Browsing by Author "Opiyo, Stephen Balaka"

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    Dynamics and drivers of land use and land cover changes in Migori River Watershed, western Kenya region
    (2022) Opiyo, Stephen Balaka; Opinde, Godwin; Letema, Sammy
    Understanding land use and land cover (LULC) change dynamics and their contributing factors are critical for developing sustainable land management strategies. Therefore, this paper assesses the trends and patterns of LULC changes and their drivers in the Migori River watershed in Kenya from 1980 to 2020. The spatial analysis is based on remote sensing data based on the maximum likelihood classifier algo- rithm; whereas the analysis of the drivers is based on index-based ranking and logistic regression of 318 households’ survey data. The results show that between 1980 and 2020, the watershed experienced a considerable decline in shrub lands by 40.63% ( 235.97 km2), grasslands by 84.86% ( 59.14 km2), for- ests by 52.90% ( 98.36 km2), water by 82.03% ( 39.27 km2) and wetlands by 38.44% ( 3.69 km2); whereas cultivated land, bare land and built-up areas expanded over the same period by 34.25% (+347.42 km2), 132.28% (+60.95 km2) and 461.20% (+25.32 km2), respectively. The results of the house- hold survey revealed that the perceptions of the locals tended to corroborate these observed LULC pat- terns obtained from spatial analysis, with 60.50% (n = 192) of the respondents reporting a significant expansion in agricultural land use (at p < 0.05), and 75.80% (n = 241) observing a significant decline in forest areas in the watershed (at p < 0.05). Fuel wood collection, timber/poles production, agricultural expansion, population pressure, and high poverty are the major drivers of these LULC changes. The find- ings also revealed that educational level significantly influenced the survey participants’ perceptions con- cerning these drivers. The paper concludes that the watershed’s natural landscapes have been undergoing destruction at the expense of human settlement and infrastructural developments driven by anthro- pogenic activities. Therefore, there is a need, among others, for land use zoning to regulate conflicting land uses on the watershed between settlement, conservation, and agricultural lands.
  • Publication
    Publication
    Spatio-Seasonal Variations in Water Quality Status of Migori River in Kenya and Associated Household Health Risk Implications: An Application of a Multidimensional Water Quality Index Approach
    (Taylor and Francis, 2022) Opiyo, Stephen Balaka; Opinde, Godwin; Letema, Sammy
    Water quality monitoring is imperative in providing the objective evidence required to make sound decisions about water quality management. This study aimed to examine the water quality status of the Migori River by determining spatio-seasonal variations in water quality parameters, along with associated influencing factors and potential health risks. Therefore, eighteen physico-chemical and bacteriological variables were sampled and analyzed monthly for six months covering the wet and dry seasons from the upstream, midstream, and downstream stations, and a health risk survey was conducted with 90 watershed households. ANOVA and T-test were used to test for the significant spatial and seasonal variations (p<0.05), respectively; whereas Pearson’s correlation was used to identify relationships between parameters. Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were used to find various spatial patterns in the river water quality datasets, while the Canadian Council of Ministries of the Environment Water Quality Index (CCMEWQI) showed the suitability status of the river water quality. The assessed variables showed significant seasonal variability but no significant spatial differences in the river. HCA generated 3 clusters suggesting that water quality deteriorated downstream from the upstream of the watershed. The PCA extracted four PCs explaining 80.5% of the total variance, which suggested that the variations in water quality are attributed to point and nonpoint sources of pollution. While most of the physico-chemical variables were within maximum permissible limits, the bacteriological levels exceeded the prescribed standards. The index ranked the river’s water condition between ‘poor’ to ‘marginal’; upstream has better water condition that gradually decreases toward the downstream, and water quality is better in the wet season than the dry season. The study revealed that the water of the Migori River is polluted and potentially hazardous for human usage, and thus suitable pollution control measures are urgently needed to safeguard public health
  • Publication
    Publication
    Spatio-Seasonal Variations in Water Quality Status of Migori River in Kenya and Associated Household Health Risk Implications: An Application of a Multidimensional Water Quality Index Approach
    (Taylor & Francis, 2022-11) Opiyo, Stephen Balaka; Opinde, Godwin; Letema, Sammy
    Water quality monitoring is imperative in providing the objective evidence required to make sound decisions about water quality management. This study aimed to examine the water quality status of the Migori River by determining spatio-seasonal variations in water quality parameters, along with associated influencing factors and potential health risks. Therefore, eighteen physico-chemical and bacteriological variables were sampled and analyzed monthly for six months covering the wet and dry seasons from the upstream, midstream, and downstream stations, and a health risk survey was conducted with 90 watershed households. ANOVA and T-test were used to test for the significant spatial and seasonal variations (p<0.05), respectively; whereas Pearson’s correlation was used to identify relationships between parameters. Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were used to find various spatial patterns in the river water quality datasets, while the Canadian Council of Ministries of the Environment Water Quality Index (CCMEWQI) showed the suitability status of the river water quality. The assessed variables showed significant seasonal variability but no significant spatial differences in the river. HCA generated 3 clusters suggesting that water quality deteriorated downstream from the upstream of the watershed. The PCA extracted four PCs explaining 80.5% of the total variance, which suggested that the variations in water quality are attributed to point and nonpoint sources of pollution. While most of the physico-chemical variables were within maximum permissible limits, the bacteriological levels exceeded the prescribed standards. The index ranked the river’s water condition between ‘poor’ to ‘marginal’; upstream has better water condition that gradually decreases toward the downstream, and water quality is better in the wet season than the dry season. The study revealed that the water of the Migori River is polluted and potentially hazardous for human usage, and thus suitable pollution control measures are urgently needed to safeguard public health