Geography Socio-hydrological Perspectives on Water Quality in an Arid Mountain Catchment

Natural resource extraction such as agriculture or mining can pose a serious threat to water quality, especially in vulnerable dry mountain areas like North-Central Chile.  
The interplay of multiple factors across various scales influencing water quality is often neglected in science and policy agendas. Using the case of the upper Huasco Valley. This study addresses this neglect and analyses the underlying processes against the backdrop of multidimensional socio-economic and political drivers. The socio-hydrological framework adapted for this study allows combining interdisciplinary methods in order to generate a more holistic perspective. The study takes an actor-oriented approach with a focus on those organizations that shape the decisions of water usage, and therefore also the water quality. Water samples of the local surface and groundwater system were collected during field stays in the austral summer of 2015/16.  Additional interviews and household surveys were carried out to contextualise the findings. The results of the water quality sampling show an overall good water quality that currently does not pose any risks for irrigation or human consumption. A classification of the major ions and an analysis of the measured stable water isotopes indicate a strong influence of sedimentary formations and climate. The use of fertilizers and irrigation by farmers depends on their financial means and the support by governmental organizations. Agricultural practices so far have only led to a minor increase of nitrate in shallow aquifers close to areas of monocultures. In contrast, surface water shows a slight increase of manganese concentrations close to the construction site of the Pascua Lama Mine. In the rest of the catchment, rock weathering seems be the main source of manganese. Ongoing (inter-) national protests of people in fear of negative impacts on water security and quality stopped the Pascua Lama Mine in 2013. These perceptions subsequently influence the way the local community interacts with water in their daily lives. The local drinking water management is based on a fragmented system with various organizations. Limited financial resources for frequent water quality monitoring and a lack of sewage water treatment pose further challenges to safe drinking water. The study concludes with a discussion of possible future threats to water quality. It shows how an integrative analysis of water quality at the interface of society and environment can establish a deeper understanding of current global water quality problems. 

PhD Candidate: Carina Zang
Funding: Nachwuchsgruppe Dr. Juliane Dame (HCE)
Duration:

Dame J, Nüsser M, Schmidt S & Zang C (2023): Socio-hydrological dynamics and water conflicts in the upper Huasco valley, Chile. Frontiers in Water 5: doi: doi.org/10.3389/frwa.2023.1100977

Hess K, Schmidt S, Nüsser M, Zang C & Dame J (2020): Glacier Changes in the Semi-Arid Huasco Valley, Chile, between 1986 and 2016. Geosciences 10, 429. doi: 10.3390/geosciences10110429

Zang C, Dame J & Nüsser M (2018): Hydrochemical and environmental isotope analysis of groundwater and surface water in a dry mountain region in Northern Chile. Environmental Monitoring and Assessment 190: 334. https://doi.org/10.1007/s10661-018-6664-9