Application of ADCP to Ocean Current Measurement in Ceuta Port

1. Where is Ceuta Port?

Ceuta belongs to Spain. It lies on the northern coast of the African continent, bordering at its southern extreme the Strait of Gibraltar. Ceuta Port is a privileged maritime facility for that matter. The port is of a moderate scale in terms of throughput. It handles general merchandise, food supplies, and construction materials, among others. Due to its location, it also acts as an important transit point for goods traveling between Europe and Africa. The annual throughput is significant considering its role as a connecting point between two continents.

Routes and Business

The Port of Ceuta represents an important link in the transport routes crossing over the Strait of Gibraltar. Ceuta is a point of participation in the merchandise transport and also in ferry services, transportation of passengers and cars between Ceuta and the Iberian Peninsula. From the commercial point of view, the Port participates in the importation and exportation relevant to regional trade, supplying basic products for the needs of the place.

Management and Operation of Port

The port management plans for smooth operation and running of the port. They take control of traffic flow both on commercial and ferry vessels. Additionally, they supervise the infrastructure concerning repair since there is harshness in the sea, coupled with many users. There is also enforcement on safety and security matters to the port and those around. **Port Facilities Within the port, there are facilities like several docks for the different vessels, cargo-handling equipment such as cranes and fork-lifts that facilitate the loading and unloading of goods, a ferry service terminal that has passenger waiting areas, ramps for the vehicles, while storage facilities for many types of cargo are available.

Channel and Direct Navigation

Ceuta Port has a properly maintained channel giving way to the sea. The strong currents in the Strait of Gibraltar make navigation along this area very complicated. However, the port has been fitted with modern navigation aids such as buoys, lighthouses, and radar that guarantee safe passage. It is possible to navigate directly to and from the port, but ships need to be cautious because of the unfavorable oceanographic conditions.

2. Why should we measure the ocean currents in the port of Ceuta?

Measurement of ocean currents in Ceuta Port is very important. Knowledge about the pattern of current flow is absolutely necessary for shipping safety. Ships would require proper and correct information on currents while planning routes or docking procedures, since the area is very near the Strait of Gibraltar, where currents are strong and variable. Ferries depend on this information to provide a safe and comfortable journey for passengers and vehicles.

Understanding the currents in and around a port enables its operators to carry out cargo handling effectively. The ability of tugboats to assist ships in berthing and unmooring is much enhanced when their masters are aware of the prevailing current conditions. In addition, measurement of currents helps ensure the long-term stability of ships in mooring and prevents these from drifting and damaging port facilities or other vessels.

From an environmental point of view, the measurement of currents is important in understanding the dispersion of pollutants. The port is a potential source of pollution, and knowing the current patterns helps in managing waste disposal and minimizing the impact on the marine environment. Acoustic Doppler Current Profiler (ADCP) provides a more accurate and efficient way to measure these currents compared to traditional methods.

3. How do ADCPs using the Doppler principle work?

Working of ADCP

The ADCP current meter is based upon the Doppler principle. These send acoustic pulses in water. Because of the interaction of the emitted pulses with the particles of the water-so it may include the planktons and sediment-the reflected sound waves produce changes in the frequency due to motions of such particles.

It measures the frequency difference between the emitted and the received signal. By using the Doppler equation, it calculates the velocity of the particles proportional to the velocity of the water current. An ADCP flow meter can measure the current velocity at various depths in the entire water column and thus gives a vertical profile of the current.

Ship-borne ADCP

When a ship-borne ADCP is used, this device is fitted on a ship. The ship goes around the area of the port. During these movements, an ADCP profiler continuously sends and receives acoustic signals. As the ship transverses various parts of a port, its data will allow a good coverage of the general current patterns across the port area.

Fixed ADCP

Fixed ADCPs would be installed in fixed locations around the port-some on the bottom, some mounted on a pier. These can continuously measure the currents at that single point. The instruments are also useful in monitoring long-term current patterns in the areas of high traffic or near any critical port infrastructure.

4. What will ensure a high-quality measurement of currents in Ceuta port?

The equipment will require reliable materials for high-quality current measurement at Ceuta port. In the real sense, it requires equipment that is able to resist corrosion and physical stress caused by strong currents and saltwater. A small size is beneficial in equipment since it allows for greater flexibility in installation, especially in spaces of limited size, like on ships or in crowded port facilities.

The weight of the ADCP should be light to ease the installation process and put less load on the supporting structures. Low power consumption is required for continuous operation, as it may not always be convenient to have a large power supply available. Cost-effectiveness is also an important factor, as the port may need to deploy multiple units for comprehensive current measurement.

The casing of the ADCP meter is preferably made of titanium alloy. Besides being resistant to corrosion, especially in a salty marine environment, the alloy is tough but lightweight enough to satisfy the durability and ease-of-installation requirements.

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

Based on Usage Purpose

• Ship-borne ADCP: This is suitable for mobile measurements. It is ideal for ships that move around the port area, like ferries and commercial vessels. The ship-borne ADCP provides a means of measuring currents along the ship's track and is useful in understanding the general current patterns at the port.
• Bottom-mounted ADCP: Suitable for fixed-point monitoring near the docks, channels, or other critical infrastructure. It gives a continuous record of current conditions at that location and is important for the long-term safety and operation of the port.
• Buoy - based ADCP: This can be used in areas where it is not practical to install fixed - bottom or ship - borne ADCPs. It provides a floating option for current measurement and can cover areas in the open water of the port.

Based on Frequency

• The choice of frequency depends on the water depth. In Ceuta port, a 600kHz ADCP is suitable for water depths up to 70m. This can be used in the shallower areas near the shore or in the inner parts of the port. A 300kHz ADCP is appropriate for water depths up to 110m and can cover a wider range of depths. For deeper waters in the port area, a 75kHz ADCP is suitable for water depths up to 1000m and can be used in areas such as the approach channels.
• There are well-known ADCP brands like Teledyne RDI, Nortek, and Sontek. However, a Chinese brand, China Sonar PandaADCP, is also a great option. It is made of all-titanium alloy material, providing excellent durability and a high level of corrosion resistance. It also offers an attractive cost-performance ratio. You can visit their website (https://china-sonar.com/) for more details.

Here is a table with some well known Acoustic Doppler Current Profiler(ADCP)  instrument brands and models.