Bio

CITATION FOR PROFESSOR ERIC ONYANGO ODADA

Eric Onyango Odada, born in Nyanza is a full Professor of Geology at the University of Nairobi. He obtained his PhD in Marine Geochemistry from Imperial College, London University (1986) and has been with the University of Nairobi as a Lecturer since 1989. Before joining the University, he served as Chief Research Officer, Kenya Marine and Freshwater Research Institute (KMFRI) and Principal Geologist with the Mines and Geology Department, Ministry of Environment and Natural Resources, Kenya.

Publications


2014

Loiselle, S, zar A´s C´, Adgo E, Ballatore T, Chavula G, Descy JP, Harper DM, Kansiime F, Kimirei I, Langenberg V, Ma R, Sarmento12 H, Odada E.  2014.  Decadal Trends and Common Dynamics of the Bio- Optical and Thermal Characteristics of the African Great Lakes. PLOS ONE. 9(4):1-6. Abstract

The Great Lakes of East Africa are among the world’s most important freshwater ecosystems. Despite their importance in providing vital resources and ecosystem services, the impact of regional and global environmental drivers on this lacustrine system remains only partially understood. We make a systematic comparison of the dynamics of the bio-optical and thermal properties of thirteen of the largest African lakes between 2002 and 2011. Lake surface temperatures had a positive trend in all Great Lakes outside the latitude of 0u to 8u south, while the dynamics of those lakes within this latitude range were highly sensitive to global inter-annual climate drivers (i.e. El Nin˜o Southern Oscillation). Lake surface temperature dynamics in nearly all lakes were found to be sensitive to the latitudinal position of the Inter Tropical Convergence Zone. Phytoplankton dynamics varied considerably between lakes, with increasing and decreasing trends. Intra-lake differences in both surface temperature and phytoplankton dynamics occurred for many of the larger lakes. This inter-comparison of bio-optical and thermal dynamics provides new insights into the response of these ecosystems to global and regional drivers.

2013

Omuombo, C, Odada EO, Olago DO.  2013.  Coastal Erosion: A Natural Outlook-Geonvironmental Resources and Hazards. Abstract

This chapter focuses on the existing information on the hydrodynamics and sediment transport processes along the Kenyan coastline. Although the low-lying coastline is under threat from coastal erosion that has led to its destabilization, the factors are linked to local and global processes. Changes in land used for agriculture have led to increase sediment fluxes which have resulted in increase in turbidity and siltation. Other activities such as coral and mangrove harvesting, seawall construction, urbanization and lack of regulations on the construction of structures along of the coastline can be linked to the coastal erosion processes. Among the global factors, the Kenyan coastline has been affected by the extreme events such as the El Niño event of 1997/1998, which led to devastating effects such as an increase in sediment fluxes and turbidity, coral bleaching and mortality and substantial sea level rise. A 1.3 °C sea surface temperature rise on the western side of the Indian Ocean has been recorded since 1880; this makes the coastline vulnerable to the impacts of the predicted 6 °C temperature rise in East Africa due to climate change. It is estimated that the biggest coastal city of Mombasa will be 17% submerged by 2100 and the Tana delta will experience a 5% loss as a consequence of climate change due to the frequent storms that are anticipated. Although the 2004 global tsunami events did not have devastating effects on the Kenyan coast, the event hit the coastline at low tide and this led to the limited damage. In the management of the shoreline, currently an Integrated Coastal Zone Management strategy does not exist although efforts are underway to develop a shoreline management strategy that incorporates the principles of the integration in the management of the coastline. These efforts are encouraged by the success of the marine protected areas of Malindi and Watamu and the current co-management strategy adapted by the Ministry of Fisheries through the Beach Management Units that engages the resource users as equal partners in the management of the coastal resources.
Keywords

Urbanization;
Sediment flux;
El Niño;
Sea surface temperature;
Tsunami;
Mombasa;
Tana delta;
Marine protected areas;
Beach Management Units

Mark, SR, Kelly MR, Gheorghe C, Raymond M, Nikolay A, Sansanee C, Navy H, Karen KA, Odada EO, Oscar P, Geoffrey P, Sergei R.  2013.  Science and Management of Transboundary Lakes: Lessons Learned from the Global Environment Facility Program. AbstractWebsite

The International Waters Science Project Lakes Working Group reviewed 58 Global Environment Facility (GEF) projects that addressed serious environmental and human development issues in transboundary lakes. The lessons learned from the review of these projects were integrated with the intention to contribute to the design and success of future projects. Issues that will continue to impact lake ecosystems and their management include changing agricultural practices, resource extraction, emerging contaminants, energy policies, and water allocation. Future lakes projects addressing these issues must also consider the potential confounding effects of changing land use and climate on watershed processes, water quality, food web structure and biodiversity. Current and future scientific challenges include developing strategies for climate adaptation, improving the capacity to detect change and enhancing the application of an ecosystem approach within lakes management. Failure to consider the unique physical and biological features and processes in lakes can be a barrier to effective remediation. The spatial and temporal variability in lakes and their often slow response to remedial actions need to be considered in the design of monitoring programs. Factors that improved the success of GEF transboundary projects included early and strong communication, engagement of stakeholders, rigorous peer review and international science teams linked to local capacity building and policy development. The application of both natural and socio-economic science based assessment, and adaptive management were essential for full project implementation and led to optimization of water resources allocation while sustaining ecosystems on which social and economic systems depend.

Odada, EO, Cherlet M.  2013.  Impacts on climate variability and change.

2011

Higgins, S, Odada EO, Becht R.  2011.  Lake Naivasha: experiences and lessons learned brief.
Odada, EO, Olaka LA, Trauth MH, Olago DO.  2011.  The sensitivity of East African rift lakes to climate fluctuations. Journal of Paleolimnology. 44(2):629-644. Abstractspringer

Sequences of paleo-shorelines and the deposits of rift lakes are used to reconstruct past climate changes in East Africa. These recorders of hydrological changes in the Rift Valley indicate extreme lake-level variations on the order of tens to hundreds of meters during the last 20,000 years. Lake-balance and climate modeling results, on the other hand, suggest relatively moderate changes in the precipitation-evaporation balance during that time interval. What could cause such a disparity? We investigated the physical characteristics and hydrology of lake basins to resolve this difference. Nine closed-basin lakes, Ziway-Shalla, Awassa, Turkana, Suguta, Baringo-Bogoria, Nakuru-Elmenteita, Naivasha, Magadi-Natron, Manyara, and open-basin Lake Victoria in the eastern branch of the East African Rift System (EARS) were used for this study. We created a classification scheme of lake response to climate based on empirical measures of topography (hypsometric integral) and climate (aridity index). With reference to early Holocene lake levels, we found that lakes in the crest of the Ethiopian and Kenyan domes were most sensitive to recording regional climatic shifts.

Their hypsometric values fall between 0.23–0.29, in a graben-shaped basin, and their aridity index is above unity (humid). Of the ten lakes, three lakes in the EARS are sensitive lakes: Naivasha (HI= 0.23, AI = 1.20) in the Kenya Rift, Awassa (HI = 0.23, AI = 1.03) and Ziway-Shalla (HI = 0.23, AI = 1.33) in the Main Ethiopian Rift (Main Ethiopian Rift). Two lakes have the graben shape, but lower aridity indices, and thus Lakes Suguta (HI = 0.29, AI = 0.43) and Nakuru-Elmenteita (HI = 0.30, AI = 0.85) are most sensitive to local climate changes. Though relatively shallow and slightly alkaline today, they fluctuated by four to ten times the modern water depth during the last 20,000 years. Five of the study lakes are pan-shaped and experienced lower magnitudes of lake level change during the same time period. Understanding the sensitivity of these lakes is critical in establishing the timing or synchronicity of regional-scale events or trends and predicting future hydrological variations in the wake of global climate changes.

Keywords: East African Rift-Tectonics-Geomorphometry-Aridity index-Sensitive lakes

Odada, E, Langenberg V.  2011.  A Review of the impact of climate change on East African lake productivity: implications for future carrying capacity. Scientific Conference on the NASAC-KNAW Collaboration Initiative. :5-6., Nairobi: KNAW

2010

E.O, O.  2010.  Integration of coastal and marine areas into sustainable development strategies: A case study of Africa. Journal of Oceanography and Marine Science. 1(3):40-52. AbstractJournal of oceanography and marine sciences

The coastal and marine environments of the African region are uniquely situated to support a variety of activities and to serve diverse human needs for food, transport, and recreation. The pressures from growing populations in coastal zones of Africa, expanding coastal tourism, intensified fisheries, and a large number of other economic activities pose an increasing threat, which jeopardize the quality of these coastal and marine environments. Large-scale destruction of some of Africa’s most valuable resources, the coastal forests and mangroves, the lagoons and coral reefs has caused serious degradation of the environment, thus affecting the life of the coastal inhabitants and the economic development of the countries of the African region.

The Seychelles Island in the western Indian Ocean for example, was famous for its luxuriant forests and an incredible abundance of wildlife. But many reefs have been mined for coral for the purpose of construction. Mangrove forests on the granitic islands have been raised to the ground or drained and reclaimed. Severe erosion is as a result of this destruction. Many African countries are confronted with serious manpower problems, which are proving to be great impediments in the economic development, especially of their coastal and marine areas. In many cases, the most important cause underlying these problems is the lack of adequate training facilities for the type of manpower required. The teaching of marine science and marine technology in universities of the region is a recent development and in many of the universities, there are as yet no comprehensive study programmes covering the whole spectrum of marine science and technology at the undergraduate or postgraduate level. The situation in regard to research in marine science and technology is equally unsatisfactory. To implement sustainable development of coastal and marine resources of the African region, there is an urgent need to:

(1) build human resources by undertaking short-term academic training to strengthen existing capabilities;

(2) promote public awareness by producing educational materials on the ecological and socio-conomic contributions of the marine resources and the consequences of unsustainable exploitation

(3) organise policy workshops, seminar and/or conferences involving relevant policy and law-makers to increase their understanding of and commitment to the sustainable use of the resources in their coastal and marine areas, and

(4) implement integrated coastal zone management programmes by establishing case studies in pilot sites in selected countries of the African region.

The object of this paper is to review background information on the present status and trends of coastal and ocean development in Africa, and on the existing capabilities in the region to implement sustainable development strategies. It is intended to lay out the framework and strategy to be used in the design of an integrated management of coastal and marine areas in the region.

Key words: Coastal ecosystems, marine environments, sustainable development, population pressure, environmental degradation, sea level rise, capacity building, management planning.

Odada, E, Johnson TC, Whittaker KT.  2010.  The Limnology, Climatology and Paleoclimatology of the East African Lakes. , Amsterdam: Gordon and Breach Publishers
Odada, E.  2010.  Metal accumulation rates in sediments and ferromanganese oxide crusts from the Romanche Fracture Zone (RFZ), equatorial atlantic. Journal of African Earth Sciences. 4(22):579-588. Abstract

A suite of sediments and FeMn oxide crusts from the Romanche Fracture Zone (RFZ) in the equatorial Atlantic has been investigated by radiochemical techniques to determine the rates of metal accumulation in the deposits. This approach was used to assess any possible hydrothermal inputs to the deposits.The metal accumulation rate data for the sediments indicate that there is no significant hydrothermal influence in the deposits. The concentration of metals can be accounted for largely in terms of normal oceanic sedimentation processes. This was confirmed by metal accumulation rate data of the crusts that represent hydro-genetic deposit formed by slow accumulation of trace-enriched oxides directly from the water column.

Odada, E, Strecker MR, Olago DO, Olaka LA, Trauth MH.  2010.  Human evolution in a variable environment: the amplifier lakes of Eastern Africa. Quaternary Science Reviews. volume 29(Issues 23–24,):Pages2981–2988. AbstractSCIENCE DIRECT

Abstract

The development of the Cenozoic East African Rift System (EARS) profoundly re-shaped the landscape and significantly increased the amplitude of short-term environmental response to climate variation. In particular, the development of amplifier lakes in rift basins after three million years ago significantly contributed to the exceptional sensitivity of East Africa to climate change compared to elsewhere on the African continent. Amplifier lakes are characterized by tectonically-formed graben morphologies in combination with an extreme contrast between high precipitation in the elevated parts of the catchment and high evaporation in the lake area. Such amplifier lakes respond rapidly to moderate, precessional-forced climate shifts, and as they do so apply dramatic environmental pressure to the biosphere. Rift basins, when either extremely dry or lake-filled, form important barriers for migration, mixing and competition of different populations of animals and hominins. Amplifier lakes link long-term, high-amplitude tectonic processes and short-term environmental fluctuations. East Africa may have become the place where early humans evolved as a consequence of this strong link between different time scales.

Odada, E, Barange M, Goddard L.  2010.  Needs Assessment for Climate Information on Decadal Timescales and Longer. Procedia Environmental Sciences. VOLUME 1:Pages275–286. AbstractSCIENCE DIRECT

Abstract

Societal needs for climate information on decadal timescales is confirmed in terms of its potential value and relevance as a driver in sector decision-making, but such information is currently lacking. Predictions and observationally based analyses for decadal climate variability and change are needed. In addition, the following issues have been identified as those that must be addressed in order to facilitate effective use of climate information on decadal timescales in the decision-making processes of different socio-economic sectors: building effective partnership systems linking stakeholders, users and decision-making sectors and climate information providers; more research and investment is to translate information of large-scale decadal variations into the regional and local scales required for decisions; maintaining and sustaining the Global Climate Observing System (GCOS), in particular, enhancement of the global ocean observing system; and, ways to assemble, check quality, reprocess and reanalyse datasets relevant to decadal prediction. Ways of securing climate observing systems particularly in least developed regions are urgently needed.

Keywords
Agriculture and food production; water management;energy;marine fisheries and ecosystems; land degradation and fire management: health

Odada, EO, Olago DO, Ochola WO.  2010.  Environment for Development: An Ecosystems Assessment of Lake Victoria Basin Environmental and Socio-economic Status, Trends and Human Vulnerabilities. , Nairobi: United Nations Environment Programme (UNEP) and PASS AbstractUNEP/PASS

Discussions on social and policy dimensions of the Lake Victoria Basin (LVB) centre on the inhabitants of the basin and their livelihood strategies which are defined by environmental stewardship and natural resource utilization. This paper presents a contextual narrative of the people of the LVB and their livelihood. It sets the stage for an ecosystem assessment of the basin’s social and economic implication of natural resource state, trends and vulnerabilities. The demographic characteristics and selected social indicators for the basin are presented with a focus on implications to sustainable resource management. A description of fishing together with other main occupational activities of the basin’s inhabitants is presented with emphasis on strategies, impacts, challenges and vulnerabilities that the current resources extraction activities impose on the people and environment. Owing to the transboundary nature of the basin, it is recognised that the people and institutional framework of the basin including the East African Community (EAC) together with subsidiary arrangements such as the Lake Victoria Development Programme (LVDP) hold the key to a joint and sustainable management of the basin. The policy areas singled out as important include: ecosystems, natural resources and environment; production and income generation; living conditions and quality of life; population and demography; and governance and institutional order.

Keywords: Socio-economics, policy framework, Lake Victoria basin, livelihoods, sustainable development

2009

Odada, EO, Ochola WO, Olago DO.  2009.  Factors driving land use change: Effects on ecosystems services and human wellbeing in Lake Victoria basin. AbstractWebsite

To offer an increased understanding of the spatial patterns, temporal, social and physical predictors of the conversion and transformations of land use and land cover in Lake Victoria basin, an assessment of proximate and underlying forces is presented. This paper discusses key theoretical underpinnings for the manifold linkages existing between selected drivers and land use and cover change around the basin and their consequences on human wellbeing. Using a meta-analytical research design, the paper analyses ecosystems level cases of the causes ofland use and cover change in the basin, in order to determine any spatio-temporal or institutional patterns and dynam.ics. A suite of recurrent core variables have been identified to influence land use and cover changes in the basin. The most prominent of these at the underlying category are climatic factors, economic factors, institutions, national and regional policies, population growth, and other remote influences. At the proximate level, these factors drive cropland expansion, overgrazing, infrastructure extension and rates of land degradation. These are supported by empirical evidence from the basin. This assessment is crucial for appropriate local and transboundary policy interventions, which have to be fine-tuned to the locale-specific dynamic patterns associated with the inherent land use and land cover changes.

E.O, O.  2009.  The role of isotope geology in the reconstruction of the Cenozoic history of Kenya. Academic Journals . 1(2):42-47. AbstractAcademic Journals

Geochronology has had a dramatic impact on the understanding of African geology. Consideration of the radiometrically dated geological phenomena in the continent has led to a more complete view of the evolution of Africa. In this paper, the role of isotope geology in constructing the cenozoic history of Kenya is systematically reviewed. The general sequence in the cenozoic volcanics shows a continuous history of rift formation and volcanic activities from mid-Tertiary times. Stable isotope measurements on carbonates have been used to elucidate climatic conditions prevailing at the time of deposition of these materials. Radio-isotopic dates on igneous material have helped to erect an overall time scales for homonid evolution in East Africa. Despite shortcomings in the available ages, isotope geology has played a significant role in the construction of the geological history of Kenya.

Key words: geochronology, isotopes, cenozoic, rifting, volcanism, palaeoclimate, fossils, homonids, reconstruction,evolution.

2008

2007

Odada, E, Olago D.  2007.  Challenges of an ecosystem approach to water monitoring and management of the African Great Lakes. Aquatic Ecosystem Health & Management. Volume 9( Issue 4):pages433-446. AbstractWebsite

The Great Lakes Belt of Africa cuts across five major drainage basins: The Nile, Congo-Zaire, Rift Valley, Coastal and Zambezi basins. The region contains the earth's largest aggregation of tropical lakes. Three of these lakes–Victoria, Tanganyika and Malawi—hold one quarter of the earth's total surface water supply, and are home to rich and diverse assemblages of fish. Apart from the diversity and endemicity of their biota, properties that distinguish the African Great Lakes from their North American counterparts include their great age, sensitivity to climate change, long residence times, persistent stratification, continuously warm temperatures at all depths, major ion composition, and propensity for nitrogen limitation. Current management problems include over-fishing, increased input of sediment and nutrients, and in the case of Lake Victoria, loss of endemic fish species and the proliferation of the introduced water hyacinth. The harmonization of research programmes and management strategies among the various riparian countries is a challenge. Among the other challenges currently facing the African Great Lakes, perhaps none is more important, nor more often overlooked, than the ecosystem-based management. Ecosystem integrity is beginning to receive acknowledgement in some quarters as a foundation upon which sound management must be built. Recent changes in the African Great Lakes have resulted in an increased realization that individual components of these systems cannot be understood in isolation, and that effective management must expand beyond conventional fisheries management to account for the interaction of physical, geological, chemical and biological processes at the ecosystem scale. Although specific processes in tropical aquatic ecosystems, such as hydrodynamics, plankton production and fisheries production have received some attention, there remains a need to integrate these processes in order to gain a better understanding of ecosystem functioning. One means of achieving this is through the development of conceptual and numerical models, which can facilitate both the theoretical understanding and applied management of these ecosystems. As management problems move from the relatively simple issue of fishery control to the more complex issues of climate change and land use, models will play an important role in decision-making processes regarding sustainable utilization of these vital natural systems.

Keywords biophysical aspects, natural and anthropogenic pressures, policy applications

E.Odada, D.Olago.  2007.  Sediment impacts in Africa's transboundary lake/river basins: Case study of the East African Great Lakes. , London: Taylor and Francis Ltd Abstract

The current population pressure, inappropriate cultivation practices, forest removal and high grazing intensities on forests, wetlands, rangelands and marginal agricultural lands leads to unwanted sediment and stream flow changes that mainly impacts the downstream human and natural communities. Forests and bush are cleared, and wetlands are encroached to create space for human settlement, roads construction and to satisfy wood fuel energy demands. Similarly, pastoral areas are subjected to growing human and livestock populations, leading to land degradation, soil erosion and to an increase in the load of non-point pollutants. Landscape disturbance over many decades, and the resulting increase in soil erosion and sedimentation is the dominant cause of the ongoing eutrophication in many of the lakes in eastern Africa. Increased sedimentation in the rivers and lakes has many impacts. For example, it has altered some aquatic habitats and communities, contributed to increasing eutrophication, abetted the proliferation of algal blooms and water hyacinth reduced the amount of dissolved oxygen, etc. This paper outlines some of the problems created by increased sedimentation within the East African Great Lakes basin, and provides some possible solutions to the mitigation of sediment flux through integrated sediment management approaches.

Keywords: deforestation; erosion; agriculture; eutrophication; ecosystem change; conservation

2006

Bouwer, LM, Odada E, de Moel H, Ward PJ, Renssen H, Aerts JCJH.  2006.  Sensitivity of global river discharges under Holocene and future climate conditions. AbstractWebsite

A comparative analysis of global river basins shows that some river discharges are more sensitive to future climate change for the coming century than to natural cliniate variability over the last 9000 years. In these basins (Ganges, Mekong, Volta, Congo, Amazon, Murray-Darling, Rhine, Oder, Yukon) future discharges increase by 6-61 %. These changes are of similar magnitude to changes over the last 9000 years. Some rivers (Nile, Syr Darya) experienced strong reductions in discharge over the last 9000 years (17- 56%), but show much smaller responses to future warming, The simulation results for the last 9000 years are validated with independent proxy data. Citation: Aerts, J. C. J. H., H. Renssen, P. J. Ward, H. de Moel, E. Odada, L. M. Bouwer, and H. Goosse (2006), Sensitivity of global river discharges unde~ Holocene and future climate conditions, Geophys. Res. Lett., 33, L19401, doi:10.1029/2006GL027493.

Odada E.O., Olago DO, W. O.  2006.  Lake Victoria Basin Environment Outlook: Environment and Development, 2006. :140., Nairobi: UNEP
E.O, O, D.O O.  2006.  Challenges of an Ecosystem approach to water monitoring and management of the African Great Lakes. Aquatic Ecosystem Health and Management. 9(4):433-446. Abstractwww.aehms.org

Abstract

Chambo is an important fish to Malawi's economy and to the livelihoods of local people in the southern end of Lake Malawi. Overexploitation of the chambo has been a source of concern since the 1930s. The biological and economic collapse of the fishery in Lake Malombe and the Upper Shire River in the early 1990s, and growing evidence in recent years of its decline in the Southeast Arm of Lake Malawi (the major productive area for the species) have galvanised the Government of Malawi into making an attempt to restore the chambo to former levels of production.
This paper argues that while the proposed solutions for restoring the chambo might be well intentioned, they nevertheless ignore existing knowledge and scholarship about fisheries management in African freshwater lakes gathered over the last six decades. A body of knowledge on the biological and scientific basis for regulating the chambo already exists. The missing link is an understanding and appreciation of the social, economic, political and institutional drivers on exploitation patterns of the chambo. Future management solutions must be based on the collective concerns of all potential users. More specifically, such solutions should be cognisant of local knowledge, fishers' experiences and the way they view and define their problems. If these are disregarded, finding solutions to the enormous challenge of restoring chambo stocks to their former status will be as difficult as grappling in the dark.

Keywords: restoration, existing knowledge, stakeholder involvement

Odada, E, Olago D, A K, A B, S W, M N, J K.  2006.  East African Rift Valley Lakes,GIWA regional assessment 47, 2004. :1-138., Nairobi: United Nations Environment Programme
E.Odada, Onyando JO, Obudho PA.  2006.  Lake Baringo: Addressing threatened biodiversity and livelihoods. Lakes & Reservoirs: Research & Management. Volume 11(4):287-299. AbstractWebsite

Lake Baringo is a shallow, internal drainage, freshwater lake located in the Kenyan Rift Valley. The lake is an important source of water for humans and livestock, as well as a significant income source for local communities through activities such as tourism, biodiversity conservation, and fish sold in local markets. The lake has been subject to overfishing, as well as to greatly enhanced sedimentation as a result of land use changes in the drainage basin. This paper provides an analysis of the conditions prevailing at Lake Baringo, and examines in detail the management response to the problems facing the lake. The roles of the many and varied institutions in the lake basin's management are discussed, and an analysis of internationally funded projects designed to ameliorate the situation is provided.

Keywords: biodiversity; fishing moratorium; Global Environment Facility; Lake Baringo; lake basin management; land use change; sedimentation

E.Odada, H.A.Bootsma, R.Hecky.  2006.  African lake management initiatives: The global connection. Lakes & Reservoirs: Research & Management. Volume 11(Issues 4):203-213. AbstractWebsite

There is a global dimension to lake management in Africa and elsewhere that will require a concerted action not only from individual riparian states, but also from regional, continental and global communities. The current global lake threats arise from climate change, regional land degradation and semivolatile contaminants, and share the common feature that the atmosphere is the vector that spreads their impacts over large areas and to many lakes. The Great Lakes of Africa (Malawi, Victoria and Tanganyika) are particularly sensitive to these problems because of their enormous surface areas, slow water flushing rates, and the importance of direct rainfall in their water budgets. Their response times might be slow to yield a detectable change and, unfortunately, their recovery times might also be slow. It is possible for atmospheric effects to act antagonistically to the impacts of catchment change, but antagonistic effects could become synergistic in the future. Improved understanding of the physical dynamics of these lakes, and development of models linking their physical and biogeochemical behaviour to regional, mesoscale climate models, will be necessary to guide lake managers.

2005

Odada, EO, Onyando J, Obudho PA.  2005.  Lake Baringo: Experience and lessons learnt brief.
Crossland, JIM, Morcom N.  2005.  The catchment to coast continuum. Website
Odada E.O., A. O, H.E B, K AZ, Highes AA, A KS, K.A. K, Saayman I.C.  2005.  Facing the facts: Assessing the vulnerability of Africa’s water resources to environmental change., 2005. , Nairobi, Kenya: UNEP-DEWA
Odada, EO, Olago, D. O..  2005.  Holocene Climatic, Hydrological and Environmental Oscillation in the Tropics with Special Reference to Africa. Climate Change and Africa.. , London: Cambridge University Press
Odada, E, Olago D, Ochola W, Wandiga S.  2005.  11TH WORLD LAKES CONFERENCE. 11TH WORLD LAKES CONFERENCE. :1-619., Nairobi: international lake environment committee
Odada, E, Olago D.  2005.  Holocene climatic, hydrological and environmental oscillations in the tropics with special reference to Africa. Climate Change in Africa. , London: Cambridge University Press Abstract

The tropics have experienced large and sometimes abrupt fluctuations in the water balance since the beginning of the Holocene period. Water levels were generally high in the equatorial region and northern hemisphere at the beginning of the Holocene, a trend that was asynchronous with many southern hemisphere records. Apart from a desiccation event in many African lakes between 8, 000 and 7, 500 yr BP (Before Present), water levels continued to be high until c.5, 000 yr BP. Southern hemisphere sites experienced intermediate to high lake levels at c.6, 000 yr BP. The tropical lakes experienced a drying phase between 5, 000 and 3, 000 yr BP, and these arid conditions have continued to the present day. Tropical glaciers have, on the other hand, been gradually receding during the Holocene period, but there have been several minor advances. After about 8, 000 yr BP, glacial events show much less spatial consistency. The environmental response has been less marked, but the major trend is from wet/moist vegetation in the early Holocene to drier vegetation from the middle Holocene to the present. The climatic, hydrological and environmental oscillations of the low-latitude regions during the Holocene are linked to changes in earth surface temperatures, sea surface temperatures (SSTs), ocean and atmospheric circulation patterns, regional topography, land surface albedo, etc.

Keywords

Tropical Africa; Holocene climate; hydrological fluctuations; environmental oscillations

E.Odada, D.Olago, M. Ntiba, Gichuki SO, N.Oyieke, W.Ochola.  2005.  BASIC HYDROGEOLOGY IN GEOTHERMAL SYSTEMS . 11th World LAkes Conference. :P10-12., South Africa
Odada, PEO, Olago PDO, Ochola W, Ntiba M, Wandiga S, Gichuki N, Oyieke H.  2005.  PROCEEDINGS OF THE 11 TH WORLD LAKES CONFERENCE, NAIROBI, KENYA, 31 OCTOBER TO 4TH NOVEMBER 2005 . , Nairobi: PASS Publication AbstractWebsite

Abstract
Winam Gulf is a large (surface area ~ 1400 km2) and shallow (<20 m) bay of northeastern Lake Victoria with only one connection to the open lake through Rusinga Channel. To understand the exchange dynamics between Winam Gulf and the offshore waters of Lake Victoria and the hydrodynamics of the region, field studies were carried out from Apr. 22-May 4 and Aug. 5-16 of 2005. A meteorological station (shortwave, total radiation, air temperature, relative humidity, wind speed and direction), thermistor chain (0.75 m vertical resolution) and ADCP (40cm vertical resolution) were deployed in Rusinga Channel in a depth of 20 m. Similarly, at an offshore station in northeastern Lake Victoria another thermistor chain was deployed in a water depth of 40 m along with wind speed and direction sensors.

Over both field campaigns the exchange dynamics through Rusinga Channel behaved similar to a tidally- driven system with surface level fluctuations of between 5-15 cm at the ADCP location, and much larger excursions at the eastern end of Winam Gulf. In general, these surface level movements led to barotropically driven flows into the Gulf during rising surface levels and currents towards the open lake during falling lake level. The frequency of these currents was found to vary between 6 and 12 hours and current speeds ranged from 10-50 cm s-1. Field data and ELCOM simulations indicate that despite the high current velocities in the channel the net exchange is low due to the oscillatory nature of the forcing. This implies that the Gulf is relatively decoupled from the main lake.

Key words: Lake Victoria, Exchange flow, Flushing times

2004

Odada, EO, Karlén W, Svanered O.  2004.  Organic content and X-ray density of lacustrine sediments from Hausberg Tarn, Mount Kenya. AbstractOrganic content and X-ray density of lacustrine sediments from Hausberg Tarn, Mount Kenya

The variations in the organic content of a sediment core from a pro-glacial lake, Hausberg Tarn, located on the NW slope of Mount Kenya has been determined. Two types of methods for determining organic content were compared using sediments from the same core. One type was direct measurement of organic carbon using a carbon analyser and the other was X-ray analysis. The results show that both techniques reveal changes in organic content, which are believed to reflect changes in the glacier size during the last 5700 years. However, the X-ray technique discloses a much more detailed view of the changes in the environment. In addition, the method is considerably faster than the methods of determining organic carbon content or weight loss on ignition.

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