Browsing by Author "Stehr, Alejandra"
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Item Distributional impacts of climate change on basin communities: an integrated modeling approach(2017) Ponce Oliva, Roberto; Fernández, Francisco; Stehr, Alejandra; Vásquez Lavín, Felipe; Godoy Faúndez, AlexAgriculture is one of the most vulnerable economic sectors to the impacts of climate change, specifically those related with expected changes in water availability. By using a hydro-economic model, this study assesses the distributional impacts of climate change, considering the geographical location of each farmer’s community and the spatial allocation of water resources at basin scale. A hydrological model, the Soil and Water Assessment Tool model, describes the basin hydrology, while farmers’ economic responses are represented using a non-linear agricultural supply model. We simulated a reduction in both water endowment—by perturbing the hydrologic model with a regionalized climate change scenario—and agricultural yields, in order to assess the behavior of farmers’ communities. We also assessed the effectiveness of a water policy aimed at decreasing the vulnerability of farmers’ communities to climate change. At the aggregated level we found relatively small impacts, consistent with the existent literature. However, we found large distributive impacts among both farmer’s communities and agricultural activities. The water policy showed to be effective to reduce those impacts, but our results suggest the existence of unwanted effects on rainfed agriculture, as in some communities the level of income decreases when the policy is implemented.Item Forest hydrology in Chile: Past, present, and future(2023) Balocchi, Francisco; Galleguillos, Mauricio; Rivera Salazar, Diego; Stehr, Alejandra; Arumi, José Luis; Pizarro, Roberto; Garcia-Chevesich, Pablo; Iroumé, Andrés; Juan J. Armesto, Juan J.; Hervé-Fernandez, Pedro; Oyarzún, Carlos; Barría, Pilar; Little, Christian; Mancilla, Gabriel; Yépez, Santiago; Rodríguez, Rolando; White, Don A.; Silberstein, Richard P.; Neary, Daniel G.; Ramírez de Arellano, PabloThis paper reviews the current knowledge of hydrological processes in Chilean temperate forests which extend along western South America from latitude 29° S to 56° S. This geographic region includes a diverse range of natural and planted forests and a broad sweep of vegetation, edaphic, topographic, geologic, and climatic settings which create a unique natural laboratory. Many local communities, endangered freshwater ecosystems, and downstream economic activities in Chile rely on water flows from forested catchments. This review aims to (i) provide a comprehensive overview of Chilean forest hydrology, to (ii) review prior research in forest hydrology in Chile, and to (iii) identify knowledge gaps and provide a vision for future research on forest hydrology in Chile. We reviewed the relation between native forests, commercial plantations, and other land uses on water yield and water quality from the plot to the catchment scale. Much of the global understanding of forests and their relationship with the water cycle is in line with the findings of the studies reviewed here. Streamflow from forested catchments increases after timber harvesting, native forests appear to use less water than plantations, and streams draining native forest yield less sediment than streams draining plantations or grassland/shrublands. We identified 20 key knowledge gaps such as forest groundwater systems, soil–plant-atmosphere interactions, native forest hydrology, and the effect of forest management and restoration on hydrology. Also, we found a paucity of research in the northern geographic areas and forest types (35-36°S); most forest hydrology studies in Chile (56%) have been conducted in the southern area (Los Rios Region around 39-40° S). There is limited knowledge of the geology and soils in many forested areas and how surface and groundwater are affected by changes in land cover. There is an opportunity to advance our understanding using process-based investigations linking field studies and modeling. Through the establishment of a forest hydrology science “society” to coordinate efforts, regional and national-scale land use planning might be supported. Our review ends with a vision to advance a cross-scale collaborative effort to use new nation-wide catchment-scale networks Long-term Ecosystem Research (LTER) sites, to promote common and complementary techniques in these studies, and to conduct transdisciplinary research to advance sound and integrated planning of forest lands in Chile.Item Nexus Thinking at River Basin Scale: Food, Water and Welfare(2021) Ponce Oliva, Roberto; Fernández, Francisco J.; Vásquez Lavín, Felipe; Arias Montevechio, Esteban; Julio, Natalia; Stehr, AlejandraWater resources face an unparalleled confluence of pressures, with agriculture and urban growth as the most relevant human-related stressors. In this context, methodologies using a Nexus framework seem to be suitable to address these challenges. However, the urban sector has been commonly ignored in the Nexus literature. We propose a Nexus framework approach, considering the economic dimensions of the interdependencies and interconnections among agriculture (food production) and the urban sector as water users within a common basin. Then, we assess the responses of both sectors to climatic and demographic stressors. In this setting, the urban sector is represented through an economic water demand at the household level, from which economic welfare is derived. Our results show that the Nexus components here considered (food, water, and welfare) will be negatively affected under the simulated scenarios. However, when these components are decomposed to their particular elements, we found that the less water-intensive sector—the urban sector—will be better off since food production will leave significant amounts of water available. Moreover, when addressing uncertainty related to climate-induced shocks, we could identify the basin resilience threshold. Our approach shows the compatibilities and divergences between food production and the urban sector under the Nexus framework.Item Water Use and Climate Stressors in a Multiuser River Basin Setting: Who Benefits from Adaptation?(2021) Ponce Oliva, Roberto; Arias Montevechio, Esteban; Fernández Jorquera, Francisco; Vásquez Lavín, Felipe; Stehr, AlejandraAdapting to new climate conditions will require an intricate mix of knowledge, planning, coordination, and foresight. There is increasing sectoral evidence on the implementation of successful adaptation actions. However, the success of these actions when we consider the interdependencies among sectors remains debatable. This paper aims to assess who benefits from implementing adaptation options in a multiuser river basin to both climate-induced and demographic stress on water use. Our analysis relies on a hydro-economic model that considers two sets of water users: agriculture and urban households. We innovate in our modelling approach by analyzing and explicitly integrating the household-level economic behavior through its water demand. We assess the cross-user consequences of autonomous and planned adaptation actions. We provide insights into the different trade-offs at the basin level, demonstrating the compatibilities and divergences between agriculture and household-level water demand. We found different consequences of implementing either autonomous or planned adaptation measures. For instance, a decentralized scheme would drive negative implications for the entire basin, although the less water-intensive sector will be better off. On the other hand, different policy interventions would drive positive consequences for the entire basin, with the most water-intensive sector benefiting the most. These results highlight the distributional consequences across users of different adaptation measures