Integrated Approach for Spatio-Temporal Variability Analysis of Wetlands: A Case of Wetlands of Abayachamo Lakes; Southern Ethiopa
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Date
2007-03
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Addis Ababa Universty
Abstract
Starting with the intensification of irrigation activities in the beginning of 1980s in Abaya and
Chamo lakes area, the decreasing water inflow to the lakes caused relatively denudation of the
wetlands of Abaya and Chamo. The ecological situation in the lake region changed significantly
during last four decades. This research is geared with major objectives to map and assess the spatial
and temporal variability of these changes with respect to the driving forces. It also aimed to
determine wetlands priority area for conservation based on the direction and magnitude of
denudation using RS and GIS techniques. To accomplish the objectives data were collected and
analyzed utilizing field observations, satellite image analysis, hydro-meteorological data analysis and
interviews. Five basic methods of wetlands variability analysis were used namely; Satellite image
analyses and change detection, Lakes morphomotric property analysis, Lake level fluctuation
analysis, water balance analysis and sediment load analysis. Wetland and non-wet areas were
identified and mapped using criteria and satellite images. Based on the TCT and classified images
the temporal and spatial variability of the wetlands have been analyzed from the digital image.
The change detection showed that permanent wetland portions from 1973 to 1986 have been
reduced by 12.9 km2 in both lakes Abaya and Chamo. The change is from permanent wetland to
other seasonal wetlands ecosystems. But from 1986 to 2000 a significant decrement has been
observed but lesser than the previous decades (6.4 km2). The reason behind this change is that the
free settlement and shoreline cultivation of the wetlands and uplands, land use land cover changes
that fasten the soil erosion and eventually adds the sediment to the permanent wetlands. However the
greater lion share of this temporal and spatial variability of the lakes comes from extreme wasteful
utilization of the water from the rivers entering to the lakes and onshore cultivation. The time series
analysis and water balance of the permanent lake in this research result shows that the wetlands are
in danger and the outlook is bad. To safeguard wetland degradation or loss, a possible solution could
be awareness creation to change the attitudes of the resident communities by linking the economic
and social benefits of wetlands to its conservation for its protection.
Key Words: Wetlands, Spatial and temporal variability, GIS/RS, LU/LC change, lakes Abaya and
Chamo
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Keywords
Wetlands, Spatial and temporal variability, GIS/RS, LU/LC change, lakes Abaya and Chamo