Impacts of Climate Change on Irrigated Agriculture in the Maipo Basin, Chile: Reliability of Water Rights and Changes in the Demand for Irrigation

Abstract

Agricultural regions located in snowmelt-dominated Mediterranean climate basins have been identified as being highly vulnerable to the impacts of climate change. The Maipo basin in central Chile is one such region. Projections of future climate conditions suggest major challenges for this basin. Precipitation levels are projected to decrease by the end of the century, and temperature levels in the mountains are expected to increase by around 3-4°C. Such changes would affect both river discharge and irrigation water demand. This paper illustrates potential climate change impacts on the hydroclimatological regime of the Maipo basin, focusing on irrigated agriculture and its demands on water use rights. The impact assessment was carried out by combining a multisite stochastic weather generator with a disaggregation technique for historical monthly flows of the Maipo river at El Manzano. Demand for irrigation was simulated with a daily water budget model. Data showed that water demands from irrigated agriculture tend to increase as a consequence of the simulated changes in temperature and precipitation. The magnitudes of these changes depend on crop types and their prevalence in the region. It was concluded that the reliability of water allocations under the current water rights system may be strongly negatively affected. In particular, projected hydrological impacts for the climate change scenario considered indicate that the 15th percentile currently used as the basis for water rights may become the 40th or 50th percentile in the future, suggesting that present water allocations will become overcommitted.

Unpacking Resilience for Adaptation: Incorporating Practitioners’ Experiences through a Transdisciplinary Approach to the Case of Drought in Chile

“…Droughts have a profound effect on agricultural production and, therefore, were one of the greatest concerns expressed by participants of the workshops. The former is consistent with the study by Meza et al [42] and Vicuña et al [43], who found that the potential negative impact on crop production is sensitive to high seasonal water demand in Chile, which in turn is influenced by climate change-induced drought. A more optimistic interpretation is presented in the models developed by [44], on the basis of which the author foresees no harm to production potential in the southern regions, given the possibility of a general adaptive strategy based, for example, on implementing earlier planting dates to capture winter rains.…”

“…First, the results emphasize the need to generate more information on, and raise awareness of, the causes and effects of drought, as well as the vulnerability of social and ecological systems. Second, participants mentioned a need for community adaptation through different practices, which is consistent not only with research findings on this topic in various regions of the country [42,47], but also with a series of concrete experiences of communities supported by international organizations and national NGOs [48,49]. Third, participants mentioned the need to improve institutional responses, in particular in relation to the adjustment of norms and regulations and the creation of flexible yet specific public policies.…”

Assessing glacier melt contribution to streamflow at Universidad Glacier, central Andes of Chile

“…Hydropower generation on the Tinguiririca River at La Higuera and La Confluencia (Pelto, 2011) will be affected by interannual variability in water supply and future streamflow trends in the medium to long term. Finally, more long-term highelevation stations in the Andes are necessary to establish the interannual variability of glacier contribution to river discharge in order to help manage future water availability, considering climate change and the increasing demand for water in the region (Meza et al, 2012).…”

“…This region, incorporating the capital city, Santiago, has more than 10 million inhabitants representing 60 % of the country's population. In addition to domestic supply, water is a crucial resource for agriculture irrigation, industries, mining, hydropower generation, tourism and transport (Aitken et al, 2016;Masiokas et al, 2006;Meza et al, 2012;Ayala et al, 2016;Valdés-Pineda et al, 2014). Population growth and urban expansion in recent years have increased the demographic pressure on water resources (Meza et al, 2012).…”

Design water demand of irrigation for a large region using a high-dimensional Gaussian copula

“…Among the many factors, precipitation which is regarded as stochastic is an uncertain factor influencing irrigation (Wisser et al, 2008;Thomas, 2008;Cai et al, 2011;Meza et al, 2012). In general, the more precipitation is, the less water demand of irrigation is, and vice versa.…”