Browsing by Author "Kashaigili, Japhet J."
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Item Developing rating curves in the Ruvu river Sub-basin(iWASH, 2013) Kashaigili, Japhet J.The Florida International Research iWASH Initiative Limited commissioned this study to assess and develop rating curves in the Ruvu River Sub-basin. The work concentrated at the six key strategic stations within the Sub-basin that include: Ngerengere at Konga 1HA9A, Ngerengere at Mgude, Ruvu at Morogoro - Dar es Salaam Road 1H8, Ruvu at Kibungo 1H5, Mgeta at Mgeta 1HB2 and Mgeta at Duthumi 1HB1411. Specifically, the work reviews the existing rating curves for the existing stations on the Ruvu, update and validate cross-sections at the six strategic stations, conduct flow measurements, conduct analysis and produce new rating equations for the six strategic stations. The work utilizes the historical stage-discharge measurements and the new measurements collected during the period November 2012 to May 2013. Results indicate that most of the stations were established in the early 1950s and discharge measurement in these stations continued until late 1980s, with no measurements between early 1990s and mid 2000s. Review of the rating relationships indicates validity of historical data up to the early 1980s for most of the stations, but cannot be used to transform gauge heights (water levels) without modification. Assessment of physical characteristics at the six key stations revealed fair hydraulic controls. Nevertheless, special attention will be required to attend some observed threats at the channel hydraulic sections. Validation of the new developed rating curves at the key gauging stations indicate that stage- discharge relationships require updating by new current meter measurements, as for some stations the number of data points that were used to develop the rating relationships were too few. Data records reveal existence of outliers, which is likely attributable among others to use of un-calibrated current meter/sampling equipment, poor measurement techniques, inexperienced sampling technicians and/or computational errors. The new developed rating curves revealed absence of bias for all the stations except for 1H8. Of the six stations, only three stations namely 1H5, 1HB2 and 1HB1411 passed the ‘goodness of fit’ test, while the rest of the stations, 1HA15, 1HA9A and 1H8 the test criterion t was found to be consistently greater than the critical value, leading to the rejection of the null hypothesis of the assumption of random fluctuations. Therefore, the test detected the presence of abnormal long runs of positive or negative deviations. This most likely indicates presence of systematic trend in the deviations with time, indicating that the rating curves need adjustment for a shift in control. The study recommends for a need to increase the number of measured discharges at different stages so as to increase reliability of the rating curve equations. The findings are also considered to be indicative of the situation country wide, thus it is strongly recommend that the MoW (through its WSDP and other donors) make available additional funds to enable revisiting, testing and revision of rating curves on all major rivers to ensure higher confidence in the flow measurements.Item Dynamics of Usangu plains wetlands: use of remote sensing and GIS as management decision tools(Elsevier, 2006) Kashaigili, Japhet J.; Mbilinyi, Boniface P.; Mccartney, Matthew; Mwanuzi, Fredrick L.Wetlands are resources of paramount importance with many values and functions that need proper management for their continued functioning and the delivery of benefits to the community. Sustained functioning of wetlands requires proper use of land and management of water. It is commonly said that increased human activities have had negative impacts on the Usangu Plains wetlands and that these wetlands are on the verge of total collapse due to altered flows. Nevertheless, these beliefs are little supported by quantitative data. A study on the dynamics of Usangu Plains wetlands therefore investigated long-term and seasonal changes that have occurred as a result of human and developmental activities in the study area for the periods between 1973 and 1984, and between 1984 and 2000. Landsat- MSS and Landsat-TM images were used to locate and quantify the changes. The study revealed a 14% increase in area covered by veg- etated swamp between 1973 and 1984, and a decline by 77% and 70% in area covered by closed and open woodlands respectively. Between 1984 and 2000, the vegetated swamp cover declined by 67%, while the closed woodland and open woodlands declined by 83% and 77% respectively. It has also been revealed that the differences in spatial resolution could impair the detection of change. The continued decline in wetland covers has the potential to cause irreversible changes in these wetlands. Remote sensing and GIS tech- nologies have proved to be useful tools for assisting decision-makers to locate and quantify changes in land resources, and hence to iden- tify appropriate solutions for sustainable management of wetlands. 2006 Elsevier Ltd. All rights reserved.Item E-Ng’ombe: a mobile phone ICT to tackle the pitfall of information asymmetry in the value chain of indigenous beef cattle in Mwanza Region, Tanzania(Sciknow, 2013) Kadigi, Ibrahim L.; Muhiche, Lupyana; Kadigi, Reuben M.J.; Makindara, Jeremiah; Laswai, Germana; Kashaigili, Japhet J.A value chain (VC) study was conducted in Ilemela and Magu Districts of Mwan za region in Tanzan ia to evaluate the performance of different actors in the VC of indigenous beef cattle and identify opportunities for upgrading the VC. Specifically, the study mapped the VC, assessed profitability in each node and identified priority issues for short term intervention. Two major working hypotheses were tested. First is the hypothesis that the profits gained by beef cattle actors in the VC are unevenly distributed. Second is the hypothesis that efficiency in cattle and beef product production and marketing will translate into increased market margins for producers and other actors in the VC. We identify several pitfalls: importantly is perhaps the p itfall of info rmation asymmetry, especially among actors upstream the VC. We develop an electronic mobile phone Information and Co mmunicat ion Technology (ICT) system namely, “e-Ng‟o mbe” in an attempt to tackle this problem. This is in line with our fundamental argu ment that the introduction and use of appropriate ICT, especially by beef cattle producers, is likely to add value and upgrade the VC. We reco mmend that the Govern ment of Tan zania, through the Ministry of Livestock Development and Fisheries (M LDF) should own the process of out-scaling and up-scaling the use of e-Ng‟o mbe ICT system in the country. We underline the fact that the provision of market ing information is by large a public good, though public -private partnerships may go a long way in realizing the benefits of using mobile phone ICT in the indigeno us beef cattle sub-sector in Tan zania.Item Environmental flow assessment as a tool for achieving environmental objectives of African water policy, with examples from East Africa(International Journal of Water Resources Development, 2013) McClain, Michael E.; Kashaigili, Japhet J.; Ndomba, PreksedisAfrica has set ambitious targets for development of water resources over the coming decades. Africa Water Vision 2025 calls for a doubling of irrigated agriculture and a five-fold increase in water use for agriculture, industry, and hydropower. The ambitious development targets are framed in the context of integrated water resources management, which also seeks to simultaneously allocate sufficient water for environmental sustainability. Over the past two decades scientists have devised a number of practical and robust approaches to determine environmental water requirements in rivers and wetlands based on the objectives set in water planning. We review the most widely applied approaches to assess environmental flow requirements and consider their application in Africa through case studies in the transboundary Mara River basin of Kenya and Tanzania and the Great Ruaha River basin in Tanzania.Item Landcover dynamics and hydological functioning of wetlands in the Usangu plains in Tanzania(Sokoine University of agriculture, 2006) Kashaigili, Japhet J.In the Usangu Plains of the Upper Great Ruaha River Catchment in Tanzania, the hydrology of the wetlands and the downstream flow regime changes in response to changes in land use and cover was investigated through analysis of remotely sensed images and modelling. A hydrological model for the Eastern wetland that accounts for the water balance was developed. This model was used to evaluate the hydrology of the Eastern wetland in response to changes in land use and cover and the amount of inflows into the Eastern wetland required to maintain a specified outflow downstream of the wetland. A small wetland locally called Ifushiro located in the upstream of the Eastern wetland was also investigated to evaluate its contribution to dry season flows. The analysis involved a detailed hydrometric monitoring and modelling using Visual MODFLOW software. The Ifushiro wetland was shown to have no contribution to dry season flow, since much of its water was lost through evaporation. The hydrology of the Eastern wetland was shown to be modulated by the changes in land use and cover on the upstream. Since 1958. increasing diversions of water has caused average dry season inflows to the Eastern wetland to decrease from approximately 15.0 mV to 4.3 mV. This has led to a reduction in the average minimum dry season surface area of the wetland from approximately 160 km2 to 93 km2. Since the early 1990s the decrease in dry season water-levels within the wetland has resulted in prolonged periods of zero flow in the Great Ruaha River, with severe consequences for the ecology of the Ruaha National Park. The wetland model enabled calculation of the inflows required to maintain specified discharges. To maintain a flow of 0.5 m’s'1, as the minimum required flow for maintenance offishiii habitat and the current ecology of the Park, requires an average dry season inflow of approximately 7.0 mV into the Eastern wetland in the dry season. The results from this research demonstrate the value of combining different research methods/approaches and the use of simple models to examine system functioning to assist decision-making.Item Use of a hydrological model for environmental management of the usangu wetlands, Tanzania(IWMI Research, 2016-05) Kashaigili, Japhet J.; McCartney, Matthew P.; Mahoo, Henry F.; Lankford, Bruce A.; Mbilinyi, Boniface P.; Yawson, Daniel K.; Tumbo, Siza D.This report presents the findings of a study to assess changes to flows into, and downstream of, the Usangu Wetlands, located in the headwaters of the Great Ruaha River, Tanzania. Hydrological data, in conjunction with remote sensing techniques, were used to provide insights into changes that have occurred to the Eastern Wetland. Results indicate that, between 1958 and 2004, inflows to the wetland declined by about 70 percent in the dry season months (July to November) as a consequence of increased human withdrawals, primarily for irrigation. This resulted in a decrease in the dry season area of the wetland of approximately 40 percent (i.e., from 160 km 2 to 93 km 2 ). In the last decade, outflows from the wetland have ceased for extended periods. An environmentalflow model indicates that a minimum dry season outflow of approximately 0.6 m 3 s -1 is essential to sustain the basic ecological condition of the river. To maintain this outflow from the wetland, a minimum average dry season inflow of approximately 7 m 3 s -1 (i.e., approximately double current dry season flows) is required. To achieve this, dry season flows in the perennial rivers discharging into the wetland would have to be apportioned so that 20 percent is used for anthropogenic purposes and the remaining 80 percent discharges into the wetland. There issignificant potential for improving water use efficiency. However, to ensure minimum downstream flow requirements, consideration should also be given to active water management within the wetland itself.Item Value chain of indigenous cattle and beef products in Mwanza region, Tanzania: market access, linkages and opportunities for upgrading(Academia Publishing, 2013) Kadigi, Reuben M. J.; Kadigi, Ibrahim L.; Laswai, Germana. H; Kashaigili, Japhet J.The potentials of the traditional beef cattle sector in Lake Victoria Basin (LVB) have only been utilized marginally. The sector still suffers from limited access and linkages to premium markets, lack of entrepreneurial dynamisms by actors, as well as, use of poor production and processing technologies. This paper applies the results of participatory market analysis and questionnaire surveys to map the value chain and assess profitability in each node. The study findings suggest that the value chain was generally operating inefficiently. Overall, cattle producers received lower prices and profit margins. Vertical integration of livestock farmers, beef processors, and traders was limited. The paper recommends tailor made campaigns and training that will sensitize producers to treat beef cattle keeping as a business, set aside at least few animals for sale in each year, fatten them using locally available feeds and produce animals of good quality which will earn them good money.