ADCP in Heraklion Port: Ocean Current Measurement

1. Where is Heraklion Port?

Overview of Heraklion Port

Heraklion Port is situated on the island of Crete in Greece. It is a large-scale and high-throughput port. The port plays a very important role in transportation, connecting Crete with the mainland and other parts of the world. It deals with a wide range of cargo, from containers and agricultural products like olive oil and fruits to various tourist-related goods.

The shipping links of this port are on a large scale, with regular ferry services to the other Greek islands and other mainland ports and connected with international shipping lanes. Heraklion Port management is well organized for excellent services provision, whether in passenger service or cargo handling. There exists well-organized teams: vessel traffic management, cargo storage and distribution, customs procedures.

Facilities

Berths: The port contains a number of berths, for receiving different kinds of vessels. Deep-water berths for large container ships and cruise liners are also included. These have been equipped with advanced mooring and docking facilities. High-strength bollards and fenders have been installed to ensure that the ships can safely arrive and depart without damage, even in bad weather and strong currents.

Cargo-handling Equipment: On the quay, a cargo-handling equipment stands in line. It has modern gantry cranes for container handling with efficient loading and unloading of containers; for agricultural products, there are cranes and conveyor systems for moving fruits, vegetables, and olive oil; while there is also a forklift and other general handling equipment for general cargo.

Storage Facilities: Huge storage facilities of various cargo exist. For containers, there are well-organized container yards with an efficient storage and retrieval system. For agricultural products, there are appropriate warehouses with proper temperature and humidity control to preserve the quality of the goods. The port also has cold-storage facilities for perishable items and storage areas for other general cargo.

Channel and Navigation Aids: The channel in the port is dredged to a sufficient depth and width to be able to pass ships through safely. Continuous dredging is done to ensure it remains navigable for vessels with big drafts. Navigation aids such as buoys, beacons, and radar systems are installed to guide the ships in and out of the port. The radar systems provide real - time information about the position and movement of other vessels in the area.

2. Why should we measure the ocean currents in the Heraklion Port?

Importance for Port Operation and Management

Measuring ocean currents in Heraklion Port is of utmost importance. First of all, for the safety of vessel navigation. It is the current speed and direction knowledge that remains critical to ship captains' ability when approaching berths or negotiating through the channel. A strong cross-current in the neighborhood of a berth may turn the docking process painful and hazardous. For instance, a ship that is approaching a berth against a strong current should make sure that its adjustment of speed and angle of approach are appropriately made to have smooth and safe docking. Captains use accurate current measurements to make informed decisions about navigation and reduce the risk of collisions and other accidents.

The reason is that it is very crucial for the optimization of the port's operations. Current data assists in efficient scheduling of ship arrivals and departures. By having an understanding of tidal currents and other periodic flow patterns, port authorities are better able to allocate berthing resources and plan loading and unloading activities. It contributes to the enhancement of productivity because now cargo-handling operations can be coordinated much more effectively.

In addition, from an ecological point of view, this knowledge of ocean currents can be useful in case accidental spills of pollutants such as oil and chemicals occur. With a view to the type of cargo handled in this port, it is important to forecast any spill dispersal. Data on currents can be utilized immediately after the accident for undertaking containment and mitigation measures so as to reduce environmental damage.

Acoustic Doppler Current Profilers (ADCPs) have made the measurement of such currents more accurate and considerably easier than earlier methods.

3. How do ADCPs using the Doppler principle work?

Measurement Principle

In principal, an Acoustic Doppler Current Profiler (ADCP) is a device relying on the principle of the Doppler Effect: when an acoustic signal originally emitted by the ADCP meter into the water is altered through scattering produced by the moving particles, the frequency of the scattered acoustic signal that bounces back to the ADCP profiler from such shifting particles will be changed because ocean water is in motion owing to the ocean current. In accordance with the Doppler Effect, this frequency shift bears a relation to the water flow's velocity.

Calculation of Current Speed and Direction

By the analysis of magnitude and direction of this frequency shift, the ADCP flow meter can determine the speed and direction of the ocean current at different depths in the water column. By transmitting signals at multiple angles and different depths, it is able to create a profile of the ocean current, showing how the current varies with depth.

ADCP Deployment in the Port

Shipborne ADCP

The shipborne ADCP will be installed on ships operating within the Heraklion Port area. During its movements within the port, it will be continuously emitting an acoustic signal into the underlying water. These movements give the ADCP current meter a good, wide area so it will be able to acquire the current data at each position in a sequential manner. For instance, in a normal survey of the port by a research or inspection ship with a shipborne ADCP, it can acquire data on the current patterns across various parts of the port for a comprehensive understanding of the water flow situation.

Fixed ADCP

Fixed ADCPs are positioned in specific, fixed locations within the port at some locations on the seabed, near important navigational areas, or at the entrance/exit of the port. The fixed ADCPs continuously measure ocean currents at their positions for a long period. Such information is useful in analyzing the regular patterns of currents in specific areas within the port. For example, a bottom-moored ADCP placed at the port entrance can measure the currents going in and out, which would be useful for understanding the tidal effects and other consistent flow characteristics of that area.

4. What's needed for high - quality measurement of Heraklion port currents?

Equipment Requirements

In general, high-quality measurements of the currents in Heraklion port will be obtained if the equipment possess specific characteristics. First and very important is the material reliability. The equipment must withstand the corrosive marine environment. Salts and other chemicals found in seawater corrode most of the materials after a long exposure to contact. In addition to corrosion, equipment needs to face a number of pressure variations because of changes of depth of the water but also by forces of waves and currents.

Secondly, the desirable features are smaller size, lighter weight, and lower power consumption. With a compact size, installation in various locations in the port will be easier, whether on ships, fixed structures like piers, or on the seabed. A lighter weight will make the installation and transportation process easier. This will ensure that the equipment operates continuously over long periods with minimal replacement of batteries or supply of excess power, which is most important in applications requiring monitoring over a very long time.

Cost is another issue. A lower cost allows a port to deploy a larger number of measuring devices to monitor current in greater detail over more areas in the port.

The Advantage of Titanium Alloy for ADCP Casing

In ADCPs, the casing is preferably made of titanium alloy. The reason for using this material is its very good resistance to corrosion. That means even after a long time under seawater, it will still be able to hold and function properly. Its high strength-to-weight ratio allows for the building of a durable yet relatively lightweight casing. For instance, in deeper areas of the Heraklion port where higher water pressures prevail, an ADCP current profiler with a casing made of a titanium alloy can resist such pressures effectively and keep on measuring current with accuracy.

5. How to Choose the right equipment for current measurement?

Selection Based on Usage

Shipborne ADCP: If the aim is to conduct wide-area surveys of the port waters while the ship is in operation, then shipborne ADCP will be suitable. It can cover different sections of the port as the ship moves around, collecting a large amount of data for a comprehensive understanding of the overall current situation in the port. This is useful for mapping general flow patterns and variations across different areas of the port waters.

Sitting - bottom ADCP: For long-term and fixed-point monitoring of specific locations within the port, such as near important infrastructure or areas with complex current behaviors, sitting - bottom ADCPs are more appropriate. They can continuously record the current data at those fixed positions, providing valuable insights into the local current characteristics and any changes over time.

Buoy-mounted ADCP: In cases when it cannot be conveniently done to install the fixed equipment on the seafloor or vessels, buoy-mounted ADCPs can be used. They float on the surface of the water and allow for measurements of currents in the upper layers of the water column. Comparatively easy to deploy and repositioned if necessary, they can serve very well for the monitoring of certain areas within the port that can be either dynamic or hard to access.

Selection Based on Frequency

The choice of frequency for ADCPs depends on the water depth in Heraklion port. For areas with a water depth of up to 70 meters, an ADCP with a frequency of 600 kHz is usually a good choice as it can provide accurate current measurements in this relatively shallow depth range. In waters as deep as about 110 meters, an ADCP current meter with a frequency of 300 kHz is more advisable. In very deep sections of the port, with water up to 1000 meters deep, it is recommended to use an ADCP with a frequency of 75 kHz to reliably profile ocean currents at such great depths.

There are several well - known ADCP profiler brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, there is also an excellent Chinese ADCP brand-China Sonar PandaADCP. It is made entirely of titanium alloy material, which not only ensures its durability in the marine environment but also offers an excellent cost-performance ratio. For more information, you can visit its official website: (https://china-sonar.com/).

Here is a table with some well known ADCP instrument brands and models.