31 / 2023-12-21 13:53:40

Modeling of water erosion and sediment transport in a basin of the Pao- Cachinche water reservoir, Venezuela. Case: Chirgua River Basin

mathematical models,erosion,sediment transport,water reservoir

The research deals with the modeling of erosion and sediment transport in a basin of the Pao- Cachinche water reservoir. Models based on physical processes, regressions and artificial intelligence techniques are used. Models based on physical processes included: infiltration, rainfall-runoff, solid particle detachment capacity, sediment transport and erosion-deposition. Among the erosion models used are: WEPP, DWEPP, EUROSEM and CIHAM-UC. Regression-based erosion models include: multiple linear regression and multiple nonlinear regression. Erosion models based on adjustments to artificial intelligence techniques include: artificial neural networks and fuzzy inference systems. In general, calibration, validation and testing stages are followed for all models. The field data used for model calibration were collected on agricultural lands, during dry and rainy seasons in the Chirgua River Basin, Carabobo State, Venezuela for two years (2008-2009). The field information was characterized by: climatic, edaphic, topographic and management factors. 526 infiltration tests were carried out, 97 rain storms and 300 irrigation events were measured. The soil of the basin varies, both vertically in a stratum of 0 to 60 cm and spatially between a low plasticity organic silt (OL) and a silty sand (SM). The saturated hydraulic conductivity approached 1 mm/h. Total precipitation for one-hour and two-hour events ranged from 20 to 30 mm to 35 to 40 mm. The maximum infiltration rate achieved varied between 1000 and 2000 mm/h, while stabilization began approximately 60 minutes from the start of the test. The steady-state flow rate varied between 0.30 and 0.50 L/s; decreasing between 0.05 and 0.1 L/s after the seventh irrigation. The maximum sediment load observed during the one-hour events varied between 100 and 400 mg/s for irrigation, 600 and 100 mg/s for rainfall. The maximum sediment load observed for the two-hour events varies as follows: between 500 and 2000 mg/s for irrigation, 2500 and 7000 mg/s for rainfall. It was found that the models used estimate the erosion rate and sediment transport satisfactorily, R ² greater than 0.6. The model selected to be used in the Chirgua River basin is the one developed by CIHAM-UC.