Browsing by Author "Mwita, Emiliana"

Now showing 1 - 7 of 7
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    Detection of Small Wetlands with Multi Sensor Data in East Africa
    (2012-12) Mwita, Emiliana; Menz, Gunter; Misana, Salome; Nienkemper, Pamela
    The dynamic nature and inaccessibility of wetland ecosystems restricts in situ data collection and promote the use of various remote sensing platforms. This is because of their ability to record large areas in comparatively short time peri-ods and map physically unreachable areas. Sensors in the optical and microwave range of the electromagnetic spectrum play a critical role in wetlands detection and delineation, as they complement each other in data collection. This study examined the potential of optical and microwave remote sensing in detecting the diversity of small wetlands (<500 ha) in the semi-arid and sub humid parts of Laikipia and Pangani plains and the humid parts of Mt. Kenya and Usambara highlands in Kenya and Tanzania, respectively. An intensive field survey was conducted to supplement the remotely sensed data. Decision tree, supervised and unsupervised classification techniques, facilitated the detection of floodplains and inland valley wetlands within the study sites. The results reveal that although optical and microwave data work ef-fectively in the detection of wetlands the latter would be more effective in larger wetlands than those in the scope of this study.
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    Land Cover and Land Use Dynamics of Semi arid Wetlands: A Case of Rumuruti (Kenya) and Malinda (Tanzania)
    (2013-01) Mwita, Emiliana
    In Sub-Saharan Africa, wetlands particularly those located in dry areas are intensively used and have caused significant loss of the wetlands and their riparian areas. The uses are intensified because of climate variability and the demand to feed the ever growing population. This paper presents results of assessment of land cover and use change in semi arid floodplains of Rumuruti and Malinda in Kenya and Tanzania respectively. Field survey, unsupervised classification and change vector analysis were used to map the uses and assess the changes. Results show that the wetlands are diversely used, agriculture is one of the main land uses (24-35%); other uses and cover include grazing and shrubs (11-39%), built up area (14%, in Rumuruti), burnt area (7%, in Malinda), forest and natural wetland vegetation (5%) and open water (3%). Significant part of natural vegetation (47.76% in Malinda and 72.60% in Rumuruti) has been converted into farms and other uses and as a consequence some parts of the wetlands have been abandoned due to over use. Anthropogenic factors are the main drivers of the changes. The data generated in this study is seen to contribute in monitoring and management of the particular wetlands.
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    Monitoring Restoration of the Eastern Usangu Wetland by Assessment of Land Use and Cover Changes
    (2016-01) Mwita, Emiliana
    Conflicting interests in the use and management of wetlands have always resulted in their degradation. The degradation of wetlands affects their natural functioning, environmental health and livelihood of the people who depend on them. The eastern Usangu wetland has suffered a lot from multiple-use pressure arising from both national and local interests. As a result, the government banned the use of the wetland in 2006 to support its restoration process. The aim of the current study was to assess the restoration process of the eastern Usangu wetland using time-series Landsat images over a 20-year period, from 1995 to 2015. Cross-tabulation of composite NDVI images was used to examine the changes. The results indicate that the land cover declined by 20% between 1995 and 2005, and increased by more than 25% between 2005 and 2015. The size of the permanent swamp increased consistently, by more than 15% between 1995 and 2015. Wetland use has declined to about 15% over the 20 years. Wetland restoration seems to be a slow process that depends on multiple factors. It thus is important that wetlands are managed well for sustained benefits, rather than waiting to rescue them in a crisis. The well-being of the people depending on the wetlands should be considered when implementing measures to protect the wetlands. Awareness creation among the users, diversification of sources of income and enforcement of the laws and policies governing the use of wetlands by the government may improve status of wetlands.
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    Seasonal Shifts in Primary Water Source Type: A Comparison of Largely Pastoral Communities in Uganda and Tanzania
    (2016-01) Pearson, Amber L.; Zwickle, Adam; Namanya, Judith; Rzotkiewicz, Amanda T.; Mwita, Emiliana
    Many water-related illnesses show an increase during the wet season. This is often due to fecal contamination from runoff, yet, it is unknown whether seasonal changes in water availability may also play a role in increased illness via changes in the type of primary water source used by households. Very little is known about the dynamic aspects of access to water and changes in source type across seasons, particularly in semi-arid regions with annual water scarcity. The research questions in this study were: (1) To what degree do households in Uganda (UG) and Tanzania (TZ) change primary water source type between wet and dry seasons?; and (2) How might seasonal changes relate to water quality and health? Using spatial survey data from 92 households each in UG and TZ this study found that, from wet to dry season, 26% (UG) and 9% (TZ) of households switched from a source with higher risk of contamination to a source with lower risk. By comparison, only 20% (UG) and 0% (TZ) of households switched from a source with lower risk of contamination to a source with higher risk of contamination. This research suggests that one pathway through which water-related disease prevalence may differ across seasons is the use of water sources with higher risk contamination, and that households with access to sources with lower risks of contamination sometimes choose to use more contaminated sources.
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    Seasonal Vegetation Changes in the Malinda Wetland Using Bi-Temporal, Multi-Sensor, Very High Resolution Remote Sensing Data Sets
    (Scientific Research, 2014) Kuria, David N.; Menz, Gunter; Misana, Salome B.; Mwita, Emiliana; Thamm, Hans P.; Alvarez, Miguel; Mogha, Neema; Becker, M.; Oyieke, Helida
    Small wetlands in East Africa have grown in prominence driven by the unreliable and diminished rains and the increasing population pressure. Due to their size (less than 500 Ha), these wetlands have not been studied extensively using satellite remote sensing approaches. High spatial resolu- tion remote sensing approaches overcome this limitation allowing detailed inventorying and re- search on such small wetlands. For understanding the seasonal variations in land cover within the Malinda Wetland in Tanzania (350 Ha), two periods were considered, May 2012 coinciding with the wet period (rainy season) and August 2012 coinciding with a fairly rain depressed period (substantially dry but generally cooler season). The wetland was studied using very high spatial resolution orthophotos derived from Unmanned Aerial Vehicle (UAV) photography fused with TerraSAR-X Spotlight mode dual polarized radar data. Using these fused datasets, five main classes were identified that were used to firstly delineate seasonal changes in land use activities and secondly used in determining phenology changes. Combining fuzzy maximum likelihood clas- sification, knowledge classifier and Change Vector Analysis (CVA), land cover classification was undertaken for both seasons. From the results, manifold anthropogenic activities are taking place between the seasons as evidenced by the high conversion rates (63.01 Ha). The phenological change was also highest within the human influence class due to the growing process of cropped land (26.60 Ha). Much of the changes in both cover and phenology are occurring in the mid upper portion of the wetland, attributed to the presence of springs in this portion of the wetland along the banks of River Mkomazi. There is thus seasonality in the observed anthropogenic influence between the wetland and its periphery.
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    Seasonal Vegetation Changes in the Malinda Wetland Using Bi-Temporal, Multi-Sensor, Very High Resolution Remote Sensing Data Sets
    (2014-03) Kuria, David N.; Menz, Gunter; Misana, Salome; Mwita, Emiliana; Thamm, Hans P.; Alvarez, Miguel; Mogha, Neema; Becker, M.; Oyieke, Helida
    Small wetlands in East Africa have grown in prominence driven by the unreliable and diminished rains and the increasing population pressure. Due to their size (less than 500 Ha), these wetlands have not been studied extensively using satellite remote sensing approaches. High spatial resolu-tion remote sensing approaches overcome this limitation allowing detailed inventorying and re-search on such small wetlands. For understanding the seasonal variations in land cover within the Malinda Wetland in Tanzania (350 Ha), two periods were considered, May 2012 coinciding with the wet period (rainy season) and August 2012 coinciding with a fairly rain depressed period (substantially dry but generally cooler season). The wetland was studied using very high spatial resolution orthophotos derived from Unmanned Aerial Vehicle (UAV) photography fused with TerraSAR-X Spotlight mode dual polarized radar data. Using these fused datasets, five main classes were identified that were used to firstly delineate seasonal changes in land use activities and secondly used in determining phenology changes. Combining fuzzy maximum likelihood classification, knowledge classifier and Change Vector Analysis (CVA), land cover classification was undertaken for both seasons. From the results, manifold anthropogenic activities are taking place between the seasons as evidenced by the high conversion rates (63.01 Ha). The phenological change was also highest within the human influence class due to the growing process of cropped land (26.60 Ha). Much of the changes in both cover and phenology are occurring in the mid upper portion of the wetland, attributed to the presence of springs in this portion of the wetland along the banks of River Mkomazi. There is thus seasonality in the observed anthropogenic influence between the wetland and its periphery.
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    Teaching Spatial Science Courses in Public Universities in Tanzania: Challenges and Opportunities
    (2013-12) Mwita, Emiliana
    Spatial science courses that are Remote Sensing (RS) and Geographic Information System (GIS) are increasingly grow-ing into extremely important disciplines that accommodate various applications in wider sectors of development. Effec-tive teaching and learning of the courses, however, requires intensive investment in facilities and human resources, since the technology is sophisticated and growing fast. This study aims at exploring the challenges of teaching and learning spatial science courses, RS and GIS, particularly in public universities in Tanzania. The study also identifies possible opportunities to improve the situation. Using social survey techniques in data gathering and analysis and au-thor’s own experience, lack of resources, poor background to the courses, delivery methods, limited number of staff and large classes were seen to be the major obstacles in successful learning and teaching. Opportunities exist in using open source resources, collaboration with other institutions within and outside the country and for the universities to give due weight to the courses by building capacity of their staff and procuring facilities, especially laboratories equipments.