scholarly journals TERRESTRIAL PHOTOGRAMMETRIC MEASUREMENTS OF BREAKING WAVES AND LONGSHORE CURRENTS IN THE NEARSHORE ZONE

1976 ◽  
Vol 1 (15) ◽  
pp. 38 ◽  
Author(s):  
Joseph W. Maresca ◽  
Erwin Seibel
Keyword(s):  
Water Level ◽  
Surf Zone ◽  
Vertical Plane ◽  
Weather Conditions ◽  
Breaking Waves ◽  
Water Levels ◽  
Wind Speeds ◽  
Longshore Currents ◽  
Run Up ◽  
Oblique Images

We conducted a study to determine the feasibility of shore-based, oblique photographic monitoring of breaking waves, water levels, and currents within the surf zone. The purpose of this paper is to describe a new method of oblique single-image and stereoscopic-image analysis, the potential errors, and the types of measurements that can be made in the surf zone. Examples of application are presented to demonstrate the technique. Sophisticated photographic equipment is not required to collect, analyze, and interpret the data. The analysis and error discussions are directed toward the problems encountered using common equipment. Vertical images from aircraft, helicopters, and balloons have been used in the past to study shoreline changes, directional ocean-wave spectra,8 and longshore currents.3 Oblique images taken from the bridge of a ship have been successfully used to measure whitecap coverage under different wind speeds.4 Terrestrial oblique images have been used to study longshore currents,5 ice-ridge formation and breakup,6'7 and beach changes .8 Oblique images, taken with a 35-mm single-lens reflex camera from an elevated point such as a bluff, are particularly suitable for the measurement of breaking waves, water level, beach run-up, and current in the surf zone under storm conditions. In contrast to other techniques of monitoring the surf zone, the photographic technique described in this paper is simple to install, reliable, accurate, and inexpensive. It can be used in all weather conditions, and the analysis of the images is simple. Both stereoscopic and single oblique images can be analyzed, depending on the specific needs and existing environmental conditions. Since the scale of an oblique photograph changes with increasing distance from the camera, the technique is limited in range to about 250 m for a cliff approximately 8 m above the mean water level. Accuracies to within 1% in the horizontal plane and better than 10% in the vertical plane are achievable at this distance.

Smart Water Level Monitoring System for Farmers

2019 ◽  
pp. 213-228
Author(s):  
Nalina Suresh ◽  
Valerianus Hashiyana ◽  
Victor Panduleni Kulula ◽  
Shreekanth Thotappa
Keyword(s):  
Water Level ◽  
Monitoring System ◽  
Cost Effective ◽  
Weather Conditions ◽  
Water Levels ◽  
Measurement Systems ◽  
Smart Water ◽  
Level Measurement ◽  
Level Monitoring ◽  
Water Level Monitoring

With advancement in technology and ever-changing weather conditions, accurate and affordable water level measurement systems has become necessary for farmers. This therefore brings about the need for a system incorporating the use of IoT technology that will monitor water levels at a cost-effective price with accurate and dependable results. The prototype will monitor water levels on a regular basis and the data captured will be stored in a database to help farmers improve the way they manage their water resource. Farmers will be able to monitor the water levels from any location at any given time. This chapter focuses on a Smart Water Level Monitoring System for Farmers and provides a smart way to manage water resources on farms in the most cost-effective and convenient manner for farmers.

scholarly journals MEASUREMENTS OF SURFACE KINEMATICS AND TEMPERATURE IN THE SURF AND SWASH ZONES USING INFRARED IMAGE VELOCIMETRY

2012 ◽  
Vol 1 (33) ◽  
pp. 55
Author(s):  
Zhi-Cheng Huang ◽  
Kao-Shu Hwang ◽  
Luc Lenain ◽  
W. Kendall Melville ◽  
Hwung-Hwang Hwung
Keyword(s):  
Water Surface ◽  
Large Scale ◽  
Surf Zone ◽  
Thermal Structure ◽  
Infrared Image ◽  
Breaking Waves ◽  
Electromagnetic Current ◽  
Correlation Algorithm ◽  
Image Velocimetry ◽  
Run Up

High intensity air bubbles generated in the surf zone and the thinning of swash flow make velocity measurements particularly challenging in coastal areas. These facts have led the need for a new measurement technique to quantify the surf and swash flow dynamics. Here, we tested infrared image techniques to measure the surface temperature and then to derive the velocity fields using cross-correlation algorithm for large-scale solitary waves breaking in the surf and swash zones. From the comparison with unspiked electromagnetic current meter (EMCM) data and previous validation, it is suggested that the infrared image velocimetry (IRIV) is satisfactory to quantify the surface turbulent flow in the surf and swash zones. The data obtained in the experiment provides a new description of surface thermal structure and kinematics for solitary breaking waves. Two-dimensional organized streaks of temperature structures are evident on the water surface behind the head of rebounding jet. Wavenumber spectrum analysis shows that the directionality of these thermal signatures evolves with time. Evolution of vorticity on the water surface during the run-up and run-down process of the solitary broken wave is discussed.

scholarly journals VALIDATION OF A BUOYANCY-MODIFIED TURBULENCE MODEL BY NUMERICAL SIMULATIONS OF BREAKING WAVES OVER A FIXED BAR

2018 ◽  
pp. 71
Author(s):  
Brecht Devolder ◽  
Peter Troch ◽  
Pieter Rauwoens
Keyword(s):  
Numerical Simulations ◽  
Wave Breaking ◽  
Surf Zone ◽  
Breaking Waves ◽  
Navier Stokes ◽  
Two Phase ◽  
Numerical Wave Flume ◽  
Wave Flume ◽  
Nearshore Sediment Transport ◽  
Run Up

The surf zone dynamics are governed by important processes such as turbulence generation , nearshore sediment transport , wave run-up and wave overtopping at a coastal structure. During field observations , it is very challenging to measure and quantify wave breaking turbulence . Complementary to experimental laboratory studies in a more controlled environment , numerical simulations are highly suitable to understand and quantify surf zone processes more accurately. In this study, wave propagation and wave breaking over a fixed barred beach profile is investigated using a two­ phase Navier-Stokes flow solver. We show that accurate predictions of the turbulent two-phase flow field require special attention regarding turbulence modelling. The numerical wave flume is implemented in the open­ source OpenFOAM library. The computed results (surface elevations , velocity profiles and turbulence levels) are compared against experimental measurements in a wave flume (van der A et al., 2017) .

scholarly journals Run-up parameterization and beach vulnerability assessment on a barrier island: a downscaling approach

2016 ◽  
Vol 16 (1) ◽  
pp. 167-180 ◽  
Author(s):  
G. Medellín ◽  
J. A. Brinkkemper ◽  
A. Torres-Freyermuth ◽  
C. M. Appendini ◽  
E. T. Mendoza ◽  
...  
Keyword(s):  
Water Level ◽  
Water Depth ◽  
Shallow Water Equation ◽  
Barrier Island ◽  
Water Levels ◽  
Tidal Level ◽  
Extreme Water Level ◽  
Extreme Water Levels ◽  
Run Up ◽  
Wave Induced

Abstract. We present a downscaling approach for the study of wave-induced extreme water levels at a location on a barrier island in Yucatán (Mexico). Wave information from a 30-year wave hindcast is validated with in situ measurements at 8 m water depth. The maximum dissimilarity algorithm is employed for the selection of 600 representative cases, encompassing different combinations of wave characteristics and tidal level. The selected cases are propagated from 8 m water depth to the shore using the coupling of a third-generation wave model and a phase-resolving non-hydrostatic nonlinear shallow-water equation model. Extreme wave run-up, R2%, is estimated for the simulated cases and can be further employed to reconstruct the 30-year time series using an interpolation algorithm. Downscaling results show run-up saturation during more energetic wave conditions and modulation owing to tides. The latter suggests that the R2% can be parameterized using a hyperbolic-like formulation with dependency on both wave height and tidal level. The new parametric formulation is in agreement with the downscaling results (r2  =  0.78), allowing a fast calculation of wave-induced extreme water levels at this location. Finally, an assessment of beach vulnerability to wave-induced extreme water levels is conducted at the study area by employing the two approaches (reconstruction/parameterization) and a storm impact scale. The 30-year extreme water level hindcast allows the calculation of beach vulnerability as a function of return periods. It is shown that the downscaling-derived parameterization provides reasonable results as compared with the numerical approach. This methodology can be extended to other locations and can be further improved by incorporating the storm surge contributions to the extreme water level.

scholarly journals RUN-UP DUE TO BREAKING AND NON-BREAKING WAVES

1974 ◽  
Vol 1 (14) ◽  
pp. 113
Author(s):  
F. Raichlen ◽  
J.L. Hammack
Keyword(s):  
Water Level ◽  
Incident Wave ◽  
Wave Length ◽  
Breaking Waves ◽  
Relative Depth ◽  
Order Unity ◽  
A Value ◽  
Wave Parameters ◽  
Linear Effects ◽  
Run Up

This study was conducted to Investigate the effect of incident wave parameters on run-up for both a smooth-faced structure and a structure armored with quarry-stone. The ratio of the depth-to-wave length (the relative depth) was found to be important in defining wave run-up for both cases. The relative run-up (expressed as the ratio of the run-up elevation above still water level to the incident wave height) for waves which break at the toe of the structure was less than the maximum relative run-up for non-breaking waves for the same relative depth. For both structures, the maximum relative run-up for experiments with long waves occurred at a value of the modified Ursell number, (1/2IT) (HL2/h3) , of order unity which indicates that the nonlinear and linear effects are approximately equal in the incident wave.

scholarly journals Combining probability distributions of sea level variations and wave run-up to evaluate coastal flooding risks

2018 ◽  
Vol 18 (10) ◽  
pp. 2785-2799 ◽  
Author(s):  
Ulpu Leijala ◽  
Jan-Victor Björkqvist ◽  
Milla M. Johansson ◽  
Havu Pellikka ◽  
Lauri Laakso ◽  
...  
Keyword(s):  
Water Level ◽  
Sea Level ◽  
Probability Distributions ◽  
Water Levels ◽  
Total Water ◽  
Mean Sea Level ◽  
Sea Level Variations ◽  
Wave Conditions ◽  
Run Up ◽  
Total Water Level

Abstract. Tools for estimating probabilities of flooding hazards caused by the simultaneous effect of sea level and waves are needed for the secure planning of densely populated coastal areas that are strongly vulnerable to climate change. In this paper we present a method for combining location-specific probability distributions of three different components: (1) long-term mean sea level change, (2) short-term sea level variations and (3) wind-generated waves. We apply the method at two locations in the Helsinki archipelago to obtain total water level estimates representing the joint effect of the still water level and the wave run-up for the present, 2050 and 2100. The variability of the wave conditions between the study sites leads to a difference in the safe building levels of up to 1 m. The rising mean sea level in the Gulf of Finland and the uncertainty related to the associated scenarios contribute notably to the total water levels for the year 2100. A test with theoretical wave run-up distributions illustrates the effect of the relative magnitude of the sea level variations and wave conditions on the total water level. We also discuss our method's applicability to other coastal regions.

scholarly journals Image-Based River Water Level Estimation for Redundancy Information Using Deep Neural Network

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6706
Author(s):  
Gabriela Rocha de Oliveira Fleury ◽  
Douglas Vieira do Nascimento ◽  
Arlindo Rodrigues Galvão Filho ◽  
Filipe de Souza Lima Ribeiro ◽  
Rafael Viana de Carvalho ◽  
...  
Keyword(s):  
Neural Network ◽  
Water Level ◽  
Deep Neural Network ◽  
Weather Conditions ◽  
Water Levels ◽  
Hydroelectric Power ◽  
Basin Management ◽  
Proposed Model ◽  
Human Eyes ◽  
Resources Planning

Monitoring and management of water levels has become an essential task in obtaining hydroelectric power. Activities such as water resources planning, supply basin management and flood forecasting are mediated and defined through its monitoring. Measurements, performed by sensors installed on the river facilities, are used for precisely information about water level estimations. Since weather conditions influence the results obtained by these sensors, it is necessary to have redundant approaches in order to maintain the high accuracy of the measured values. Staff gauge monitored by conventional cameras is a common redundancy method to keep track of the measurements. However, this method has low accuracy and is not reliable once it is monitored by human eyes. This work proposes to automate this process by using image processing methods of the staff gauge to measure and deep neural network to estimate the water level. To that end, three models of neural networks were compared: the residual networks (ResNet50), a MobileNetV2 and a proposed model of convolutional neural network (CNN). The results showed that ResNet50 and MobileNetV2 present inferior results compared to the proposed CNN.

AUTOMATIC WATER LEVEL MONITORING WITH IOT AND LPWAN

2019 ◽  
pp. 95-103
Author(s):  
Krum Videnov ◽  
Vanya Stoykova
Keyword(s):  
Water Level ◽  
Real Time ◽  
Early Warning ◽  
Water Sources ◽  
Water Levels ◽  
Water Level Fluctuations ◽  
Level Monitoring ◽  
Water Level Monitoring

Monitoring water levels of lakes, streams, rivers and other water basins is of essential importance and is a popular measurement for a number of different industries and organisations. Remote water level monitoring helps to provide an early warning feature by sending advance alerts when the water level is increased (reaches a certain threshold). The purpose of this report is to present an affordable solution for measuring water levels in water sources using IoT and LPWAN. The assembled system enables recording of water level fluctuations in real time and storing the collected data on a remote database through LoRaWAN for further processing and analysis.

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