public agency representatives, and affected communities. This paper aims to present what is being done in Manaus about the Negro River floods, with the development of a flood alert dissemination project, which uses a linear regression statistical model, based on the historical series over 100 years. The follow-up to the one-year flood forecast begins the previous year, more precisely when the ebb ends and the rainy season begins. Several factors contribute to the flood event, but the main one is the rainy season and how the basin will behave during the six months of rising waters. Manaus station receives contributions from two major rivers: Negro and Solimões, which form the Amazon River downstream. The position of the city, allied to the difference in depth, speed, and flow of the rivers, added to the rainfall period in the basin reveal the flooding characteristic in this locality. Considering the last 15 years, the near-real flood forecast interval in 87% of cases reveals that the project has fulfilled the purpose of alerting the population and public representatives about the flood of Negro River.

The magnitude of the Amazon basin, associated with geological, geomorphological and hydrological factors, as well as the distribution of rainfall, contribute to the existence of large rivers, both in extension and flow, such as the Negro and Solimões rivers, which are selected to be evaluated in this study. Manaus city is bathed by the Negro river, near the confluence of the two rivers, in which the water level of Negro river is controlled by Solimões river level. This study proposes to analyse a project named Negro River Flood Warning System that presents a river level or stage forecast about Negro river by the Geological Survey of Brazil in Manaus since 1989, where the annual flood and ebb monitoring process is performed in the Solimões, Negro and Amazonas hydrological system. Flood forecasting models are important for the composition of extreme events alerts, as well as for the knowledge of decisionmakers, representatives of public agencies and affected communities. Many factors contribute to the flooding event: how the various tributaries are integrated down the river main stem and how the basin behaves during the six months of flooding in the rainy season. For the forecast, it is important to monitor the evolution of the level of rivers such as Negro and Solimões, understanding the dynamics of the basin and also the events associated with major floods that have already occurred, as recorded in the historical series of the port of Manaus, all this combined with a statistical methodological approach. In the Manaus alert system, linear regression analysis is used. According to results obtained for the past 15 years, the flood forecast interval reveals that the forecast in 87% of cases has fulfilled the objective of presenting a stage very close to the water level peak. Furthermore, it was noticed that a height of 27 m in Negro river turned to be an alert quota with a return period of 10 years. Once the river water level reaches a height of 29 m, it can be considered a 'severe flood water level' with a return period of 17 years.

Flood and ebb processes are common events in any hydrological system. In some cases, due to natural or anthropogenic conditions, such events can take place in an extreme manner, causing a lot of damage to the population. In 2021, in several municipalities in the Amazon basin, rivers reached levels higher than the maximum observed until then, making this year the biggest flood in the entire history of monitoring. Most Amazonian rivers have a high annual pulse of floods, as a result of the precipitation period in the upper part of their large basins. Most of the floodplains located in the central region of Amazonia become inundated from May to July, from which the water drains into the river systems slowly over the drought time. In the Amazon Basin, extreme events are mainly related to El Niño or La Niña events, resulting in some big floods and a long rainfall period. In 2021, the Negro river level exceeded the maximum level observed in the entire 119-year historical series of monitoring. On 30 May 2021, the previous record of 29.97 m observed in 2012 was equaled. The river continued to rise until reaching the level of 30.02 m on 16 June 2021. Other stations monitored by Geological Survey of Brazil, which were accomplished through bulletins, reached historical records in the same year, such as São Gabriel da Cachoeira, Barcelos and Manaus (Negro river), Manacapuru (Solimões river), Careiro da Várzea (Amazon river basin), Itacoatiara and Parintins (Amazon river), all located in the state of Amazonas. This study analyzes the conditions that favored the event of the greatest flood recorded in the Rio Negro in 2021. Some factors contribute to the flooding event, such as the rainfall regime distributed throughout the basin and how the main river and its various tributaries behave during the flooding period.

Palavras -Chave: acessibilidade, mobilidade, sistemas dinâmicos, corredor urbano, viabilidade.

Walking as a means of locomotion contributes to pedestrian health, traffic and, hence, the environment. In 230 cities surveyed worldwide, Manaus, in Amazonas, Brazil, is the 125th in the quality-of-life ranking according to global consultancy Mercer, presenting a deficiency in walking practices. Perhaps the reason is related to the lack of adapted public pavements in the peripheral areas of the city, blocked and irregular sidewalks, among others, generated by lack of planning or structure. In addition to structural problems, there is also the climate region issue, which at certain times makes it difficult to commute long walking distances due to high temperatures. Several cities have adopted foot mobility encouragement parameters, such as Portland, in Oregon, US, which has adopted an urban growth boundary, narrower streets and the encouragement of walking and bicycle use. As a result, automotive use was reduced, pedestrian pathways were improved or created, the life quality of the residents improved and the mortality rate decreased, contributing to cultural, social and economic aspects. This work aims to present aspects that make sidewalks difficult to use in Manaus and, according to this research, reveals the accessibility measures required for the observed problems, for fluidity, comfort and safety during the pedestrian's journey. Considering these arguments, this study conducted bibliographic surveys and questionnaires with several pedestrianized areas of the cities, emphasizing social, physical, cultural and environmental factors. Through this research, problems were identified in relation to the structure, the carelessness of local residents and traders improperly situated on the sidewalks. With the data acquired, it was possible to elaborate a scheme with possible solutions that meets the needs of all citizens, with an appropriate lighting, accessibility, convenience and sustainability system.