Behaviour of rainfall over lakes around Bombay

Analysis of monthly rainfall brings out two distinctly different areas of rainfall affinity-one comprising of the lakes situated in Greater Bombay and the other in Thane districts. Rainfall of different sub-periods/months was found to be independent of the rainfall of preceding sub-periods/months. Multiple regression equations between lake levels and monthly rainfall have been computed to predict the anticipated lake levels at the end of different months.

Natural and anthropogenic changes threatening the ecological and limnological integrity of Lake Baringo, Kenya: A Review

Lakes are characterized by dynamic responses to ecological and limnologic disturbances that occur within a constrained timeframe. Some endorheic lakes in the Kenyan Rift valley are presently regarded as environmental hotspots because of complex changes that are revealed through multiple proxies; changing lake levels and surface area, turbidity and sedimentation, proliferation of macrophytes and loss of aquatic biodiversity. Lake Baringo is characterized by widespread catchment degradation accompanied by high levels of turbidity during erratic and decline of native fishery based on Oreochromis niloticus baringoensis. A careful analysis implicates potential natural factors such as catchment topography and increasing anthropogenic pressure as the main causes of lake ecosystem degradation. This paper recommends several strategies for restoration of Lake Baringo based on an integrated multi-faceted approach which combines catchment rehabilitation, pollution control and provision of alternative livelihoods such as agriculture to the riparian communities.

Assessment of Rising Water Levels of Rift Valley Lakes in Kenya: The Role of Meteorological Factors

The impacts of increased water levels in Kenyan lakes are a major problem that is affecting communities and their livelihoods. Upsurge in water levels of the Rift Valley Lakes is one of the recent climate extremes witnessed over Eastern Africa where the rises appear to be consistent with the occurrence of enhanced seasonal rains between 2016 and 2020. Considering that many explanations have been provided as possible causes, there is still little empirical evidences. This study aimed at assessing the link between meteorological factors and the rises in lake levels in order to see if these can explain the causes. Further using surface observations potential to predict the water levels was examined. Datasets on rainfall, temperature and water levels from four Lakes in Kenya were used to establish the changes in these variables using statistical methods. Generalized Linear Models were used to predict the water levels in the study lakes. Results indicate that rainfall and temperature as well as other climate drivers has been changing over the last recent years with increased precipitation being consistent with the observed high stands in the Rift Valley lakes. Specifically, the results of the forecasted levels indicate substantial and slight increase for lake levels in Naivasha while the Lake Baringo levels are predicted to rise sharply within the study data periods.

Physicochemical Properties and Heavy Metal Concentration in Borehole Water of Boko Haram Affected Areas of Madagali and Michika, Adamawa State, Nigeria

The impacts of increased water levels in Kenyan lakes are a major problem that is affecting communities and their livelihoods. Upsurge in water levels of the Rift Valley Lakes is one of the recent climate extremes witnessed over Eastern Africa where the rises appear to be consistent with the occurrence of enhanced seasonal rains between 2016 and 2020. Considering that many explanations have been provided as possible causes, there is still little empirical evidences. This study aimed at assessing the link between meteorological factors and the rises in lake levels in order to see if these can explain the causes. Further using surface observations potential to predict the water levels was examined. Datasets on rainfall, temperature and water levels from four Lakes in Kenya were used to establish the changes in these variables using statistical methods. Generalized Linear Models were used to predict the water levels in the study lakes. Results indicate that rainfall and temperature as well as other climate drivers has been changing over the last recent years with increased precipitation being consistent with the observed high stands in the Rift Valley lakes. Specifically, the results of the forecasted levels indicate substantial and slight increase for lake levels in Naivasha while the Lake Baringo levels are predicted to rise sharply within the study data periods.

Social-Ecological Change on the Mongolian Steppe: Herder Perceptions of Causes, Impacts, and Adaptive Strategies

Pastoral people in rangelands worldwide are experiencing uncertainty due to a combination of climatic, economic, and political stressors. Our study seeks to create a full view of the drivers, impacts, and adaptations to change for livestock herders in rural Mongolia, making use of herder traditional knowledge and select instrumental data. Interview respondents described undesirable trends in livestock herds, pasture, wildlife, and their livelihoods in three sites in northern, central, and eastern Mongolia from 1995 to 2015, including decreased lake levels. There was more agreement for precipitation trends than for temperature. We developed a systems model based on herder descriptions of the sequence and prominence of interacting drivers of change. Finally, we describe measures herders are taking to adapt to these changes, such as more frequent livestock movement. We present a transdisciplinary view of social-ecological change and applications for more regionally focused governance in an era of climate uncertainty.

Changes in the prairie–forest ecotone in northwest Ontario (Canada) across the Holocene

Pollen and diatom assemblages from well-dated sediment cores from three lakes forming a west-to-east transect across the boreal forest in northwest Ontario (Canada) were used to evaluate the timing and nature of the movement of the prairie–forest ecotone (PFE) across the Holocene. Changes in vegetation, temperature, and effective moisture were inferred from pollen and pollen-based transfer functions. Analyses indicated site-specific vegetational and climate changes across short spatial distances, with prolonged prairie-like conditions during the middle Holocene at the westernmost site. Increased reconstructed temperatures at this westernmost site occurred from ~9000 to 3000 cal yr BP, alongside increases in diatom-inferred lake levels beginning at ~6000 cal yr BP. The abundance of Quercus peaked concurrently with rising lake levels before declining to trace levels by ~3000 cal yr BP. Increases in the abundance of non-arboreal pollen between ~8500 and ~4500 cal yr BP at the more eastern lakes suggest relatively delayed and truncated PFE influence, before the reestablishment of primarily boreal taxa by ~4500 cal yr BP, coincident with diatom-inferred increases in lake levels. This study shows that the PFE moved both farther east and north than previously determined, but generally agrees with established patterns in vegetation from other studied regions along the PFE.

Extent of Sedge/Grass Meadow in a Lake Michigan Drowned-River-Mouth Wetland Dictated by Topography/Bathymetry and Lake Level

Water-level fluctuations are critical in maintaining the diversity of plant communities in Great Lakes wetlands. Sedge/grass meadows are especially sensitive to such fluctuations. We conducted vegetation sampling in a sedge/grass-dominated Lake Michigan drowned-river-mouth wetland in 1995, 2002, and 2010 that followed high lake levels in 1986 and 1997. We also conducted photointerpretation studies in 16 years dating back to 1965 to include responses to high lake level in 1952 and 1974. Topographic/bathymetric data were collected to assess their influence on areal extent of sedge/grass meadow. Dominant species in short emergent and submersed/floating plant communities changed with water availability from 1995 to extreme low lake levels in 2002 and 2010. Sedge/grass meadow was dominated by Calamagrostis canadensis and Carex stricta in all years sampled, but Importance Values differed among years partly due to sampling in newly exposed areas. Photointerpretation studies showed a significant relation between percent of wetland in sedge/grass meadow and summer lake level, as well as the number of years since an extreme high lake level. From the topographic/bathymetric map created, we calculated the cumulative area above each 0.2-m contour to determine the percent of wetland dewatered in select years following extreme high lake levels. When compared with percent sedge/grass meadow in those years, relative changes in both predicted land surface and sedge/grass meadow demonstrated that accuracy of lake level as a predictor of area of sedge/grass meadow is dependent on topography/bathymetry. Our results regarding relations of plant-community response to hydrology are applicable to other Great Lakes wetlands.