Water allocation under climate change

Abstract

Chile is positioned in the 20th rank of water availability per capita. Nonetheless, water security levels vary across the territory. Around 70% of the national population lives in arid and semiarid regions, where a persistent drought has been experienced over the last decade. This has led to water security problems including water shortages. The water allocation and trading system in Chile is based on a water use rights (WURs) market, with limited regulatory and supervisory mechanisms, where the volume to be granted as permanent and eventual WURs is calculated from statistical analyses of historical streamflow records if available, or from empirical estimations if they are not. This computation of WURs does not consider the nonstationarity of hydrological processes nor climatic projections. This study presents the first large sample diagnosis of water allocation system in Chile under climate change scenarios. This is based on novel anthropic intervention indices (IAI), which were computed as the ratio between the total granted water volume to the water availability within 87 basins in north-central and southern Chile (30°S–42°S). The IAI were evaluated for the historical period (1979–2019) and under modeled-based climatic projections (2055–2080). According to these IAI levels, to date, there are 20 out of 87 overallocated basins, which under the assumption that no further WURs will be granted in the future, increases up to 25 basins for the 2055–2080 period. The results show that, to date most of north-central Chilean catchments already have a large anthropic intervention degree, and the increases for the future period occurs mostly in the southern region of the country (approximately 38°S), which has been considered as possible source of water for large water transfer projects (i.e., water roads). These indices and diagnosis are proposed as a tool to help policy makers to address water scarcity under climate change.

Review article: Drought as a continuum: memory effects in interlinked hydrological, ecological, and social systems

“…It is critical that actions are taken now. Water management recommendations to reduce drought-related risks include: 1) Adapting the water management system to account for a changing climate (Barría et al, 2019(Barría et al, , 2021a 2) Strengthening the protection of environmental flows to avoid water scarcity (Alvarez-Garreton et al, 2023)…”

Participation in water resources management in Latin America 2017-2022: A systematic review

“…The World Economic Forum (2020), included the water crisis among the five major problems in the world, placing it between the fifth in terms of impact and sixth in terms of probability, showing that the crisis in water management is increasingly considered a risk issue that affects our society (UNESCO, 2003;Greve et al, 2018;Barria et al, 2021); this affectation in terms of the decrease in quantity and affectation in quality occurs mainly to fresh water that is fundamental for population consumption and productive economic activities carried out by man and has been causing serious problems to human health due to water-related diseases, mainly to poor populations (UNESCO, 2003) and the productive economic activities developed by man translated into food insecurity, conflict and migration and financial instability (Sánchez, et al, 2018). Institutional management should be promoted in a participatory manner (United Nations Development Program [UNDP], 2015) to build sustainable multi-secular governance with the cooperation of government actors and individuals (Gutiérrez et al, 2020), supported by the agreement based on the institutional roles around this management (Schmeier, 2015), guaranteeing the flow of information with those represented to legitimize the agreements and improve the institutionality in water management (Martínez and Villalejo, 2018).…”

The influence of human activities on streamflow reductions during the megadrought in Central Chile

“…Hydrological drought vulnerability is associated with those conditions that cause an increase in the frequency, duration, and intensity of the hydrological droughts when a precipitation deficit threat is faced. Vulnerability should be addressed by looking for sensitivity variables that come from the biophysical basin's characteristics, such as aridity, location, geomorphology, hydrological regime, natural land cover, and snow and glacier cover (Saft et al, 2015;Van Loon and Laaha, 2015), and human activities such as management and extraction of water, land use, land cover changes, urbanisation, between others (Barría et al, 2021a;Van Loon et al, 2016, 2022. Although several articles have assessed hydrological drought vulnerability by evaluating biophysical basin characteristics (Alvarez-Garreton et al, 2021;Van Loon and Laaha, 2015;Saft et al, 2015;Van Lanen et al, 2013), there is still a gap in understanding how human activities contribute to basin's vulnerability to drought.…”

“…National statistics indicate that spending on cistern trucks to deliver potable water to rural communities in the six main watersheds of Coquimbo and Valparaíso regions reached US$56 million during 2010-2020. Human activities that affect catchment vulnerability in central Chile include groundwater extractions (Taucare et al, 2020), overallocation of water use rights (Alvarez-Garreton et al, 2021;Barría et al, 2021a), and continuous land use change for agricultural purposes (Madariaga et al, 2021). For example, agriculture is sometimes established on hillsides with high slopes, exacerbating water consumption problems and changing runoff mechanisms.…”