The Effects of Climate Change on the Tagus–Segura Transfer: Diagnosis of the Water Balance in the Vega Baja del Segura (Alicante, Spain)

Abstract

Climate change is one of the most important problems facing society in the 21st century. Despite the uncertainty about the behaviour of rainfall due to climate change, what is clear is that average rainfall has been reduced in the inland areas and headwaters of Spain’s river basins. The Tagus basin is one of the most affected, with implications for the Jucar and Segura basins. The working hypothesis is to corroborate with the data collected on the effects of climate change on the TTS. To this end, the following methodology has been applied: (a) analysis in the headwaters of the Tagus, using data on precipitation, surface runoff and reservoir water; (b) analysis of the resources of the Segura basin (supply and demand), based on the basin organisation’s own data; (c) construction of a water balance adjusted to the Bajo Segura district (Alicante), a user of the water transferred for agricultural use. Likewise, the data provided by the basin organisation have made it possible to corroborate the data on consumption and allocation of the corresponding volumes of water. The results obtained make it possible to put forward a novel proposal in the scientific field related to hydrological planning based on the principles of sustainability.

Precipitation and drought trends (1952–2021) in a key hydrological recharge area of the eastern Iberian Peninsula

“…Given its importance, any alteration to this type of rainfall may have major effects on the evolution of the water resources in the studied area and downstream areas, which are fed by the water that comes from the rivers that arise there. In fact, the impact on the economic system of the eastern coastal regions in the Iberian Peninsula (Valencian Community, Region of Murcia and eastern Andalusia) is fundamental given that the tourism and agricultural sectors are basic pillars of their economic system (Cañizares et al, 2022;Miró et al, 2021). The reduction in captured volumes is notorious throughout the study area, but is more significant in CHT, where loss is general throughout its territory, and also in CHG and CHE.…”

Proposal of the “Wastewater Use Basin” Concept as an Integrated Sewage and Rainwater Management Unit in Semiarid Regions—A Case Study in the Southeast of the Iberian Peninsula

“…In semi-arid areas, the traditional paradigm of hydrological planning-predominantly based on conventional resource supply policies-must be modified. Efforts must be directed towards a "sustainable" hydrological planning in which the territories seek water self-supply through the use of water resources of diverse origin (conventional and non-conventional), thus trying to reduce dependence on other hydrographic basins-transfers of water [5]-and frequent atmospheric conjunctures-droughts [6]. In the current context of climate change, one of the main ways of obtaining water resources that are not subjected to climatic variations is by increasing the so-called non-conventional sources, particularly the use of treated sewage and desalinated water [5].…”

“…Efforts must be directed towards a "sustainable" hydrological planning in which the territories seek water self-supply through the use of water resources of diverse origin (conventional and non-conventional), thus trying to reduce dependence on other hydrographic basins-transfers of water [5]-and frequent atmospheric conjunctures-droughts [6]. In the current context of climate change, one of the main ways of obtaining water resources that are not subjected to climatic variations is by increasing the so-called non-conventional sources, particularly the use of treated sewage and desalinated water [5]. Collection of rainwater in large-capacity tanks and its use can also be considered [7], which makes it possible to take advantage of the intense rainfall that has occurred frequently, in recent decades, in some climatic regions such as the Mediterranean [8].…”

“…However, the new reality of hydrological planning, conditioned by the effects of climate change [5], now allows the consideration of new possibilities in the water-resources planning protocol of the territories, especially in those with natural rainfall deficit and a scarcity of conventional sources (surface and groundwater). In this context, the territories can be adapted to the geographical area where resources are obtained to guarantee existing demands.…”

“…The climate change models evidence the reduction in water resources in river basins, associated with the scenarios of reduced rainfall in the headwaters of the river basins [20][21][22], and, for its part, an increase in the volume of reused water from the STPs and an increase in the volume of desalinated water [5].…”