Modelagem de processos erosivos hídricos lineares no município de Mineiros - GO
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2015-04-29
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Universidade Federal de Goiás
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This thesis deals with the constraints of linear water erosion in the municipality of Mineiros-
GO, taken as causal explanatory model variables. It is emphasized in soils of high
susceptibility which underwent extensive and indiscriminate deforestation along the 1970s and
especially 1980, followed by the use of pastures; today they present extensive areas with
exposed soil. To develop the model it was sought to correlate the linear erosion focuses, their
concentration and contribution area in 2012 with the morphopedological compartments (CMP)
and associated pedological systems (SP), in order to identify the most susceptible and in them
the most critical segments of studies concerning the risk of occurrence of the phenomenon. The
methodology is based on multi-scale integrated analysis of the landscape, initially valuing the
scale of 1: 100,000 for the morphopedological partitioning followed by progressively larger
scales, that is, detailed to assess the superficial runoff based on the modified rational method
adapted from estimated distribution of the flow in the sub-basins associated with the variation
of the altimetry amplitude interclass along the studies, the survey and morphology of
representative pedological partitions where it was detected a higher magnitude of the erosive
phenomenon. It were located and mapped approximately 5678 linear erosion focuses, wherein
the concentration can reach 2,46 focuses every Km2, sometimes resulting in environments with
up to 36% of the area totally compromised. Among the seven CMP set out , it was stood out (i)
the North CPM formed by sandstones and siltstones with the predominance of red-yellowish
Oxisol with medium texture and slopes ranging from 5 to 8% that concentrates 33.35% of the
outbreaks, and the red Paleudult succeeded by Fluvisol, both with medium texture; (ii) the west
CMP formed by windy slope of sandstone ranging from 3-5% where it concentrates 19.60% of
the focuses, therefore, comparatively with low incidence of erosion, marked by the presence of
pedological systems consisting of red and red-yellowish Oxisols followed by
Quartzipsamments in long convex slopes with concave ending; (iii) the Southeast CMP also
supported by windy slope of sandstone and it has the predominance of Quartzipsamment with
sandy texture where it concentrates 37.81% of outbreaks, shorter slopes, greater dissection of
the soil due to the further deepening of the draining channels. The removal of vegetation cover
when it reaches fragile pedological systems as the first two, leads to the generation and
accelerated evolution of erosion focuses, particularly in drainage headwaters and the middle
and lower segments of slopes where the kinetic energy tends to increase exponentially because
of spatial and temporal allegiance of surface and groundwater flows. The dynamics of these
systems is confirmed and better understood through the analysis of morphometric,
morphographic, pedological variables and soil use, resulting in a model that allows
representation of critical segments along the slope. The model proved to be efficient to
represent the spatial and temporal allegiance of the superficial runoff, thus confirming the
concept of power distribution in a system and how this manifests itself in the execution of
morphogenetic work. The methodology adopted to associate the morphopedological
partitioning and their respective pedological systems in order to develop a four-dimensional
linear erosion model was also efficient for allowing the integration of factors, which the
resulting intensity converges to the emergence and evolution of erosive processes and can
serve as an indicator of risk areas to the phenomenon of installation.
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Citação
NUNES, Elizon Dias. Modelagem de processos erosivos hídricos lineares no município de Mineiros - GO. 2015. 242 f. Tese (Doutorado em Geografia) - Universidade Federal de Goiás, Goiânia, 2015.