Browsing by Author "Mjemah, Ibrahimu Chikira"
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Item Evaluation and prediction of the impacts of land cover changes on hydrological processes in data constrained southern slopes of Kilimanjaro, Tanzania(MDPI, 2021) Said, Mateso; Hyandye, Canute; Mjemah, Ibrahimu Chikira; Komakech, Hans Charles; Munishi, Linus KasianThis study provides a detailed assessment of land cover (LC) changes on the water balance components on data constrained Kikafu-Weruweru-Karanga (KWK) watershed, using the integrated approaches of hydrologic modeling and partial least squares regression (PLSR). The soil and water assessment tool (SWAT) model was validated and used to simulate hydrologic responses of water balance components response to changes in LC in spatial and temporal scale. PLSR was further used to assess the influence of individual LC classes on hydrologic components. PLSR results revealed that expansion in cultivation land and built-up area are the main attributes in the changes in water yield, surface runoff, evapotranspiration (ET), and groundwater flow. The study findings suggest that improving the vegetation cover on the hillside and abandoned land area could help to reduce the direct surface runoff in the KWK watershed, thus, reducing flooding recurring in the area, and that with the ongoing expansion in agricultural land and built-up areas, there will be profound negative impacts in the water balance of the watershed in the near future (2030). This study provides a forecast of the future hydrological parameters in the study area based on changes in land cover if the current land cover changes go unattended. This study provides useful information for the advancement of our policies and practices essential for sustainable water management planningItem Geospatial application on mapping groundwater recharge zones in Makutupora basin, Tanzania.(Elsevier Ltd, 2022-09) Kisikia, Clarance Paul; Bekelea, Tilaye Worku; Ayenewa, Tenalem; Mjemah, Ibrahimu ChikiraManagement of groundwater systems is indispensable to countries that depend on groundwater as the primary source of community water supply (e.g. Dodoma, Tanzania). Urbanization and industrialization lead to groundwater over-pumping and reduced recharge zones in the basin. This study used Remote Sensing and geo- spatial datasets to determine the groundwater recharge zones (GWRZ) followed by sensitivity analysis to identify the influence of geologic and hydrologic factors on the variation of the GWRZ in the case of the Makutupora basin, Tanzania. The implementation of weighted overlay analysis aimed to determine the GWRZ using different the- matic maps created from land use land cover (LULC), drainage density, lithology, lineament density, rainfall, slope and soil datasets. The analytical hierarchy process (AHP) and multi-influencing factor (MIF) are the multi- criteria decision analysis (MCDA) implemented to assign weights to the selected influencing factors. Either, the map removal method was implemented for the sensitivity analysis. Pumping wells were overlaid to validate the GWRZ map determined. The overlay of seven thematic maps resulted in the GWRZ map being categorized as good (35.79% for AHP and 21.68% for MIF), moderate (40.98% for AHP and 58.39% for MIF) and poor (23.22% for AHP and 19.95% for MIF). Good recharge potential areas lie in an area characterized by thick forest, high lineament and water bodies around the northwestern and central-eastern side of the basin. Validation of GWRZ indicated that 33.33% for AHP and 30% for MIF are in good GWRZ, 41.6% for AHP and 28% for MIF are in moderate GWRZ and 25% for AHP and 42% for MIF are in poor GWRZ. The sensitivity analysis revealed the high effect of GWRZ on the removal of the LULC, lithology and lineament thematic layer in both AHP and MIF- generated GWRZ maps. This implies that the expansion of settlements is not considering recharge zone protection. Lineaments are also a very important factor governing groundwater recharge which needs to be protected. The result displays that urbanization dramatically reduced the potential area for groundwater recharge. Protecting the potential recharge zone from any activity that reduces the recharge is vital for the sustainability of groundwater.Item Groundwater exploitation and hydraulic parameter estimation for a Quaternary aquifer in Dar-es-Salaam, Tanzania.(Elsevier Ltd, 2009-07-03) Mjemah, Ibrahimu Chikira; Van Camp, Marc; Walraevens, KristineThe fact that groundwater exploitation has largely increased since 1997 in the Dar-es-Salaam aquifer, calls for a directed attention towards possible problems of aquifer overexploitation that may arise in the near future. Hydraulic parameters are important for developing local and regional water plans as well as developing numerical groundwater flow models to predict the future availability of the water resource. The determination of aquifer parameters through pumping tests has become a standard step in the evaluation of groundwater resource potential. The pumping tests in the study area were con- ducted in August 2004 and August 2005, where 39 boreholes were tested out of 400 visited. In the study area there are over 1300 recorded boreholes drilled by Drilling and Dam Construction Agency (DDCA) by the year 2005. Total groundwater exploitation in the study area was estimated at 8.59 10 6 m 3 /year, based on yield data collected during the 2004–2005 field campaigns. The pumping tests included single- well tests and tests with measurements on the pumping well and at least one observation well. The tests were conducted for 6 h and 30 min. The pump was shut down after 6 h of pumping and the remaining 30 min were used for recovery measurements. The pumping test analysis methods used include: Neuman type curve matching and Walton type curve matching, checked by specific well capac- ity assessment and Thiem–Dupuit/Thiem’s method. The curve-matching results from the aquifer tests show the following parameters: an average transmissivity and hydraulic conductivity of 34 m 2 /d and 1.58 m/d, respectively for the unconfined aquifer; the semi-confined aquifer has an average value of 63 m 2 /d and 2.14 m/d for transmissivity and hydraulic conductivity, respectively. For the case of the storativity, the unconfined aquifer has an average elastic early-time storativity of 0.01, while the lower aquifer has an average storativity of 3 10 4 . Specific well capacity method and Thiem–Dupuit/Thiem’s method confirm results for transmissivity and hydraulic conductivity of the semi-confined aquifer, while values for the unconfined aquifer are somewhat larger (by a factor of 2–3). The hydraulic param- eters calculated appear to reasonably agree with the geological formation of the aquifers, as deduced from borehole descriptions.Item Groundwater exploitation and recharge rate estimation of a quaternary sand aquifer in Dar-es-Salaam area, Tanzania(Springer-Verlag, 2010-09-10) Mjemah, Ibrahimu Chikira; Van Camp, Marc; Martenes, Kristine; Walraevens, KristineDar-es-Salaam City gets water supply from surface water and groundwater. The groundwater is used to supplement surface water supply and has increasingly become a major source of water supply in the city. The study area comprises three major parts: the central coastal plain with quaternary fluvial–deltaic sediments, the deltaic Mio-Pliocene clay-bound sands and gravels in the north- west and southeast and the Lower Miocene fluviatile sandstones of Pugu Hills in the west of the study area. The main objective of this study was to quantify the integrated water balance. The major source of renewable groundwater in the aquifer is rainfall. Hence, the average recharge of 256.2 mm/year (for the year 2006) to the aquifer was estimated using the balance method of Thornthwaite and Mather, which is equal to 99.4 hm 3 /year for the whole alluvial aquifer. This value was balanced with total groundwater abstraction of 8.59 hm 3 /year, baseflow to rivers of 75.7 hm 3 /year and discharge into the sea (15.11 hm 3 /year).Item Hydrochemical characteristics of groundwater and its suitability for drinking and irrigation uses in makutupora sub-basin, Tanzania(AIP Publishing, 2023-01-10) Mjemah, Ibrahimu Chikira; Mariki, Eliapenda ElisanteThe focus of this study was to assess the suitability of groundwater for drinking and irrigation uses in Dodoma Municipality. Hydrochemical investigations was conducted in Dodoma urban where twenty water samples were collected from boreholes/wells to monitor physico-chemical quality. Groundwater samples were measured for pH, Chloride, Nitrate, Electric Conductivity, Total Dissolved Solids and Temperature in situ while major ions (Na + , Ca 2+ , K + , Mg 2+ , NO 3- , Cl - , SO4 2- and HCO 3- ) were analyzed in the laboratory. It was found that the physico-chemical properties of the groundwater varies from fresh to brackish and it is slightly acidic to alkaline. The Na + and Mg 2+ were dominant cations while Cl − and HCO 3− were dominant anions. Furthermore, the results show that for most groundwater quality parameters in Dodoma Municipality are suitable for drinking and irrigation uses. As for Chloride, the average concentration of about 1568.21mg/l seems to be unpalatable for drinking. However, for the Chloride which was found at a range of 710-960mg/l in few boreholes can be used for grapes irrigation, the main crop in the area, and 180-600 mg/l that was found in only one borehole is suitable for stone fruits irrigation. The Nitrate concentration complies with the Tanzania Bureau of Standards (TBS) and the World Health Organisation (WHO) limits for drinking purposes since its concentration was below 50 mg/l. Several groundwater management strategies and recommendations were proposed to control the quality of the groundwater and to get rid of groundwater problems. Furthermore, the study recommends frequent groundwater quality monitoring and integration of groundwater into the water resources management for the benefit of all of Dodoma Municipal peopleItem Hydrogeochemical analysis of water quality dynamics under anthropic activities on the southern slopes of Mount Kilimanjaro, Tanzania(The Tunisian Chemical Society and Springer Nature Switzerland AG, 2022) Said, Mateso; Komakech, Hans Charles; Mjemah, Ibrahimu Chikira; Lufingo, Mesia; Munishi, Linus Kasian; Kumar, SudhirWater quality management requires consideration of surface water and groundwater dynamics. This study utilizes hydrogeochemical and isotopic techniques to understand anthropic influences on surface and groundwater resources in the Kikafu– Weruweru–Karanga (KWK) watershed southern slopes of Mount Kilimanjaro. The KWK watershed had two distinct characteristics, i.e., the upper region (above 1000 m.a.m.s.l) with surface water and few groundwater features and the lower part (below 1000 m.a.m.s.l) characterized by most groundwater sources and rivers. Water sampling and analysis were done between July and August 2019; multivariate statistical analysis aided the understanding of analytical findings. The results revealed NaHCO3 enrichment and Mixed CaNaHCO3 water type. The groundwater chemistry is chiefly controlled by aquifer lithology rather than anthropic activities. Stable isotopes show recharge from both regional and local rainfall as traced from the shallow wells. The levels of anthropic pollution indicators such as nitrate, chloride, and sulfate in deep wells are generally low in groundwater than in shallow wells. Anthropic activities such as irrigation, wastewater discharges and severe water abstraction confirmed significant contaminant agents at the dynamic levels. Next to geogenic releases, anthropic pollution as well is affecting groundwater quality in the aquifer. The current findings call for improved monitoring of the groundwater sources to track any changes in quality since there is a potential evolution to an undesirable state for domestic uses.Item Hydrogeological mapping and estimation of potential evapotranspiration and recharge rate of Quaternary sand aquifers in Dar-es-Salaam, Tanzania(International Journal of Geomatics and Geosciences, 2015-11) Mjemah, Ibrahimu Chikira; Walraevens, KristineDar-es-Salaam City is the largest urban centre in Tanzania, with a population of over 4 million. It gets water for domestic use from surface water (Ruvu and Kizinga rivers) and groundwater. The groundwater was used to supplement surface water supply and has by now become the major source of water supply in the city. However, despite the importance of groundwater in the city, limited researches on water quantity and quality have been conducted and generally the groundwater database is inadequate. The main objective of this research is to investigate the availability of groundwater by developing a hydrogeological map of the area and estimate the groundwater recharge rate of the Quaternary sand aquifer in the plain. The deposits in the study area cover two major periods, Quaternary and Neogene. They are made up of sedimentary rocks, which were proposed to be deposited in a fluviatile/deltaic environment with marine intercalations along the seaward margin. The Uluguru Mountains were probably the source of much of the materials deposited in the area. Nearly 150 m of Quaternary deposits consist of basically three geological layers: alluvial, coastal plain and coral reef limestone deposits. These deposits are mostly of Pleistocene to recent age and are found mainly moving from the coast towards the mainland within the river valleys. The Neogene deposits are of Miocene and Pliocene period. Two types of formations characterize these deposits: undifferentiated deposits (Mio-Pliocene clay-bound sands and gravels) and the fluviatile kaolinitic Pugu Sandstone (Lower Miocene). Hydrogeologically, the study area has two types of aquifers in the Quaternary deposits: an upper unconfined sand aquifer (5-50 m thick) and the lower semi-confined sand aquifer (the most productive zone 10-100 m thick). The groundwater recharge is estimated by using monthly precipitation data for 36 years, runoff and potential evapotranspiration. The average groundwater recharge rate in the area is 121.7 mm per year. This delivers substantial amounts of groundwater stored in the sand aquifers of the area.Item Indigenous knowledge systems for climate change detection and adaption planning in mountainous areas in Tanzania(Journal of Resources Development and Management, 2015) Mussa, Kassim Ramadhani; Mjemah, Ibrahimu ChikiraThe study was carried out to gather perceptions and experiences of the Uluguru mountains communities on climate change and its impacts, and to understand their traditional innovations in detecting climate change and coping with the impacts. It took place in three villages of Luale ward namely Luale, Masalawe and Londo in Mgeta division, Mvomero district. Participatory research methods were employed in generating the perceptions, information and experiences about climate change, its impacts and community based adaptation strategies. Climate-related hazards were identified using traditional knowledge, skills and experiences. Historical timelines developed by the local people themselves revealed an increase in the frequency of drought incidences and shifting rainfall seasons, with unprecedented wildland fires devastating the study area. Community-based coping strategies as a response to the observed climate change impacts were also identified. However, the coping strategies practised by the traditional communities are mainly oriented towards survival, not continuous, motivated by crisis, reactive, often degraded the available resource base and are usually prompted by lack of alternatives. Therefore, local communities and traditional people in general need the support of the international community to continue their role as traditional caretakers of marginal and fragile ecosystems, at the same time, building their capacities to adapt to the impacts of the current and future changes of global and local climates using more proactive approaches integrated into their indigenous knowledge base.Item Modeling approaches and strategies for data-scarce aquifers: example of the Dar es Salaam aquifer in Tanzania(Springer, 2013) Camp, Marc Van; Mjemah, Ibrahimu Chikira; Farrah, Nawal Al; Walraevens, KristineManagement of groundwater resources can be improved by using groundwater models to perform risk analyses and to improve development strategies, but a lack of extensive basic data often limits the implementation of sophisticated models. Dar es Salaam in Tanzania is an example of a city where increasing groundwater use in a Pleistocene aquifer is causing groundwater-related problems such as saline intrusion along the coastline, lowering of water-table levels, and contamination of pumping wells. The lack of a water-level monitoring network introduces a problem for basic data collection and model calibration and validation. As a replacement, local watersupply wells were used for measuring groundwater depth, and well-top heights were estimated from a regional digital elevation model to recalculate water depths to hydraulic heads. These were used to draw a regional piezometric map. Hydraulic parameters were estimated from short-time pumping tests in the local wells, but variation in hydraulic conductivity was attributed to uncertainty in well characteristics (information often unavailable) and not to aquifer heterogeneity. A MODFLOW model was calibrated with a homogeneous hydraulic conductivity field and a sensitivity analysis between the conductivity and aquifer recharge showed that average annual recharge will likely be in the range 80–100mm/year.Item Natural groundwater recharge response to climate variability and land cover change perturbations in basins with contrasting climate and geology in Tanzania(MDPI, 2021) Mussa, Kassim Ramadhani; Mjemah, Ibrahimu Chikira; Machunda, Revocatus LazaroThe response of aquifers with contrasting climate and geology to climate and land cover change perturbations through natural groundwater recharge remains inadequately understood. In Tanzania and elsewhere in the world, studies have been conducted to assess the impact of climate change and variability, and land use/cover changes on stream flow using different models, but similar studies on groundwater dynamics are inadequate. This study, therefore, examined the influence of land use/cover and climate dynamics on natural groundwater recharge in basins with contrasting climate and geology in Tanzania, applying the modified soil moisture balance method, coupled with the curve number (CN). The method hinges on the balance between the incoming water from precipitation and the outflow of water by evapotranspiration. The different parameters in the soil moisture balance method were computed using the Thornthwaite Water Balance software. The potential evapotranspiration (PET) was calculated using the daily maximum and minimum temperatures, utilizing two-temperature-based PET methods, Penman–Monteith (PM) and Hargreaves–Samani (HS). The rainfall data were obtained from the gauging stations under the Tanzania Meteorological Agency and some additional data were acquired from climate observatories management by water basins. The results show that there has been a quasi-stable CN in the Singida semi-arid, fractured crystalline basement aquifer (74.2 in 1997, 73.64 in 2005, and 73.87 in 2018). In the Kimbiji, humid, Neogene sedimentary aquifer, the CN has been steadily increasing (66.69 in 1997, 69.08 in 2008, and 71.42 in 2016), indicating the rapid land cover changes in the Kimbiji aquifer as compared to the Singida aquifer. For the Kimbiji humid aquifer, the PET calculated using the Penman– Monteith (PM) method for the 1996/1997, 2007/2008, and 2015/2016 hydrological years were 1156.5, 1079.5, and 1143.9 mm/year, respectively, while for the Hargreaves–Samani (HS) method, the PET was found to be 1046.1, 1138.3, and 1204.4 mm/year for the 1996/1997, 2007/2008, and 2015/2016 hydrological years, respectively. For the Singida semi-arid aquifer, the PM PET method resulted in 2083.3, 2053.6, and 1875.4 mm/year for the 1996/1997, 2004/2005, and 2017/2018 hydrological years, respectively. The HS method produced relatively lower PET values for the semi-arid area (1839.4, 1814.7, and 1710.2 mm/year) for the 1996/1997, 2004/2005, and 2017/2018 hydrological years, respectively. It was equally revealed that the recharge and aridity indices correspond with the PET calculated using two temperature-dependent methods. The decline of certain land covers (forests) and increase in others (built-up areas) have contributed to the increase in surface runoff in each study area, possibly resulting in the decreasing trend of groundwater recharge. An overestimation of the PET using the HS method in the Kimbiji humid aquifer was observed, which was relatively smaller than the overestimation of the PET using the PM method in the Singida semi-arid aquifer. Despite the difference in climate and geology, the response of the two aquifers to rainfall is similar. The combined influence of climate and land cover changes on natural groundwater recharge was observed to be prominent in the Kimbiji aquifer, while only climate variability appreciably influences natural groundwater recharge in the Singida semi-arid aquifer. El Nino and the Southern Oscillation as part of the climate variability phenomenon dwarfed the time lags between rainfall and recharge in the two basins, regardless of their difference in climate and geology.Item Open-source software application for hydrogeological delineation of potential groundwater recharge zones in the Singida semi-arid, fractured aquifer, central Tanzania(MDPI, 2020) Mussa, Kassim Ramadhani; Mjemah, Ibrahimu Chikira; Machunda, Revocatus LazaroThis study attempted to delineate and map potential groundwater recharge zones of the Singida, semi-arid, fractured crystalline basement aquifer using open source remote sensing and GIS software. Various thematic maps such as lithology/hydrogeology, soil, land-cover/use, slope, lineament density, drainage density and rainfall distribution were integrated in QGIS software. Vector input layers were rasterized and resampled using QGIS wrap projection function to make sure that the grid cells are of the same size. Reclassification using SAGA and GRASS reclass algorithms in QGIS was carried out to realign the factor classes in a consistent scale, and reclassification to a scale of 1 to 5 was carried out to harmonize the results. The study identified a number of potential areas for groundwater recharge, groundwater exploration, groundwater development and potential areas for artificial groundwater recharge. Potential groundwater recharge zones for the Singida semi-arid fractured aquifer are restricted to areas with high lineament density, cultivated areas, grassland and flat to gentle slopes. The potential of groundwater recharge is also observed in areas with low drainage density. The delineated zones provide a good understanding of the potential recharge zones, which are a starting point for recharge zone protection. This blended approach can be utilized for carrying out suitability analysis using the weighted overlay analysis approach. Areas designated good and very good are recommended for artificial recharging structures as an alternative technique for enhancing groundwater recharge through rainwater harvesting. This will help to augment groundwater storage in this semi-arid environment.Item Participation of ecosystem service providers in a watershed pes project in Tanzania: connection with the coasean perspectives(Journal of Ecosystem & Ecography, 2017) Mussa, Kassim Ramadhani; Mjemah, Ibrahimu ChikiraThe equitable payment for environmental service projects seem to have good objectives, but not so many households participated in it. Limited empirical information surrounds the most Payment for Environmental Services (PES) schemes with regard to which factors could influence the commitment of environmental service providers to switch to improved land management practices. Are these factors stemming from the Coasean theorem? The answer to this question is imperative as it paves way to more robust approach of PES implementation in Tanzania and worldwide. This study therefore sought to explore the challenges which either, held back or threatened the participation of ecosystem service providers in the Uluguru Mountains to the equitable payment for watershed services scheme, linking them to the main treatise of the Coasean theorem. This study employed a partially mixed concurrent dominant status design in which quantitative and qualitative approaches were used simultaneously, but with the quantitative approach being dominant. The mixed-methods design brought together different strengths of quantitative and qualitative methods, while offsetting the weaknesses of using a single method and expanding the set of collected data.Item Quantification of groundwater exploitation and assessment of water quality risk perception in the Dar es salaam quaternary aquifer, Tanzania(MDPI, 2019) Mussa, Kassim Ramadhani; Mjemah, Ibrahimu Chikira; Walraevens, KristineThis study quantified groundwater exploitation and assessed water quality risk perception in the Dar es Salaam quaternary aquifer through a socio-economic survey. Annual total groundwater exploitation was estimated, using the daily per capita consumption of groundwater derived from the household survey. A logistic regression analysis was performed to ascertain the influence of sex, marital status, education level, employment, income, and cost of water on groundwater quality risk perception. It was revealed that most residents of Dar es Salaam use groundwater as a main source of water supply. The results of this study further showed that 78% consider groundwater as a reliable source. Averting strategies for insu cient quantity of groundwater consist of minimizing less necessary water uses, while for poor quality, buying bottled water and water treatment by boiling and using chemicals. The chance for water quality risk perception is 0.205 times greater for married than unmarried household heads, and it is 623 times higher for employed versus unemployed household heads. To get an overall view of the importance of groundwater for domestic needs in Dar es Salaam it is imperative to combine a time series data of groundwater and surface water exploitation.Item A review on the state of knowledge, conceptual and theoretical contentions of major theories and principles governing groundwater flow modeling(Springer, 2020) Mussa, Kassim Ramadhani; Mjemah, Ibrahimu Chikira; Muzuka, Alfred Nzibavuga NyarubakulaDecision-makers require correct and adequate information on groundwater flow systems in a basin in order to formulate sustainable water resources development strategies. However, the practicality and realism of groundwater flow system models depend on the validity, reliability and availability of quality data and information, and how they are used in model development and calibration. This goes hand in hand with how the underlying theories, tenets and assumptions are understood, interpreted and applied. The more uncertain and contentious the information is, the wider are the knowledge and theoretical gaps, and thus the less useful the model results are for decision-making. The understanding of water table types in groundwater basins has become one of the additional factors for an in-depth understanding and modeling of nested groundwater flow systems. The classification of water table types using a water table ratio provides that if the ratio is more than 1, this depicts a topography-controlled area and a ratio of less than 1 depicts a recharge-controlled terrain. Log transformation of the water table ratio proved the same interpretation. This paper therefore reviews the evolution of groundwater flow systems theory, the prevailing knowledge and theoretical gaps by specifically pinpointing the theoretical and conceptual contentions and additional factors which can possibly limit the application of groundwater flow theories in regional groundwater modeling studies. The implications of how the conceptual and theoretical contentions affect groundwater modeling for decision-making in groundwater development and management are also pinpointed in this paper.Item The role of development projects in strengthening community-based adaptation strategies: the case of Uluguru mountains Agricultural development project (UMADEP)-Morogoro-Tanzania(International Scholars Journals, 2012) Mussa, Kassim Ramadhani; Mjemah, Ibrahimu Chikira; Malisa, Emmanuel TimothyThis study was trying to find out whether the designing and implementation of the Uluguru Mountain Agricultural Development Project (UMADEP) has taken into account the hazards, impacts and risks associated with climate change and the local coping strategies of their project beneficiaries, since its inception, 17 years ago . Data were gathered using the Community-based Risk Screening–Adaptation and Livelihoods (CRiSTAL) tool, complemented with a series of semi-structured and structured interviews containing both close and open-ended questions. The Vulnerability and Capacity Assessment (VCA) method was also used in identifying resources, capacities and vulnerabilities which pertained to different livelihood settings in the study area. The study found out that coping strategies applied by affected people in the study area vary from one community to the other, depending on level of education, income, household size and agro-ecological zone. Ranking of the identified livelihood resources revealed that natural resources are very crucial in adapting to climate change. Generally, the results indicate a moderate influence of project activities towards enhancing adaptive capacities of the surrounding communities, with the observed positivity of the project activities towards community-based adaptation being more of a coincidence than a planned state-of-affairs. Lack of training to development project officers, managers and planners on the importance of integrating climate change management during the early stages of project development was clearly depicted as a key hindrance to mainstreaming climate change into development planning.Item The role of development projects in strengthening community-based adaptation strategies: the case of Uluguru mountains agricultural development project (umadep)-Morogoro-Tanzania.(International Journal of Agricultural Sciences, 2012) Mussa, Kassim Ramadhani; Mjemah, Ibrahimu Chikira; Malisa, Emmanuel TimothyThis study was trying to find out whether the designing and implementation of the Uluguru Mountain Agricultural Development Project (UMADEP) has taken into account the hazards, impacts and risks associated with climate change and the local coping strategies of their project beneficiaries, since its inception, 17 years ago . Data were gathered using the Community-based Risk Screening– Adaptation and Livelihoods (CRiSTAL) tool, complemented with a series of semi-structured and structured interviews containing both close and open-ended questions. The Vulnerability and Capacity Assessment (VCA) method was also used in identifying resources, capacities and vulnerabilities which pertained to different livelihood settings in the study area. The study found out that coping strategies applied by affected people in the study area vary from one community to the other, depending on level of education, income, household size and agro-ecological zone. Ranking of the identified livelihood resources revealed that natural resources are very crucial in adapting to climate change. Generally, the results indicate a moderate influence of project activities towards enhancing adaptive capacities of the surrounding communities, with the observed positivity of the project activities towards community-based adaptation being more of a coincidence than a planned state-of-affairs. Lack of training to development project officers, managers and planners on the importance of integrating climate change management during the early stages of project development was clearly depicted as a key hindrance to mainstreaming climate change into development planningItem Saltwater intrusion and nitrate pollution in the coastal aquifer of Dar es Salaam, Tanzania.(Springer, Environimental Earth Science., 2013-11-03) Mtoni, Yohana; Mjemah, Ibrahimu Chikira; Bakundukize, Charles; Van Camp, Marc; Martenes, Kristine; Walraevens, KristineDar es Salaam Quaternary coastal aquifer is a major source of water supply in Dar es Salaam City used for domestic, agricultural, and industrial uses. However, groundwater overdraft and contamination are the major problems affecting the aquifer system. This study aims to define the principal hydrogeochemical processes control- ling groundwater quality in the coastal strip of Dar es Salaam and to investigate whether the threats of seawater intrusion and pollution are influencing groundwater qual- ity. Major cations and anions analysed in 134 groundwater samples reveal that groundwater is mainly affected by four factors: dissolution of calcite and dolomite, weathering of silicate minerals, seawater intrusion due to aquifer over- exploitation, and nitrate pollution mainly caused by the use of pit latrines and septic tanks. High enrichment of Na ? and Cl - near the coast gives an indication of seawater intrusion into the aquifer as also supported from the Na–Cl signature on the Piper diagram. The boreholes close to the coast have much higher Na/Cl molar ratios than the boreholes located further inland. The dissolution of calcite and dolomite in recharge areas results in Ca–HCO 3 and Ca–Mg–HCO 3 groundwater types. Further along flow paths, Ca 2? and Na ? ion exchange causes groundwater evolution to Na–HCO 3 type. From the PHREEQC simu- lation model, it appears that groundwater is undersaturated to slightly oversaturated with respect to the calcite and dolomite minerals. The results of this study provide important information required for the protection of the aquifer system.Item Sources of salinity and urban pollution in the Quaternary sand aquifers of Dar es Salaam, Tanzania(Elsevier, 2014) Walraevens, Kristine; Mjemah, Ibrahimu Chikira; Mtoni, Yohana; Camp, Marc VanGroundwater is globally important for human consumption, and changes in quality can have serious consequences. The study area is within a coastal aquifer where groundwater quality is influenced by various potential sources of salinity that determine the composition of water extracted from wells. Groundwater chemistry data from the aquifer have been acquired to determine the geochemical conditions and processes that occur in this area and assess their implications for aquifer susceptibility. Analysis of groundwater samples shows that the dominant watertype is mostly NaCl with pH < 7 in both aquifers (i.e. upper and lower) except for the shallow wells where CaHCO3 prevails with pHP7, and boreholes located near the Indian Ocean, where coral reef limestone deposits are located and the watertype evolves towards CaHCO3. In the lower aquifer, Cl is higher than in the upper aquifer. The origin of salinity in the area is strongly influenced by groundwater ascending from deep marine Miocene Spatangid Shales through faults, seawater incursion on the border of the Indian Ocean, and throughout, there is some salinity within the Quaternary aquifer, especially in intercalated deltaic clays in the fluviatile deposits, showing some marine influences. The seawater intrusion is linked to the strongly increasing groundwater exploitation since 1997. Another process that plays a major role to the concentration of major ions in the groundwater is calcite dissolution. Next to geogenic salinity and seawater intrusion, anthropogenic pollution as well is affecting groundwater quality in the aquifer. An important result of this study is the observation of high nitrate concentrations, that call for improved sanitation in the area, where domestic sewage with on-site sanitation (mainly pit latrines) also threatens the groundwater resource