The vulnerability of regional agriculture regarding irrigation water from the Tagus-Segura transfer Jos´e Daniel Buendía Azorín a,*,1 , Rub´en Martínez Alpa˜ nez b,2 , María del Mar S´ anchez de la Vega c,3 a Department of Applied Economics, University of Murcia, Campus de Espinardo S/N, Murcia 30100, Spain b Researcher at GAIA Group “CSR, Sustainability, and Innovation” UCAM c Department of Quantitative Methods for Economy and Business, University of Murcia, Campus de Espinardo S/N, Murcia 30100, Spain ARTICLE INFO Handling Editor: J.E. Fern´andez JEL Classification: O18 Q15 Q25 R11 R15 Keywords: Agriculture and environment Water Infrastructure Non-survey method Regional input–output tables Regression analysis ABSTRACT Input–output tables provide a useful tool for analysing economic and environmental impacts, which has led to their extension beyond the national level to the regional level. The availability of the intermediate demand matrix allows for the extraction of income multipliers and employment multipliers to assess the environmental impacts of different economic activities. This can intuitively be expected to play an important role in economic growth and employment in many regions, and to allow for more precise policy decision-making and application in sustainable development strategies. Despite the relevance of these input-output tables at regional level, there is an almost total absence of official data in most countries. This has led to the development of regionalisation methodologies, among which are those based on the application of location quotients. In these methods, cor- rections are applied to the obtained variables that depend on the value given to certain unknown parameters. This paper use a proposal of a simple and efficient procedure for estimating these parameters from generally available information on road freight transport and goods imports from the rest of the world. Applying them to estimate the input-output matrix of the Region of Murcia (Spain) made it possible to measure the economic impact of the Tagus-Segura transfer and to assess the impact of a reduction in the volume of transferable water. A hybrid approach was applied to obtain the Bi-Regional Input-Output matrix, which combines pure non-survey methods with matrix-balancing methods. This study quantifies the total contribution (direct, indirect and induced) of the agricultural branches associated with the irrigation water of the Tagus-Segura transfer to the economic output of the Region of Murcia. In addition, it estimates that a 50 % reduction of the current trans- ferable volume of water would reduce regional output, Gross Value Added and regional employment by 1.6 %, 1.5 % and 3.8 %, respectively. 1. Introduction In the field of river transfers, researchers have expressed concerns about the economic, social, and environmental impacts on the benefiting areas. However, the majority of studies have approached these impacts separately. On one hand, environmental assessments, for instance, have been conducted by various studies (e.g., Davies et al., 1992; Meador, 1992; Gibbins, 2000; Ib´a˜ nez and Prat, 2003; Matete and Hassan, 2005; Das, 2006; Hu et al., 2008; Islar and Boda, 2014) using cause-effect interaction matrices. On the other hand, research on eco- nomic impacts, which is the focus of this study, has gained momentum since the seminal work of Howe and Easter (1971) 4 . This interest is evidenced by numerous publications, including those by Beattie (1972), Howe et al. (1990), Seung et al. (1998), S´ anchez-Ch´ oliz and Duarte * Corresponding author. E-mail addresses: jdbuen@um.es (J.D.B. Azorín), ruben.ma@um.es (R.M. Alpa˜ nez), marvega@um.es (M.M. S´anchez de la Vega). 1 ORCID: 0000-0001-9302-7971 2 ORCID:0000-0002-3663-3171 3 ORCID: 0000-0002-8647-6215 4 This paper presents the conceptual framework for the economic evaluation and case study of the transfer of the Columbia River to the Imperial Valley of California in the United States, using the input-output framework. Contents lists available at ScienceDirect Agricultural Water Management journal homepage: www.elsevier.com/locate/agwat https://doi.org/10.1016/j.agwat.2025.109332 Received 26 April 2024; Received in revised form 9 October 2024; Accepted 21 January 2025 Agricultural Water Management 309 (2025) 109332 Available online 4 February 2025 0378-3774/© 2025 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).