Browsing by Author "Mubialiwo, Ambrose"
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Item Analyses of community willingness-to-pay and the influencing factors towards restoration of River Malaba floodplains(Environmental Challenges, 2021) Mubialiwo, Ambrose; Abebe, Adane; Onyutha, CharlesThe high productivity of soils along River Malaba floodplains and various functions (like, transport and recreation) increase the desire for humankind settlement adjacent to floodplain corridors. However, human life and property have unceasingly been destroyed by floods. Strategies have been established to deal with floods but the problem still exists. This study employed the double-bound dichotomous choice contingent valuation method to quantify the community willingness-to-pay (WTP) and associated influencing factors for restoration of River Malaba floodplains. Reconnaissance surveys, focus group discussions, key informant interviews, observations study, and household questionnaires from 498 out of the targeted 550 respondents were employed in data collection. Among the adaptation strategies at household and community level, the post-flood strategies were more efficient than those practiced before- and during-floods. Among the suggested structural and non-structural strategies, “embankment/river training structures” and “flood forecasting and early warning” were highly preferred, respectively. The results revealed that 55% of the households expressed WTP an individual amount between Uganda shillings (UGX) 5,000 (United States Dollar, US$ 1.35) to UGX 500,000 (US$ 135.14), with a monthly average of UGX 97,080 (US$ 26.24). Total monthly amount would be UGX 38,249,500 (US$ 10,333.70) considering the 498 households. Among the factors analysed, age, gender, marital status, education level, occupation, household income, business affected, lost property due to floods, flooding a major problem had significant (p<0.01) positive impact on WTP. This study findings are pertinent in supporting stakeholders’ decision regarding predictive planning of flood adaptation strategies in the study area.Item Changes in precipitation and evapotranspiration over Lokok and Lokere catchments in Uganda(Bulletin of Atmospheric Science and Technology, 2021) Mubialiwo, Ambrose; Chelangat, Cyrus; Onyutha, CharlesThis study analysed long-term (1948–2016) changes in gridded (0.25° × 0.25°) Princeton Global Forcing (PGF) precipitation and potential evapotranspiration (PET) data over Lokok and Lokere catchments. PGF-based and station datasets were compared. Trend and variability were analysed using a nonparametric technique based on the cumulative sum of the difference between exceedance and non-exceedance counts of data. Seasonal (March-April-May (MAM), June-July-August (JJA), September-October-November (SON), December-January-February (DJF)) and annual precipitation exhibited negative trends (p < 0.05). Positive anomalies in precipitation occurred in the 1950s as well as in the early 2000s till 2016. Negative anomalies existed between 1960 and 2000. Both seasonal and annual PET mainly exhibited increasing trend with alternating positive and negative anomalies for the entire period, except in the southern region. The H0 was rejected (p < 0.05) for SON PET in the North and South of the study area. The H0 was rejected (p < 0.05) for DJF PET in the North. However, H0 was not rejected (p > 0.05) for MAM, JJA and annual PET. Positive and negative correlations were observed between PGF and station precipitation varying from one location to another. The PGF-based PET were lower than the observed PET at Kotido by about 40%. Besides, a close agreement was noticeable between PGF-based and MODIS PET from May to November. This showed the need to improve on the quality of PGF data in reproducing the observed climatic data in areas with low meteorological stations density. Nevertheless, the findings from this study are relevant for planning of predictive adaptation to the effects of climate variability on the water resources management applications. Impacts of human factors and climate change on the hydrology of the study area should be quantified in future research studies.Item Historical Rainfall and Evapotranspiration Changes over Mpologoma Catchment in Uganda(Advances in Meteorology, 2020) Mubialiwo, Ambrose; Onyutha, Charles; Abebe, AdaneChanges in the long-term (1948–2016) rainfall and evapotranspiration over Mpologoma catchment were analysed using gridded (0.25° × 0.25°) Princeton Global Forcing data. Trend and variability were assessed using a nonparametric approach based on the cumulative sum of the difference between exceedance and nonexceedance counts of data. Annual and March-May (MAM) rainfall displayed a positive trend (p < 0.05), whereas October-December (OND) and June-September rainfall exhibited negative trends with p > 0.05 and p < 0.05, respectively. Positive subtrends in rainfall occurred in the 1950s and from the mid-2000s till 2016; however, negative subtrends existed between 1960 till around 2005. Seasonal evapotranspiration exhibited a positive trend (p > 0.05). For the entire period (1948–2016), there was no negative subtrend in the OND and MAM evapotranspiration. Rainfall and evapotranspiration trends and oscillatory variation in subtrends over multidecadal time scales indicate the need for careful planning of predictive adaptation to the impacts of climate variability on environmental applications which depend on water balance in the Mpologoma catchment. It is recommended that future studies quantify possible contributions of human factors on the variability of rainfall and evapotranspiration. Furthermore, climate change impacts on rainfall and evapotranspiration across the study area should be investigated.Item Hydrodynamic Modelling of Floods and Estimating Socio‑economic Impacts of Floods in Ugandan River Malaba Sub‑catchment(Earth Systems and Environment, 2022) Mubialiwo, Ambrose; Abebe, Adane; Serre Kawo, Nafyad; Ekolu, Job; Nadarajah, Saralees; Onyutha, CharlesRiver Malaba sub-catchment tends to experience dramatic flooding events, with several socio-economic impacts to the nearby communities, such as loss of lives and destructions of physical infrastructure. Analysis of spatiotemporal extents to which settlements, crops and physical infrastructures tend to be inundated are vital for predictive planning of risk-based adaptation measures. This paper presents a case study on flood risk assessment for Ugandan River Malaba sub-catchment. We applied the two-dimensional Hydraulic Engineering Center’s River Analysis System (2D HEC-RAS) for modelling of flooding extents. We considered extreme flow quantiles, lower and upper quantiles corresponding to the 95% confidence interval limits aimed at determining uncertainties in the flooding extents. Spatial extents of inundation on human settlement, land cover and infrastructure were analysed with respect to return periods of extreme flow quantiles. Finally, we estimated economic loss on infrastructure due to flooding. Results from the 2D HEC-RAS model were satisfactorily comparable with the results of observations. Amongst the land use types, cropland exhibited the highest vulnerability with at least 10,234.8 hectare (ha) susceptible to flooding event of 100-year return period (YRP). Inundated built-up land-use exhibited the highest vulnerability percentage increase (90%) between 2- and 100-YRP. In US Dollar, about US$ 33 million and US$ 39 million losses are estimated at 2- and 100-YRP, respectively, due to inundated rice gardens and these indicate a looming high risk of household food insecurity and poverty. Several infrastructure including 15 academic institutions, 12 health facilities, 32 worshiping places remain annually vulnerable to flooding. At least 6 km and 7 km of road network are also susceptible to flooding under extreme flows of return periods 2 and 100 years, respectively. Churches exhibited the highest economic losses of US$ 855,065 and US$ 1,623,832 at 2-YRP and 100-YRP, respectively. This study findings are relevant for planning the development of sustainable flood risk adaptation pathways given the established destructions within the sub-catchment due to flooding.Item Tap versus Bottled Water in Kampala, Uganda: Analyses of Consumers’ Perception alongside Bacteriological and Physicochemical Quality(Journal of Environmental and Public Health, 2022) Onyutha, Charles; Taata Akobo, Josephine; Mubialiwo, AmbroseIn Uganda, tap water is always ensured to be potable. However, people are not sure whether tap water is generally safe for drinking without being boiled. Conversely, bottled water consumption is on the increase in Uganda. e main problem lies in the cost of energy for boiling tap water or purchasing bottled water. is study analyzed results of laboratory tests and consumers’ perception for comparison of tap and bottled water in Nakawa division, Kampala. Tap water was sampled at four representative locations. At least 16 di erent brands of bottled water were considered. e top four most consumer-preferred bottled water brands were selected for further analysis. In our study, 28.8%, 6.06%, and 13.64% of the 142 respondents indicated that bottled water had taste, color, and smell, respectively. However, 27.5%, 25.4%, and 34.5% of the respondents agreed that tap water had taste, color, and smell, respectively. Both tap and bottled water met the World Health Organization (WHO) guidelines for pH, total dissolved solids, chloride, copper, sodium, sulfate, and nitrate. However, a tap water sample was found to contain Coliform bacteria. In this line, affected communities need to thoroughly boil the raw tap water to kill the pathogens. All tap water samples yielded iron concentrations above the WHO recommended limit. Student's t-tests showed that tap and bottled water samples were significantly (p < 0.05) different with respect to total dissolved solids, pH, chloride, calcium, magnesium, iron, sodium, sulfate, and nitrate. We emphasize the need for routine maintenance of the water distribution system to check for leakages which can be potential source of contamination .Item Water availability trends across water management zones in Uganda(Atmospheric Science Letters, 2021) Onyutha, Charles; Asiimwe, Arnold; Muhwezi, Lawrence; Mubialiwo, AmbroseThis study assessed trends in gridded (0.25 0.25 ) Climate Forecast System Reanalysis (CFSR) precipitation, potential evapotranspiration (PET), and precipitation minus PET (PMP) across the four water management zones (WMZs) in Uganda including Kyoga, Victoria, Albert, and Upper Nile. The period considered was 1979–2013. Validation of CFSR datasets was conducted using precipitation observed at eight meteorological stations across the country. Observed precipitation trend direction was satisfactorily reproduced by CFSR data extracted at five out of eight stations. Negative (positive) values of longterm PMP mean were considered to indicate areas characterized by water scarcity (surplus). Areas with large positive PMP were confined to Lake Victoria and mountains such as Rwenzori and Elgon. The largest negative PMP values were in the arid and semi-arid areas of north and northeastern Uganda. The null hypothesis H0 (no trend) was rejected (p < 0.05) for increasing annual precipitation trends across the various WMZs except in the extreme eastern parts of the Upper Nile, Kyoga, and Victoria WMZs (or areas along the boundary of Uganda and Kenya). The H0 (no trend) was rejected (p < 0.05) for decreasing trends in annual PET over West Nile region of the Upper Nile, western parts of Victoria, and the Albert WMZs. For increasing trend in PMP, the H0 (no trend) was rejected (p < 0.05) across the various WMZs except around the Mount Elgon area. The study findings are relevant for planning of water resources management across the different WMZs in the country.