ADCP's Application to Ocean Current Measurement in Vigo Port

1. Where is Vigo Port?

Vigo is one of the cities in Pontevedra province, Galicia, Spain. Vigo Port ranks as one of the most important ports in Spain and one of the biggest merchant ports in Europe.

Scale of Port and Throughput

• Scale: It is a large-scale port with the vast area of the port facility. The port area has a big area and an organized layout that accommodates vessels and cargoes of various types.
• Throughput: Extremely high throughput. It is a major fishing center that handles enormous amounts of fish and seafood products. It also handles a considerable volume of container traffic, bulk cargo such as ores, grains, and chemicals, and general cargo of various types. Its strategic location and good infrastructure enable the port to handle substantial international trade.

Routes and Business

• Routes: It has a wide network of shipping routes linking it to all other world ports. There are regular links to other European ports, to North and South American, African, and Asian ones.
• Business: Major business activities range from fishing-it is an important base for the fishing fleet and fish-processing industries-to imports and exports of a wide variety of products ranging from industrial goods and consumer products to raw materials. It also has an increasing cruise ship business, which attracts many cruise liners and supports the local tourism economy in various ways.

Management and Operation of the Port

The port is run by a highly professional and efficient management team. Advanced management systems are in place for the supervision of all the aspects of port operations.

Berthing and Cargo Handling: Berthing of ships is closely monitored to reduce the waiting time and ensure smooth cargo handling. Modern cranes and other loading/unloading machinery at the port facilitate the handling of diverse cargo with efficiency.

Security and environmental protection: All security measures with regard to securing the port as well as all operations are extremely strict. Besides that, the environmental protection and taking care of ecologically clean environment follows all the principles of sustainable development: decreases in pollution, waste management, marine ecosystems protection.

Facilities

• Berths: The port has deep-water berths that can accommodate large container ships, bulk carriers, and fishing vessels. The facilities for mooring and docking are available in the berths.
• Cargo-handling Equipment: There are a number of cranes, forklifts, conveyor belts, and other equipment for loading and unloading containers, bulk cargo, and fish.
• Storage Facilities: It has wide areas of storage facilities including cold storage for fish and other perishable goods, warehouses for general cargo, and open - air storage yards for bulk materials like ores and grains.
• Other Facilities: The port also provides services such as ship repair and maintenance, bunkering-supply of fuel, and customs and quarantine facilities.

Channel and Direct Shipping

• The channel of the port is kept deep enough for the safe passage of the biggest ships. It has direct shipping connections with major ports, thereby reducing the time of transit and consequently the cost of goods in transit. Indeed, this network of direct shipping is one of the success factors of the port as a trade hub.

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

Navigation Safety

Correct current data is very important for the safe entry and exit of ships. Ocean currents can strongly affect the speed and maneuverability of vessels in the area. Knowledge of current patterns aids ship captains in making accurate decisions to avoid collisions and other navigational hazards and thus guarantees safety to the ships and port infrastructure.

Currents-For large container ships and fishing vessels that move in and out of the port, understanding currents are vital for safe navigation.

Cargo-handling Efficiency

Currents can also be an important factor in the stability of floating equipment used for cargo handling: with floating cranes or barges, the currents have to be taken into account so that optimum effectiveness and accuracy are achieved during the transfer of cargoes. In that case, it will help for the port, when accurate current measurements are obtained, to organize the operation to avoid possible damages on cargo and equipment.

The currents also tend to affect the mooring of ships. Where the currents are strong, additional stress occurs on the mooring lines, and understanding the strength and direction of flow helps in proper mooring arrangements.

Port Infrastructure Maintenance

It is basically important to understand the ocean currents for the prediction of sediment transport. The sediment movement may induce silting of the channels and berths of the port. Current measurements on a regular basis will provide the port with data for planning dredging operations with the purpose of maintaining the depth of channels and berths within their design dimensions, important for the long-term functionality of the port.

Compared with the other methods for current measurement, it is more advanced and convenient. It can provide real-time, multi-depth data about currents that is so useful for operation and management purposes in the case of the port concerned.

3. How do the ADCPs work with the use of the Doppler principle?

The ADCPs work on the principle of Doppler. They transmit acoustic signals into the water. These signals interact with particles or other substances that are in the flow of current. On the return of the acoustic signals, if the frequency of the returning signal has changed, a frequency shift has resulted due to the Doppler effect. By analyzing this frequency shift, the water current speed is found.

ADCP in Port Ocean Current Measurement

Shipborne ADCP

The shipborne ADCPs are installed on ships. During the movement of the ship in the port area, the ADCP flow meter sends acoustic pulses downwards and sideways. These pulses measure the current velocity at different depths along the path of travel of the ship. The position thus attained is then, in real-time, sent back to the vessel's navigation or monitoring system to enable appropriate change of course and speed depending on prevailing conditions.

Fixed ADCP

• Fixed ADCPs are stationed at pre-determined points in the facility, such as along the seabed and on the side of port structure facilities.
• They record continuously ocean currents within a given location. Data collected through fixed ADCPs offer a long-term view and thereby provide great insights into current patterns in the port for use in port planning and the maintenance of infrastructures.

4. What is needed to attain high-quality measurements of currents of the Vigo Port?

Reliability of the Equipment

It shall be made with robust materials for measuring high-quality current in the Vigo port, against an aggressive marine medium and subject to seawater corrosion, and variations of pressure. A reduced size and weight with a small consumption is desirable. Smaller dimensions are suitable to fit easily in almost any place on the Port area.

The low power consumption ensures longer-term operation without frequent battery replacements or issues of power supply. Cost-effectiveness enables the deployment of large-scale measurement equipment. The casing material must be waterproof to avoid water seepage during wet conditions.

The casing of ADCP meter should be made of a titanium alloy. The reason is that the titanium alloy has excellent corrosion resistance, necessary for long-time use in seawater, along with high strength with a good weight/pressure balance to bear high pressure without adding much weight. Additionally, it is biocompatible with little impact on the marine environment.

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

According to the Usage Purpose

• Shipborne ADCP: It is applicable for measuring currents in moving ships. It will be able to deliver real-time current conditions as the ship sails through a port, which will help in navigation and operational safety.
• Sitting-bottom ADCP: Suitable for long-term, fixed-point monitoring of a specific area in the port. It provides a continuous vision of the current status at that place, which is useful for long-term current pattern understanding and also for maintenance of the port infrastructure.
• Buoy-mounted ADCP: This is useful for areas where it is not practical to install fixed equipment on the seabed or on ships. The buoy-mounted ADCP can float on the water surface and measure the currents around it, thus allowing flexibility in measurement locations.

According to Different Frequencies

• For water with a depth of up to 70m, a 600kHz ADCP is ideal, because it can give very good accuracy in relatively shallow water current measurements.
• At about 110m, a 300kHz ADCP will be suited, as at this depth, it can satisfactorily measure the current.
• Further, for water as deep as 1000m, a 75kHz ADCP is the recommended model, which will help in reliable current measurement.

There are well-known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, the Chinese brand China Sonar PandaADCP is also a great option. It is made of all-titanium alloy material and offers an excellent cost-performance ratio. You can visit its website (https://china-sonar.com/) for more information.

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