Evaluating Water Supply Risk In The Middle Reaches Of Subarnarekha River Basin By Using WEAP Model

Abstract

The allocation of limited water resources poses a challenge when demand from different stakeholders are gradually increasing. Demand supply analysis for different scenarios can help the planners for better allocation of these precious natural resources. In the present study, the Water Evaluation and Planning System (WEAP) model was applied to analyse water demand and supply potential in the middle reach of the Subarnarekha river basin, Jharkhand. Demand sites used were classified as an industrial area, institutional water demands area, agricultural land and human and livestock settlement. Annual water use rate per person, per hectare and per head of livestock were determined and used as input alongwith other hydrological input parameters to the WEAP model. For WEAP modelling framework, the year 2010 was chosen as a current year. It has observed dry conditions with an annual rainfall of nearly 624.8 mm whereas, the years 2011 and 2013 experienced high rainfall (1836.4 and 1779.8 mm) resulting in wet conditions. The maximum flow to the groundwater storage was found in the monsoon months compared to the non-monsoon months as an obvious phenomenon. It was noticed that the year 2010 showed the lowest surface runoff because the year 2010 observed the minimum rainfall and the years 2011 and 2013 showed the highest surface runoff. It can be seen that rainwater is available to meet the crop water demand in monsoon months. The agriculture demand gradually increases from November end, highest in May (approximately 430000 m3) and decreases June onwards. Unmet demands were high in the very dry years, that is 2010, 2016 and 2017. The unmet water demand for agricultural use was found to be highest in the year 2010 because it receives minimum rainfall. © 2021 - Kalpana Corporation