HR: 11:10h
AN: H22A-04    [Abstracts]
TI: Use of Precipitation - Runoff Models to Generate Hydrologic Scenarios in a High-altitude Andean Basin of the Ecuadorian Amazon Region. Case study of the Quijos River Basin.
AU: * Galarraga, R
EM: remigala@server.epn.edu.ec
AF: Escuela Politecnica Nacional, Ladron de Guevara E11-253, Quito, Pic N/A, Ecuador
AU: McClain, M
EM: mcclainm@fiu.edu
AU: Ortega, F
EM: glaciar@server.epn.edu.ec
AU: Estacio, A
EM: glaciar@server.epn.edu.ec
class='hr'> AU: Febres, A
EM: alexcran.001@gmail.com
AB: Little is known of the hydrology and meteorology of the expansive Andean Amazon region in South America, which extends for approximately 600.000 Km2 and represents around the 10% of the total Amazon region. Climatic processes that occur in the Andean part of the Amazon influence the middle and lower parts of the Amazon Region. Consequently, there is a need to understand the hydro-climatic characteristics in the high lands of the Andean Amazon. Understanding hydrologic processes in the Andean Amazon is challenged by the lack of hydro meteorological data at all levels. Especially challenging is the absence of data at the appropriate scale for adequate calibration and verification of mathematical models, mainly for understanding precipitation - runoff of high altitude watersheds located on the western most part of the Amazon. The study area is located on the upper part of the Napo River named the Quijos river basin after the junction of the Oyacachi River with a surface area of about 2.500,00 Km2. It is composed mainly of high altitude lands named Paramo, Andean grass lands, primary cloudy forest known for their high water retention and regulatory capacity. The models used in the Quijos river basin in the upper part of the Amazon region of Ecuador are precipitation-runoff models widely used around the world. The Simulator for Water Resources in Rural Basins - Water Quality (SWRRBWQ ) (Arnold et. al. 1990, Williams et. al. 1985), works on a daily time steps basis with daily values of meteorological data both observed in the field or generated by the model, and by sub diving the main basin into a suitable number of sub basins with a meteorological station in it The second model used is the Hydrologic Modeling System from the Hydrologic Engineering Center which is a precipitation - runoff model run at a daily basis as well. Input data sets are basic climate data as precipitation, evapotranspiration, temperature, relative humidity basin wide at daily basis; land cover, soil type, soil characteristics, hydrographic characteristics, as well as registered discharge information in several control points of the basin, that were used for calibration purposes. Several runs of the models were done in order to assess parameter sensibility of the models using appropriate parameter for each case. Calibration for the two models were done for a period where enough information exists even though the time record for verification purposes is well ahead of time so it is assumed that basin wide conditions have not change in time. Three hydrologic scenarios for future discharge prediction based on conservation policies, urbanization, deforestation, or land use change on the area were generated by using HEC-HMS model for the January 1984 - December 1987 period because of its better performance in comparison to the SWRRBWQ model. Scenarios one and two showed almost no difference with the original discharge but scenario three showed an increase in water discharge with time. Results show that in high altitude basins the HEC-HMS performs better than SWRRBWQ model in determining mainly peak discharges but differed in reproducing the total volume of run-off, keeping a good agreement to reproduce seasonality patterns of water discharge. Better information of basin wide characteristics like soil antecedent moisture conditions, land cover, and surface albedo during the calibration period is needed in order to improve model results mainly in volume discharge.
DE: 1800 HYDROLOGY
DE: 1846 Model calibration (3333)
DE: 1847 Modeling
SC: Hydrology [H]
MN: 2007 Joint Assembly