Usable rainwater volume; results of a hydrological study conducted at the Universidad de Santander, Bucaramanga, Colombia

This study was carried out at the "Universidad de Santander", in Bucaramanga, Colombia, to calculate the volume of rainwater capturable from the roofs of five campus buildings, as the blueprints for these surfaces were available to obtain their areas. Roof areas were first obtained for the Guane, Motilón, Arhuaco, Chibcha and Yariguíes buildings, from which rainwater can be captured. Intensity, duration, and frequency curves from the "Instituto de Hidrología, Meteorología y Estudios Ambientales" were then used to calculate a design flow, yielding the diameter of the pipe necessary to evacuate the water captured. In addition, data from the "Universidad de Santander" meteorological station was evaluated to obtain monthly rainfall figures. The highest-yielding structure was the Motilón building, with approximately 80 m³ in the months of May and November, 2018, as this structure has the largest roof area, and the area experienced its greatest quantity of rain during these months. The total accumulation predicted by the study was 1837.96 m³ annually, sufficient to suggest the possibility of its use in restrooms, gardens, and floor washing at the "Universidad de Santander", Bucaramanga, Colombia. The volume of water calculated is variable on a yearly basis, and was estimated by means of one year of rainfall readings from the university's meteorological station. Hydraulic structures designed for the purpose of capturing this water would require a specific study, taking into account the records of other nearby meteorological stations, and making necessary provision for the storage of water in excess of expected volumes.