Recent changes in the level of Lake Abiyata, central main Ethiopian Rift

Abstract

The spatial and temporal variations in the level of Lake Abiyata and controlling natural and manmade factors are presented. This study has been made by combining evidence from hydrometeorological and lake level records, water budget analyses, aerial photograph and satellite imagery interpretations, and numerical groundwater flow modelling. The most important components of the water balance of the lake are precipitation, river inflow and evaporation. The lake level has been fluctuating considerably over a wide range (by 6 m during the last 60 years) strongly controlled by the precipitation trends in the adjacent highlands. Climatic changes and consequent reduction in the surface water inputs have resulted in the reduction of its size. Recent abstraction of water for irrigation and soda ash production have drastically changed both the lake level and its hydrochemistry. This change appears to have grave environmental consequences on the fragile rift lacustrine ecosystem.

Greening a Tropical Abijata-Shala Lakes National Park, Ethiopia - A Review

“…Lake Abijata is a terminal lake, without visible surface water outflow, and is therefore more vulnerable to changes. The water budget of Lake Abijata is dependent on seasonal precipitation, river inflows from Hora Kelo (contributes only about 8% of the total inflows to the lake) and Bulbula river, which was the largest inflowing river into Lake Abijata from Lake Ziway [13]. Hence, any intervention either on Lake Ziway or Bulbula River affects the water budget of Lake Abijata.…”

“…The Company was established by the Government of Ethiopia with a large production process that began in 1985 [13]. The factory has limited itself to produce trona (Na 3 H(CO 3 )2.2H 2 O).…”

“…An irrigation project on the upper reach of the river is ongoing and as the result the water flow in the Bulbula River has significantly reduced [13]. Irrigation is the largest water user activity in the basin [13,18]. Large-scale irrigation agriculture from Lake Ziway, its tributaries, and the Bulbula River is used in the production of horticulture, vegetables, and flowers [19].…”

“…Hence, any intervention either on Lake Ziway or Bulbula River affects the water budget of Lake Abijata. An irrigation project on the upper reach of the river is ongoing and as the result the water flow in the Bulbula River has significantly reduced [13]. Irrigation is the largest water user activity in the basin [13,18].…”

“…However, it is currently deteriorating: there are large numbers of households in the Park with large number of domestic animals. Deforestation is pervasive, the water level of Lake Abijata has significantly diminished, fishery has totally disappeared, and birds such as Lesser Flamingo and Pelican have migrated [9,12,13]. The environmental conditions in the Park are worsening and the lake is shrinking eventually facing imminent collapse with all its services and benefits unless appropriate measures are immediately taken [13].…”