An assessment of the urban water footprint and blue water scarcity: A case study for Van (Turkey)

Uma avaliação da pegada hídrica urbana e da escassez de água azul: um estudo de caso para Van, Turquia

Abstract

Today, most of the world’s population faces water scarcity, while global warming, urbanization, industrialization and population increases continue to increase the severity of the pressure on water resources. Management of water resources plays a key role in the sustainability of agricultural production. The water footprint (WF) is different in comparison to other water statistics because it takes direct and indirect water consumption into account, and helps in the management of water resources. Within this context, the WF of Van province, which is Turkey’s most easterly located arid region, was calculated from 2004 to 2019. The study area covers lake Van, which is Turkey's largest lake, and the Van basin with an area of 23.334 km² and a population of 1.136.757 (2019). In the calculations, crop (WF_crop), livestock (WF_livestock), and domestic and industrial water footprints (WF_{domestic+industrial}) were evaluated separately, and blue and green water footprints (WF_blue and WF_green) were analyzed in detail. According to the results, the average WF of Van province was found to be 8.73 billion m³ year^-1. Throughout the province, 87.6% of the WF is composed of WF_crop, 4.9% is WF_livestock and 7.5% is WF_{domestic+industrial}. Of the WF_crop, 62.5% depends on WF_blue, i.e., freshwater. Most of the WF_livestock consisted of dairy cattle (49%) and sheep (38%). The average WF_{domestic+industrial} for 2004 to 2019 was 0.64 billion m³ year^-1. The average per capita water footprint of Van province was found to be 889.9 m³ year^-1 capita^-1. In addition, the province is classified as severe water scarcity (257%). This study is one of the first province-based calculations of WF in Turkey and is the first study to bring a different aspect to published literature by including residual soil moisture from the winter months. As a result of this study, the WF_blue of the WF_crop is above the worldwide average and should be reduced by changing the crop pattern or synchronizing the planting and harvest dates of the crops to a period that benefits from precipitation. In addition, this study is expected to contribute to new studies for calculating the provincial scale WF and will have positive effects on agricultural planning, water allocation and the sustainability of water resources.

Keywords:
agricultural sustainability; blue water; green water; water footprint; water sustainability