**Figure 9.**

*Slope map, in which the gradient is calculated as a percentage. Source: Silva et al. [6].*

#### **Figure 10.**

*Water-level time series in Coari, indicating the maximum high- and low-water periods, as well as the levels below observations carried out in the SRTM data acquisition period (red rectangle). Source: Silva et al. [6].*

*Current Practice in Fluvial Geomorphology - Dynamics and Diversity*

described by Meyer [29] and with an algorithm elaborated by Gonzalez [30]. The objective was to simulate a flood process on the hypsometric map extracted from SRM DEM. This technique interprets the gray-scale image as the expression of the

*Illustrative diagram using 40-m contour lines, superimposed on the USTC-classified JERS-1 SAR mosaic at the high-water period (a), resulting in the interpretation of (b). The inserted time series shown in (c) indicates the maximum and minimum water levels in the Coari region. The areas in yellow represent flooded forests in USTC classification of JERS-1 SAR images. Letters (g) and (h) refer to flooded forest stretches in areas higher* 

*than the 40-m level, with restricted spatial distribution. Source: Silva et al. [6].*

*Elevation or hypsometric map of Coari with altimetric classes ranging from 0 to 80 m (see Figure 1 for location). Compare with the location of flooded forest areas in Figure 8. In a, b, c, and d, there are examples of steep scarps on the margins of the Coari and Mamia lakes. In e, f, and g, the relief seems to be structurally* 

*controlled by geologic features oriented roughly E-W. Source: Silva et al. [6].*

**74**

**Figure 8.**

**Figure 7.**

#### *Current Practice in Fluvial Geomorphology - Dynamics and Diversity*

#### **Figure 11.**

*Fluvial oil spill sensitivity index map in the Coari region (AM) during the high-water period, according to the criteria established in Araújo et al. [9] and as a modification of Petrobras [21]. Stretches from the slope map (Figure 9) corresponding to steep scarps are assigned to index 4. The points a, b, c, d, e, f, g, and h can be seen in Figures 12 and 13. Index 10 shown here includes 10a and 10b from Table 2.*

#### **Figure 12.**

*Photographic records of points checked in the field (27 May 1998; high-water period) in Lake Coari, where it is possible to observe (a) flooded forest, (b) aquatic macrophytes, (c) flooded forest, (d) aquatic macrophytes, (e) Ariá Island, Solimões River, and (f) aerial photograph of Coari city at the confluence of Lake Coari and Solimões River (see Figure 11 for location). Source: Silva et al. [6].*

**77**

**Figure 13.**

SRTM mission period (985 cm).

*Overview of Hydrological Dynamics and Geomorphological Aspects of the Amazon Region…*

topographic relief, where at each level an altitude is assigned proportional to its value, so that the procedure "flood the image" from the lower regions gradually submerges the features. By simulating the flooding process, the watershed morphological operator works with the water level information to make the results reliable. In fact, the flooding process starts from the maximum water level value found in the

*Solimões River exhibiting evidence of erosion (see Figure 11 for location). Source: Silva et al. [6].*

*Photographic records of points checked in the field, where it is possible to observe (g) panoramic view obtained in August 2008, upstream of the Solimões River's confluence with Lake Coari. From this point downstream, inundation in the high-water period contributes to the formation of the Ariá Island, (h) right margin of the* 

period of the Amazonian hydrological cycle (February 2000).

from the SRTM DEM, and the Coari water-level time series.

This method carried out a classification that maps areas of the same topographic meaning in the image. In this procedure each pixel was incorporated into a cluster by the measure of similarity of Euclidean distances. The classifier compares the Euclidean pixel distance to the average of each cluster, iteratively, until the entire image is sorted. Thus, for each level, segments were obtained by configuring the flood limits, duly obeying the topographic levels, as per the maximum value, in which the highest level of fluvial apportionment in Coari was recorded, and the minimum value, referring to the SRTM mission date which corresponds to the flood

**Figure 11** shows the results achieved with this approach, which successfully integrated the products discussed so far, i.e., the criteria for fluvial environmental sensitivity to oil spills in the Amazon region, the cartographic products extracted

*DOI: http://dx.doi.org/10.5772/intechopen.86592*

*Overview of Hydrological Dynamics and Geomorphological Aspects of the Amazon Region… DOI: http://dx.doi.org/10.5772/intechopen.86592*

#### **Figure 13.**

*Current Practice in Fluvial Geomorphology - Dynamics and Diversity*

*in Figures 12 and 13. Index 10 shown here includes 10a and 10b from Table 2.*

*Fluvial oil spill sensitivity index map in the Coari region (AM) during the high-water period, according to the criteria established in Araújo et al. [9] and as a modification of Petrobras [21]. Stretches from the slope map (Figure 9) corresponding to steep scarps are assigned to index 4. The points a, b, c, d, e, f, g, and h can be seen* 

*Photographic records of points checked in the field (27 May 1998; high-water period) in Lake Coari, where it is possible to observe (a) flooded forest, (b) aquatic macrophytes, (c) flooded forest, (d) aquatic macrophytes, (e) Ariá Island, Solimões River, and (f) aerial photograph of Coari city at the confluence of Lake Coari and* 

*Solimões River (see Figure 11 for location). Source: Silva et al. [6].*

**76**

**Figure 12.**

**Figure 11.**

*Photographic records of points checked in the field, where it is possible to observe (g) panoramic view obtained in August 2008, upstream of the Solimões River's confluence with Lake Coari. From this point downstream, inundation in the high-water period contributes to the formation of the Ariá Island, (h) right margin of the Solimões River exhibiting evidence of erosion (see Figure 11 for location). Source: Silva et al. [6].*

topographic relief, where at each level an altitude is assigned proportional to its value, so that the procedure "flood the image" from the lower regions gradually submerges the features. By simulating the flooding process, the watershed morphological operator works with the water level information to make the results reliable. In fact, the flooding process starts from the maximum water level value found in the SRTM mission period (985 cm).

This method carried out a classification that maps areas of the same topographic meaning in the image. In this procedure each pixel was incorporated into a cluster by the measure of similarity of Euclidean distances. The classifier compares the Euclidean pixel distance to the average of each cluster, iteratively, until the entire image is sorted. Thus, for each level, segments were obtained by configuring the flood limits, duly obeying the topographic levels, as per the maximum value, in which the highest level of fluvial apportionment in Coari was recorded, and the minimum value, referring to the SRTM mission date which corresponds to the flood period of the Amazonian hydrological cycle (February 2000).

**Figure 11** shows the results achieved with this approach, which successfully integrated the products discussed so far, i.e., the criteria for fluvial environmental sensitivity to oil spills in the Amazon region, the cartographic products extracted from the SRTM DEM, and the Coari water-level time series.

It is possible to verify in **Figure 11** the predominance of index 10 inside the Coari and Mamiá lakes (considering the fusion of classes 10a and 10b of **Table 2**). In these lakes, the segments of its banks are attributed to index 4 and are associated with escarpments developed in the sedimentary cover in the presence of corrugated relief subject to erosion by the fluvial action (**Figure 11**). Similar escarpments are observed on the right bank of the Solimões River, downstream of the city of Coari. Other sites in **Figure 11** were classified as confluent zones of rivers and lakes (index 9), as shown in **Figures 12e, 13g** and **h**. **Figure 8e** shows a strip of land on the edge of Ariá Island, located in the Solimões River.
