Author(s): Ramirez Leon; Jose Manue; Aparicio; Javier.
Linked Author(s): Javier Aparicio
Keywords: No Keywords
Abstract: A methodology is presented to estimate the sediment produced in watersheds and deposited in reservoirs, by combining the method of Kothyari et al. (1996) and the concept of trap efficiency (Te). The method assesses the sediment yield through the sediment delivery ratio (SDR) and the universal soil loss equation (USLE). The SDR is computed as a function of the area, slope and forested area of isochronal segments. The USLE presents difficulties to evaluate the rainfall factor (R) in Mexico, due to the lack of a sufficiently dense pluviometer network. An alternative is therefore proposed to find R by employing an automatic weather station with a 7-year record and standard rain gauge stations, by using a Monte Carlo procedure. The method of Kothyari et al. (1996) refers the output of sediments of a catchment due a storm as time-area curves and divides the watershed into isochrone segments with the same concentration time (Tc). It assumes that a part of the eroded material of the segment upstream would be deposit in the segment downstream and subsequently part of this material plus a percent of the soil loss of this segment would be deposit in the next one. The description of this process is expressed as a function of SDR and the soil loss of each segment j (Sei j). The methodology was tested in the South-East of Mexico in the State of Puebla in the Apulco river basin and 8 sub-basins, where a dam was built in each catchment. The computed sediment yield was compared with the sediment deposited in each dam. The error between computed and observed sediment departs from-32.03% to 235.11% and with a mean error of 22.42%. We consider these errors as satisfactory in account to the level of approximation of input data.
Year: 2009