Browsing by Author "Tuhumwire, Joshua"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    The Context of the Assessment
    (United Nations, 2016) Harris, Peter; Tuhumwire, Joshua
    Consider how dependent upon the ocean we are. The ocean is vast – it covers seven-tenths of the planet. On average, it is about 4,000 metres deep. It contains 1.3 billion cubic kilometres of water (97 per cent of all water on Earth). But there are now about seven billion people on Earth. So we each have just one-fifth of a cubic kilometre of ocean to provide us with all the services that we get from the ocean. That small, one-fifth of a cubic kilometre share produces half of the oxygen each of us breathes, all of the sea fish and other seafood that each of us eats. It is the ultimate source of all the freshwater that each of us will drink in our lifetimes. The ocean is a highway for ships that carry across the globe the exports and imports that we produce and consume. It contains the oil and gas deposits and minerals on and beneath the seafloor that we increasingly need to use. The submarine cables across the ocean floor carry 90 per cent of the electronic traffic on which our communications rely. Our energy supply will increasingly rely on wind, wave and tide power from the ocean. Large numbers of us take our holidays by the sea. That one fifth of a cubic kilometre will also suffer from the share of the sewage, garbage, spilled oil and industrial waste which we produce and which is put into the ocean every day. Demands on the ocean continue to rise: by the year 2050 it is estimated that there will be 10 billion people on Earth. So our share (or our children’s share) of the ocean will have shrunk to one-eighth of a cubic kilometre. That reduced share will still have to provide each of us with sufficient amounts of oxygen, food and water, while still receiving the pollution and waste for which we are all responsible.
  • Thumbnail Image
    Item
    Geothermal Energy in Uganda, Country Update
    (In International Geothermal Conference, Reykjavik, Iceland, 2003) Bahati, Godfrey; Natukunda, James Francis; Tuhumwire, Joshua
    Exploration for geothermal energy in Uganda has been in progress since 1993. The studies have focused on three major geothermal areas namely Katwe, Buranga and Kibiro.The three areas are in advanced stages of surface exploration and will soon be subjected to exploratory drilling that will pave the way for a feasibility study. The overall objective of the study is to develop geothermal energy to complement hydro and other sources of power to meet the energy demand of rural areas in sound environment. The current study has focused on geology, geochemistry, hydrology and geophysics with the aim of elucidating subsurface temperatures and the spatial extent of the geothermal systems. The results indicate that the geothermal activity in the three areas is related to the volcanic and tectonic activities of the Rift Valley, which has a higher heat flow than the surrounding Precambrian crust. Subsurface temperatures of approximately 140-200˚C for Katwe, 120- 150˚C for Buranga, and 200-220˚C for Kibiro have been predicted by geothermometry and mixing models. Anomalous areas have been delineated in Katwe and Kibiro prospects using geophysical methods. Drilling of shallow boreholes to a depth of 200-300m for temperature gradient measurement has been completed and the temperatures measured (30-36˚C/km) are slightly above the global average of 30˚C/km, which suggests deep reservoirs in Katwe and Kibiro or geothermal reservoirs offset from the drilled areas. Additional geophysical measurements to locate the deep reservoirs and drill sites in the two areas are recommended. The results will then be used to update the geothermal models that will be a basis for the drilling of deep geothermal wells. The Buranga area still needs detailed geophysical surveys to delineate anomalous areas that could be targets for drilling. The results of the preliminary geothermal investigations on other areas predict subsurface temperatures of 100 - 160˚C suitable for small scale electricity production and direct uses. These areas have been ranked based on predicted subsurface temperatures and other geothermal features for further exploration and development.
  • Thumbnail Image
    Item
    Land-Sea Physical Interaction
    (United Nations, 2016) Reyna, Julián; Wilson, William Douglas; Harris, Peter; Komatsu, Teruhisa; Mosetti, Renzo; Tõnisson, Hannes; Tuhumwire, Joshua
    This chapter deals with how human activities have changed the physical interaction between the sea and the land. This physical interaction is important because about 60 per cent of the world’s population live in the coastal zone (Nicholls et al., 2007). The “coastal zone” is defined in a World Bank publication as “the interface where the land meets the ocean, encompassing shoreline environments as well as adjacent coastal waters. Its components can include river deltas, coastal plains, wetlands, beaches and dunes, reefs, mangrove forests, lagoons and other coastal features.” (Post et al., 1996) In some places, natural coastal erosion processes cause damage to property, harm to economic activities and even loss of life. In other places, human activities have modified natural processes of erosion of the coast and its replenishment, through: (1) coastal development such as land reclamation, sand mining and the construction of sea defences that change the coastal alongshore sediment transport system; (2) modification of river catchments to either increase or decrease natural sediment delivery to the coast; and (3) through global climate change and attendant sea level rise changes to surface wave height and period and the intensity and frequency of storm events.
  • Thumbnail Image
    Item
    Offshore Mining Industries
    (United Nations (UN): New York, NY, USA., 2016) Baker, Elaine; Gaill, Françoise; Lamarche, Geoffroy; Raharimananirina, Clodette; Santos, Ricardo; Tuhumwire, Joshua
    Marine mining has occurred for many years, with most commercial ventures focusing on aggregates, diamonds, tin, magnesium, salt, sulphur, gold, and heavy minerals. Activities have generally been confined to the shallow near shore (less than 50 m water depth), but the industry is evolving and mining in deeper water looks set to proceed, with phosphate, massive sulphide deposits, manganese nodules and cobalt-rich crusts regarded as potential future prospects.
  • Thumbnail Image
    Item
    Status of Geothermal Energy Exploration and Development in Uganda
    (Department of Geological Survey and Mines, 2008) Bahati, Godfrey; Tuhumwire, Joshua; Natukunda, James Francis
    Exploration for geothermal energy in Uganda has been in progress since 1993. The studies have focused on three major geothermal areas namely Katwe, Buranga and Kibiro. The three areas are in an advanced stage of surface exploration and will soon be subjected to exploratory drilling that will pave the way for a feasibility study. The overall objective of the study is to develop geothermal energy to complement hydro and other sources of power to meet the energy demand of rural areas in sound environment. The methodology of the study has focused on geology, geochemistry, hydrology and geophysics with the aim of elucidating subsurface temperatures and the spatial extent of the geothermal systems. The results indicate that the geothermal activity in the three areas is related to the volcanic and tectonic activities of the Rift Valley, which has a higher heat flow than the surrounding Precambrian crust. Subsurface temperatures of approximately 140-200˚C, 120-150˚C and 200-220˚C for Katwe, Buranga and Kibiro respectively have been predicted by geothermometry. Anomalous areas have been delineated in Katwe and Kibiro prospects using geophysical methods. Drilling of shallow boreholes to a depth of 200-300m for temperature gradient measurement has been completed and the temperatures measured (30-36˚C/km) are slightly above the global average of 30˚C/km. These results and proposed additional geophysical measurements will be used to update the geothermal models in three areas that will be a basis for the drilling of deep exploration wells. The results of the preliminary geothermal investigations of the other areas predict subsurface temperatures of 100 - 160˚C suitable for electricity production and direct uses. The areas have been graded based on predicted subsurface temperatures and other geothermal features for further exploration and development.