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This study introduces a novel heat tracing method for estimating lateral groundwater flow velocity induced and sustained by heavy rainfall events in lowland areas, leveraging the distinct temperature difference between rainfall and groundwater. The method is motivated by the observation that the rainfall‐induced groundwater temperature signal dissipates along the flow path. To explain the observed temperature anomaly and then estimate the lateral flow velocity, we develop a semi‐analytical model for heat transport in the aquifer, accounting for conduction losses to adjacent layers. Our findings reveal that interactions between the aquifer, vadose zone, and bedrock significantly influence the temperature signal, thereby affecting velocity estimation. Inaccuracies in measured aquifer properties, such as thickness, porosity, and thermal conductivity of surrounding layers, increase the uncertainty of velocity estimates. However, variations in aquifer thermal conductivity have a minimal effect on the method's overall accuracy. When estimating multiple parameters, velocity estimates tend to be less reliable, especially if aquifer porosity remains uncertain. This is due to the challenges of simultaneously inverting both velocity and porosity. Overall, this work underscores the potential of using heat as a tracer for assessing lateral groundwater flow following rainfall, offering a practical, low‐cost solution applicable in a wide range of settings. Plain Language Summary: This study presents a new method of estimating the velocity of groundwater flowing in lowland hillslope areas, particularly during heavy rainfall. The method uses the difference in temperature between rainwater and groundwater to track the groundwater's flow. By analyzing observed temperature changes based on a semi‐analytical approach, we can estimate how fast the groundwater moves. Our findings reveal that interactions between the shallow aquifer, unsaturated soil zone, and bedrock significantly influence the temperature signal, impacting velocity estimation. Inaccuracies in measured aquifer properties, such as thickness, porosity, and surrounding layers' thermal conductivity, can adversely impact velocity estimations. Nevertheless, thermal conductivity of the aquifer layer itself doesn't noticeably affect the accuracy of this method. It is challenging in getting accurate velocity estimations when trying to estimate multiple parameters at once, especially when the aquifer porosity remains uncertain, due to the difficulty in the simultaneous determination of both velocity and porosity. Overall, this study highlights that using heat as a tracer can be an effective, affordable, and widely useable method for studying lateral groundwater flow after rainfall. Key Points: Significant temperature disturbances were observed in riparian shallow groundwater following heavy rainfallA heat tracer method was developed to estimate lateral groundwater velocity based on the attenuation of the heat signalThe accuracy of the estimated velocity depends on prior knowledge of hydrogeologic conditions [ABSTRACT FROM AUTHOR]

Field experiments were conducted on various runoff plots within the Zhangjiachong watershed, located in the Three Gorges Reservoir Area, to study rainfall‐runoff processes and sediment yields under different slope land use patterns. A hillslope run‐on model considering vegetation interception was used to simulate runoff generation and concentration. A slope erosion model including raindrop erosion, sheet erosion, and rill erosion was developed to estimate sediment yield and concentration. The parameters of both models were calibrated and validated using observed runoff and sediment yield data. The results show that the runoff simulations in the validation have relative errors below 20% for all runoff plots, except those planted with crops. The saturated hydraulic conductivity of soil was found to be ca. 10% higher on slope lands with hedgerows than those without. In addition, it was about 15% higher on slope lands with crops than on slope lands with tea plants and citrus. The sediment yield was shown to be influenced by both precipitation characteristics and antecedent sediment conditions. There was a significant relationship between sheet erosion, rill erosion, and vegetation coverage, while the amount of raindrop erosion was similar across different runoff plots. The proportions of sheet and rill erosion on slope land with crops were minimal whether hedgerows existed or not. The proportions of the three main forms of soil erosion on slope lands with tea plants and citrus were more or less the same under concentrated rainfall. For more evenly distributed rainfall, raindrop erosion was the primary form on slope lands with hedgerows‐tea plants and citrus. The proportions of sheet and rill erosion significantly increased on slope lands without hedgerows. [ABSTRACT FROM AUTHOR]

A field experiment was conducted in the Zhangjiachong watershed to analyze the characteristics of rainfall–runoff process and sediment yield under different types of terraces. Various runoff plots were utilized, and a two serial tank model was employed to simulate runoff generation and concentration processes, taking into account vegetation interception. A soil erosion model incorporating raindrop erosion and sheet erosion was established to replicate sediment yield and concentration process. The parameters of the rainfall–runoff model and soil erosion model were calibrated and validated using observed runoff and sediment yield data. The controlling factors on runoff and sediment yield were explored and compared. The results indicate that both calibration and validation outcomes were acceptable. The earth‐banked terraces–citrus demonstrated the largest coefficients of upper and lower surface runoff, while its upper runoff threshold of the upper tank and the runoff threshold of the lower tank were the lowest, suggesting that it was more likely to produce surface and subsurface runoff. On the other hand, the stone dike terraces–crops exhibited the smallest coefficients of upper and lower surface runoff, while its upper runoff threshold of the upper tank was the highest. The lower runoff threshold of the upper tank was the same across different types of terraces. Compared to the earth‐banked terraces, the stone dike terraces have a larger infiltration coefficient in the upper tank and a smaller infiltration coefficient in the lower tank. Sensitivity analysis indicates that the most sensitive factors affecting runoff simulation results are the runoff threshold and the infiltration coefficient of the lower tank. Terraces, whether constructed with earth banks or stone dikes, are effective in reducing soil erosion. However, during storm rainfall events, these terraces may be partially destroyed, resulting in a higher sediment yield than that of the same vegetation cover on slope land. Terraces with hedgerows have a more significant effect on reducing runoff and sediment than those without hedgerows. [ABSTRACT FROM AUTHOR]