Assessment of water provision under different future land use scenarios in the Cauquenes Catchment, Chile.

The landscape of south-central Chile, originally a mosaic of pristine native forests and crops, has been converted into tree plantations and agroindustry. Farmlands and native forests have undergone a rapid conversion to fast-growing non-native pine and eucalyptus plantations, as well as irrigated fruits production for international exports. These two drivers have severely transformed the socio-ecological system, resulting in less biodiversity, more erosion, emigration and work depence, less drinking water, and a fire-prone landscape. A participatory approach helps not only to visualise tensions in the territory, but it is also useful for stakeholders to explore the possible environmental futures. However, frequently the development of land-use scenarios is mostly based on the views of experts and policymakers, missing out a wealth of local knowledge about the environment which experts seek to comprehend. 

This work aims at quantifying the impacts of the aforementioned land cover changes in water provision for the population and ecosystems, by incorporating the views of the people that still live in a drought-prone rural area in the construction of different narratives representing future land management scenarios. The study area is the Cauquenes River Basin, a mediterranean catchment located in central Chile, historically known for wine production and rainfed agriculture. To develop the narratives, we conducted semi-structured interviews to collect and analyse qualitative information using a coding system systematised in the Atlas.ti software. Using 2050 as the simulation target year, narratives gave us the guidelines to develop the spatial scenarios. Then, using an open-source land use change model- called CLUE-s we constructed scenarios of future land use change. The CLUE-s algorithm allocates land uses based on the suitability of each land use as well as spatial regulations. To assess the impact on water provision of each scenario, they were evaluated using a hydrological model (SWAT+).

Our results identified two different narratives: i) rural development: where water availability could increase, if a protection strip is established near water courses, that is, scrublands and native forest are assigned in these areas and, rainfed agriculture is strengthened and reach the extension it had in 1990 and ii) agro-industrial development, in which the central government promotes irrigated agriculture for international export markets, at the same time, passive preservation plans for protect native forest are applied according to the current forestry regulation. We expect that this participatory approach will enrich and strengthen adaptive management capacity at the local level, to be able to face the challenges ahead presented by a drier future.