Assessment of Surface Water Availability and Demand Analysis for Water Resource Planning: The Case of Borkena River Watershed, Awash River Basin, Ethiopia.

Abstract

Water is a basic necessity for sustaining life and development of society with the Increasing of population and socio- economic activities demand for water has increased rapidly over the years the aim of this study is to understand the association of surface water availability and water demand for water competition scenarios with surface water variability in the Borkena watershed to assess the current surface water availability of river Borkena in terms of demand and supply potential, the current (2019) data were used into the entire time horizon in which no changes are imposed and serves as a point of comparison for the other scenarios like: medium growth and high growth in which changes are made in the system data furthermore to predict the future scenarios of water resource of Borkena watershed, Unmet, demand and demand Coverage in (%) were considered to evaluate the impact of possible surface water demand on the water resources of Borkena watershed by 2030, the General work was carry out by collecting secondary data obtaining from different data sources, the Analysis of raw data was made for data quality checking and filling of missing records the data source were Ministry of Water Irrigation & Energy Ethiopian Mapping Agency National Meteorological service Agency, Central Static Agency of Ethiopia and literatures, to evaluate water Demands for various needs in the study including domestic livestock agriculture industrial commercial and environmental are identifying, materials used in the study are Arc GIS 10.4.1 CropWat8 model and WEAP (Water Evaluation and Planning) the watershed receives the amount of rainfall estimated around 54.4 MCM annually will be by year (2020- 2030) the total annual surface runoff from a given precipitation in the study area estimated to be 15.1 (MCM) by (2020-2030) the total surface water availability in the area has been estimated to be 4.1 BCM by 2020-2030 but for the current account surface water availability has estimated to be 544.5Mm3 at the study period in 2019 the result from WEAP Model indicated that demand coverage (%) and supply potential in the study for all scenarios over the year is satisfied during the month (July to September) since the rain fall of the area is characterized by mini modal types of rain fall pattern generally in the case of water consumption between reference ,medium growth and high growth scenarios are 37%,45% and 48% the available surface water will use by year of (2030.