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CHARACTERIZATION OF GEOSPATIAL, MORPHOMETRIC, AND ENVIRONMENTAL DYNAMICS OF THE MARIANA MICROBASIN IN ALTA FLORESTA-MT, BRAZIL

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River basin environmental diagnosis and monitoring are fundamental for water resource use and conservation plans, as these systems integrate different landscape elements and may undergo impacts and changes of different levels and scales. In this context, this work aimed to characterize the geospatial, morphometric, and environmental dynamics in the Mariana microbasin, in the municipality of Alta Floresta, to provide technical-scientific subsidies for environmental management and planning at a local and regional level. The microbasin was analyzed for morphometric, topographic, and land-use and cover parameters using geospatial data processed in a geographic information system. The microbasin is classified as fourth-order, has a network of 72 channels, and its relief is mostly flat and smooth wavy. Moreover, the soil is predominantly covered by agricultural lands, encompassing 70% of the area. This feature brings the need to adopt conservation practices for soil management. This study showed the need for continuous environmental monitoring programs and expansion of conservation actions in the studied area. KEYWORDS environmental monitoring; geotechnologies; water resources
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Engenharia Agrícola
ISSN: 1809-4430 (on-line)
www.engenhariaagricola.org.br
1 Instituto Federal de Mato Grosso - Campus Alta Floresta/ Alta Floresta - MT, Brasil.
Area Editor: Teresa Cristina Tarlé Pissarra
Received in: 8-6-2020
Accepted in: 11-1-2021
Engenharia Agrícola, Jaboticabal, v.42, n.1, e20200128, jan./feb. 2022
Edited by SBEA
Technical Paper
Doi: http://dx.doi.org/10.1590/1809-4430-Eng.Agric.v42n1e20200128/2022
CHARACTERIZATION OF GEOSPATIAL, MORPHOMETRIC, AND ENVIRONMENTAL
DYNAMICS OF THE MARIANA MICROBASIN IN ALTA FLORESTA-MT, BRAZIL
Marcus H. Martins e Silva1*, Fernando L. Silva1
1*Corresponding author. Instituto Federal de Mato Grosso - Campus Alta Floresta/ Alta Floresta - MT, Brasil.
E-mail: marcus.martins@ifmt.edu.br | ORCID ID: https://orcid.org/0000-0002-9446-1064
KEYWORDS
environmental
monitoring,
geotechnologies,
water resources.
ABSTRACT
River basin environmental diagnosis and monitoring are fundamental for water resource
use and conservation plans, as these systems integrate different landscape elements and
may undergo impacts and changes of different levels and scales. In this context, this work
aimed to characterize the geospatial, morphometric, and environmental dynamics in the
Mariana microbasin, in the municipality of Alta Floresta, to provide technical-scientific
subsidies for environmental management and planning at a local and regional level. The
microbasin was analyzed for morphometric, topographic, and land-use and cover
parameters using geospatial data processed in a geographic information system. The
microbasin is classified as fourth-order, has a network of 72 channels, and its relief is
mostly flat and smooth wavy. Moreover, the soil is predominantly covered by agricultural
lands, encompassing 70% of the area. This feature brings the need to adopt conservation
practices for soil management. This study showed the need for continuous environmental
monitoring programs and expansion of conservation actions in the studied area.
INTRODUCTION
The disorderly occupation of river basins, especially
in the Amazon, increases environmental fragility, impacting
these areas environmentally and socio-economically.
Oliveira et al. (2019) verified this scenario at the northern
end of Mato Grosso State, accelerating soil degradation.
Silva & Bampi (2019) added that the increase in logging,
mineral exploration and agricultural monocultures are
factors that have significantly contributed to the socio-
environmental transformation of landscapes in this region.
The Mariana microbasin is located in the northern
end of Mato Grosso State, in the municipality of Alta
Floresta. It is an important environmental system for the
maintenance of ecological processes, urban supply, and
agricultural activities. However, as highlighted by Polachini
et al. (2018), land use and occupation in this municipality
has been intense, with deforestation and agricultural activity
growing significantly.
Oliveira et al. (2019) stated that the lack of land-
use planning often leads to depletion of natural resources
due to land degradation, freshwater scarcity, and
biodiversity losses. Thus, the intensification of the
disorderly occupation of river basins and its consequences
highlight the need for environmental studies to support
actions and strategies towards environmental planning and
management, and conservation of natural resources,
especially aquatic environments.
Environmental structures can be understood by
integrated analysis, identifying their elements, hierarchies,
functions, flows, interrelationships, and interdependence
among biotic, abiotic, and anthropic processes. Such
analysis allows diagnosing environmental weaknesses and
strengths for proper management of resources and territorial
and environmental planning and management. According to
Pessi & Loverde-Oliveira (2019), systematic analysis of an
environment is the basis for an integrated study of the
relationship among its natural elements, enabling
management aimed at the conservation of landscape
and biodiversity.
Brito & Grangeiro (2015) emphasized the
importance of geoenvironmental analysis of river basins to
understand their natural aspects for environmental and
territorial planning. These authors also added that studies on
a river basin as a unit of geographic space allows an
Marcus H. Martins e Silva & Fernando L. Silva
Engenharia Agrícola, Jaboticabal, v.42, n.1, e20200128, jan./feb. 2022
integrated understanding of anthropic actions and their
influence on the functioning of environmental dynamics.
As highlighted by Teodoro et al. (2007), the
morphometric characterization of a river basin is one of the
most important procedures for hydrological or
environmental analysis, with a view to understanding and
clarifying various issues related to local and regional
environmental dynamics. Morphometric analyses enable
identifying hydrological behavior trends, which are useful,
especially in areas where such data are incipient (Franco &
Santo, 2015).
Geospatial analysis of natural systems by
geoprocessing techniques and remote sensing are important
tools for water resources management. The advances in
geotechnology in recent years have contributed to mapping
and monitoring several areas, mainly in terms of earth
surface use and cover (Souza et al, 2019).
The relevance of environmental studies for diagnosis
and monitoring of water resources is thus evidenced, at
different levels, variables, and scales, mainly considering
the consequences of the disorderly expansion of human
activities to areas of greater environmental sensitivity.
Zaiatz et al. (2018) analyzed land-use and -cover changes in
the Teles River Basin and found intense anthropization
between 1984 and 2014 towards forest cover areas, which
showed the highest percentage reduction. The authors also
added that geographic information system (GIS) and remote
sensing techniques allow a better understanding of land
cover changes, with fast and cheap environmental change
dynamics analysis. Such analyses are fundamental for
planning and decision-making by public policymakers and
natural resource management.
Claudino et al. (2020) highlighted that remote
sensing and geoprocessing techniques are of fundamental
importance for land cover planning in river basins, as they
allow for spatial and temporal analyses that reflect the
dynamics in these areas. These authors analyzed the physical
characteristics of a microbasin in the northern region of Mato
Grosso and found significant changes in land cover, mainly
due to agricultural activity, besides a low to medium erosive
potential due to slope and land cover identified.
Alves et al. (2018) evaluated the environmental
fragility of a river basin in southeastern Goiás through
physical-natural and land-use and -cover characteristics,
using geotechnological tools. The authors identified
different fragility levels and recommended conservation
strategies for agricultural activities and recovery practices
for degraded areas. Finally, they emphasized that the use of
techniques to integrate physical characteristics and land use
in a GIS environment prove to be effective in a better
understanding of environmental fragility in river basins.
In this context, this study aimed to characterize the
geospatial, morphometric, and environmental dynamics in
the Mariana microbasin, in the municipality of Alta
Floresta, to provide technical-scientific subsidies for
environmental management and planning at a local and
regional level.
MATERIAL AND METHODS
Study Area
The Mariana microbasin is located near the urban
center of Alta Floresta, in the northern end of Mato Grosso
State, at coordinates UTM 600440.29 E and 8908270.66 S
(Figure 1). According to IBGE (2019), the municipality has
8,953,191 km² and a total population of 51,782 inhabitants.
The local economy is mainly based on the trade and services
sector, logging, and agricultural activities, especially beef
cattle and, in recent years, soybeans and corn.
FIGURE 1. Study Area Location Map.
Characterization of geospatial, morphometric, and environmental dynamics of the Mariana microbasin in Alta Floresta-MT, Brazil
Engenharia Agrícola, Jaboticabal, v.42, n.1, e20200128, jan./feb. 2022
The local climate is classified as Aw and has a
bimodal rainfall pattern, with two distinct seasons, a dry
winter season and a rainy summer (Alvares et al., 2014).
The average annual temperature is 26 ºC, and average
annual rainfall is high and ranges from 2,800 to 3,100 mm,
with rains concentrated between November and May. The
municipality is within the Amazon biome, and its floristic
composition is formed by Open and Dense Ombrophilous
Forest, Seasonal Forest, and Cerrado (Ferreira, 2001). The
relief is classified into the following geomorphological
units: Southern Amazonia Interplanaltic Depression,
Apiacás-Sucunrundi Plateaus, Dissected Plateau of
Southern Amazonia, and Residual Plateaus of Northern
Mato Grosso (Brasil, 1980).
Besides the regional importance of the rivers Teles
Pires, Santa Helena, Paranaíta, Cristalino, and Apiacás, the
water resources in the Mariana microbasin are fundamental
to the urban water supply of Alta Floresta, as its sources
form the Taxidermista river, from where water is collected
(Bambolim & Donde, 2017).
Methodological Procedures and Data Analysis
The microbasin was delimited using a digital
elevation model at a 30 m resolution (Project Topodata)
from the Shuttle Radar Topography Mission - SRTM
(http://www.dsr.inpe.br/topodata/). Oliveira et al. (2010)
pointed out that automatic basin delimitation by SRTM data
processing in a GIS (Geographic Information Systems)
environment is advantageous for standardizing layout and
minimizing inconsistencies when establishing a water
resources management unit.
In the pre-processing, the geographic coordinate
system of the DEM (SIRGAS 2000) was projected to UTM
Zone 21S plane coordinate system, with subsequent
removal of spurious depressions and cells using the “Fill
Sinks” tool in the pull-down menu of the Analysis Terrain -
Hydrology. In the processing stage, the tool "Channel
Network and drainage basins" was used to obtain the river
basin area, flow direction, flow accumulation, drainage
density, drainage order, and channel-connectivity sites.
Both pre-processing and processing were carried out using
the free software QGIS 3.4 integrated with SAGA GIS 3.2.3
algorithms for hydrological analysis.
After microbasin delimitation, the study area was
delimited, and hypsometric (altimetry data converted into
classes) and slope maps were generated based on the classes
proposed by EMBRAPA (1979). Table 1 displays the
parameters considered for the morphometric characterization.
TABLE 1. Morphometric parameters for analysis of the Mariana Microbasin.
Parameter Method
Basin Area Wisler & Brater (1964)
Basin Perimeter -
Form factor (Kf) Villela & Mattos (1975)
Circularity Index (Ic) Schumm (1956)
Compactness Coefficient (Kc) Villela & Mattos (1975)
Drainage density Villela & Mattos (1975)
Length of main river (L) Extension from the springs to the mouth
Order of the hydrographic network Strahler (1957)
Maximum and Minimum Altitude Hypsometry
For land-use and land-cover analyses, we used
SENTINEL 2-A images with 10-meter spatial resolution
and 12-bit radiometric resolution
(https://scihub.copernicus.eu/dhus/#/home ) from August
2019, which is the period of least rainfall in the studied
region, reducing the percentage of clouds in images.
First, atmospheric correction and area of interest
clipping were performed using the pre-processing tools of
the Semi-Automatic Classification Plugin (SCP) and Clip
Raster plugin, respectively. Then, a true color composite
(RGB bands 4, 3, 2) was generated to evaluate classification
targets and false color composite (RGB bands 8, 4, 3) due
to the high spectral contrast among densely vegetated,
pasture, and water body areas, which were subsequently
established for classification.
For supervised classification, the SCP plugin - Semi-
automatic Classification Plugin (Congedo, 2016) was used,
which is available in the QGIS 3.4 software. In the SCP,
training samples were added and subsequent image
classification was carried out by the Maximum Likelihood
method (Maximum Likelihood).
In post-process classification, the accuracy of
Confusion Matrix results was verified by Thematic Map
Accuracy Assessment (Llano, 2019), which assesses the
accuracy of thematic maps using as reference true-color
band images. In this assessment, accuracy is defined as the
degree to which a produced map conforms to the reference
classification, for which 397 random sampling points were
used for verification and agreement. Moreover, from
Confusion Matrix results, the Kappa index was calculated
(Landis & Koch, 1977) to assess classification map
reliability. For Confusion Matrix calculations, the data were
tabulated in an electronic spreadsheet, in which the sum of
values forming the main diagonal of the matrix is divided
(Hellden et al., 1980), representing the number of correctly
classified elements. In the final stage, after the supervised
classification, verification of the accuracy of the method
used, automatic delimitation of the watershed and extraction
of the drainage network, using the Polygonize tool from the
Raster menu, the raster files were converted into vectors for
area and other calculations morphometric parameters. The
raster files were then converted into vectors for area
calculation and other morphometric parameters. The values
of the supervised classification class areas, slope and total
area of the basin were tabulated in electronic spreadsheets
Marcus H. Martins e Silva & Fernando L. Silva
Engenharia Agrícola, Jaboticabal, v.42, n.1, e20200128, jan./feb. 2022
and from the vector files statistical analysis of absolute and
relative frequency was performed.
RESULTS AND DISCUSSION
The integrated analysis of geospatial, morphometric,
physiographic, and land-use aspects in the Mariana
microbasin allowed us to spatialize and diagnose its current
conditions and simplify its environmental dynamics. Table
2 shows the morphometric parameters of DEM
geoprocessing and drainage network characterization of the
study area.
TABLE 2. Morphometric parameters of the drainage network of the Mariana microbasin.
Parameter Unit Result
Basin Area km2 64.87
Basin Perimeter km 46.37
Axial Length km 14.35
Form factor (Kf) dimensionless 0.31
Circularity Index (Ic) dimensionless 0.37
Compactness Coefficient (Kc) dimensionless 1.61
Drainage density km/km² 1.06
Length of main river (L) km 16.86
Maximum Altitude m 378
Minimum altitude m 251
Hydrographic network order
1st Order 2nd Order 3rd Order 4th Order
Number of
watercourses 48 20 3 1
Total length (km) 34.64 14.34 10.72 9.38
Average length (km) 0.72 0.71 3.57 9.38
The microbasin area is 64.87 km² (6,487 ha), which
represents less than 1% of the municipal territory, with an
axial length of 14.35 km and a perimeter of 46.37 km. This
geosystem can be classified as a large basin. According to
Wisler & Brater (1964), basins with a total area of fewer
than 26 km2 are classified as small, while those with a total
area above this are classified as large basins. The Mariana
microbasin is located adjacent to the urban core, which
facilitates agriculture development, especially fruit orchards
and vegetable gardens, given its proximity to consumers.
According to Cochev et al. (2015), the microbasin analyzed
in our study is part of a set of 12 microbasins surrounding
the urban core of Alta Floresta.
The form factor (Kf) and compactness coefficient
(Kc) were 0.31 and 1.61, respectively. Therefore, the basin
is elongated in shape and less susceptible to flooding under
normal meteorological conditions. According to Villela &
Mattos (1975), basins with a form factor below 1.0 have low
circularity, thus less prone to flooding. Furthermore, the
more irregular the basin, the greater its compactness
coefficient; therefore, coefficients above 1.0 will indicate
low susceptibility to flooding.
The microbasin also had a circularity index of 0.37,
which corroborates its elongated shape and indicates its
lower flooding trend. It is because the value is far from 1.0
and promotes a better flow dynamic. According to Schum
(1951), circularity index values lower than 0.51 suggest
basins with a more elongated shape, whereas values higher
than 0.51 indicate more circular basins, favoring flooding.
The drainage system of basins must be analyzed to
obtain critical water outflow velocities (maximum and
minimum) and understand their degree of development
(Cardoso et al., 2006). The analyzed microbasin had a
drainage density of 1.06 km/km². According to Villela &
Mattos (1975), such density indicates a regular drainage
system, which varied from 0.5 and 3.5 km/km². Thus, in the
adopted mapping scale, the contribution surface is much
higher for the number of channels. Importantly, the greater
the drainage density, the greater the capacity of the basin to
drain water to the outlet. Cardoso et al. (2006) also
emphasized that understanding drainage density helps in
planning basin management.
After hydrographic network ordering (Figure 2), we
noted that most of the watercourses are of the first order,
totaling 48 courses and averaging 0.72 km in length.
However, even when DEM showed lower altitude points with
first-order channels, these can behave like intermittent
watercourses, once they may or may not have water flow at
certain times of the year. First-order channels do not have
tributaries and are the smallest identifiable ones characterized
by intermittent drainage (Strahler, 1957; Tucci, 2004). The
hydrographic network analyzed is composed of 72 channels,
with a total length of 69.08 km and the main river (16.86 km)
in a south-north direction. According to Strahler (1957), this
microbasin can be classified as a 4th order and dendritic type
drainage network pattern.
Characterization of geospatial, morphometric, and environmental dynamics of the Mariana microbasin in Alta Floresta-MT, Brazil
Engenharia Agrícola, Jaboticabal, v.42, n.1, e20200128, jan./feb. 2022
FIGURE 2. Hydrographic network order in the Mariana microbasin, Alta Floresta - MT.
Among other factors, relief, altitude, and slope in
the contribution area of a microbasin have a direct influence
on surface runoff and potential erosive processes.
Therefore, these aspects have to be spatially characterized
for land-use planning and managing, as well as protected
area delimitations.
Figure 3 shows the Slope map and the Hipsometric
map of the study area.
FIGURE 3. Slope Map (A) e Hypsometry Map (B) of the Mariana microbasin, Alta Floresta - MT.
Five relief classes (Table 3) were identified in the
microbasin. Predominant classes were flat and smooth-
wavy, which ranged between 0-3% and 3-8%, respectively.
The altimetric amplitude was 127.2 m, with a flow
concentration between 251 and 307 meters. Specifically for
slope factors, these two relief classes may indicate land
suitability for farming. However, soil and water
conservation practices should be implemented, and other
factors such as soil fertility, suitability for mechanization,
erosion susceptibility, and crop characteristics must be
also considered.
The association of a predominant smooth-wavy
relief and agricultural activities in the Mariana microbasin
highlights the importance of conservation practices to avoid
Marcus H. Martins e Silva & Fernando L. Silva
Engenharia Agrícola, Jaboticabal, v.42, n.1, e20200128, jan./feb. 2022
erosive processes compromising productive activities.
However, more detailed evaluations and erosion predictor
models can contribute to a better understanding of runoff
dynamics. According to Gonçalves et al. (2007), the relief
measure evolves from flatter to more sloping areas, water
infiltration into the soil reduces and surface runoff increases
concomitantly, tending to form a linear flow concentration.
According to Cardoso et al. (2006), the slope
influences the relationship between rainfall and runoff in a
basin, especially due to increases in surface runoff speed
and reductions in water infiltration into the soil. Therefore,
the topography is a key factor in predictive erosion models,
as it directly influences the rate and volume of surface
runoff of rainwater (Claudino et al., 2018).
TABLE 3. Distribution of slope classes in the Mariana microbasin, Alta Floresta - MT.
Slope Class Relief Area (ha) %
0-3 % Flat 2,088.55 32.19
3-8% Smooth-wavy 3,646.26 56.84
8-20% Wavy 734.92 11.32
20-45% Strong-wavy 17.05 0.26
45-75% Mountainous 0.37 0.005
Total 6,487.17 100
Soil physical properties, such as texture, porosity,
and density, are directly associated with erosive processes
(Simonetti et al. 2018) and hence sediment loading into
watercourses. According to a study by the Mato Grosso
State Department of Planning (Mato Grosso, 2001), the
Mariana microbasin is in a region with a predominance of
Argissolos (Ultisols), in addition to Neossolos (Entisols)
and Plintossolos (Plinthosols) at smaller proportions. These
soils, in turn, have characteristics that require specific
management practices, e.g., Argissolos (Ultisols) are
naturally susceptible to erosion. Roboredo et al. (2017)
evaluated the socio-environmental degradation in the
Mariana microbasin and the perception of rural families
about the recovery of permanent preservation areas; they
concluded that the majority of farmers perceive
environmental recovery as essential, but emphasize the need
to build contour lines and terraces for soil conservation.
Land cover in areas of alternative use, conservation
of permanent preservation areas, and type of agricultural
management are also associated with erosion intensity,
watercourse siltation and eutrophication, as well as soil
fertility losses. Guidolini et al. (2020) stated that inadequate
land-use planning leads to erosion, annual losses in crop
yield, and poor water quality. Figure 4 shows that the
surface of the Mariana microbasin is mostly occupied by
agricultural production areas.
FIGURE 4. Land Cover and Occupation Map of the Mariana microbasin, Alta Floresta - MT.
Characterization of geospatial, morphometric, and environmental dynamics of the Mariana microbasin in Alta Floresta-MT, Brazil
Engenharia Agrícola, Jaboticabal, v.42, n.1, e20200128, jan./feb. 2022
Based on the Sentinel 2 image classification (Table
4), we found that 70.63% of the area in the micro-basin is
destined for alternative land use, especially cattle-raising,
which is one of the main products of the municipal economy
(Silva et al., 2019) and for the northern Mato Grosso as well,
with Alta Floresta having one of the largest cattle herds in
the state. Such an expressive land occupation emphasizes
the importance of rational pasture management to maintain
well-adjusted stocking rates, avoiding soil compaction and
hence surface runoff, disaggregation, and transport of soil
particles, as well as maintaining good forage stands to
ensure an optimal soil coverage. For Tucci & Clarke (1997),
bare soil under compaction can have its infiltration capacity
dramatically decreased, increasing surface runoff.
TABLE 4. Absolute and relative contribution of land cover and occupation classes in the Mariana microbasin, Alta Floresta -
MT, 2019.
Class Area (ha) (%)
Remaining Vegetation 1,843.90 28.42
Agricultural use 4,582.31 70.63
Water bodies 60.45 0.93
Total 6,487.66 100
Rating Accuracy Rating Index
Global Accuracy 0.93
Global Kappa Index 0.85
The accuracy values in Table 4 denotes that the
thematic classification can be considered excellent, as the
Global Accuracy and Kappa index showed that more than
80% of the verified points were correctly classified.
According to the classification of Landis & Koch (1977),
the Kappa index obtained in our study indicates an excellent
agreement, as the higher the coefficient (i.e., closer to 1),
the better the classification accuracy.
By analyzing vegetation cover in the Mariana
microbasin using the supervised classification of Landsat 5
and 8 imageries between 1990 and 2016, Bambolim &
Donde (2017) found a decrease in forest cover, mainly
between 1990 and 2000. According to these authors, about
54% of the land was covered by native forest in 1990,
decreasing to 25.5% in 2000; however, in 2010, it increased
to 27.5% but subsequently decreased to 25.8% in 2016. As
verified in our study, the native forest area in August/2019
(satellite image acquisition period) was 1,843.90 ha
(28.42%). If compared to the study of Bambolim & Donde
(2017), forest cover increased in 2019. This increase can be
associated with the evolution of preservation areas,
integrating factors such as the adoption of conservationist
practices by farmers and public incentives for the recovery
of degraded preservation areas, in addition to more
inspection by environmental agencies.
As for Roboredo et al. (2017), environmental
recovery in Alta Floresta and consequently Mariana
microbasin has advanced due to rural environmental
registry system, georeferencing of farms, and supplying of
inputs for permanent preservation area restorations (e.g.,
seedlings, stakes, and wire). These actions have been
financed with resources from the Amazon Fund of the
National Bank for Economic and Social Development.
As the Mariana microbasin is an area under intense
agricultural use, permanent preservation and legal reserve
areas are essential to maintain its water dynamics. Tucci
& Clarke (1997) highlighted that vegetation plays a
fundamental role in energy balance, water volume, and
directional flows in river basins. Therefore,
hydrodynamics in these geosystems depends on the
structural complexity of vegetation and its interaction with
climatic and topographic elements.
About the agricultural activity, annual crop areas
have increased in the municipality in recent years,
especially soybeans and corn, both in rotation systems and
integration with beef cattle. Therefore, soil conservationist
practices, such as no-tillage, level planting, and terracing,
must be considered. In this context, the land suitability
classification by the SEPLAN-MT for these areas is
corroborated as 2(a)bc, that is, with regular suitability for
crops at medium and high technology management levels
and restricted at low technological management level (Mato
Grosso, 2001).
In Alta Floresta, the soybean plantation area grew
between the 2016/2017 and 2019/2020 harvests by
approximately 28%, which means an increase of 3,000 ha
(SOJAMAPS, 2020). Given the importance of this
microbasin for urban water supply and expansion of
agricultural activities where different chemical inputs are
used, further studies are required to monitor land use and
occupation, incorporating quality assessment parameters to
characterize potential impacts and/or changes in water
availability and quality.
CONCLUSIONS
The environmental dynamics of the Mariana
microbasin has been influenced throughout its occupation
process by gradual farming development. The predominant
land cover class is agricultural production, representing
around 70% of the contribution area; therefore,
conservationist soil management practices must be adopted.
Forest areas stand for a little more than 28% of the land cover
and are concentrated mainly along drainage network lines,
corresponding to permanent preservation areas that require
integral conservation to maintain their ecosystem functions.
Environmental analysis by geoprocessing tools,
geographic information systems, and digital elevation model
allowed to identify the physiographic and morphometric
characteristics of the Mariana Microbasin such as catchment
area, slope variations, drainage network location, flooding
trend indexes, and different land-use and -cover classes. The
Marcus H. Martins e Silva & Fernando L. Silva
Engenharia Agrícola, Jaboticabal, v.42, n.1, e20200128, jan./feb. 2022
microbasin has a low flooding trend, predominantly smooth-
wavy reliefs, and most of its area is destined for agriculture
and cattle raising. This information will contribute to
environmental planning and management, continuity of
environmental monitoring programs, as well as expansion of
strategic actions towards water resource conservation.
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