Paper Title
Assessment of The Efficiency of Water Resources in Relation to Gross Value Added of Districts in Bulgaria Through Data Envelopment Analysis (DEA)

Abstract
The coming climate changes, expressed on the territory of Bulgaria with more and more prolonged droughts, put the following question on the agenda: “Are the water resources on the territory of Bulgaria used effectively from the point of view of the well-being of the population?”. The answer to the question is sought by applying Data Envelopment Analysis (DEA) in relation to 25 administrative-territorial districts of the country and four variables: the amount of water used in economic activities “Industry”, “Agriculture, forestry and fisheries” and “Services” and the gross value added (GVA) created in each district. The first three variables are in the capacity of input resources, and the fourth in the capacity of a result characterizing the well-being of the population. Through the application of the DEA model, oriented to the input resources with variable returns to scale, it is established that in only 44% of the analyzed areas, Bulgaria's water resources are used efficiently. In addition, in order to achieve effective use of water resources in the country, the GVA should increase by about 34% compared to 2020, assuming no change in the amount of water resources used. Keywords - DEA, input, output, water resources, gross added value, efficiency, district.