Briefly tracing the history of hydrologic modeling, this paper discusses the progress that has been achieved in hydrologic modeling since the advent of computer and what the future may have in store for hydrologic modeling. Hydrologic progress can be described through the developments in data collection and processing, concepts and theories, integration with allied sciences, computational and analysis tools, and models and model results. It is argued that with the aid of new information gathering and computational tools, hydrology will witness greater integration with both technical and non-technical areas and increasing applications of information technology tools. Furthermore, hydrology will play an increasingly important role in meeting grand challenges of the twenty-first century, such as food security, water security, energy security, health security, ecosystem security, and sustainable development.

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Hydrologic modeling: progress and future directions

Erodibility of fluidized cohesive sediments in unidirectional open flows

Failure analysis method of concrete arch dam based on elastic strain energy criterion

Understanding the dynamics and mechanisms of soil water movement and solute transport is essential for accurately estimating recharge rates and evaluating the impacts of agricultural activities on groundwater resources. In a thick vadose zone (0-15 m) under irrigated cropland in the piedmont region of the North China Plain, soil water content, matric potential and solute concentrations were measured. Based on these data, the dynamics of soil water and solutes were analysed to investigate the mechanisms of soil water and solute transport. The study showed that the 0-15 m vadose zone can be divided into three layers: an infiltration and evaporation layer (0-2 m), an unsteady infiltration layer (2-6 m) and a quasi-steady infiltration layer (6-15 m). The chloride, nitrate and sulphate concentrations all showed greater variations in the upper soil layer (0-1 m) compared to values in the deep vadose zone (below 2 m). The average concentrations of these three anions in the deep vadose zone varied insignificantly with depth and approached values of 125, 242 and 116 mg/L. The accumulated chloride, sulphate and nitrate was 2179 ± 113, 1760 ± 383 and 4074 ± 421 kg/ha, respectively. The soil water potential and solute concentrations indicated that uniform flow and preferential flow both occurred in the deep vadose zone, and uniform flow was the dominant mechanism of soil water movement in this study. The piston-like flow velocity of solute transport was 1.14 m/yr, and the average value of calculated leached nitrate nitrogen was 107 kg/ha∙yr below the root zone. The results can be used to better understand recharge processes and improve groundwater resources management. This article is protected by copyright. All rights reserved.

Characterising deep vadose zone water movement and solute transport under typical irrigated cropland in the North China Plain

Effects of geometry on runoff time characteristics and time-area histogram of hillslopes

Critical rainfall for flash flood early warning is a converse result of precipitation-runoff process based on warning discharge threshold for a warning station of interest in a watershed; the key aspects of critical rainfall include rainfall amount and rainfall duration. Using hydrological modeling technique with detailed sub-basin delineation and manual for design precipitation-runoff computation, this study introduces basic concept and methods of analyzing critical rainfall for flash flood early warning. Taking South Branch of Censhui watershed in China as an example, typical critical rainfalls for flash flood dynamic early warning were estimated for 3 warning stations located in the watershed. This research illustrates that detailed watershed characteristics in the context of several warning stations can be modeled in-depth by further delineating the watershed into smaller sub-basins to simulate spatial distribution of various basin parameters. It further confirms that time of concentration of a watershed is an important factor to rainfall duration determination, and the antecedent soil moisture condition of a watershed has significant impact on critical rainfall for same rainfall duration.

Changiun

Papers

Critical Rainfall Analysis on Flash Flood Early Warning for South Branch of Censhui Watershed