The vertical distribution pattern of the fine suspended sediment concentration (SSC) plays an important role in the aquatic ecosystem of shallow water. To investigate the SSC profile in submerged vegetated river flow, a series of indoor flume experiments was conducted. Glass spherical balls of three different diameters (40, 77, and 90 μm) with a uniform specific gravity of 2.5 were used for the model sediments. A set of sampling devices was designed for the simultaneous measurements of SSCs at multipoints along a vertical line. Experimental results show that the SSC profile was re‐distributed in the vegetated region, gradually forming a new equilibrium pattern in the overcanopy flow layer with its maximum occurring near the canopy top. From this maximum point near the canopy top, the suspended sediment formed a dynamic balance between upward turbulent diffusion and downward gravitational settling. Meanwhile, the momentum diffusivity was observed to linearly decrease upward from the maximum‐SSC elevation toward the water surface, thereby allowing us to deduce an empirical negative linear formula. Based on the convection‐diffusion equilibrium mechanism and with assistance of the empirical formula of flow momentum diffusivity, a new form of the Rouse formula was derived for the overcanopy flow layer. In general, this equation agrees well with the measured data. Some undercalculated deviations appear in the well‐above canopy zone due to the upskewed turbulence and the weak upward secondary flow. This deviation decreases with increasing sediment diameter. The bed deposition mainly comes from the deep part of canopy‐occupied flow layer.

The resistance of an open-channel flow under the influence of bending deformation of submerged flexible vegetation canopy was experimentally studied in an indoor water flume. Altogether, 27 tests under the cross-combinations of three bulk flow velocities ($V$ ), three vegetation elastic moduli ($E$ ), and three vegetation stem thicknesses ($b$ ) were conducted. The total drag force experienced by the vegetation stem was accurately calculated based on the measured vertical profiles of flow velocity and the second order turbulent momentum in front of an individual plant, and this enabled the estimation of the overall drag coefficient ($C_D$ ) for bulk flow. The results show that the bending deformation of vegetation helps to transfer momentum downward toward the channel bed, thus helping to reduce the overall resistance to flow. The Cauchy number ($C_Y$ ) is an important parameter representing the bending property of the vegetation in open-channel flow; it’s functionally related to the resistance of flow. For small deformation configurations, the bending angle ($\theta$ ) and the relative bending displacement (${\delta }_z/h_p$ ) are linearly dependent on $C_Y$ and ${(C_Y)}^2$ , respectively. The $C_D$ and Manning’s $n$ for the bulk flow are both power law functions of $C_Y$ . The semiempirical formulas of $C_D$ and $n$ proposed in this study are expected to apply to further experimental studies and river engineering.

This study was designed to assess the effects of exposure to arsenic in drinking water on neurosensory function. A questionnaire including neurological signs and symptoms and a brief neurological exam consisting of pinprick testing of the arms and legs and knee-jerk test were administered to 321 residents of the Bamen region of Inner Mongolia, China. Arsenic in water was measured by hydride generation atomic fluorescence. Participants were divided into three exposure groups—low (non-detectible-20), medium (100–300) and high (400–700 μg/l) arsenic. Significant group differences were observed in pinprick scores for all four limbs. Results indicate that arsenic alters pinprick (pain) thresholds at well-water concentrations as low as 400 μg/l, well below the 1000 μg/l threshold for neurological effect specified by NRC (1999). Regression models suggest that a 50% increase in pinprick score is associated with a 71–159 ppb increase in arsenic concentration.

Plants in natural water flow can improve water quality by adhering and absorbing the fine suspended sediments. Dense plants usually form an additional permeable bottom boundary for the water flow over it. In the flow layer above dense plants, the flow velocity generally presents a zero-plane-displacement and roughness-height double modified semi-logarithmic profile. In addition, the second order shear turbulent moment (or the Reynolds stress) are different from that found in non-vegetated flow. As a result, the turbulent momentum diffusivity of flow and thus the diffusivity of sediment will shift, which will cause the vertical profile of suspended sediment and the corresponding Rouse formula deform. A set of physical experiments with three different diameters of fine suspended sediments was conducted in an indoor water flume. These experiments investigated a new distribution pattern of suspended sediment and the correspondingly deformed Rouse formula in the flow layer over the dense plants. Experimental results showed that above the dense plants, the shear turbulent momentum of flow presented a plant-height modified negative linear profile, which has been proposed by a previous study, and the vertical distribution of fine suspended sediments presented an equilibrium pattern. Based on the plant-modified profiles of flow velocity and the shear turbulent momentum a new zero-plane and plant-height double modified Rouse formula were analytically derived. This double-parameter modified Rouse formula agrees well with the measured profile of suspended sediment concentration experimentally observed in the present study. By adjusting the Prandtl–Schmidt number, i.e., the ratio of sediment diffusivity to flow diffusivity, the double-parameter modified Rouse formula can be applied to submerged dense plant occupied flow.

Soft foundation consolidation engineering applications and experimental studies have proven the effectiveness of the air–boosted vacuum preloading method (AVP). The sand well consolidation theory, a typical axisymmetric consolidation, is adapted to analyze the whole consolidation process of the saturated soil by air–boosted vacuum preloading. The present analytical solution for air–boosted vacuum consolidation of the saturated soil is more suitable for application in a deep soft foundation. With the solving method, the general solution through separation of variables is used, which is mathematically used for the homogeneous partial differential equations. However, the partial differential equations for solving the consolidation of the AVP method are nonhomogeneous. Therefore, the eigenfunction expansion method for nonhomogeneous equations is proposed and validated in this study. Results showed that the improved analytical solution by the eigenfunction expansion method is more consistent with the numerical solution than that of the previous method using the general solution by separation of variables, which leads to a lower error ratio of less than 2%. The improved analytical solution can be used to predict the consolidation of deep foundations by air–boosted vacuum preloading effectively.