Browsing by Author "Maswanganye, Sagwati Eugene"

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    Remotely sensed applications in monitoring the spatio-temporal dynamics of pools and flows along non-perennial rivers: A review
    (Taylor and Francis Group, 2022) Maswanganye, Sagwati Eugene; Dube, Timothy; Mazvimavi, Dominic
    Non-perennial rivers (NPRs) account for more than 50% of the world’s river network and their occurrence is expanding. Some rivers that were previously classified as perennial have evolved to be NPRs in response to climate change and socio-economic uses. There is inadequate understanding of the spatio-temporal dynamics of flows and pools along these rivers due to lack of data, as a priority of river monitoring has been placed on perennial rivers. The current understanding and methods used for monitoring NPRs are mostly derived from perennial rivers perspective. This review paper examines challenges for collecting data on these hydrological attributes of NPRs using current methods. Furthermore, this paper provides an overview of the potential and limitations of using remote sensing data for monitoring NPRs.
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    Spatial and temporal dynamics of flows and pools along non-perennial rivers in arid and semi-arid areas, South Africa
    (University of the Western Cape, 2023) Maswanganye, Sagwati Eugene; Dube, Timothy
    This study aimed to assess the use of multi-source remotely sensed data for monitoring the spatial distribution and dynamics of pools in two distinct sites (Touws and Molototsi) in South Africa. Various water extraction indices, including NDWI, Modified NDWI, and NDVI, were employed, along with a random forest classifier and Sentinel-1 SAR data, to map pools and their dynamics in both locations. The remote sensing methods effectively detected and mapped pools with satisfactory accuracy, except for small pools below 400 square meters. The study identified flow occurrences and rainfall as significant factors influencing changes in pool sizes. However, the interaction between pools and groundwater required further investigation and showed no conclusive evidence in this study.
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    Use of multi-source remotely sensed data in monitoring the spatial distribution of pools and pool dynamics along non-perennial rivers in semi-arid environments, South Africa
    (Taylor and Francis Group, 2022) Maswanganye, Sagwati Eugene; Dube, Timothy; Jovanovic, Nebo
    This study explored the use of multi-source remotely sensed data in monitoring the spatial distribution of pools and pool dynamics in two distinct semi-arid sites in South Africa. The factors that control the pool dynamics were also examined. Three water extraction indices were used, these included Normalised Difference Water Index (NDWI), Modified NDWI and Normalised Difference Vegetation Index. In addition, random forest classifier and Sentinel-1 SAR data were used in mapping pools and pools dynamics for both sites.