Use of GIS and remote sensing techniques to evaluate the wetland degradation in the Wami Ruvu River Basin
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Date
2024-05
Authors
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Publisher
Sokoine University of Agriculture
Abstract
Wetlands are crucial ecosystems that provide numerous ecological
services, including water purification, flood control, and habitat for
diverse plant and animal species. During the last decade, around
50% of the earth’s wetlands have already been converted to
industrial, agricultural and residential use and these lands continue
to disappear at a shocking rate without their values being
understood. Wami Ruvu river basin in Tanzania is rich in wetlands, a
total of 2482 km2 of the area is covered by wetlands both floods
plain, marsh and swamp. Little information on wetland degradation
on extent, condition, trend and drivers on wetland degradation is
available Wami Ruvu river basin. However, the aim of the study was
to assess Historical wetland degradation and prediction of future
Wami-Ruvu Basin wetland change pattern.
Multi-temporal Landsat satellite data including thematic Mapper
Landsat (TM and ETM+) and Operational Land Imager (OLI) images
were used for land use/cover (LULC) mapping in the assessment of
wetland degradation and their distribution pattern based on the
LULC by the years 2000, 2010 and 2020.
A Random Forest
Classification (RFC) approach was employed to classify the Landsat
images into different land use/cover classes which included
wetlands, water bodies, agriculture, urban areas, bush lands, bare
lands, woodlands, and forest. The future wetland map of the study
area was developed using hybrid CA- Markov in Land Cover
modeler.
The study observed the trend based on the spatial dynamics during
the two decades Which showed a progressive decrease in the
collection of wetlands coverage throughout the region, although the
degradation rate varies in time coverage area as it was found to be
about 1209.0753Km2, 949Km2, 521.33Km2 and 213Km2 of wetland
was lost, for the year 2000, 2010, 2020 and 2050 for the individual
pixel values respectively. On the other hand, the studies revealed
that -34.41Km2/y of wetlands potentially are degraded annually due to human and natural stressors in 20 years of our study. Thus this
gradual decrease in wetland area is contributed mainly by the
increase of human activities within and surrounding the wetland
boundaries which is well observed in classified land use/cover
images with kappa statistics above 75%.
The results of this study will contribute to a better understanding of
wetland degradation in the Wami-Ruvu River Basin and facilitate
informed decision-making for wetland conservation and restoration
efforts. The findings will help identify priority areas for targeted
interventions and provide a baseline for monitoring future changes in
wetland condition and trend to attain the Sustainable Development
Goals.
Description
MSc Dissertation
Keywords
Remote Sensing Techniques, Evaluate-Wetland Degradation, GIS