Browsing by Author "Nakagiri, Anne"
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Item Assessing Ambient And Internal Environmental Conditions Of Pit Latrines In Urban Slums Of Kampala, Uganda: Effect On Performance(Journal of Water, Sanitation and Hygiene for Development, 2017) Nakagiri, Anne; Niwagaba, Charles B.; Nyenje, Philip M.; Kulabako, Robinah K.; Tumuhairwe, John B.; Kansiime, FrankThere is increasing interest to improve the functionality and performance of pit latrines in low income urban areas. This study aimed at assessing the ambient and pit environmental conditions and their implications on the performance (smell and fly nuisance) of pit latrines. Forty-two pit latrines were investigated in urban slums of Kampala, Uganda, through field observation and measurements of ambient and pit environmental conditions. The implications were assessed using oxygen-reduction potential (ORP) and its association with smell/insect nuisances. The pit temperature (21 to 30.7 °C), pH (5.0–11.8) and ORP (−247 to 65.9 mV) were consistently, significantly different (p < 0.001) between the surface and 0.5 m depth of pit content. The conditions in most (95%) pit latrines were anoxic (ORP < +50 mV), and mainly within the acid formation range (ORP −199 to −51 mV). Most smelling pit latrines and flies were within the acid formation ORP range, with a significant association (gamma, G = 0.797, p = 0.014) between ORP and smell in clean latrines only. The results suggest that ventilation of pit latrines within urban slums was not sufficient. Additionally, cleanliness, moisture reduction and waste stabilisation could address bad smells in pit latrines, ultimately improving their usage in urban slums.Item Contributions of Human Activities and Climatic Variability to Changes in River Rwizi Flows in Uganda, East Africa(Hydrology, 2021) Onyutha, Charles; Nyesigire, Resty; Nakagiri, AnneThis study employed Soil and Water Assessment Tool (SWAT) to analyze the impacts of climate variability and human activities on River Rwizi flows. Changes in land use and land cover (LULC) types from 1997 to 2019 were characterized using remotely sensed images retrieved from Landsat ETM/TM satellites. SWAT was calibrated and validated over the periods 2002–2008 and 2009–2013, respectively. Correlation between rainfall and river flow was analyzed. By keeping the optimal values of model parameters fixed while varying the LULC maps, differences in the modeled flows were taken to reflect the impacts of LULC changes on rainfall–runoff generation. Impacts due to human activities included contributions from changes in LULC types and the rates of water abstracted from the river as a percentage of the observed flow. Climate variability was considered in terms of changes in climatic variables such as rainfall and evapotranspiration, among others. Variability of rainfall was analyzed with respect to changes in large-scale ocean-atmosphere conditions. From 2000 to 2014, the portion of River Rwizi catchment area covered by cropland increased from 23.0% to 51.6%, grassland reduced from 63.3% to 37.8%, and wetland decreased from 8.1% to 4.7%. Nash–Sutcliffe Efficiency values for calibration and validation were 0.60 and 0.71, respectively. Contributions of human activities to monthly river flow changes varied from 2.3% to 23.5%. Impacts of human activities on the river flow were on average found to be larger during the dry (14.7%) than wet (5.8%) season. Using rainfall, 20.9% of the total river flow variance was explained. However, climate variability contributed 73% of the river flow changes. Rainfall was positively and negatively correlated with Indian Ocean Dipole (IOD) and Niño 3, respectively. The largest percentages of the total rainfall variance explained by IOD and Niño 3 were 12.7% and 9.8%, respectively. The magnitude of the correlation between rainfall and IOD decreased with increasing lag in time. These findings are relevant for developing River Rwizi catchment management plans.Item Performance Of Pit Latrines In Urban Poor Areas: A Case Of Kampala, Uganda(Habitat international, 2015) Nakagiri, Anne; Kulabako, Robinah N.; Nyenje, Philip M.; Tumuhairwe, John B.; Niwagaba, Charles B.; Kansiime, FrankIn many urban poor areas of Sub-Saharan Africa (SSA), demand for human excreta disposal is met, predominantly by pit latrines. This study aimed at determining the status of pit latrines (design, construction, operation and maintenance) and its influence on latrine performance (filling, smell and insect nuisance). The study was conducted on 130 pit latrines in typical urban poor areas of Kampala, Uganda. Data on design, construction, usage, operation and performance of the pit latrines was collected by interviews, observations and measurements; and analysed by descriptive statistics, bi-variate analysis and logistic regression. Results showed that the level of pit content was predicted by rain or storm water entry, terrain, cleaning before or after use and number of households using the latrine. Smell was predicted by cleanliness, stance length, superstructure material and whether the latrine was private or public. The predictor of presence of flies was the superstructure material. To improve the performance of pit latrines in urban poor areas, researchers and practitioners should develop local latrine design standards (dimensions, construction materials and number of users) and cleaning guidelines for local policy makers to implement.