Análise espaço-temporal da variação dos pulsos de inundação na região do interflúvio Purus-Madeira no sudoeste da Amazônia

Abstract

In the Amazon region, flood pulses occur as a result of the high volumes of precipitation observed and distributed between dry and rainy periods. The region of the middle Purus and middle Madeira river sub-basins are in a scenario of development and modification in land use and coverage as a result of the implementation of the hydroelectric plants of Santo Antônio and Jirau, the restructuring of roads, mineral exploration and plant, agriculture and urbanization. With this, the objective of this study is to detect the variation of the flood pulses using the digital elevation model and the maximum and minimum levels in order to provide information to collaborate with the territorial order using tools that can subsidize and promote public policies that guide the land use and occupation. Statistical analysis included monthly means, standard deviation, median, maximum and minimum values, correlation analysis between precipitation and water level, linear regression and flood pulse modeling using geotechnologies. The average Madeira River ranged from 1061.3 cm in September to 2235.1 cm in March. The middle Purus River, on the other hand, showed significant variations over the analyzed period, with higher values in the rainy season (December to March) and lower values in the dry season (May to September). The highest elevation in the middle Madeira River was recorded in 2014, reaching 2556.50 cm in Humaitá/AM, while the lowest level was observed in September 2005 with 909.5 cm. The highest elevation of the middle Purus River was recorded in April 1997 with 2141.00 cm, while the lowest was observed in the driest period in September 2016 with 409.50 cm. Thus, the Purus river sub-basin is more sensitive to changes in precipitation than the Madeira sub-basin, with stronger correlations and faster response times. Thus, this information is important to understand the impacts of flood pulses on riverside communities and on the economy of the southwest region of the Amazon.