A novel permanent gauge-cam station for surface-flow observations on the Tiber River

Tauro, Flavia; Petroselli, Andrea; Porfiri, Maurizio; Giandomenico, Lorenzo; Bernardi, Guido; Mele, F.; Spina, Domenico; Grimaldi, Salvatore

doi:10.5194/gi-5-241-2016

Cited by 38 publications

(23 citation statements)

References 44 publications

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“…The performance of PIV in this study is consistent with the previous studies that exploited LSPIV for flow analysis [24]. Previous research has shown that LSPIV based on standard FFT correlation or DCC is prone to underestimating flow velocities due to insufficient seeding density [48,49,63,64]. Our results have also indicated that independent on the correlation method employed, LSPIV tends to underestimate flow velocities; however, the use of ensemble correlation that averages correlation matrices before determining the correlation peak, in many cases reduces the magnitude of differences between the reference velocities and the PIV values.…”

Section: Discussionsupporting

confidence: 89%

Drone-Based Optical Measurements of Heterogeneous Surface Velocity Fields around Fish Passages at Hydropower Dams

et al. 2020

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In Austria, more than a half of all electricity is produced with the help of hydropower plants. To reduce their ecological impact, dams are being equipped with fish passages that support connectivity of habitats of riverine fish species, contributing to hydropower sustainability. The efficiency of fish passages is being constantly monitored and improved. Since the likelihood of fish passages to be discovered by fish depends, inter alia, on flow conditions near their entrances, these conditions have to be monitored as well. In this study, we employ large-scale particle image velocimetry (LSPIV) in seeded flow conditions to analyse images of the area near a fish passage entrance, captured with the help of a ready-to-fly consumer drone. We apply LSPIV to short image sequences and test different LSPIV interrogation area sizes and correlation methods. The study demonstrates that LSPIV based on ensemble correlation yields velocities that are in good agreement with the reference values regarding both magnitude and flow direction. Therefore, this non-intrusive methodology has a potential to be used for flow monitoring near fish passages on a regular basis, enabling timely reaction to undesired changes in flow conditions when possible.

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Section: Discussionsupporting

confidence: 89%

Drone-Based Optical Measurements of Heterogeneous Surface Velocity Fields around Fish Passages at Hydropower Dams

et al. 2020

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“…A video recorded at the gauge-cam station on the Tiber River underneath the bridge "Ponte del Foro Italico" in the city of Rome, Italy [52,53], on February 2015, at 7:40 a.m., was analyzed through OTV, Figure 1c. The gauge-cam station acquires one-minute long videos every ten minutes through a Mobotix FlexMount S15 weatherproof internet protocol camera.…”

Section: A Moderate Flood Event In the Tiber Rivermentioning

confidence: 99%

Optical Tracking Velocimetry (OTV): Leveraging Optical Flow and Trajectory-Based Filtering for Surface Streamflow Observations

et al. 2018

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Nonintrusive image-based methods have the potential to advance hydrological streamflow observations by providing spatially distributed data at high temporal resolution. Due to their simplicity, correlation-based approaches have until recent been preferred to alternative image-based approaches, such as optical flow, for camera-based surface flow velocity estimate. In this work, we introduce a novel optical flow scheme, optical tracking velocimetry (OTV), that entails automated feature detection, tracking through the differential sparse Lucas-Kanade algorithm, and then a posteriori filtering to retain only realistic trajectories that pertain to the transit of actual objects in the field of view. The method requires minimal input on the flow direction and camera orientation. Tested on two image data sets collected in diverse natural conditions, the approach proved suitable for rapid and accurate surface flow velocity estimations. Five different feature detectors were compared and the features from accelerated segment test (FAST) resulted in the best balance between the number of features identified and successfully tracked as well as computational efficiency. OTV was relatively insensitive to reduced image resolution but was impacted by acquisition frequencies lower than 7-8 Hz. Compared to traditional correlation-based techniques, OTV was less affected by noise and surface seeding. In addition, the scheme is foreseen to be applicable to real-time gauge-cam implementations.

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“…Conventional methods may be used to monitor flash floods in wadi systems, for instance, the measuring of water levels and the slope-area method to generate water level-discharge relationships (rating curves). However, the field measurements and observations for peak discharge values have a limited range for establishing accurate rating curves [6]. Moreover, the slope-area method in wadi systems relies on flood marks from post-flood surveys, for example, floating debris and sediments deposited on both banks of the channel, to obtain the water surface slope in each cross-sectional area, which affects the reliability of discharge predictions.…”

Section: Introductionmentioning

confidence: 99%

“…The LSPIV technique is among the most commonly investigated type of flash flood monitoring systems, and several studies of image-based methods have been undertaken in riverine systems [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Real-Time Measurement of Flash-Flood in a Wadi Area by LSPIV and STIV

et al. 2019

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Flash floods in wadi systems discharge large volumes of water to either the sea or the desert areas after high-intensity rainfall events. Recently, wadi flash floods have frequently occurred in arid regions and caused damage to roads, houses, and properties. Therefore, monitoring and quantifying these events by accurately measuring wadi discharge has become important for the installation of mitigation structures and early warning systems. In this study, image-based methods were used to measure surface flow velocities during a wadi flash flood in 2018 to test the usefulness of large-scale particle image velocimetry (LSPIV) and space–time image velocimetry (STIV) techniques for the estimation of wadi discharge. The results, which indicated the positive performance of the image-based methods, strengthened our hypothesis that the application of LSPIV and STIV techniques is appropriate for the analysis of wadi flash flood velocities. STIV is suitable for unidirectional flow velocity and LSPIV is reliable and stable for two-dimensional measurement along the wadi channel, the direction of flow pattern which varies with time.

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A novel permanent gauge-cam station for surface-flow observations on the Tiber River

Cited by 38 publications

References 44 publications

Drone-Based Optical Measurements of Heterogeneous Surface Velocity Fields around Fish Passages at Hydropower Dams

Drone-Based Optical Measurements of Heterogeneous Surface Velocity Fields around Fish Passages at Hydropower Dams

Optical Tracking Velocimetry (OTV): Leveraging Optical Flow and Trajectory-Based Filtering for Surface Streamflow Observations

Real-Time Measurement of Flash-Flood in a Wadi Area by LSPIV and STIV

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