Author(s)

J. Lafragua, A. Gutiérrez, A. Bahena, G. Moriel & S. Férnández

Abstract

A new main road called Copandaro-La Cinta was built in the state of Michoacán, México; with a length of seventeen kilometers this road crosses Lake Cuitzeo (the section under study). In order to preserve the hydrological regime of this water area, the road structure was built with twenty sewers and four boat passages. With a 4000 km2 basin area, Lake Cuitzeo’s watershed transports 1,296,461 tons of sediment per year. Due to this great amount of material, a hydrological study was carried out. A hydraulic study was prepared including elevation-storage and elevation-area relationship curves since 1930. Using a longitudinal profile of the study section from April 2003, several bank levels are used to make an adjustment between the bathymetric curve and longitudinal profile, fixing some main structures points. In order to select the best alternative (to verify hydraulic works dimensions), soil erosion in the watershed is calculated using the Universal Soil Loss Equation (USLE); a sediment yield ratio is also obtainable. The results show that only 7 percent of the soil loss computed by the USLE appears as sediment yield in the watershed outlet. In the alternative selected, this quantity represents approximately 19 cm of sediment near the study section. With this alternative, the zero level in the longitudinal profile and in the bathymetric curve is at an elevation of 1823.34 and 1818.00 masl, respectively. Thus, all points of the bathymetric curve were adjusted at 5.34 m. Flow routing through Lake Cuitzeo shows that the structures hydraulic capacity was enough to allow free water flow. Keywords: soil erosion, hydrologic routing, inflow hydrographs, bathymetric curve, Lake Cuitzeo.

Keywords

soil erosion, hydrologic routing, inflow hydrographs, bathymetric curve, Lake Cuitzeo.