Water Depth Distribution Research Articles

Assessing braking performance on wet-road through water-depth estimation and vehicle-pavement dynamic simulation

ABSTRACT The presence of water on wet roads due to rainfall has emerged as a critical factor influencing driving safety. During severe weather, the non-uniform water distribution on the road can significantly diminish pavement friction, elevating the risk of traffic accident. Furthermore, the tire-pavement friction coefficient varies with vehicle velocity, rendering wet braking analysis complex. Conventional braking risk analysis often assumes a fixed friction coefficient, neglecting the impact of uneven pavement-induced water depth irregularities. This paper introduces a novel braking performance assessment method based on water-depth estimation and vehicle-pavement simulation. The uneven water-depth distribution is first estimated using LiDAR-measured pavement geometry. A co-simulation framework is then proposed to analyze the tire-pavement friction and study the dynamic braking performance. The 85th percentile stopping distance is adopted as the evaluation index for quantifying braking risk. Results from case studies highlight the substantial influence of rainfall intensity and vehicle velocity on braking risk. Additionally, pavement rutting accumulates deeper water depth, thereby elevating braking safety risks. The proposed model offers a novel perspective on vehicle braking risk analysis and can serve as a valuable safety indicator for highway transportation management and decision-making in driving strategies during wet weather conditions.

Heuristic estimation of river bathymetry in braided streams using digital image processing

AbstractMeasurement of river bathymetry has been revolutionized by high‐resolution remote sensing that combines UAV platforms with SfM‐MVS photogrammetry. Mapping inundated and exposed areas simultaneously are possible using either two‐media refraction correction or some form of the Beer–Lambert Law to estimate water depths. If, as in turbid glacially‐fed braided streams, the bed is not visible then traditional survey techniques (e.g. differential GPS systems) are required. As an alternative, here we test whether the spatial distribution of water depths in a shallow braided stream can be modelled from basic planimetric data and used to estimate inundated zone bathymetry. We develop heuristic rules using; (1) distance from the nearest river bank; (2) total inundated width along a line tangential to the local flow direction; (3) local curvature magnitude and direction; and distance from the nearest flow (4) divergence and (5) convergence regions. We parameterize them using a sample of measured water depths in stepwise multiple linear regressions and validate them using independent data. Resulting water depth distribution maps explain between 50% and 60% of the measured water depth spatial variability when compared to independent data. After incorporating modelled water depths into digital elevation models (DEMs) of exposed areas, we show that the developed method is suitable for volumetric change calculations in both dry and inundated areas.

Introducing Pour Points: Characteristics and Hydrological Significance of a Rainfall‐Concentrating Mechanism in a Water‐Limited Woodland Ecosystem

AbstractThe interception of rainfall by plant canopies alters the depth and spatial distribution of water arriving at the soil surface, and thus the location, volume, and depth of infiltration. Mechanisms like stemflow are known to concentrate rainfall and route it deep into the soil, yet other mechanisms of flow concentration are poorly understood. This study characterizes pour points, formed by the detachment of water flowing under a branch, using a combination of field observations in Western Australian banksia woodlands and rainfall simulation experiments on Banksia menziesii branches. We aim to establish the hydrological significance of pour points in a water‐limited woodland ecosystem, along with the features of the canopy structure and rainfall that influence pour point formation and fluxes. Pour points were common in the woodland and could be identified by visually inspecting trees. Throughfall depths at pour points were up to 15 times greater than rainfall and generally comparable to or greater than stemflow. Soil water content beneath pour points was greater than in adjacent controls, with 20%–30% of the seasonal rainfall volume infiltrated into the top 1 m of soil beneath pour points, compared to 5% in controls. Rainfall simulations showed that pour points amplified the spatial heterogeneity of throughfall, violating assumptions used to close the water balance. The simulation experiments demonstrated that pour point fluxes depend on the interaction of branch angle and foliation for a given branch architecture. Pour points can play a significant part in the water balance, depending on their density and rainfall concentration ability.

Quantitative assessment of building risks and loss ratios caused by storm surge disasters: A case study of Xiamen, China

China is severely affected by storm surge disasters, which result in substantial economic losses and casualties in coastal regions. Assessing the risk of storm surge disasters can provide valuable insights into the expected losses and severity of future impacts, offering critical foresight for disaster prevention and mitigation strategies. This study assesses the quantitative risk of storm surge disasters, focusing on coastal buildings since they are particularly susceptible to storm surges and frequently bear the brunt such disasters. Xiamen city, China, was used as case study. A high-precision numerical model, using Finite Volume Community Ocean Model (FVCOM), was developed to simulate inundation during storm surges. By referencing historical storm surge records, we defined key parameters for probable maximum typhoon-induced storm surge (PMTSS) in Xiamen. These parameters were used to calculate the corresponding inundation range and water depth distribution within the region. Subsequently, the results were integrated with vulnerability curves that represent the susceptibility of buildings in Xiamen to storm surge-induced damage, enabling the quantitative risk assessment for associated loss risks. The study findings offer valuable guidance for urban planning and functional layout design in coastal areas. Furthermore, the findings contribute to understanding storm surge disaster risks and facilitating informed decision-making processes, ultimately enhancing disaster preparedness and resilience in vulnerable coastal regions.

The importance of water depth distribution maps in the sprinkler irrigation system performance assessment

Abstract The assessment of sprinkler system performance is crucial in ensuring the efficient use of water resources. The commonly used indicators of the uniformity of water distribution in sprinkler systems are Christiansen's uniformity (CU) and distribution uniformity (DU) coefficients. A more comprehensive analysis of water distribution is essential in situations where the reliability of these coefficients as indicators of water distribution patterns is limited. In the present research, distribution maps of water depth were prepared from water application profiles using catch cans experiments that were carried out in the research farm of the Agriculture and Natural Resources Faculty of the University of Tehran, which is located in Alborz province. In this way, water application profile data were obtained at different operating pressures (200, 250, 300, 350, and 400 kPa). By using this data, 2D and 3D distribution maps of water depth were created due to the overlapping of sprinklers in different arrangements, spacing, and pressures. In addition, CU and DU coefficients in square, rectangular, and triangular arrangements with different spacing and pressures from 200 to 400 kPa. A total of 11,250 different simulations were calculated and analyzed. Distribution maps of water depth contribute to advancing the understanding of sprinkler irrigation system performance and aid in the optimization of water management practices.

Sensitivity of fish habitat suitability to multi-resolution hydraulic modeling and field-based description of meso-scale river habitats

In-stream habitat models at the meso-scale are increasingly used to quantify the effects of hydro-morphological pressures in rivers. The spatial distributions of water depth and velocity represent key attributes of physical habitat. Choosing between field surveys, hydraulic modeling or their integration is made depending on available tools, technical skills, budget and time. However, the sensitivity to such choices of estimated habitat conditions suitable for biological organisms, such as fish, is poorly known.In this study, three commonly used approaches in hydraulic-habitat modeling were compared and tested on a mountain stream, the Mareta River (NE Italy). Two approaches were based on 2D hydraulic modeling, calculated on computational meshes with varying resolution and quality: (1) high-resolution meshes derived from topographical data obtained from Airborne Bathymetric LiDAR; (2) a mesh extrapolated from topographical cross-sectional profiles. The third approach (3) was based on in-stream surveys. From these, suitable channel-area for two fish species, the marble trout (juvenile and adult), and the European bullhead (adult), were estimated.Results showed that decreasing mesh resolution and quality affects the simulated water depth and velocity distributions, both in terms of their average and their standard deviation. The largest differences were found for the in-stream survey-based results. Morphologically complex unit types, such as steps, rapids and pools were more sensitive than simpler mesohabitats, such as glides and riffles. The most sensitive hydro-morphological unit types to the chosen approach were backwaters, glides being the least sensitive, also in terms of their suitability as mesohabitats. Despite that, a key finding is that errors are minimized when deriving habitat - streamflow rating curves at the reach scale, for which all approaches were largely able to reproduce the main characteristics of the curve, i.e. maxima, minima and inflection points.

Numerical Modelling on Physical Model of Ringlet Reservoir, Cameron Highland, Malaysia: How Flow Conditions Affect the Hydrodynamics

The relative impacts of changes in the storage capacity of a reservoir are strongly influenced by its hydrodynamics. This study focused mainly on predicting the flow velocities and assessing the effectiveness of groynes as control mitigation structures in changes in the water depth and velocity distributions in Ringlet Reservoir. Initially, the physical model of the Habu River (the main part of Ringlet Reservoir) was fabricated, and flow velocities were measured. Then, a two-dimensional HEC-RAS was adapted to numerically simulate the hydrodynamics of the annual recurrence intervals of 1, 5, and 100 years in the Ringlet Reservoir. Experimental data acquired at the Hydraulic and Instrumentation Laboratory of the National Water Research Institute of Malaysia (NAHRIM) was used to calibrate and validate the numerical models. The comparison of simulation and experimental results revealed that the water levels in all simulations were consistent. As for the velocity, the results show a comparable trend but with a slight variation of results compared to the experiments due to a few restrictions found in both simulations. These simulation results are deemed significant in predicting future sediment transport control based on hydrodynamics in this reservoir and can be of future reference.

A well-balanced moving mesh discontinuous Galerkin method for the Ripa model on triangular meshes

A well-balanced moving mesh discontinuous Galerkin (DG) method is proposed for the numerical solution of the Ripa model – a generalization of the shallow water equations that accounts for effects of water temperature variations. Thermodynamic processes are important particularly in the upper layers of the ocean where the variations of sea surface temperature play a fundamental role in climate change. The well-balance property which requires numerical schemes to preserve the lake-at-rest steady-state is crucial to the simulation of perturbation waves over that steady state such as waves on a lake or tsunami waves in the deep ocean. To ensure the well-balance, positivity-preserving, and high-order properties, a DG-interpolation scheme (with or without scaling positivity-preserving limiter) and special treatments pertaining to the Ripa model are employed in the transfer of both the flow variables and bottom topography from the old mesh to the new one and in the TVB limiting process. Mesh adaptivity is realized using an MMPDE moving mesh approach and a metric tensor based on an equilibrium variable and water depth. A motivation is to adapt the mesh according to both the perturbations of the lake-at-rest steady-state and the water depth distribution (bottom topography structure). Numerical examples in one and two dimensions are presented to demonstrate the well-balance, high-order accuracy, and positivity-preserving properties of the method and its ability to capture small perturbations of the lake-at-rest steady-state.

Fully-covered bathymetry of clear tufa lakes using UAV-acquired overlapping images and neural networks

Accurate and updated bathymetric data is of great significance for the management and protection of alpine tufa lakes. In recent years, unmanned aerial vehicle (UAV)-borne optical remote sensing has become a cost-effective technique for obtaining water depth of small and clear waters like tufa lakes. UAV-based bathymetry can be categorized into photogrammetric approach and spectrally derived approach. Photogrammetric bathymetry is contactless but invalid in water areas with uniform texture, while spectral-based bathymetry requires a large amount of in-situ depth measurements. In this paper, we combined the strengths of the two bathymetric methods to retrieve the depth of clear tufa lakes using neural networks. The surface elevation and orthoimage were first produced from UAV-acquired overlapping images, and then water color-depth tie points were sampled in the orthoimage and refraction-corrected bathymetric map. Next, the shallow and deep neural networks were separately used to train the regression models for predicting water depth. Lastly, the combined bathymetric methods were compared with the single ones in terms of effective spatial coverage and bathymetry accuracy. The results indicated that the combined methods were superior to single bathymetric methods in fully-covered bathymetry of clear tufa lakes. The shallow neural network-based model achieved the highest accuracy, with the coefficient of determination (R2) of 0.91 and the Root Mean Square Error (RMSE) of 1.12 m, whereas the deep neural network-based model increased the details of water depth distribution.

Atlantic Spotted and Bottlenose Dolphin Sympatric Distribution in Nearshore Waters Off Bimini, The Bahamas, 2003–2018

Within nearshore waters off Bimini, The Bahamas, Atlantic spotted (Stenella frontalis) and common bottlenose (Tursiops truncatus) dolphins are sympatric but separated spatially in different geographic areas and water depth ranges. Afternoon surveys during summer months across a 16-year period showed S. frontalis used the northern part of the nearshore area more, while T. truncatus used the southern area more. Generally, examination of geographic zones and water depth distributions of both species before and after construction of a pier in the study area suggested these dolphins were not impacted, long-term, by this anthropogenic activity. Still some differences in use of the nearshore area were identified. For water depth, S. frontalis varied use between 5–<12 m and 12–<20 m, depending on location along the coast. In contrast, T. truncatus consistently used the 5–<12 m depths. This difference may be related to how each species used the nearshore area, with T. truncatus feeding more and S. frontalis travelling and doing other activities. A small change in the distribution of S. frontalis by water depth off the northern coast of Bimini was found, specifically an increased use of deeper (12–20 m) water post 2014, which is unlikely an effect of pier construction as S. frontalis continued to use the 5–12 m depths as they had before pier construction. How this change might be related to an unprecedented 2013 S. frontalis immigration event, which might have disrupted the social structure, habitat/resource use, and distribution of both species, is discussed.

Quantifying fluvial habitat changes due to multiple subsequent floods in a braided alpine reach

During flood events, river topography and fluvial habitats can change drastically, potentially affecting the ecological status. In case of multiple floods, whether each single event modifies the habitat characteristics in the same direction or not, is still an open question. We gathered high quality topographical data of one braided Alpine reach before, between and after multiple floods. Considering the full dynamics of the hydrological regime affected by hydropower production, we calculated water depth and flow velocities distributions for relevant discharge conditions using hydrodynamic modelling. We then calculated four ecological indicators related to habitat diversity, habitat quantity, habitat connectivity and stranding risk. Despite the consistent depositional morphological trend, the habitat diversity and stranding metrics returned to pre-floods values after an initial deviation. The habitat quantity and connectivity metrics did not show a clear trend towards an alternative state. Habitat prevalence varied seasonally and with hydropower water release, and also changed markedly between floods, possibly affecting species composition. We show the possible intrinsic variability in several ecological indicators which can aid in the management and restoration of river floodplains.

The adsorption-release behavior of sediment phosphorus in a typical “grass-algae” coexisting lake and its influence mechanism during the transition sensitive period

In the early stage of eutrophication, the coexistence of “grass and algae” in lakes is obvious. Understanding the P sorption–desorption behavior in natural sediments during the ecologically sensitive transition period has important scientific value for predicting the deterioration of lake ecosystems and formulating restoration measures, but the related mechanisms are still unclear. In this study, the analysis results of sedimentary dissolved organic matter (DOM) fractions, extractable Fe (hydr)oxide fractions and P adsorption experiments showed that sedimentary DOM fractions, especially the tyrosine-like protein fractions and microbial humic-like fractions, played a part in determining the EPC0 and Kd values of sediments in the plateau lake environment. The compound effect of amorphous Fe (hydr)oxides and sedimentary OM affected the increase of sedimentary P adsorption. Interestingly, these phenomena were strongly correlated with water depth. Furthermore, the distribution of water depth to aquatic plants indirectly regulated the values of sedimentary EPC0 and Kd. Meanwhile, the ability of submerged plants to control the sedimentary EPC0andKd values will be forced to shift shallowly, thereby forcing a significant reduction of areas with low EPC0 and high Kd values. This not only enhanced the risk of endogenous P release in lakes, but also accelerated the further deterioration of aquatic ecosystems. Therefore, studying the long-term scale changes of sedimentary EPC0 and Kd values can help to understand the duration of the lake ecological transition period and prevent the transitional deterioration of ecosystem.

Flow at an Ogee Crest Axis for a Wide Range of Head Ratios: Theoretical Model

The discharge coefficient of an ogee crest is a function of the ratio of the effective head to the design head. The purpose of the present study is to derive a theoretical model of this relation, which does not depend on empirical coefficients and whose predictions over a wide range of head ratios are accurate enough for practical use. The developments consider unsubmerged ogee crests without approach flow or lateral contraction effects, heads large enough to enable surface tensions to be neglected, and heads small enough to avoid flow separation. The method is based on potential flow theory, depth integration in a curvilinear reference frame, and critical flow theory. The characteristics of the crest shape are defined by the trajectory of a free jet passing over the crest at the design head. The dimensionless equations show that the position of the critical section is not at the apex of the crest. Nevertheless, they also suggest an approximate equation at the apex of the crest from which the discharge coefficient is derived, together with the local water depth, velocity, and pressure distribution. The results compare well with experimental data for head ratios between 0 and 5, which validates the underlying assumptions of the theoretical model.

Experimental topology-optimized cloak for water waves

Rendering an object invisible has fascinated humanity for centuries and become more tangible with the advent of metamaterials and transformation optics. The pioneering methodology on electromagnetic waves has quickly carried over to water waves due to the similar governing Helmholtz equations. Despite the elegant theory, necessary compromises have to be made in practice to relax the extreme requirements on anisotropic and inhomogeneous hydrodynamic metamaterials, leading to a deteriorated cloaking performance. Here we numerically design and experimentally demonstrate a topology-optimized cloak for water waves. By inversely designing the water depth distribution, the topology-optimized cloak can flexibly meet different user-defined scattering demand, without stereotyped material constrains. The underlying mechanism relies on the control of complicated scattering events inside the cloaking shell to suppress the scattering strength of a cylindrical obstacle to near zero. Our work has potential applications in protecting offshore structures and sheds a new light into the inverse design of novel hydrodynamic metamaterial.

Bathymetric mapping and estimation of water storage in a shallow lake using a remote sensing inversion method based on machine learning

ABSTRACT Accurate lake depth mapping and estimation of changes in water level and water storage are fundamental significance for understanding the lake water resources on the Tibetan Plateau. In this study, combined with satellite images and bathymetric data, we comprehensively evaluate the accuracy of a multi-factor combined linear regression model (MLR) and machine learning models, create a depth distribution map and compare it with the spatial interpolation, and estimate the change of water level and water storage based on the inverted depth. The results indicated that the precision of the random forest (RF) was the highest with a coefficient of determination (R 2) value (0.9311) and mean absolute error (MAE) values (1.13 m) in the test dataset and had high reliability in the overall depth distribution. The water level increased by 9.36 m at a rate of 0.47 m/y, and the water storage increased by 1.811 km3 from 1998 to 2018 based on inversion depth. The water level change was consistent with that of the Shuttle Radar Topography Mission (SRTM) method. Our work shows that this method may be employed to study the water depth distribution and its changes by combining with bathymetric data and satellite imagery in shallow lakes.

Satellite-derived bathymetry based on machine learning models and an updated quasi-analytical algorithm approach.

Retrieving the water depth by satellite is a rapid and effective method for obtaining underwater terrain. In the optical shallow waters, the bottom signal has a great impact on the radiation from the water which related to water depth. In the optical shallow waters, the spatial distribution characteristic of water quality parameters derived by the updated quasi analysis algorithm (UQAA) is highly correlated with the bottom brightness. Because the bottom reflection signal is strongly correlated with the spatial distribution of water depth, the derived water quality parameters may helpful and applicable for optical remote sensing based satellite derived bathymetry. Therefore, the influence on bathymetry retrieval of the UQAA IOPs is worth discussing. In this article, different machine learning algorithms using a UQAA were tested and remote sensing reflectance at water depth in situ points and their detection accuracy were evaluated by using Worldwiew-2 multispectral remote sensing images and laser measurement data. A backpropagation (BP) neural network, extreme value learning machine (ELM), random forest (RF), Adaboost, and support vector regression (SVR) machine models were utilized to compute the water depth retrieval of Ganquan Island in the South China Sea. According to the obtained results, bathymetry using the UQAA and remote sensing reflectance is better than that computed using only remote sensing reflectance, in which the overall improvements in the root mean square error (RMSE) were 1 cm to 5 cm and the overall improvement in the mean relative error (MRE) was 1% to 5%. The results showed that the results of the UQAA could be used as a main water depth estimation eigenvalue to increase water depth estimation accuracy.

A study on spatial variation of water flow at confluence connected to non-orthogonal channels

Most studies on the flood flow characteristics at a confluence focus on channels connected orthogonally or at right angle, but studies on non-orthogonally connected channels remain limited. In this study, hydraulic-model experiments and numerical simulations are conducted to analyze the spatial variation of water flow in and around a confluence connected to non-orthogonal channels. Comparison of the measured and simulated water depth distributions in and around the confluence indicates that the results are in relatively good agreement. In the experiment where the angle between two upstream channels is 45°, the water flow pattern in and around the confluence corresponds approximately to Type I proposed by (Mignot et al. J Hydraul Res 46:723–738, 2008). However, it was found that there is no any flow type to correspond to the water flow pattern measured in the case of the angle of 135°. For analyzing the variation of the water depth in and around the confluence with inflow, numerical simulation is performed by setting the inflow ratio of the two inlet channels to one, three, and six, respectively.

Paths of soil erosion controlled by typical soil and water conservation practices based on the SIMWE model: A case study of the Tongshuang watershed.

Due to the basic topographical characteristics of the gentle and long slope lengths in the Mollisol region of Northeast China, severe soil erosion is easily aggravated by the concentration of surface flow. The spatial distribution of water depth and hydrological connectivity index were introduced to evaluate the effects of typical soil and water conservation practices on the overland flow path and hydrological connectivity based on the GIS and SIMWE (SIMulated Water Erosion) model. We analyzed the effects of different soil and water conservation practices on the hydrological connectivity, water flow path, and spatial distribution of soil erosion and sediment yield by quantifying the variations of soil infiltration rate and surface manning roughness, as well as by constructing an artificial terrain digital elevation model (DEM). The results showed that: 1) terraces could effectively affect the hydrological connectivity of the slope and regulate flow path, with significant differences between the responses of hydrological connectivity and flow path under different forms of terraced fields and ridges. The characteristics of spatial distribution of soil erosion and sediment yield varied with changes in water flow path, which would eventually lead to the intensification of local erosion; 2) practices of vegetated buffer strips and contour tillage presented limited effectiveness on runoff path controlling, though they played a significant role in sediment retention; and 3) conservation tillage could reduce the hydrological connectivity and improve the retention capacity of runoff by increasing surface roughness. This study quantified the effects of different soil and water conservation practices on the hydrological connectivity, flow path, and spatial distribution of soil erosion and sediment yield, and could provide a theoretical reference for scientific layout of soil and water conservation practices in black soil region.

Quantitative analysis of ecological suitability and stability of meandering rivers.

As the most widely distributed river form in the world, meandering river is of great significance for stabilizing the physical structure of the river and maintaining ecosystem. To quantitatively study the positive effects of meandering rivers, the Chishui River, a natural tributary of the Yangtze River in Southwest China, is selected as the research area, and two typical river sections with different meandering degrees are selected as the research objects. Based on the field survey data, the local endemic fish Procypris rabaudi (Tchang) is considered the object fish, and a hydrodynamic model was used to simulate the distribution of water depth and flow velocity in certain river reaches at different flows. By introducing the weighted usable area (WUA) and hydraulic unit diversity index, combined with the suitability curves of the study species, the hydraulic characteristics and habitat suitability changes of two river reaches under different flows are summarized and analyzed, and the hydrogeomorphological process of the studied river section is generalized. With the change in discharge, a positive correlation is observed between the maximum velocity and depth of the meandering river and the discharge, whereas the WUA and hydraulic unit index of the meandering river have relatively small changes. Under low discharge, the distribution of pool-riffle sequences can be seen in the meandering reach, which is essential to improve the ecological suitability and stability of the river. This study provides scientific sustentation for river restoration and fish conservation.

A Well-Balanced Moving Mesh Discontinuous Galerkin Method for the Ripa Model on Triangular Meshes

A well-balanced moving mesh discontinuous Galerkin (DG) method is proposed for the numerical solution of the Ripa model -- a generalization of the shallow water equations that accounts for effects of water temperature variations. Thermodynamic processes are important particularly in the upper layers of the ocean where the variations of sea surface temperature play a fundamental role in climate change. The well-balance property which requires numerical schemes to preserve the lake-at-rest steady state is crucial to the simulation of perturbation waves over that steady state such as waves on a lake or tsunami waves in the deep ocean. To ensure the well-balance, positivity-preserving, and high-order properties, a DG-interpolation scheme (with or without scaling positivity-preserving limiter) and special treatments pertaining to the Ripa model are employed in the transfer of both the flow variables and bottom topography from the old mesh to the new one and in the TVB limiting process. Mesh adaptivity is realized using an MMPDE moving mesh approach and a metric tensor based on an equilibrium variable and water depth. A motivation is to adapt the mesh according to both the perturbations of the lake-at-rest steady state and the water depth distribution (bottom structure). Numerical examples in one and two dimensions are presented to demonstrate the well-balance, high-order accuracy, and positivity-preserving properties of the method and its ability to capture small perturbations of the lake-at-rest steady state.