Statistics in Climate Variability, Dry Spells, and Implications for Local Livelihoods in Semiarid Regions of Tanzania: The Way Forward

Shemsanga, Ceven; Muzuka, Alfred N. N.; Martz, Lawrence W.; Komakech, Hans C.; Omambia, Anne Nyatichi

doi:10.1007/978-1-4614-6431-0_66-1

Cited by 2 publications

(15 citation statements)

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“…and higher ET (about 2000 mm/yr.) all of which affect net recharge (Shemsanga et al 2015). Previous studies also indicated Plate 2 Representation of major processes involved in making lime powder.…”

Section: Discussionmentioning

confidence: 97%

“…; roughly 4 times annual rainfall (Shemsanga et al 2015). Except for HD, the area lacks permanent surface water bodies and the river network is largely seasonal flowing only during wet seasons and a few weeks thereafter.…”

Section: Case Study Descriptionmentioning

confidence: 99%

“…Geologically, it occurs in the fractured, faulted and tectonically active crystalline basement of the Dodoma craton. The metasedimentary rocks are mainly quartzites, ironstones, micaceous quartzites, quartzo-feldspathic schists and ferruginous quartzites (Nkotagu 1996, Shemsanga et al, 2015.…”

Section: Case Study Descriptionmentioning

confidence: 99%

“…Thus, the best way to manage water quality is tracing its catchment movements (Parmar 2013). In recent years, however, global freshwater quality has been worsened by humans and ongoing climate change impacts (Taylor et al 2012, Shemsanga et al 2015). Yet, even without these problems, water quality/salinity management; is difficult as water molecules constantly move between different states and locations (Biswas 2004(Biswas 2008.…”

Section: Introductionmentioning

confidence: 99%

“…All, previous studies, however, did not show the spatial source of the salts that would end up being concentrated by ET nor assess water suitability for various uses. Furthermore, available data at Hombolo Irrigation Scheme (HIS), which started in 1995, do not suggest a significant rainfall dilution and that the dam retains high salinity year-round (Shindo 1991;Shemsanga et al 2015). This suggests that the water feeding the dam could already be saline, details of which remains to be investigated.…”

Section: Introductionmentioning

confidence: 99%

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Origin and mechanisms of high salinity in Hombolo Dam and groundwater in Dodoma municipality Tanzania, revealed

et al. 2017

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The Hombolo dam (HD), in central Tanzania, is a shallow reservoir characterized by high salinity that limits its use for human activities. The origin of the salinity, mechanisms of reaching and concentrating in the dam remain unclear. These were assessed using hydrogeochemical facies, water type evolutions and mapping. The source of HD salinity was identified to be shallow groundwater (SG) and runoff from a seasonal floodplain with NaCl-rich lithological materails, along Little Kinyasungwe River that feeds the dam. The NaCl-rich lithological units, about 5-7 km upstream of the dam, were highly concentrated with NaCl to the extent that the local community was commercially separating table salt from them. The physicochemical parameters from these NaCl-rich lithological materials were well represented in HD and nearby groundwater sources, which suggests active water interactions. Water type evolution and surface hydrology assessments clearly showed that SG in the salty-floodplain was influenced by evaporation (ET) and was periodically carried to the HD. Clearly; HD water had high chemical similarity with the nearby SG. This agrees with previous studies that HD is partly fed by the local aquifer. However, this is the first attempt at mapping its physical origin. The origin of HD salinity was further supported by the spatial distribution of electrical conductivity (EC), where very high EC (up to 21,230 lScm ) was recorded in SG within the NaCl-rich lithological unit while water sources far away from the NaClrich materials had much lower EC values. Thus, the study disagrees with previous conclusions that HD salinity was sorely due to high dam surface ET but is primarily due to geological reasons. Comparisons of HD with a nearby Matumbulu dam (MD), another earthen dam in climatologically similar settings, reveals that MD water was less saline/ mineralised. This further shows that HD high salinity is most likely a geologic phenomenon, but local climatic factors, namely high ET, decreasing rainfall and warming trends are likely to have concentrated the salts further. Although HD is widely/ideally used for grape vine irrigation, it was clearly revealed that its prolonged usage would potentially affect the soil and grape productivity due to high salinity.

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Section: Discussionmentioning

confidence: 97%

Section: Case Study Descriptionmentioning

confidence: 99%

Section: Case Study Descriptionmentioning

confidence: 99%