Please cite this article in press as: Kucukmehmetoglu, M., Geymen, A., The significance and impacts of large investments over the determination of irrigated agricultural land use: The case of the Euphrates & Tigris River Basin. Land Use Policy (2014), http://dx.doi.org/10.1016/j.landusepol.2014.04.006 ARTICLE IN PRESS G Model JLUP-1609; No. of Pages 12 Land Use Policy xxx (2014) xxx–xxx Contents lists available at ScienceDirect Land Use Policy j o ur na l ho me page: www.elsevier.com/locate/landusepol The significance and impacts of large investments over the determination of irrigated agricultural land use: The case of the Euphrates & Tigris River Basin  Mehmet Kucukmehmetoglu a,∗ , Abdurrahman Geymen b a Department of City and Regional Planning, Gebze Institute of Technology, Istanbul Cad. No: 101, Gebze, 41400 Kocaeli, Turkey b Department of Geomatics Engineering, Erciyes University, 38039 Kayseri, Turkey a r t i c l e i n f o Article history: Received 24 August 2013 Received in revised form 29 January 2014 Accepted 8 April 2014 Keywords: Trans-boundary Water Resources The Euphrates and the Tigris Rivers Mixed Integer Programming Basin Management Agriculture Irrigation Land Use a b s t r a c t During the construction and especially water filling periods of Keban and Atatürk dams in the Euphrates River Basin, there have been a series of high level political tensions among Turkey, Syria, and Iraq for the allocation of trans-boundary water resources. It has been claimed that those large investments not only contribute to those investing countries but also to those affected ones. This research measures the contributions and impacts of major investments on the basin to the riparian countries. And how spatial land use decisions on irrigated agricultural areas in rival basin countries are made by means of opti- mization techniques. The model application is based on with and without analyses for the selected group of dams, which are Keban, Karakaya, Atatürk, Ilısu, Tabqa, Haditha, and Mosul dams, Habbaniye Reser- voir, and Urfa Tunnels. The mixed integer programming (MIP) based on the Inter Temporal Euphrates and Tigris River Basin Model (ITETRBM) is used as an optimization tool for the necessary analysis. The impacts are presented by countries and by the generated economic benefits, water withdrawals, coverage areas of irrigated agricultural land, cities feasibly supplied from the reservoirs. The results have shown that large reservoirs in Turkey provide extensive contribution to the basin countries especially during drought periods when all major reservoir investments are considered together. That can be considered as potential for coalition during drought periods instead of competition. © 2014 Elsevier Ltd. All rights reserved. Introduction The Euphrates is the longest river in the Middle East Region and is heavily fed from the precipitations in Turkey (89%). After Turkey the river flows sequentially into Syria, and Iraq. Iraq does not have any contribution, and Syria contributes only remaining 11%. The second river in the region is the Tigris River, which, again, emerges in Turkey with a contribution more than half of its flow (51%). The Tigris River makes a 32 km border between Turkey and Syria. Iraq’s contribution to the river is 39% of flow and remaining 10% is from Iran (Kaya, 2009). At Shatt Al-Arab both the Euphrates and the Tigris confluence and make a 81.9 Bm 3 average river flow in the region (Kolars, 1994).  Earlier version of this paper is presented in the 6th International Perspective on Water Resources & the Environment conference (IPWE 2013), January 7–9, 2013, Izmir, Turkey. ∗ Corresponding author. Tel.: +90 262 605 16 25; fax: +90 262 653 84 95. E-mail addresses: mkucuk@gyte.edu.tr (M. Kucukmehmetoglu), ageymen@erciyes.edu.tr (A. Geymen). Optimization techniques introduced into water resources allo- cation models by Flinn and Guise (1970), Vaux and Howitt (1984), and Booker and Young (1994). Game theory concepts added into trans-boundary water resource allocation studies by Rogers (1969, 1993), and Dinar and Wolf (1994). Both optimization and game theory methods have been utilized in the context of the Euphrates and Tigris basin by Kucuk- mehmetoglu since 2002. Later on, a series of extensions are provided by Kucukmehmetoglu and Guldmann (2004, 2010), Kucukmehmetoglu (2009, 2010, 2012), Kucukmehmetoglu and Geymen (2012a, 2012b, 2013), and Kucukmehmetoglu et al. (2010). The first publication (Kucukmehmetoglu and Guldmann, 2004) is on the game theoretic applications of the Euphrates and Tigris River Basin Model (ETRBM) for the allocation of scarce water resources. The second publication is based on inter-temporal extension of the model that the number of periods is increased from 1 to 2 (Kucukmehmetoglu, 2009). In this way, the model is improved to measure the impacts of reservoirs for seasonal and monthly inter- temporal allocations. The third publication is on the generation of three-party Pareto frontier surfaces and searches for an admissi- ble allocation from this surface regarding the political nature of http://dx.doi.org/10.1016/j.landusepol.2014.04.006 0264-8377/© 2014 Elsevier Ltd. All rights reserved.