Situation in the Copiapó River Basin
To further understand the current situation of the basin, we have to understand the context and the general characteristics of this aquifer system. Is it sustainable? That depends on different factors, but also on the users, on how we organize ourselves, of how we face the challenges and how, from science, do we apply the possible answers.
The area of the study corresponds to the Copiapó River basin, located about 800 km north of Santiago in the Atacama dessert between 27º and 29º South latitud. The basin has an area of 18.540 km2 which is more vast to the East where the Andes sierra rises up and stretches out to the Pacific Ocean. The Copiapó basin receives less than 30 mm of annual rainfall concentrated in the highest parts of the basin, and therefore, there are no surface tributaries and contribute to the main water flow of the river in the lower sections of the basin.
The elevation of the Eastern limit reaches altitudes greater than 5.000 meters above sea level with approximately 11% of the surface of the basin under the 1.000 m.s.n.m. In the northern area of the Chile, the snow line of the Andes mountain range es considerably high (approximately 5.800 m.s.n.m); and therefore, this is now permanent coverage of snow in the Copiapó basin, although there is a limited amount of glaciers. However, snow melting contributes significantly to water flow in the basin, reaching its maximum flow in the summer months (McFarlane and Norgate, 2012).
The climate conditions in the Copiapó river valley are influences by a great variety of factors related to latitude, the proximity to the great heights of the Andes and the regulator effect of the ocean temperature. While the descent of dry air coming from the subtropical Hadley cell at this location reduces convection, the presence of the Humboldt current reduces the capability of cold fronts to provoke winter rainfall. At the same time, the Andes mountain range acts as an orographic barrier, impeding the development of rainfall proceeding from the East. Annual average rainfall for the Copiapó basin is estimated to just 28 mm. It is also projected that climate change will cause a diminishing of rainfalls towards the year 2040, and a gradual growth towards the end of this century. However, it is also projected that the temperature will rise in the basin and an increase of the risk of flooding, due to an increase of frequency and intensity of rainfall.
Lack of recharge for the aquifer system
The Copiapó river has approximately 162 km of length and is located in a transversal valley with a pronounced inclination that runs through the Atacama region. It begins at 1.230 meters high at the skirts of the Andes mountain range, and then converges with its three affluents, Manflas, Jorquera and Pulido rivers. The Copiapó river corresponds to a fluvial system that has a low water flow which possesses a snow and rainfall regime. While surface water is extracted mainly from the top part of the basin, subterranean water constitutes an important source for the river below. Except under special conditions, scarce rainfall observed in the lower part of the basin does not allow for an aquifer system recharge. Subterranean water levels have gone underneath the bed of the river since 1998, causing an increase in infiltration. As a result, the Copiapó river has been channelled through a channel made of cement in Sector 4 of the basin, so that the superficial water flow can supply groups of irrigators down the river.
Social factors and water sustainability in the basin
During the last 20 years there has been a significant increase in economic development in the Copiapó river basin, based on an expansive and modern agriculture of export products with high profits, in the boom and development of its mining industry and in the exploitation of new mineral deposits. Therefore, there has been an explosive demand of water, including its use for drinking water, fundamentally based in the exploitation of water resources in the valley.
Given the limited offer of water in the basin, due to the hydrometeorological condition of aridity in the area and due to the over assignment of water rights in the sector, there have been serious and growing problems in the meeting of these demands that have placed consumption and sustainability of the resource in a critical situation, and has provoked social tension among the communities. This has led to the deterioration of the social capital present in the basin, which has been exemplified with inter-sectorial conflicts, the lack of cooperation to seek integrated solutions, low trust levels, and other indicators of social and cultural deterioration.
This is not the first attempt
Recently, different organization instances have developed to confront the dilemas aforementioned. The ENGICH initiative began the establishment of a “Private-public Discussion Table for Water” in 2006 with the objective to operate as a Basin Organism that would implement and facilitate the strategies identified by the Management Plan for the Copiapó River Basin by CONAMA-DGA in 2009. Recently, the 2014, the Regional Government of Atacama, through the Corporation for Competitiveness and Innovation of the Atacama Region (CCIRA) established a Regional Water Resource Advisory Council (CARRH), which includes a Territorial Discussion Table for Water in the Copiapó basin, whose mission is to facilitate the analysis, discussion and implementation of a consensus that can translate to the development of proposals and measures in water management matters.
CSIRO’s contributions can add to these past initiatives, with solutions based on applied science, in the development of technology and the opening to different actors in order to understand their needs and incorporate them to the proposed models. The solutions are many and the opportunities to contribute as well.