The available numerical data suggests that there is upward trend with regard to rainfall in this region, while evaporation remains the same. Therefore, its good news for hydro electric power generation and irrigation scheme here, said the eminent oceanographer, Dr Mark R Jury.

Dr Mark, an Associate Professor of Meteorology in University of Puerto Rico, US, has been to Arba Minch University to talk on ‘Ethiopian Rift Valley hydrological fluctuations and climate.’ Apart from his well-researched presentation, he has vividly exemplified the ongoing hydrological and meteorological changes occurring in this region and their geological and sociological impact as well.

The seminar was organized by the College of Natural Science. The talks began with Dean Dr Alemayehu Hailemichael introducing Dr Mark to the audience. The seminar was attended by some of the faculty members and students from different departments. Head of the Department of Meteorology and Hydrology, Mr Assefa Derbew, proposed the vote of thanks.

Dr Mark in his presentation spoke on fluctuations of Abaya-Chamo basin flows and levels. He touched upon the comparative study of local station and international gridded datasets, and evaluation of the influence of global fields on rainfall, run-off and flows. He also informed about the meteorological drivers of flood, drought and evaluated seasonal and long-term model predictions.

On hydrological aspect pertaining to both Abaya and Chamo lakes he said, ‘‘The Lake levels are fluctuating and fluctuation is due to the climate variability in the last 30 years. And I have been interested to know as to how the lake reflects the climate variability in last three decades in terms of cycle of floods and drought and what causes it. We heard, Lake Abaya is expanding, it has grown vertically by about one meter over the last 30 years, and Chamo has shrunken a little bit.

Elaborating further Dr Mark said, ‘‘The expansion may be due to geological uplift by the plate Tectonic and Lake Chamo isn’t affected by that and there is some evidence that the climate has recovered from the drought of 1980 and things are getting better.’’

On the changes impacting agricultural aspect of the region, he said, ‘‘Well, Lake is like a big rain gauge, so when it’s high that means over surrounding areas are getting adequate rains and farming would be good. If the lake level drops due to the past history of drought over last years that would adversely affect the agricultural production and people would suffer.’’

On usage of satellite simulation data, he added, ‘‘In this area, Rift Valley is very near, you can actually look across from one side to other. So it’s necessary to have models and satellite estimate that are better than 50 kilometers of higher resolution, which is about 25 degree latitude and longitude. If you have models and satellite data that have lower resolution that won’t give you appropriate results.

On hydrological and meteorological changes in these areas, ‘‘The changes occurring in the last 30 years appear to be recovery from drought and increase in lake level and outflow towards the south.

As far as impact is concerned, if rainfall becomes heavier means heavier runoff that takes more sediment with it causing soil erosion. Although, land use could be playing the role and increased overgrazing might be causing more runoff. Inevitably, evidences we have like lake flow and increased river discharge, so soil conservation is the important aspect to be looked into by the local community, Dr Mark averred.

By Philips Joseph