Author(s): Carla Idely Palencia-Aguilar; Fidelia Nnadi
Linked Author(s):
Keywords: No Keywords
Abstract: Water management and risk assessment had been studied at Guasca Municipality in Colombia-South America. Eco-hydrology was used as a media to determine water quality along the Siecha river. HEC-RAS program allowed modelling of more than 103 measured cross sections suggesting changes to be implemented in order to reduce velocities and Froude numbers less than 1. Local Authorities did not approve the required changes and flood took place a year after. Consequences were measured in some of the cross sect ions with erosion that counted for 34791 m3 in two years in only 498 meters’ length. For Risk assessment, remote sensing and GIS as well as meteorological stations data were used to develop models that helped to predict floods. Results from NDVI and water column from MODIS images in a 10 years’ period from 2006 to 2016 showed that 76% of the cases when NDVI values indicated floods with values less than 0.14, the Water Vapor Column also detected them by low column values less than 3.25 cm. It was also found that the variability of the algorithms depended upon the characteristics of rain (dry and wet years), El Nino and La Nina events, and the intensity of the phenomena e. g. strong, weak and moderate. Empirical formulas were proposed for water column determination that were tested against measured downward solar radiation. Results showed fittings higher than 70% is most of the methodologies applied. Empirical ps (partial pressure of water vapor at saturated air) was found to vary as: ps = exp (27-5490/T) with R2 of 0.74 when MODIS and Water Vapor column were studied ensemble. Better results were obtained when measured and calculated solar radiation were compared on hourly basis. The results showed ps = exp (27-3200/T) with R2 of 0.79. Other periodicity (yearly and every trimester) was not recommended because the obtained R2 was lower than 40% in all scenarios. The residence time was found to be 11 days, two days more than the water vapor’s residence time at global scale. The former with an average of 5 mm per day and the latter with 1 m per year of evapotranspiration. Evapotranspiration was found by applying 4 methodologies: SEBS and SEBAL algorithms, ILWIS software and calculations.
Year: 2018