dc.description.abstract |
The development of irrigated agriculture has multi-directional benefits for the economic
development of a country. However, it has negative consequences including
environmental effects, land degradation, waterlogging, salinization, and social instability
when the irrigation water is not properly managed. This research has been conducted at
Koga Irrigation Scheme to assess the effect of irrigated agriculture on spatial and
temporal fluctuations of the groundwater table and water quality. This study has
attempted to highlight the status of spatial and temporal fluctuations of the groundwater
table depth at Koga irrigation scheme, Northwest Ethiopia. Purposive representative
samples of six shallow wells inside the irrigation scheme and four shallow wells outside
the irrigation scheme were selected for evaluation of the impact of irrigation on
groundwater table fluctuation and groundwater quality. Arc GIS tool has been applied for
interpolation of the spatial variation of the groundwater level. The result of the study
clearly showed that irrigation has affected the groundwater level and groundwater
quality. For instance, under the irrigated field, a rise in the groundwater table that ranges
from 0.77 m to 0.52 m observed compared with non-irrigated field. The groundwater
table was found to have high fluctuation in space and time owing to spatial and temporal
variation of irrigation amount, soil type, topography, and other factors. The groundwater
quality also showed that the concentration of nitrate and sulfate was higher in the
irrigated land than non-irrigated land. However, the concentration of the nutrients was
below the world health organization drinking water quality parameters. This study
indicated the need to pay more attention to the irrigation water management of the
scheme to control the groundwater level rise. This study showed that irrigation has effect
on groundwater level and there is high spatial and temporal variation of groundwater
level in the area. Therefore, continuous follow-ups and assessment of the groundwater
table and Physico-chemical properties of the study area is essential for the sustainability
of the Koga irrigation scheme and human health of the people who live in the scheme. |
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