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Towards an understanding of human impact upon the hydrology of Lake Naivasha, Kenya
Abstract and Figures
The water balance of Lake Naivasha, has been calculated from a model based upon the long-term meteorological data of rainfall, evaporation and river inflows. The lake is Kenya's second Ramsar site because of its international importance as a wetland, but supplies drinking water to Nakuru and irrigation water to the nationally important industries of horticulture and power generation. Groundwater flows into and out of the lake are estimated from the model's success in predicting water level fluctuations over the same period. The most accurate predictions of lake level were derived from the data sets of river discharges known to be from the most-reliable time period and gauging stations. The model estimated a current annual abstraction rate of 60 106 m3 ann–1, a figure perhaps six-times higher than that calculated as a `safe' yield in the 1980s. There is an urgent need to accurately measure all abstractions and provide consistent, reliable, hydrological and meteorological data from the catchment, so that a `safe' yield may be agreed upon by all stakeholders and sustainable use of the lake waters achieved.
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... They are key in controlling the global water cycle and are the most dynamic transport agents in the hydrological cycle [7]. Lake resources are highly important for human life and the economy and are the main source of water for drinking, irrigation of lands, and industrial activities, with the lack of water considered an obstructive socioeconomic factor for a country [8]. ...
... In Lake Naivasha, for instance, Rivers Malewa, Gilgil, and Karati discharge considerable nutrients from their catchments into Lake Naivasha [22]. Also, of great importance source of nutrients in the lake is the mixing of the lake, which distribute nutrients during strong wind [8,16,25]. Studies by Njuguna [25] and Kitaka et al., [17] found that the lake is polymictic. According to this study, Soluble Reactive Phosphorous (SRP) ...
... In shallow water, wind waves and current leads to the resuspension of bottom materials and nutrients due to the upwelling of the lake. Currently, most evidence shows that freshwater eutrophication ultimately arises from a persistent increase in phosphorous influx from urban and other anthropogenic sources [8,16,25]. The mean Total Nitrogen levels depicted seasonal shifts in concentration, ...
Lake Naivasha is a freshwater lake whose water quality is of great concern because of human and natural influences that affect its water chemistry and limnological characteristics. The main objective of this paper was to determine the temporal variation of physical and chemical characteristics of water in Lake Naivasha. Physico-chemical parameters were studied monthly and collected in triplicates from seven pre-defined stations from February 2019 to July 2019. Samples were collected in triplicates to determine nitrate nitrogen, SRP, TN, TP, ammonium nitrogen, and silicates. Water temperature, conductivity, DO, secchi, and pH were measured in situ using a multimeter probe. The findings of the study showed that the mean temporal variations in TN were 471 µg/L ± 170.61 SD, TP 97.97 µg/L ± 49.06 SD, NO3-N 6.70 µg/L ± 3.55 SD, NH4-N 18.93 µg/L ± 10.91 SD and SiO2 3.18 mg/L ± 2.99 SD. The temporal in situ readings showed a mean temperature of 22.73 °C ± 1.6 SD, DO 8.51 mg/L ± 0.87 SD, and pH 8.13 ± 0.3 SD. Single-factor ANOVA test revealed that temperature, dissolved oxygen, conductivity, pH, TP, TN, and silicates were significantly different between the sampled months (p <.05). The results depict that anthropogenic activities, seasonal shifts, and variation play a key role in determing the lake's water quality and limnological characteristics. There is a need for monitoring the limnological characteristics of Lake Naivasha basin to understand the water quality dynamics of the ecosystem and to come up with relevant management strategies.
... Nutrient levels dynamic in the lake has also been attributed to the lake level fluctuations that influence its area and productivity. According to the study conducted by Harper and Becht (2002), they classified Lake Naivasha as moderately eutrophic as a result of higher nutritents loads into the lake from the point sources of pollution (River Malewa Mouth and Sewage Discharge Point). ...
Lake Naivasha in Kenya is an important livelihood resource for its adjacent communities. However, this freshwater lake is under significant strain due to anthropogenic activities. The study aimed to determine the water quality status of Lake Naivasha in order to establish its trophic state. Physico-chemical parameters were studied in seven pre-defined stations in the main lake from February to July 2019 (autumn and winter months). Monthly samplings were done and sample analyses using standard procedures were undertaken. Samples were collected in triplicates for the determination of nitrate nitrogen, soluble reactive phosphorous, total nitrogen (TN), total phosphorous (TP), ammonium nitrogen, silicates, and chlorophyll a. Water temperature, conductivity, dissolved oxygen (DO), and pH were measured in situ using a multimeter probe. The results showed the mean water temperature to be 22.73 ± 1.6°C, DO 8.51 ± 0.87 mg/L, conductivity 233.85 ± 26.94 μS/cm, pH 8.13 ± 0.3, TN 471 ± 170.61 µg/L, PO 4 5.88 ± 2.12 µg/L, TP 97.97 ± 49.06 µg/L, NO 3-N 6.70 ± 3.55 µg/L, NH 4-N 18.93 ± 10.91 µg/L, SiO 2 3.18 ± 2.99 mg/l and Chlorophyll a 21.51 ± 4.25 Mg/m³. The study revealed that secchi depth, total phosphorous, and chlorophyll a showed significant differences spatially (P = 0.05). The results imply that Lake Naivasha is contaminated with pollutants from domestic wastewater, agricultural and/or surface run off. A sewage discharge point and the R. Malewa mouth were identified as the main point sources of pollution. Therefore, there is a need for measures to be put in place to reduce water contamination from these points in order to improve the water quality of the lake.
... The spreadsheet-based hydrological models as excel applications are preferred because of their flexibility, requirement of fewer input data, easier availability, and simplicity to develop a water balance between inflow and outflow parameters. This type of model needs only time-series climatic and hydrometric data and determines unknown components using a mass balance (Becht & Harper 2002;Ayenew & Gebreegziabher 2006). The advantages that can be attributed to the use of spreadsheet are (i) it is streamlined as compared with the other conventional software that means it requires less coding and reduces the complication of using and (ii) the spreadsheet model can be recomputed quickly all affected dependent parameters as any independent parameters are changed (Dexter & Avery 1991). ...
This study aims to calculate the water balance, interaction with irrigation water inflow, and hydrodynamics of Lake Beseka by a spreadsheet-based model using climatic, hydrological, multi-temporal satellite images, groundwater, and lake chemistry data. The rainfall for the catchment was estimated as 558.4 mm/year, whereas the mean evaporation was computed as 2,214 mm/year by the Penman method. The annual direct rainfall contribution to the lake was found to be 25.84 MCM (million cubic meters) with a runoff inflow in the catchment area of 37.2 MCM. This balance pointed to the mean evaporation of 108.2 MCM/year in the lake indicating that the water inflow was greater than the outflow. A major cause for the rise of the lake level was the drainage of excess irrigation water toward the lake, mainly from the Fentale Irrigation Farm. The average increment of the groundwater level in the area was 12 cm/year from 2010 to 2014. From 1998 to 2014, the electrical conductivity was reduced by 25.6%, and calcium was increased by 96%. The study outlined that appropriate irrigation drainage should be implemented in the catchment to ensure the balance between the rainfall, infiltration, and surface runoff to optimize economic and social welfare in the area. HIGHLIGHTS
This study investigated the water balance, hydrological variability, and main cause of water level increment of Lake Beseka.;
Hydrological, climatic, satellite images, and groundwater chemistry data were used to analyze lake hydrodynamics.;
Spreadsheet-based water balance model and ArcGIS were used for the investigation of hydrological variability and water balance.;
It explained the interaction of lake level and irrigation drainage.;
... The dynamic nutrient levels in the lake can be attributed to the high nutrient inputs from within and without the lake which is currently regarded as moderately eutrophic (Becht and Harper, 2002). Prior to eutrophication, Lake Naivasha was more phosphorus limited than nitrogen (Kitaka et al., 2002). ...
Kindly attend to the highlighted references and include citation in yellow in the reference section. Phytoplankton community structure plays a vital role in freshwater ecosystems. Besides the provision of dissolved oxygen through photosynthesis, they also form an important diet for several fish and zooplankton species. Plankton are also used as biological indicators of water quality. The objective of this paper is to provide a comprehensive review on the changes in phytoplankton community structure and their ecological functional roles. Phytoplankton is the primary producers in Lake Ecosystem. The diversity, distribution, and abundance of phytoplankton are influenced by both abiotic and biotic factors. Lake Naivasha has undergone drastic ecological changes due to the growth in human population, horticultural and floricultural developments and changes in its fisheries. Lake Naivasha is surrounded by horticultural farms that are greatly influencing its ecosystem health and the major fish species in the lake are of introduced species. These anthropogenic activities together with hydrological changes are expected to play a role in the changes in phytoplankton community structure. Previous investigations indicate that there are more than 143 species of phytoplankton and seasonal shift in phytoplankton dominance overtime between Chlorophyta, Bacillariophyta, and Cyanophyta. Due to various limnological, hydrological, and ecological changes being witnessed in the lake, there is need for the monitoring of phytoplankton community structure. Such information would be useful in the lake's management and conservation.
... Lake Naivasha is a shallow-basin freshwater lake that lies between 0° 45' S and 36° 26' E (Becht and Harper 2002;Everard and Harper 2002). It is the second largest freshwater lake in Kenya and has a catchment size of 3,400 km². ...
The Ramsar wetland sites are important habitats for biodiversity and provide ecological services to communities that otherwise have no access to water resources. In Kenya, some wetlands are more prominent and are recognized worldwide as tourist hot spots, biodiversity-rich zones and wildlife habitats. However, these wetlands face overexploitation and degradation from surrounding communities. The efforts to halt underlying threats and the projected declines in the size and quality of inland wetlands at local levels are not sufficient. The question guiding this study is as follows: to what extent do a Ramsar designation and formal and informal education support communities and institutional efforts in the protection of inland wetlands? This research was conducted at inland wetland lakes of Naivasha, Nakuru and Bogoria that have been designated as Ramsar sites to examine the extent to which existing education has influenced communities’ efforts in protecting wetlands. Primary data were collected via questionnaire from three study sites. Using both descriptive and inferential statistics, a logistic regression to determine the significance of various predictor variables, including education, for changes in biodiversity as a proxy for wetlands protection outcomes was performed. The results indicated that education, awareness and other key variables that were expected to support wetlands protection had no significant impact on changes in biodiversity. The study concludes that the designation as Ramsar Convention-protected status alone cannot stop the degradation of inland wetlands in an environment where existing formal and informal education has not empowered communities and institutional efforts.
... Lake Naivasha is a shallow-basin freshwater lake that lies between 0° 45′ S and 36° 26′ E (Becht & Harper, 2002;Everard & Harper, 2002). It is the second-largest freshwater lake in Kenya and has a catchment size of 3400 km 2 . ...
The Ramsar wetland sites are important habitats for biodiversity and provide ecological services to communities that otherwise have no access to water resources. In Kenya, some wetlands are more prominent and are recognized worldwide as tourist hot spots, biodiversity-rich zones and wildlife habitats. However, these wetlands face overexploitation and degradation from surrounding communities. The efforts to halt underlying threats and the projected declines in the size and quality of inland wetlands at local levels are not sufficient. The question guiding this study is as follows: to what extent do a Ramsar designation and formal and informal education support communities and institutional efforts in the protection of inland wetlands? This research was conducted at inland wetland lakes of Naivasha, Nakuru and Bogoria that have been designated as Ramsar sites to examine the extent to which existing education has influenced communities’ efforts in protecting wetlands. Primary data were collected via questionnaire from three study sites. Using both descriptive and inferential statistics, a logistic regression to determine the significance of various predictor variables, including education, for changes in biodiversity as a proxy for wetlands protection outcomes was performed. The results indicated that education, awareness and other key variables that were expected to support wetlands protection had no significant impact on changes in biodiversity. The study concludes that the designation as Ramsar Convention-protected status alone cannot stop the degradation of inland wetlands in an environment where existing formal and informal education has not empowered communities and institutional efforts.
... While the focus of this study is on water stakeholders' interactions and related conflicts, a number of previous studies have discussed the potential of human impact on the lake's ecosystems, challenges in ecology and water management (e. g. Harper et al. 1990;Becht and Harper 2002;Crona and Bodin 2006;Hahn et al. 2006;Newman and Dale 2007;Provan and Kenis 2007;Harper et al. 2011;Verstoep 2015). Other studies have also focused on the problems of water quality, fluctuation of water levels and the competition of water resources (Kitaka et al. 2002;Ndungu 2014). ...
Recent years have seen unprecedented pressure from numerous water stakeholders with different interests in Lake Naivasha basin, the only freshwater lake in the Great Rift Valley of Kenya. The pressure on this water resource results in high competition over access to water source, unsustainable resources management practices, poor water quality, and emergence of conflicts between institutions and its users. Presently, there is a knowledge gap and paucity of information on water resources stakeholders’ interactions in Lake Naivasha basin. This study, therefore, analyses the ways resource stakeholders interact and play in the conflict dynamic, and ultimately propose a better water resource use and management approaches. Drawing on field assessments, individual interviews, focus group discussion, and secondary literature reviews, this paper illustrates how both local, national and multi-national stakeholders interact and contribute to water resources conflicts. Results suggest unclear county and national institutional structures, fragmented land use activities and ownership, a feeling of marginalization by the local population contributing to resource-based conflict within the lake basin. A comprehensive policy framework and enforcement of existing regulations will ensure there is sustainable water access, reduce conflicts and enhance sustainable water resource governance and use of the lake.
Lake Naivasha is a shallow freshwater lake that supports a wide but uneven biodiversity of plants and animals but no native fish as most of the fish species in the lake were introduced. The lake’s ecosystem has been undergoing major changes due to anthropogenic and natural factors that influence its limnology. This study aimed to determine the diversity, distribution, and biomass of the phytoplankton community in this lake. For a period of 6 months from February 2019 to July 2019 covering dry and wet season, water samples from the lake were analyzed to determine the spatio-temporal trends of phytoplankton and associated environmental variables which included nutrients concentrations, temperature, conductivity, DO, pH and transparency. Monthly samplings were done and samples analyses using the standard procedures. Samples were collected in triplicates for the determination of nitrate nitrogen, soluble reactive phosphorous, total nitrogen, total phosphorous, ammonium nitrogen, silicates, and chlorophyll a. Water temperature, conductivity, DO, and pH were measured in situ using multimeter probe YSI model. The results showed the mean temperature of 22.73 ± 1.6 °C, DO 8.51 ± 0.87 mg/L, conductivity 233.85 ± 26.94 μS/cm, pH 8.13 ± 0.3. TN were 471 ± 170.61 µg/L, PO4-P 5.88 ± 2.12 µg/L, TP 97.97 ± 49.06 µg/L, NO3-N 6.70 ± 3.55 µg/L, NH4-N 18.93 ± 10.91 µg/L and SiO2 3.18 ± 2.99 mg/l and Chlorophyll a 21.51 ± 4.25 mg/m³. Total phosphorous, total nitrogen, silicates, temperature, pH, dissolve oxygen, conductivity, TDS and secchi depth showed significant seasonal differences. A total of one hundred and twenty four (124) species of phytoplankton belonging to six (6) taxonomic families were identified. Chlorophyceae was represented by 43 species consisting of 34.68 % by species composition, Bacillariophyceae was represented by 38 species consisting of 30.65 % by species composition. Cyanophyceae was represented by 24 species leading to 19.35 % species composition. Zygnematophyceae, Euglenophyceae, and Dinophyceae recorded the least species composition. Chlorophyceae recorded the highest total phytoplankton biovolume of 623.41 mm3/L, followed by Bacillariophyceae with 533.16 mm3/L and Cyanophyceae with 114.55 mm3/L. Dinophyceae recorded the least phytoplankton biovolume of 82.36 mm3/L. The total number of algal species was highest at Hippo point sampling site with 72 species, followed closely by 68 species in Crescent Island, then Oserian Bay sampling site with 66 species. Mouth of R. Malewa recorded 59 species, Sher Bay had 58 species, this was followed by Mid Lake station with 56 species, and Sewage Discharge Point had 55 species. Shannon-Wiener diversity (H’) index ranged from 2.0455 at the Mouth of R. Malewa to 2.7077 at Oserian Bay and was highest in July. Lake Naivasha showed a high phytoplankton diversity with significant physico-chemical parameters relationship. There is need for long-term and continuous ecological and hydrological monitoring especially on nutrients seasonal dynamics for proper understanding of seasonal effects of nutrients to algal biomass and diversity, which could be used as an indicator of eutrophication level in the lake.
'Novel ecosystem' is a concept which was introduced in the 21st Century to describe ecosystems heavily modified by humans, about 15 years after 'ecohydrology' had been introduced as concept within UNESCO IHP, to facilitate the sustainable management of aquatic ecosystems by humans and about 5 years after the concept of IHP 'Demonstration Sites' had been introduced to promote ecohydrological principles globally. The tropical African Lake Naivasha became a DS initially to demonstrate the importance of papyrus-dominated wetland edges for nutrient and climate control in an aquatic ecosystem driven by regional hydrological instability, but it already represented a ‘novel’ ecosystem.
This paper critically examines the consequences of the aquatic food web restructuring by the latest alien species, common carp (Cyprinus carpio L.) – whose arrival is directly an ecological consequence of hydrological instability. Carp were first recorded in Lake Naivasha in 2001 and reached dominance in the commercial fishery by 2003. The costs and benefits of its dominance are shown by comparing aspects of the ecosystem state before and after arrival. These were hypothesized and tested by comparing data in 2012-4 with data gathered in the 1990s using the same methodologies. Carp have filled a previously vacant benthivorous niche. The species achieved moderate density but has not caused ecological disruption. Overall, carp has been a positive contributor to the local community. More intensive management strategies, better post-harvest processing and new marketing techniques need to be developed to enhance financial gain.
Endorheic freshwater lakes can be vital water resources for sustaining large populations. However, their land-locked nature can lead to overexploitation and long-term sediment accumulation, reducing water storage and quality. Lake Naivasha supports a rapidly expanding population and agricultural industry. Therefore, maintaining good water storage and quality within this endorheic lake is crucial for the Kenyan economy and population. The lake has a long history of level fluctuations and the region is considered to be suffering from a chronic imbalance between water supply and demand.
This study quantifies the sediment deposition rate and its impact on Lake Naivasha's water levels and volume, using inexpensive remote sensing techniques that could be easily replicated for future monitoring.
Evidence of sedimentation in the northern area averaging 23 mm yr⁻¹ was identified, which is likely annually displacing between 40.2 – 576 × 10³ m³ of water. The volume displaced each year is equivalent to the water required to sustain between 40 – 1152 people. These results imply that current abstraction management, based purely upon lake level readings that govern a ‘traffic lights’ system, are detrimental to the long-term survival of the lake. The results also imply that lake health is decreasing. We recommend that future monitoring of this water resource and all endorheic lakes consider measurements of available water volume in combination with lake level data using the remote sensing methods we describe.
Some 85% of Africa's water resources are comprised of large river basins that are shared between several countries. High rates of population growth accompanied by continued increases in the demand for water have resulted in several countries passing the point where the scarcity of water supplies effectively limits further development. Present population trends and patterns of water use suggest that more African countries will exceed the limits of their economically usable, land-based water resources before 2025. Normally, water allocation and distribution priorities within a country are aligned with national development objectives. While this may achieve national "water security" objectives, greater emphasis needs to be placed on regional efforts to ensure that the available water resources are used to derive sustainable long-term benefits for the peoples of Africa as a whole. Ideally, each country's water-resource management strategy needs to be aligned with that of its neighbors if peace and prosperity are to be maintained and conflict is to be avoided in the region.
Analysis of a 28-m core from a relict fresh-water lake in Kenya had provided a detailed limnologic and climatic history covering 9,200 years. The core is an incomplete section through the sediments of a submerged crater near the eastern shore of Lake Naivasha. The overall sedimentation rate, 0.33 cm wet sediment per year, is the most rapid on record for a lake whose sediments are essentially autochthonous and organic. A three-stage limnologic history is inferred from the microfossils (particularly diatoms), chemistry, and mineralogy of the core: (A) From before 9,200 B.P. until about 5,650 B.P. a lake significantly larger than the present one existed in the basin. Algal productivity was high, and the water temperature was probably above the present average. The surface waters of this lake were evidently depleted in silica, suggesting some stratification, but the total ion content was not far below today's (B) Between 5,650 B.P. and 3,040 B.P. the lake shrank, aquatic macrophytes increased in abundance near the core site, and the water grew more dilute. The crater became isolated from the main lake and finally dried briefly. (C) For the past 3,000 years a small lake has existed in the basin. It has been frequently smaller and its water sometimes much more concentrated than that of the modern lake. The lake discharged through a southern outlet prior to 5,650 B.P., but since that time has had no surface outlet. Various freshening mechanisms have operated during the past 5,000 years, probably including deflation, burial of alkaline layers, underground seepage, and perhaps ion removal by aquatic plants. The climate during the period of the large lake (Leakey's Gamblian Pluvial period) was much wetter and probably warmer than today, and rainfall at Naivasha was more seasonal. Rainfall was perhaps 65% above the modern average. We find no convincing evidence for an early post-Gamblian wet phase, the Makalian, proposed by earlier workers for this region. A later wet phase, the Nakuran, may be represented by the small, fluctuating lake of the past 3,000 years, but this lake probably never stood as high as the strandline previously assigned to the Nakuran. The climatic inferences from this study are in substantial agreement, but provide interesting points of contrast, with those from other recent investigations in sub-Saharan Africa.
STRANDLINES high above the present levels of three small lakes in Kenya provide some of the earliest-recognized evidence for past climatic changes in tropical Africa. The terraces above Lakes Nakuru, Naivasha and Elmenteita were studied intensively by Nilsson1,2 more than 30 years ago, and are one of the major bases on which the pluvial theory of Pleistocene climates in Africa was constructed. Despite later disagreements on the number and interpretation of these strandlines, it is still generally accepted that they provide good evidence for at least one pluvial period (the Gamblian) and two lesser post-pluvial wet phases (the Makalian and Nakuran)3,4.
A previously unpublished record of lake levels from Lake Naivasha, Kenya from 1880 to 1976 has been analysed and shows little similarity to the level record from nearby Lake Victoria. Level changes from year to year of the two lakes show no significant correlation (at 5%) and spectral analysis of the two records shows no common significant peaks. Both lakes show significant correlations between their level changes and the strength of the North Atlantic winter circulation, with the correlation coefficients in opposing directions indicating important, but different, large scale climatic links.Lake Naivasha's major level increases occur during May and September. Lake Victoria's level increases mainly in May with a small December increase. East African rainfall is generally during April and November, corresponding with Lake Victoria's changes. Rainfall records from Kenyan highland areas, however, show an August rainfall peak and little rainfall in November. Rainfall amounts from Equator, a highland meteorological station, for July, August and September are highly correlated (at 1% significance level) with the change in Naivasha's level during September. Winds at the highland stations are westerly during August while the lower level stations experience the drier S.E. Trades. The level changes of Lake Naivasha indicate changes in the extent of the penetration of moist air from West Africa between the Trade winds and the 200 mb easterly jet.
Some 85% of Africa's water resources are comprised of large river basins that are shared between several countries. High rates of population growth accompanied by continued increases in the demand for water have resulted in several countries passing the point where the scarcity of water supplies effectively limits further development. Present population trends and patterns of water use suggest that more African countries will exceed the limits of their economically usable, land-based water resources before 2025. Normally, water allocation and distribution priorities within a country are aligned with national development objectives. While this may achieve national "water security" objectives, greater emphasis needs to be placed on regional efforts to ensure that the available water resources are used to derive sustainable long-term benefits for the peoples of Africa as a whole. Ideally, each country's water-resource management strategy needs to be aligned with that of its neighbors if peace and prosperity are to be maintained and conflict is to be avoided in the region.
The fluctuations of the key East African lakes discussed are summarized in Fig. 4 which also includes the available evidence from Lake Rukwa (42) and Lake Chad (43) Exceot for Lake Victoria, all of these now lack surface outlets and are situated in much drier climates than the major lakes of the Western Rift Valley, which remain filled to their overflow levels. The apparent differendes among the fluctuations of the lakes are partly due to differendes in the nature of the evidence or the intensity of research or both, although there must also have been important local differences in the histories of the lakes Yet the consistencies are far more striking, most notably the coincidence of early Holocene high stands. Between 10,000 and 8,000 years ago, it seems that lakes in many parts of tropical Africa were greatly enlarged. Where evidence for the previous span of time is well resolved, it appears that transgressions leading to this high stand began about 12,000 years ago, and evidende from three basins (Victoria, Nakuru, and Chad) indicates a pause or minor recession just at or before 10,000 years ago. Wherever information is available for the period preceding 12,000 years ago, it can consistentlybe shown that lakes were much small-er . Several basins (Rudolf, Nakuru, and Chad) also show traces of much earlier phases of lake expansion. which are not yet well dated but which all occurred more then 20,000 years ago. The Holocene record subsequent to the maximum of 10,00 to 8,000 years ago is more complex. Three basins (Rudolf, Nakuru, and Chad) show an apparently concordant, positive oscillation at some point between 6000 and 4000 years ago, but it is uncertain how widely this episode is represented.
Isavwa & A. Oroda 1999 Modelling lake level changes: examples from the Eastern Rift Valley, Kenya The Sustainable Management of Tropical Catchments
- M Stuttard
- J B Hayball
- G Narciso
- M Suppo