Lake Turkana, major Omo River developments, associated hydrological cycle change and consequent lake physical and ecological change

Avery, Sean T.; Tebbs, Emma

doi:10.1016/j.jglr.2018.08.014

Cited by 43 publications

(74 citation statements)

References 23 publications

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“…The integration of the land cover mapping with the data from the participatory mapping demonstrated that though a new suite of provisioning services are now more relied on, they are found in land covers (e.g., shrubland and wetlands) reducing in spatial extent ( Table 5). Satellite land cover mapping showed a loss of seasonally-inundated river-adjacent lakes, no longer replenished by the annual Omo River flood given the Gibe III dam [47]. Our analyses also highlight other long-term environmental changes affecting ES that were not predicted in a recent synthesis of social-ecological change in the region [46], namely a reduction in grassland and shrubland and increase in bare ground.…”

Section: Es Change In the Lower Omomentioning

confidence: 51%

“…We found that between 2013 and 2018, ES supply and demand has changed drastically. In particular, communities reported the loss of riverine flood-retreat crop production, associated with the removal of the annual flood due to the Gibe III dam [44,47]. As a result, communities are now more dependent on rain-fed cultivation, and a range of other provisioning ES such as fodder for livestock, wild fruits, bushmeat and fish, but focus groups reported that many of these services are also becoming increasingly scarce.…”

Section: Discussionmentioning

confidence: 99%

“…The most recent developments are the Gilgel-Gibe III (hereafter 'Gibe III') dam, Africa's tallest, inaugurated in 2016, and the establishment of irrigated sugar estates, begun in 2013 and covering a projected 100,000 hectares (ha) as well as largescale cotton schemes [42], in addition to population growth and migration. There is considerable uncertainty about the impact of these social-ecological changes, as there has been relatively little study from the scientific community thus far [43][44][45][46][47]. However, prior work by [46] concluded that the Gibe III dam is posited to impact multiple ES and thus the livelihoods of the Lower Omo communities, mostly through loss of the seasonal flood.…”

Section: Mapping Ecosystem Servicesmentioning

confidence: 99%

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Integrating Participatory Methods and Remote Sensing to Enhance Understanding of Ecosystem Service Dynamics Across Scales

Hodbod

Tebbs

Chan

et al. 2019

Land

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The value of Traditional Ecological Knowledge (TEK) for informing resource management has long been recognized; however, its incorporation into ecosystem services (ES) assessments remains uncommon. Often “top-down” approaches are utilized, depending on “expert knowledge”, that are not relevant to local resource users. Here we propose an approach for combining participatory methods with remote sensing to provide a more holistic understanding of ES change. Participatory mapping in focus group discussions identified TEK regarding what ES were present, where, and their value to communities. TEK was then integrated with satellite imagery to extrapolate to the landscape-scale. We demonstrate our method for Nyangatom communities in the Lower Omo Valley, Ethiopia, showing for the first time the ES impacts of regional environmental change, including the Gibe III dam, for communities in the Omo River basin. Results confirmed the collapse of flood-retreat cultivation associated with the loss of the annual Omo flood. Communities reported declines in many other provisioning ES, and these results were supported by satellite mapping, which showed substantial reductions in land covers with high ES value (shrubland and wetland), leading to consequent ES declines. Our mixed-methods approach has potential to be applied in other regions to generate locally relevant information for evaluating ES dynamics and improving management of natural resources.

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Section: Es Change In the Lower Omomentioning

confidence: 51%

Section: Discussionmentioning

confidence: 99%

Section: Mapping Ecosystem Servicesmentioning

confidence: 99%

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Integrating Participatory Methods and Remote Sensing to Enhance Understanding of Ecosystem Service Dynamics Across Scales

Hodbod

Tebbs

Chan

et al. 2019

Land

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“…Monthly Omo inflows were estimated using a water balance model (Avery, 2009;Avery, 2012;Avery & Tebbs, 2018), which uses lake level changes from radar altimetry to estimate Omo inflows after accounting for evaporative losses and other river inflows.…”

Section: Environmental Driversmentioning

confidence: 99%

“…Satellite altimetry data are a reliable proxy for in situ lake levels in ungauged waterbodies such as Lake Turkana (Avery, 2009;Avery & Tebbs, 2018;Velpuri, Senay, & Asante, 2012), and the G-REALM dataset has an accuracy of 3 -5 cm for large lakes (USDA, n.d.).…”

Section: Data Uncertainty and Validationmentioning

confidence: 99%

Satellite remote sensing reveals impacts from dam‐associated hydrological changes on chlorophyll‐a in the world's largest desert lake

Tebbs

Avery

Chadwick

2019

River Research & Apps

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We present an approach that uses satellite products to derive models for predicting lake chlorophyll from environmental variables, and for investigating impacts of changing environmental flows. Lake Turkana, Kenya, is the world's largest desert lake, and environmental flows from the Omo River have been modified since 2015 by the Gibe III dam in Ethiopia. Using satellite remote sensing, we have evaluated the influence of these altered hydrological patterns on large-scale lake phytoplankton concentrations for the first time. Prior to dam completion, strong seasonal cycles and large spatial gradients in chlorophyll have been observed, related to natural fluctuations in the Omo River's seasonal discharge. During this period, mean lake chlorophyll showed a strong relationship with both river inflows and lake levels.Empirical models were derived which considered multiple hydro-climatic drivers, but the best model for predicting chlorophyll-a was a simple model based on Omo River discharge. Application of this model to data for 2015-2016 estimated that during the filling of Gibe III annual mean Lake Turkana chlorophyll declined by 30%.Future water management scenarios based on Gibe III operations predict reduced seasonal chlorophyll-a variability, while irrigation scenarios showed marked declines in chlorophyll-a depending on the level of abstraction. These changes demonstrate how infrastructure developments such as dams can significantly alter lake primary production. Our remote sensing approach is easy to adapt to other lakes to understand how their phytoplankton dynamics may be affected by water management scenarios.

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Climate Change, Lacustrine Zone

Wright¹

2021

The Encyclopedia of Ancient History

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Due to its position in the trough of the East African Rift Valley, the Great Lakes region has experienced significant effects from changes to earth's climate during the Holocene. Annually migrating atmospheric pressure systems bring oceanic moisture inland, causing precipitation mainly in the highlands that charges groundwater systems in the lowlands. Although the Holocene has been a relatively stable climatic epoch for most of the planet, the lacustrine region of eastern Africa has experienced significant hydrologic variability. The African Humid Period brought significantly higher rainfall to the northern two‐thirds of the continent, including most of the lacustrine zone, but had a minimal impact on lake levels in the southern aspect of the region. Lake records show that after 2000 bce the northern region experienced lower average precipitation while lake levels rose on balance across the southern region. However, high‐resolution records consistently demonstrate that there is significant variability in the tempo and spatial application of precipitation and vegetation in East African lakes. Additionally, since the advent of the Common Era, there are increasingly obvious impacts of human landscape disturbance on the region's ecology, affecting lake levels and biodiversity.

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Lake Turkana, major Omo River developments, associated hydrological cycle change and consequent lake physical and ecological change

Cited by 43 publications

References 23 publications

Integrating Participatory Methods and Remote Sensing to Enhance Understanding of Ecosystem Service Dynamics Across Scales

Integrating Participatory Methods and Remote Sensing to Enhance Understanding of Ecosystem Service Dynamics Across Scales

Satellite remote sensing reveals impacts from dam‐associated hydrological changes on chlorophyll‐a in the world's largest desert lake

Climate Change, Lacustrine Zone

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