## 3 Results and Discussion
### Landscape Disturbance
When comparing aerial images obtained in July 2013 (before EN 15-16) and April 2016 (after EN 15-16) it is possible to observe the development of large erosive (Figure 7A), and depositional (Figure 7B) features during the period. The gully erosion exceeded 700 m in length, triggered evidence of lateral, longitudinal, and vertical connectivity. Initially, the rainfall intensity caused lateral connectivity in sections of the slope with sediment transport into the channel, followed by longitudinal connectivity, which resulted in a large flow of sediments deposited both in the floodplain and in the Santo Inacio river. The deposition of sediments (up to 3 m in thickness, as observed in loco) buried reservoirs (fish farming) and swine farming structures (Figures 6 and 7). With the rise in the water table and the large volume of sediments, and, consequently, the  
Figure 6: (**A**) Linear erosion (rills and gullies) developed in a sugarcane plantation area in the municipality of Nossa Senhora das Gracas, Paraná state, Brazil; (**B**) sediments deposited downstream, in the same basin of the observed erosional features; dead vegetation is observed between the sediments and the margin of the river plain. Date of the photographs: 23 May 2017. Figure 7: Aerial view of pre and post EN 15–16 landscape in a rural area of Nossa Senhora das Gracas, Paraná state, Brazil: (**A**) at the upstream sector, extensive and deep linear erosional features (gullies) were developed on a sugarcane plantation (yellow square) as well as deposition of sediments generated on the slopes (white square); (**B**) at the downstream sector of the same basin, the depositional processes were predominant. Source: Google Earth. increase in vertical connectivity, the floods also caused the eradication of riparian vegetation (Figure 6B). Significant erosive processes occurred in urban areas of the municipality of Umuarama (Figure 8). A sports center had problems with erosive processes previously, as observed in the aerial images. However, with the extreme rainfall concentrated in EN 15-16, the erosion progressed rapidly, expanding beyond the limits of the sports center and reaching side streets and avenues, leading to road closures. Large erosive processes in urban areas are historical in Umuarama, located in the Northwest Parana region. Previous erosive processes were already stabilized in the watershed of the Pinhalzinho II stream in 2013, where the sports center is located. With the EN 15-16 event, the entire downstream fluvial system, which had vegetated and stable margins [32], returned to an expressive dynamic of marginal erosion and channel movement, due to the energy input (Figure 8). Figure 8: Erosional feature (ravine) in a sport center located in the municipality of Umuarama (date of the photography: 10 December 2015). (**A**): Aerial images of the sports center area, from May 2013 and June 2016; the yellow circle represents the area of the photography above; (**B**) downstream area where the sediments were deposited; the red circle indicates sandy bars formed in the river channel. Source: Google Earth. The works to contain erosive processes, drainage and recovery of the destroyed structures have had a major financial impact in the state and municipal budgets. Based on the occurrences observed in the field, in [28], and in media reports, a cartographic compilation of the effects that consecutive heavy rainfall has caused in the North of Parana was developed (Figure 9). In this compilation, the processes were categorized as road interdiction, geomorphological processes, and interruption in the water supply. It can be observed that in the north-central region, there were many water shortage problems, especially in January 2016. It can also be noted that interdictions were numerous in the vicinity of Colorado, Paranavai, and between Umuarama and Cianorte. Although interdictions also occurred in other areas, the role of the differences in soil characteristics between northwest and north-central Parana is emphasized.