ADCP Application to Ocean Current Measurement in Algiers Port

1. Where is Algiers Port?

Algiers Port is located on the Mediterranean coast of Algeria and is the country's largest and most important seaport.

Scale and Throughput of the Port

It is of large scale with many berths and quays of big sizes. The port has high annual throughput and a variety of cargoes handled. It is one of the big hubs for all import and export activities of the country of Algeria in commodities: hydrocarbons, agricultural products, machinery, and consumer goods. For hydrocarbons, it is essential for the exportation of the oil and gas resources of the country. The port's capacity has been rising yearly to keep pace with the heightened demands of the country's economy.

Routes and Business

Algiers Port has very wide shipping routes linking it to major ports throughout the world. It has regular liner services to Europe, mainly to French, Italian, and Spanish ports because of historical and economic relationships. These routes provide business connections between Algeria and the European Union regarding goods trade. In addition to this, it connects to other destinations within the Mediterranean region, thereby connecting trade with all neighboring countries like Tunisia, Libya, and Morocco. The port manages a variety of business activities: general cargo handling, shipping of containers, and bulk cargo shipment.

Administration and Operations

The port is managed by the relevant Algerian port authorities, which are responsible for ensuring smooth operations, safety, and compliance with international regulations. They oversee activities such as berth allocation, vessel traffic management, and cargo handling procedures. The port has modern operational facilities and a professional workforce to ensure efficient handling of vessels and cargo.

Port Facilities

The port is equipped with a variety of facilities. There are well - maintained container terminals with modern gantry cranes for efficient container handling. Bulk cargo terminals are equipped with specialized loading and unloading equipment for handling substances like grains and minerals. Storage facilities, including warehouses and open storage areas, are available to accommodate different types of cargo. The port also has facilities for ship repair and maintenance, offering services to vessels calling at the port.

Channels and Direct Navigation

The port has well-dredged navigable channels to accommodate vessels of different sizes. These channels are regularly maintained to ensure safe passage. Algiers Port has direct shipping routes to many major international ports, which greatly facilitates the import and export of goods, reducing transit times and costs.

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

Ocean current measurement in Algiers Port is of great significance for port operation management.

Safe Vessel Navigation

Accurate knowledge of ocean currents is crucial for the safe navigation of vessels. Currents can affect a ship's speed, direction, and maneuverability. In Algiers Port, where a large number of vessels enter and exit daily, understanding the current patterns helps pilots and ship captains to plan their routes more effectively. For example, during strong ebb or flood currents, appropriate adjustments need to be made to the ship's course and speed to avoid collisions with other vessels, port structures, or to ensure smooth berthing and unberthing operations.

Cargo Handling Efficiency

In addition to navigation, currents may also influence cargo handling. In case adverse currents exist, this may either pose a challenge to aligning the ship at berth or affect cargo handling equipment. By taking the measurements of the currents, the port operator is able to time cargo handling in periods with relatively stable or favorable current conditions; this has resulted in higher overall efficiency in port operations.

Coastal Erosion and Sedimentation

Ocean currents play a role in coastal erosion and sedimentation processes. In Algiers Port, monitoring currents helps in understanding how sediment is transported along the coast. This information is essential for port authorities to plan for long - term coastal protection measures and to maintain the stability of the port's infrastructure. For instance, if strong currents are causing excessive sedimentation in the port channels, appropriate dredging operations can be carried out in a timely manner.

ADCP (Acoustic Doppler Current Profiler) has emerged as a more advanced and convenient method for measuring ocean currents in Algiers Port compared to traditional methods, which often involve time - consuming and less accurate techniques.

3. How do ADCPs using the Doppler principle work?

ADCP Measurement Principle

ADCPs operate based on the Doppler principle. When an acoustic wave is emitted from the ADCP current profiler transducer and encounters moving particles (such as suspended sediments or plankton) in the water, the frequency of the reflected wave will change. This change in frequency, known as the Doppler shift, is proportional to the velocity of the particles along the direction of the acoustic beam.

ADCPs typically have multiple acoustic beams (usually 3 or 4) that are angled relative to the vertical. By measuring the Doppler shifts of the acoustic waves reflected from different depths along these beams, the ADCP current meter can calculate the three - dimensional velocity components of the water flow at various depth intervals. The vertical velocity can be determined from the vertical beam, and the horizontal velocities are calculated from the angled beams using trigonometric relationships.

ADCP in Port Current Measurement-Specific Methods

Ship-borne ADCP

A ship-borne ADCP is installed on a moving vessel. As the ship sails through the water, the ADCP flow meter continuously measures the water currents at different depths along the ship's track. This method is useful for obtaining a broad - scale view of the current patterns in the port area. For example, it can be used to map out the general flow direction and speed of currents across different sections of the port, helping to identify areas with strong or variable currents.

Fixed ADCP

Fixed ADCPs are installed at specific locations in the port, such as on the seabed or on port structures. These devices provide continuous and long - term measurements of the currents at a particular point. Fixed ADCPs are valuable for monitoring the long - term trends of current patterns, such as seasonal variations in current speed and direction. They can also be used to obtain data for calibration and validation of ship-borne ADCP measurements.

4. What’s needed for high-quality measurement of Algiers Port currents?

Equipment Requirements

Material Reliability

For high-quality current measurements in Algiers Port, the material of the ADCP is of great importance. The casing of the ADCP should be made of a reliable material that can withstand the harsh marine environment. Titanium alloy is an excellent choice for the casing. Titanium alloy has high corrosion resistance, which is crucial as it can prevent the ADCP from being corroded by seawater over long-term use. It can also resist the erosion caused by the flow of water and suspended particles in the port.

Size, Weight, and Power Consumption

The ADCP meter should be small in size and light in weight. A compact size makes it easier to install, whether it is on a ship or at a fixed location in the port. A lightweight design also reduces the impact on the installation platform. In addition, low power consumption is necessary, especially for fixed-installed ADCPs that may rely on battery power or a limited power supply. This ensures long-term and continuous operation without frequent power replacements or recharges.

Cost-effectiveness

For large-scale measurements in the port, the cost of the ADCP is a significant factor. A cost - effective ADCP allows for more widespread deployment, enabling comprehensive monitoring of the port's current conditions. Lower - cost devices also make it more feasible for port authorities with limited budgets to carry out regular current measurements.

5. How to Choose the Right Equipment for Current Measurement?

Selection Based on Usage

Ship-borne ADCP

If the goal is to obtain a broad - scale overview of the current patterns in the port area during vessel transits, a ship - borne ADCP is the appropriate choice. It can quickly cover large areas of the port, providing valuable data for general current mapping.

Bottom-mounted (Sit-on-the-bottom) ADCP

When long - term and continuous measurements at a specific location are required, such as for monitoring the current conditions near a particular berth or in a channel, a bottom - mounted ADCP is more suitable. It can provide stable and long - term data for detailed analysis of local current variations.

Buoy-mounted ADCP

For monitoring the surface-layer currents and for more flexible deployment in different parts of the port, a buoy-mounted ADCP can be used. It can be easily moved to different locations as needed and is useful for obtaining data on the upper - layer current dynamics.

Selection Based on Frequency

The choice of ADCP profiler frequency depends on the water depth. For water depths within 70m, an ADCP with a frequency of 600kHz is suitable. The higher frequency provides better resolution in shallow waters, allowing for more accurate measurement of the current profiles. For water depths up to 110m, a 300kHz ADCP is a better option. It offers a good balance between measurement range and resolution. When measuring in deeper waters, such as up to 1000m, a 75kHz ADCP is recommended. The lower frequency can penetrate deeper into the water column, although it may have a slightly lower resolution compared to higher - frequency ADCPs.

There are several well-known ADCP brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, for those looking for cost-effective and high-quality options, the Chinese brand China Sonar PandaADCP is highly recommended. It is made of all-titanium alloy materials, ensuring excellent corrosion resistance and durability. With its incredible cost-performance ratio, it provides a great solution for ocean current measurement in Algiers Port. You can find more information on their website: (https://china-sonar.com/).

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