A THESIS SUBMITTED TO THE FACULTY OF WATER SUPPLY AND ENVIRONMENTAL ENGINEERING, INSTITUTE OF WATER TECHNOLOGY, SCHOOL OF GRADUATE STUDIES, ARBAMINCH UNIVERSITY.

Abstract

The WSI and WTA ratio, the two most commonly used metrics for describing water shortage, had a basic lack of rigorous investigation into their meaning and actual application to estimate water scarcity levels. The goal of the study was to use the Baro River Catchment as a test area for two frequently used indicators of water scarcity—the WSI and WTA ratio indicator—in order to examine how descriptions of water scarcity have changed over time. The research is crucial because it advances the methodology for defining water scarcity in Gambella Plain where the lack of water is the severe problem. The literature study revealed that current water scarcity indicators use equations derived from mean annual river runoff (river discharge) to estimate renewable freshwater availability. Research objectives were met using secondary data on river discharge, population change, and irrigation withdrawals over three time periods (1973 - 1980, 1999 - 2006, and 2007 - 2011), interviews and a household survey of three districts in the Gambella Plains, where a sample (n = 82 respondents) were also used in primary data inquiry. The Baro River Catchment was shown to have an abundance of water, but when it was applied downstream at Itang, it showed rising levels of water stress that were below the absolute water stress threshold (500 m3 capita yr-1. There were increasingly more frequent instances of water stress between 1999 and 2011, with ratio scores above 0.4, which is the crucial level for water stress. The results of the home survey measured residential water consumption at 28 LCPD, which is below the 100 LCPD WSI standard. ERS and IRS all agreed that the significant temporal and geographical variability in freshwater supply best describes the BRC's water scarcity. The main difficulties in estimating inter- and intra-annual variability in freshwater resource availability in the BRC are related to the fact that the observed daily discharge data had significant gaps in them and would need to be filled in through modeling. Therefore, accepting the idea of variability and placing it at the center of developing future water scarcity indicators are necessary if we are to advance the measurement of water shortage in a meaningful way