**2. Area of Study**

The area where the risk managemen<sup>t</sup> method is to be implemented is located between the municipalities of Uberaba and Uberlândia, in the Brazilian State of Minas Gerais, mesoregion of Triângulo Mineiro. The municipality of Uberlândia is the second most populous in Minas Gerais, and the 30th in Brazil, with 676,613 inhabitants according to the Brazilian Institute of Geography and Statistics—IBGE [16]. The municipality of Uberaba has a population of 328,272 inhabitants, as estimated in 2017, being the 8th largest municipality in the state and the 81st in the country [17]. The sector under study comprises a 97-km segmen<sup>t</sup> of highway BR 050, from km 77 at the junction of BR 050 to kilometer 174 at the intersection with BR 262. The BR 050 is an important connecting corridor between the central-west and southeast regions of Brazil, receiving the flow of several highways that cross the country from north to south, namely the traffic from the Federal Highways BR 365/452/455/497. The BR 050 highway was built in the 1970s with the main purpose to connect the capital of the country to the Port of Santos SP. In 2010 the segmen<sup>t</sup> under study was doubled, increasing the highway capacity.

Along the studied segmen<sup>t</sup> the BR 050 highway intersects several watercourses that drain small watersheds (Figure 1). The climate of Triângulo Mineiro region is qualified as Aw according to the Köeppen classification. The Aw climate is a tropical mega thermal climate, with winter droughts and an average temperature for the coldest month around 18 ◦C. Precipitation is characterized by annual averages of 1200 to 1450 mm, according to the climatic norm of Brazil (1961–1990) published by the National Institute of Meteorology [18]. The dry period runs from May to September and the wet period from October on [19]. As regards geomorphology, the Triângulo Mineiro is located in the so-called "Plateaus and Mesas of the Paraná Sedimentary Basin", which comprise the "Northern Plateau sub-unit" [20]. Geologically, this plateau is characterized by deposits of Uberaba, Marília and Vale do Rio do Peixe formations belonging to the Bauru group; Serra Geral formation belonging to the São Bento group; and undifferentiated dendritic and/or lateritic [21].

**Figure 1.** Geographic location of the studied BR 050 highway segment, in Brazil and Minas Gerais State, with representation of intercepted water courses and distribution of road accidents involving spills of hazardous substances. In the northern and central parts of this segmen<sup>t</sup> the road was built nearly along a water divide. In these sectors the water channels are likely to be equally vulnerable to contamination at both sides of the road, because the spill of a harmful substance will potentially leach in both directions. For similar reasons, in the southern part the water channels from the west side are potentially more vulnerable than the channels from the east side.
