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http://hdl.handle.net/123456789/2161
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| Title: | DETERMINATION OF SPATIO-TEMPORAL DIFFERENCES OF WATER HYACINTH AND ITS EFFECTS AROUND LAKE ABA SAMUEL, SOUTH OF ADDIS ABABA, ETHIOPIA |
| Authors: | Abraham, Hailemelekot |
| Advisors: | Dr Dagnachew Legesse |
| Keywords: | Water hyacinth,
Classification
Change Detection,
Spatio-Temporal variations
Nutrients level and Temperature
Lake Environment |
| Copyright: | Jun-2009 |
| Date Added: | 3-May-2012 |
| Abstract: | Abstract
The objective of this study is to determine the spatio-temporal differences of water
hyacinth and its effects in Lake Aba Samuel and its surroundings.
Satellite images of 1986, 2000 and 2005 with satellite path 168 and row 054 were used
for the analysis. Digital image classifications as well as change detection were carried
out with over all accuracy of 84% and the finding of these analysis shows that water
hyacinth have changed spatially and temporally over the time in the study area. At the
beginning of the study period (1986) the water hyacinth were located on the northern
part of the lake but in later periods it was concentrated mostly on the southern part of the
lake. Water hyacinth increase over time from 1986 (0.7 %) up until 2000 (5.0 %)
afterwards it starts to decline and in 2005 (1.8%). The change detection analysis shows
that the lake environment was subject to more changes in cover types over time than
other classes; and farmland exhibits the highest changes in terms of increase in area or in
hectare. The derivers of water hyacinth expansion were also assessed. Temperature and
nutrient level were among the factors that enhance water hyacinth establishment on the
lake. Temperature increases and variations were observed on the study area. It was
determined that different landcover types have shown different temperature attributes.
Nutrient level on the lake shows high load and is beyond the limit as a result it has
polluted the reservoir and caused eutropication. The NDVI values where water hyacinth
found in high density and temperature attributes of the same location were assessed and
the correlation was strong and was inversely related. And similar assessment was made
for NDVI values where water hyacinth found in high concentration and the Nitrogen
level of the same location and the correlation was less strong and the two were directly
related. From this assessment it can be said that even if temperature and nitrogen are
essential factors for plant growth temperature appears to be the determinant factor for
water hyacinth expansion. The existence and expansion of water hyacinth on the lake has
an impact on the lake ecosystem biodiversity by reducing fish stock, migratory birds and
socioeconomic problem by increase in trend of malaria cases. To monitor and apply one
of the control methods such as mechanical removal and biological means of water
hyacinth prioritized spatial locations were identified. To rehabilitate the Aba Samuel
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Lake environment buffer zone width around the lake and majors rivers that empties to
the lake were suggested based on IUCN recommendation and as indicated in various
literatures. |
| URI: | http://hdl.handle.net/123456789/2161 |
| Appears in: | Thesis - Geography & Environmental Education
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