Feature ArticleMonitoring Northern Adriatic Seashore At Jesolo Resort
Test area position in the Adriatic Sea and overview of subtidal bathymetry (m) and position of AWAC wave and current meter and video monitoring station (VMS).
The development of innovative modeling and monitoring approaches will lead to more efficient coastal planning and management, in the wake of the increasing awareness about coastal vulnerability issues, including climate change-related phenomena. In the framework of the Italian Flagship Project RITMARE—the Italian Research for the Sea, Subproject 3 (Coastal Waters), Workpackage 4 (Coastal Oceanographic Modeling), the Jesolo littoral zone has been identified as the Strategic Test Area for the study of coastal dynamics and for the collection of a time series of integrated measurements to support comprehensive, detailed insight on coastal circulation, wave dynamics, sediment transport and coastal erosion.
The research plan, launched in spring 2013, envisaged the deployment of an acoustic system for the continuous measurement of vertical 3D current profiles and wave spectral parameters approaching the coast. A video monitoring system was installed for a high-frequency survey of the key morphological metrics along the coastal reach. This is flanked by a morphobathymetric survey plan allowing a high-detail description of morphological variations, a thorough estimate of sediment fluxes and the validation of the video monitoring system.
The research area covers approximately 1.5 square kilometers, ranging nearly 1 kilometer in the long-shore direction and 1.5 kilometers in the cross-shore direction, reaching an offshore depth of 10 meters and enclosing the whole active beach. The data collected will be used for calibrating and validating state-of-the-art hydrodynamic models, which will help the physical interpretation of observed phenomena and the formulation of inferences concerning the coastal zone at a larger scale.
Wave-Current Monitoring Station
Waves spectral parameters and vertical profiles of 3D velocity components are recorded by means of an acoustic Doppler current profiler (ADCP), Nortek (Rud, Norway) AWAC N3650, deployed 800 meters offshore at a 7-meter depth (approximately the limit of the active beach) and moored in an aluminum framework stabilized by concrete blocks. Besides the traditional computation of velocity via analysis of the echo of a known emitted signal (1-megahertz frequency for this device), the configuration of the four acoustic transducers installed in this system together with an embedded pressure gauge allows the reconstruction of the spectral parameters from an estimate of free water level oscillations (acoustic surface tracking, or AST) and orbital velocity statistics. In addition, given prior calibration, the intensity of the returning echo registered by the transducer can provide an estimate of suspended sediment concentration along the water column. An integrated orientation sensor records the rotation components of the instrument around three dimensions, permitting a retrospective control on the geotechnical stability of the system and on the fulfillment of the tolerance requirements for an appropriate operation of the wave measurements.
The case hosting the instrument and its battery canister has a permeable bottom that allows sediment outflow and can be easily disengaged from its framework and retrieved for in-situ maintenance and data downloading. It provides an additional slot for the possible deployment of further oceanographic instrumentation.
Current velocities along the water column are recorded every 600 seconds within 50-centimeter cells, with a precision of 1.1 centimeters per second and 3.4 centimeters per second on the vertical and horizontal directions, respectively. Waves are measured hourly by collecting 2,400 samples at a 2-hertz sampling rate. The expected duration of a standard alkaline battery in these conditions is approximately 100 days, but the bottleneck for system maintenance is caused by severe biofouling occurring in the shallow working environment, requiring at least monthly upkeep inspections. To continue this article please click here.
Dr. Davide Bonaldo is a research fellow at the Institute of Marine Sciences of the National Research Council in Venice, Italy. His current research interests focus on coupled wave, current and sediment dynamics modeling in shallow basins and coastal systems, and off-shelf sediment transport phenomena.
Dr. Renata Archetti is an assistant professor of hydraulics at DICAM, University of Bologna and an expert in coastal and ocean engineering. She is the author of more than 130 scientific publications and has participated in high-profile research projects funded by Italian institutions and by the EU. She has been a consultant for maritime works since 1992.
Dr. Sandro Carniel is a physical oceanographer and senior scientist at the Institute of Marine Sciences of the National Research Council in Venice, Italy. He is an expert in numerical modeling of coastal areas and turbulence measurements, and he is a principal investigator and leader in several international and national projects, including the RITMARE SP3-WP4 project. He was awarded the U.S. Naval Research Laboratory Command Coin in 2006. Carniel can be reached at firstname.lastname@example.org.