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Design and installation of monitoring wells
Published in Neal Wilson, Soil Water and Ground Water Sampling, 2020
The direction of ground water flow should be ascertained prior to the installation of permanent monitoring wells. Accurate, longer-term information on the direction of ground water flow is provided by the installation of piezometers. A piezometer is a device (similar to a monitoring well) which is used to obtain water level measurements, but not ground water samples. Ideally a piezometer has a very small diameter so it can respond quickly to changes in the potentiometric surface. A typical piezometer is constructed from 1.5-in.-diameter PVC casing to facilitate using water level measuring devices including continuous data loggers with pressure transducers. A piezometer usually has a screen length of 2 to 5 ft.
Laboratory experiments on initiation of rainfall-induced slope failure
Published in H. Rahardjo, D.G. Toll, E.C. Leong, Unsaturated Soils for Asia, 2020
Failure was induced in a number of 1 m high soil slopes by raising water level within the slopes. Three different modes of raising the water level in the experimental slope were considered in the experiments. In the first experiment, a slow rise of water level was introduced to the slope model from a constant head tank at the rate of 5 cm/h. The second experiment considered a condition of rapid water level increase by raising the constant head tank at the rate of 0.63 cm/min. In the third experiment, rainfall at intensity 100 mm/h was simulated to induce the rise of water level in the slope model. Prior to the first two experiments, a water level of about 20 cm was introduced to produce initial water level across the base of each slope from a constant head tank.
Problem Formulation and Solving Methods
Published in Arnold H. Lobbrecht, Dynamic Water-System Control, 2020
Aquatic ecological requirements may be an undisturbed and stable surface water quality and maintaining a minimum surface water level. Especially during spring, water quality is of extreme importance, since flora and fauna start to spring up. Flushing surface water should be prevented as much as possible, in principle during the entire year. A problem is that, especially in drought-sensitive areas, canals may run dry without external water supply. This may necessitate water inlet into such canals. Because of these problems, weighing may be required within the aquatic ecological interest.
Instability analysis of a quaternary deposition slope after two sudden events of river water fluctuations
Published in European Journal of Environmental and Civil Engineering, 2023
Yue Zhou, Shun-chao Qi, Lei Wang, Ming-liang Chen, Chen Xie, Jia-wen Zhou
Nowadays, landslides and the following blockages of river have presented great threat to human life and property all around the world (Hewitt, 1982; Costa & Schuster, 1988; Dai et al., 2005; Dunning et al., 2006; Yin et al., 2009; Zhou et al., 2013). Very often, landslides occurred in a sudden and the landslide dams failed shortly after formation, resulting in the dramatic fluctuations of the water level in the upstream lake and the coming of downstream floods (King et al., 1989; Korup, 2002; Meng et al., 2019). The hydraulic characteristics and properties of soil and rock mass on bank slope surface or adjacent location (such as pore water pressure and water content), which strongly affect the slope stability can change as the water level fluctuates (Fredlund & Rahardjo, 1993; Duncan, 1996; Yan et al., 2019; Hu et al., 2020a).
Implementation of polymer optical fibre sensor system for monitoring water membrane thickness on pavement surface
Published in International Journal of Pavement Engineering, 2021
Yanqiu Bi, Jianzhong Pei, Fucheng Guo, Rui Li, Jiupeng Zhang, Ning Shi
Measuring water membrane thickness on the surface of pavement during intense rainfall events is necessary for ensuring vehicle safety and managing urban drainage (Gallaway et al.1900, Russam and Ross 1968). The anti-skid performance on a wet pavement is markedly lower than that on a dry surface. If the water membrane thickness increases beyond the critical point at which the tire can disperse it, the water membrane in front of the tire will accumulate, resulting in a reduction of the contact area between the tires and the pavement. If the tire completely loses contact with the pavement, a condition known as aquaplaning will occur (Mancosu et al.2000). Therefore, accurate information of road water membrane thickness is necessary to ensure vehicle safety. Commonly used water level measuring equipment includes the float-type water level gauge, bubble-type water level gauge, the ultrasonic water level gauge, the radar water level gauge, the laser water level gauge, and the electronic water gauge (Mezikov et al.1991, 1993). However, these equipment show some limitations such as their expensive price and lower precision; thus, they cannot be used to monitor water membrane thickness on the pavement surface. Therefore, innovative, precise, inexpensive, and feasible techniques are required to monitor the water membrane thickness of the road surface. The application of sensors is a critical component of smart roads, and it is also one of the hotspots of current road engineering research.
Towards a high-resolution modelling scheme for local-scale urban flood risk assessment based on digital aerial photogrammetry
Published in Engineering Applications of Computational Fluid Mechanics, 2023
Changbo Jiang, Yuantai Kang, Ke Qu, Yuannan Long, Yuan Ma, Shixiong Yan
The curves presented in Figure 22 show the changes of cell number for each flood hazard classification over time at different frequencies. H1 increases gradually from zero to maximum within the time step 2500–6000, and then decreases. Although the slope is disparate in different return periods, the trend is basically the same, and the process of flooding and retreating is basically symmetric under certain return periods. The law for H2, H3, and H4 is similar to that for H1, but there are local fluctuations in the process of flooding for H2 and H3, even retreating for H2. The main reason is that the flow velocity at certain places will change with the water level in the process of flood evolution, thus the risk level will change accordingly.