Modelamiento de precipitación - escorrentía de la quebrada Caicedo.

Abstract

The purpose of this curricular integration work was to carry out a rainfall-runoff modeling in the Caicedo Creek basin. The watershed has an area of 1.2 km2 and is located in the northwest of the Metropolitan District of Quito. To analyze the hydrological response of the watershed to extreme events occurring on December 13, 2021, and January 31, 2022, information on vegetation and soil cover was used, as well as climatic data from the P11 Antenas and P70 El Bosque rainfall stations. These stations recorded daily rainfall of 37.30 mm and 38.70 mm during the first storm, and 51.40 mm and 55.30 mm during the second storm, respectively. In addition, a frequency analysis was performed using Hydrognomon4 software to determine rainfall intensities in the northwestern zone of the DMQ. This analysis made it possible to determine the exceedance probability of recurrence of storms similar to or greater than those that occurred on December 13, 2021, and January 31, 2022. The results indicated that, for station P11 Antenas, the mean ± 1 standard deviation indicates that about 68.3% of the data are between 20 mm and 38 mm. For station P70 El Bosque, the mean ± 1 standard deviation indicates that about 68.3% of the data are between 23 mm and 47 mm. Return periods for 10, 20 and 50 years were determined for both stations. For station P70 El Bosque, the values were 41.4 mm, 44.7 mm and 48.5 mm, respectively. For station P11 Antenas, the values were 52.0 mm, 58.3 mm and 71.5 mm, respectively. These data show the probability of occurrence of precipitation of a certain intensity in a given period. Subsequently, a hydrological model was constructed using the HEC-HMS software. For this purpose, the SCS Curve Number loss method and the SCS Unit Hydrograph transformation method were used to simulate both storms and obtain information on the flows generated in each of the storms. In the first storm, the flow rate reached a value of 0.4 m3/s, while in the second storm it was 0.8 m3/s. The total precipitation for each event was also recorded, being 37.71 mm for the first storm and 52.38 mm for the second storm. The different components of precipitation were also analyzed, including the loss prior to conversion to runoff, which was 33.61 mm and 41.92 mm respectively. The precipitation that contributed to runoff was also determined, which was 4.10 mm for the first storm and 10.46 mm for the second storm. And finally, surface runoff, which had values of 3.38 mm and 10.45 mm respectively. All these data allowed us to obtain a comprehensive view of the hydrological response of the basin to these extreme storms.