ADCP's Application to Ocean Current Measurement in the Port of Aliveri

1. Where is Aliveri Port?

Overview of Aliveri Port

Aliveri Port is located in Greece. In the local maritime context, it is a very important facility. It is of a medium scale and throughput, meeting both the domestic and some international shipping requirements. The port assists in the transportation of materials such as minerals, agricultural products, and industrial raw materials.

The port is well-connected with the local transportation network, which allows for the distribution of goods to the surrounding regions quickly. The management of Aliveri Port is highly focused on safety and operational efficiency. There are specialized teams for vessel traffic management, cargo handling, and infrastructure maintenance.

Facilities

Berths: The port has a number of berths to handle different types of vessels. There are berths suited for medium-sized cargo ships and barges. These are fitted with modern mooring and docking facilities to ensure that ships arrive and leave the harbor safely. High-quality fenders and bollards were used to protect both the ships and berths in case of any up and down movement during docking and undocking.

Cargo-Handling Equipment: There is a set of cargo-handling equipment up the quay. The conveyors and grabs handle the minerals and bulk materials, forklifts, and cranes for agricultural products and other general cargo. The equipment shall be capable of moving goods efficiently between the ships and the storage areas.

Storage Facilities: There are storage facilities for various types of cargo. In the case of minerals, large-scale stockpiles with appropriate containment and drainage systems are provided. For agricultural products, there are warehouses that have temperature and humidity control to preserve the quality of the goods. There are also container yards and general-cargo storage areas.

Channel and Navigation Aids: The channel in this port is maintained to proper depth and width so that there may safely pass vessels through. These channels are usually kept properly dredged in view of changing drafts of ships and sizes. Navigation aids such as buoys, beacons, and radar systems also guide the vessel inward and outward from the ports. The radar systems provide real - time information about the position and movement of other vessels in the vicinity of the port.

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

Importance for Port Operation and Management

The measurement of ocean currents in Aliveri Port is very important. First of all, for the safety of vessel navigation. It is the current speed and direction knowledge that plays an important role for the captain in case of approaches to berths or channel design. A strong cross-current near a berth may render the docking process cumbersome and hazardous. For instance, a ship approaching a berth against a strong current has to adjust its speed and angle of approach to ensure smooth and safe docking. It helps the captains to make correct decisions by taking proper current measurements to reduce the possibility of collisions and other accidents.

It is also crucial for the optimization of the port's operations. Current data enables better scheduling of the arrival and departure of ships. With knowledge of tidal currents and other regular flow patterns, port authorities can better allocate berthing resources and plan loading and unloading activities. This leads to improved productivity since it allows for better coordination of cargo-handling operations.

Moreover, from an environmental perspective, in case of an accidental spill of pollutants such as oil or chemicals, knowledge of ocean currents is valuable. Since the nature of the cargo handled in the port is critical, the forecast of the spread of a spill is very important. The current data can be used to quickly implement containment and mitigation measures to minimize environmental damage.

The measurement of currents with Acoustic Doppler Current Profilers is far more advanced and easier to use compared to conventional techniques.

3. Measurement principle of ADCPs using the Doppler principle

Measurement Principle

The ADCPs work on the Doppler principle. When an ADCP current meter sends out an acoustic signal into the water, those acoustic signals interact with moving particles of water. The frequency of the reflected acoustic signal picked by the ADCP current profiler will then change due to the motion given by the water particles via an ocean current. Due to the Doppler effect, this shifted frequency is proportional to the flow of the water.

Calculation of Current Speed and Direction

With the magnitude and direction of this frequency shift analyzed, the ADCP flow meter calculates the speed and direction of the ocean current at various depths in the water column. By transmitting signals at different angles and depths, it creates a profile of the ocean current, which shows how the current varies with depth.

ADCP Deployment in the Port

Shipborne ADCP

A shipborne ADCP will be installed on ships operating within the Aliveri Port area. While the ship moves around the port area, it continuously sends acoustic signals into the water from the ADCP profiler installed on it. The movement of the ship will enable the ADCP flow meter to cover a wider area for current data acquisition in different locations. For instance, in a normal survey of the port by a research or inspection ship with a shipborne ADCP, it will be able to collect data on current patterns over different areas of the port for a whole understanding of the water flow situation.

Fixed ADCP

Fixed ADCPs are mounted on fixed, designated locations within the harbor: for example, on the ocean floor near key places that are used by various ships for navigation or at any other place of entrance/exit within the harbor. These long-term current measurements at the steady positions of the ADCP meter enable the study of recurrent patterns in specific areas of the port's current structure. For instance, a bottom-moored ADCP installed near the port entrance can measure the currents flowing in and out to assist in assessing the tidal effects and other persistent flow features in the area.

4. What's required for high-quality measurement of currents at Aliveri port?

Equipment Requirements

High-quality measurement of the currents in Aliveri port requires certain equipment characteristics. First of all, material reliability is crucial. The equipment should be resistant to the harsh marine environment. Seawater contains salts and other chemicals that can destroy materials over time. The equipment also needs to withstand the pressure changes at different water depths and the mechanical forces caused by waves and currents.

It should be of a smaller size, with lighter weight and lower power consumption. The compact size will be easier to install in several locations at the port, whether on ships, fixed structures such as piers, or on the seabed. Lighter weight will simplify installation and transportation processes. This means that lower power consumption allows the equipment to continue operating for long periods without frequent battery replacement or excessive power supply, which is quite essential in long-term monitoring applications.

Cost is another important factor: the lower the cost, the more measuring devices the port can deploy to monitor currents in greater detail over various areas of the port.

The Advantage of Titanium Alloy for ADCP Casing

The casing is preferably made from a titanium alloy. For such an application, titanium alloy is particularly useful because it resists corrosion even in seawater for extensive use and, thus, preserves its structure and function. Due to its high strength-to-weight ratio, one will be able to build a tough yet reasonably lightweight casing. For example, in deeper parts of the Aliveri port with higher water pressures, an ADCP profiler in a casing made from titanium alloy can easily bear such pressure and keep measuring the currents correctly.

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

Selection Based on Usage

Shipborne ADCP: Where the objective is to carry out wide-area surveys of the port waters, with the ship in operation, the shipborne ADCP will be suitable. It can cover different sections of the port as the ship moves around, collecting a large amount of data to provide a comprehensive understanding of the overall current situation in the port. This is useful for mapping general flow patterns, variation in different areas of port waters.

Sitting-bottom ADCP: Sitting-bottom ADCPs shall be more appropriate for the long-term and fixed-point monitoring of some places in the port, such as those near main infrastructure or areas where the current has a complex behavior. They can record the continuous current data at fixed positions with valuable insights into the local current characteristics and any changes over time.

Buoy-mounted ADCP: When it is not convenient to install fixed equipment on the seabed or on ships, buoy-mounted ADCPs can be used. They float on the water surface and can measure the currents in the upper layers of the water column. They are relatively easy to deploy and can be relocated if needed, making them suitable for monitoring certain dynamic or hard-to-reach areas within the port.

Frequency Selection

The choice of frequency for the ADCPs will depend on the water depth in the area of Aliveri port. For water up to a depth of 70 meters, an ADCP with 600 kHz normally works well, as in that fairly shallow depth range, accurate measurements of current can be performed. In waters as deep as approximately 110 meters, the more advisable is an ADCP with a frequency of 300 kHz. In very deep sections of the port, where the water reaches as much as 1000 meters deep, it is recommended to use an ADCP current meter with a frequency of 75 kHz for reliable profiling of ocean currents at such great depths.

There are several well-known ADCP 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.