Groundwater investigation for small scale irrigation purpose Merab Abaya Woreda, Gamo Gofa zone, Southern Ethiopia

Presently the problem of the global warming is becoming the main issue of the world as well as the country which results increase in temperature and decrease in rainfall both in amount and distribution. This unreliable rainfall and desertification in turn reduce the production return from the existing limited natural resource. This problem is becoming the main constraint for development and increasing agricultural production. Besides increase in population is another constraint which needs special mechanism to facilitate food availability for the rapid increasing population. To enhance agricultural production and escape out from the rain feed cultivation, groundwater is paramount important. This groundwater investigation is used different methods such as geological, geomorphological and vertical electrical sounding. When to consider groundwater availability we have to know the geology and topographic setting of the area. Geology of the area is characterized as low laid flat land is covered by unconsolidated sediments; mountains, ridges and domes are covered by ignimbrite, rhyolite and basalts. These rocks covered in upland areas are characterized not as such weathered and there are no penetrative fractures. Most of mountain ridges and domes which composed of ignimbrite and rhyolite are considered as recharge area rather than discharge area. The location of VES points were on unconsolidated sediments covered on the flat land of the study area. A number of VES point indicate that the thickness of unconsolidated sediment is ranges between 40-70m. The main aquifer of the area is below 45m over laid by clay soil. The total thickness of the main aquifer is 200m expected from VES data.