Ecological vulnerability and water quality diagnosis of the stream La Central, Pacayas de Alvarado, Costa Rica

Abstract

Changes in the environment, such as land use, type of geomorphology of the area near rivers, as well as the intensity and frequency of rainfall causing runoff processes or intensive use in agriculture and livestock; affect not only the quality but also the quantity of water resources. The aim of the study was to develop a preliminary proposal for comprehensive management of the stream La Central oriented to prevent the introduction of pollutants and on the other hand, improve its quality through an environmental management program. The research was done in the stream La Central that is responsible for supplying the inhabitants of water for human consumption of several towns in the province of Cartago, Costa Rica.First, water quality was evaluated through a water quality index (ICA) in the spring water and several points of the nearby river, for a period of three months of the rainy season. In addition, the ecological vulnerability was assessed in the study area analyzing different ecological indicators. Interviews were also made to assess agricultural practices in the area. Finally, some recommendations leading to reduce the risk of contamination of the creek and also improve the water quality caused by the environmental effect.
ICA values showed an increasing deterioration of water quality of the spring water, led by increases in nitrate content, probably associated with runoff phenomena caused by major rainfalls. Although in all cases, the value is less than 50 mg/L which is allowed in our legislation for drinking water, pollution may be higher in the months of higher rainfalls. The other sampling points showed the presence of fecal coliforms, probably caused by livestock in the highlands. The assessment of ecological vulnerability was High or Very High vulnerabilities in particular ecological indicators.
It was recommended to carry out monitoring of water quality during the months of highest rainfalls and implementing management and environmental culture programs with farmers and ranchers in the area, along with good agricultural practices.