IWRA Proceedings

AbstractThe objective of this work is to propose a methodology for the identification of water resources in mountain basins, being able to contribute to the analysis and selection of small hydraulic works destined to improve the possibilities to develop sustainable projects of populations located in regions of scarce economic resources. Many isolated populations of Argentina still do not have access to water resources able to be supplied in proper amount and good quality such that the sustainable development of these communities can be guaranteed. The severe climatic conditions, the absence of roads, the lack of electrical energy are, among others, daily problems that must be also borne in mind to understand the social complexity of these people. The problems previously exposed concerning water resources involve technical and social issues that must be considered from a global viewpoint. This article deals with the guidelines considered for water resources identification and the preliminary project of collection and distribution works for a small community located in the northwestern area of Argentina. The rural population is known as San Isidro (province of Salta), with 350 inhabitants, being located at 2,800 m elevation above sea level. San Isidro is located close to the homonymous river, which is tributary to Iruya River. The surface of the river basin reaches 90 km2, with an average slope close to 10%. The hydrological regime is pluvial, with a mean annual precipitation near 300 mm, mainly concentrated between the months of December and March. In this season, there is a high probability of occurrence of convective summer storms that may generate flash floods with the characteristics of debris flows. These facts imply a restriction in the use of the water resource by the population as well as of the works that could be considered, which are mainly restricted to the underground water resource. The previous concepts were considered when proposing a methodology for the identification of the adequate tools for proceeding to the hydrological computation that are necessary to quantify run-off and underground water resource. Different methodologies of calculation for the estimation of extreme flow discharges (minimum and maximum) in a region with scarce hydrological and meteorological information were evaluated. At this stage, the convenience of avoiding the use of complex hydrological and hydraulic methods was specially considered because that would demand data and investments beyond the scope of a project trying to solve the problem of the access to the water of these communities. The hydrological and hydraulic studies carried out allowed defining a basic project of a work of water collection from the sub-stream bed, able to guarantee the water supply along the whole year attending needs coming from human consumption, basic agriculture, breeding and a possible micro-hydroelectric project. The proposed methodology has allowed defining the scope of different criteria of hydrological calculation in basins like San Isidro catchment basin, where it is very important to bring a technical answer bearing in mind the social and cultural issues of the communities.