Surface runoff and participatory actions for environmental management in Sub-basin III of the South Basin of Lake Managua, Nicaragua

Abstract

In Sub-basin III of the South Basin of Lake Managua, Nicaragua, there is an increase in surface runoff caused by the increase in urban coverage, agriculture, and the fluctuating trend of forest cover. In this study, the surface runoff was evaluated based on the land cover of the years 2003, 2010, 2016, and the projected the year 2025. Methodologically, the area under study was delimited in 23 Hydrological Response Units (URH) to identify the areas where the greatest runoff occurs. In each URH, the Curve Number (NC) method of the Soil Conservation Service (SCS) was applied, and to discretize the method, a hietogram, the hydrological type of soil, and the antecedent humidity condition were used. The hyetogram was generated based on the calculation of the Curves of Intensity, Duration, Frequency. Furthermore, the hydrological number was estimated based on the type of soil and the preparation of land cover maps for each year evaluated. The results indicate that the URH associated with agriculture and urban coverage generate the greatest runoff (47 m³.s^-1, 36 m³.s^-1, 25 m³.s^-1, 13 m³.s^-1, and 10 m³.s^-1). Therefore, in these URH´s it is recommended the implementation of participatory actions of a regulatory, economic, educational, and organizational nature for the environmental management of the area under study.