ADCP's Application to Ocean Current Measurement in Dar es Salaam Port

1. Where is Dar es Salaam Port?

Dar es Salaam Port is located on the eastern coast of Tanzania, facing the Indian Ocean.

Port Scale and Throughput: It is one of the largest and busiest ports in East Africa. The port has a significant number of berths and can handle a wide variety of cargoes. In recent years, its annual throughput has been increasing steadily, handling millions of tons of cargo annually, including containers, bulk cargo such as coal and grain, and liquid cargo like oil.

Routes and Services: It has extensive shipping routes connecting to various parts of the world. There are regular liner services to Asia, Europe, and the Americas. The port offers a full range of services including cargo handling, storage, and transshipment. It also provides services for cruise ships, contributing to the development of the local tourism industry.

Port Management and Operation: The port is managed by the Tanzania Ports Authority. It has a professional team responsible for the daily operation and management, ensuring the efficient operation of the port and the safety of ships and cargo.

Port Infrastructures: The port uses the most updated cargo handling tools such as crane, forklifts and conveyor belts to ensure effective services. Also there are huge and big storerooms and big storage yards and for the difference type of stores. Furthermore the advanced navigation as well as other communication infrastructures have been offered for safe ship entry and release.

Waterways and Direct Navigation: The port has deep and wide waterways that can accommodate large ships. It has good direct navigation conditions, and ships can directly enter and exit the port without significant obstacles.

2. Why should we measure the ocean currents in the Dar es Salaam Port?

Measuring ocean currents in Dar es Salaam Port is of great significance for the following reasons:

Shipping Safety: Ocean currents affect the navigation of ships. If the current situation is accurately grasped, the captains can make more reasonable navigation plans to avoid the influence of strong currents and reduce the possibility of ship collisions and stranding.

Cargo Handling Efficiency: The flow of ocean currents affects the berthing and unberthing of ships. Appropriate current conditions can help ships berth and unload more smoothly, improving cargo handling efficiency.

Port Construction and Maintenance: Knowledge of ocean currents is crucial for the design and construction of port facilities. It helps to determine the reasonable layout of breakwaters, wharves and other facilities to resist the erosion of ocean currents. In addition, it is also helpful for the maintenance of port facilities to understand the law of current erosion.

Environmental Protection: Ocean currents play an important role in the distribution of marine organisms and the diffusion of pollutants. Measuring ocean currents can help monitor the spread of pollutants and protect the marine ecological environment of the port area.

ADCP flow meter is a more advanced and convenient measurement method at present, which can provide more accurate and detailed current data.

3. How do ADCPs using the Doppler principle work?

ADCP (Acoustic Doppler Current Profiler) works based on the Doppler principle.

Measurement Principle: ADCP current profiler emits acoustic signals into the water. When these acoustic signals encounter moving water particles, the frequency of the reflected signals will change due to the Doppler effect. By measuring this frequency change, the velocity of the water particles can be calculated. ADCP usually has multiple acoustic transducers to measure the velocity components in different directions, so as to obtain the three-dimensional velocity vector of the water flow.

Specific Methods in Port Current Measurement

• Shipborne ADCP: It is installed on the bottom of the ship. When the ship is sailing, the ADCP can continuously measure the current velocity at different depths along the ship's track. This method is suitable for measuring the current distribution in a large area of the port.
• Fixed ADCP: It is fixed on the seabed or on port facilities. It can continuously monitor the current changes at a specific location, providing long-term and stable current data for the port.

4. What’s needed for high-quality measurement of Dar es Salaam Port currents?

For high-quality measurement of currents in Dar es Salaam Port, the following requirements should be met:

• Material Reliability: The equipment used for measurement needs to have high material reliability to withstand the harsh marine environment, including seawater corrosion and mechanical stress.
• Small Size and Light Weight: It is convenient to install and operate. Smaller and lighter equipment can be more easily installed on different platforms such as ships and buoys.
• Low Power Consumption: This is especially important for equipment that needs to work independently for a long time, such as fixed ADCP and buoyant ADCP. Low power consumption can ensure the long-term stable operation of the equipment.
• Low Cost: It is conducive to large-scale measurement and application. Reducing costs can make more ports afford to use advanced measurement equipment.

For ADCP current meter, using titanium alloy material for the casing is a good choice. Titanium alloy has many advantages, such as high strength, good corrosion resistance, and light weight. It can effectively protect the internal components of ADCP and prolong the service life of the equipment in the marine environment.

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

Determined by Usage

• Shipborne ADCP: It is suitable for measuring currents during ship navigation, suitable for quickly obtaining current data in a large area.
• Bottom-mounted ADCP: It is mainly used for long-term monitoring of current changes at a specific location on the seabed, providing stable and continuous data.
• Buoyant ADCP: It can float on the water surface and move with the current, which is suitable for monitoring the surface current and the overall current trend.

Determined by Frequency

• 600kHz: It is suitable for water depths within 70m, which is suitable for some shallow water areas in the port.
• 300kHz: It is suitable for water depths of about 110m, which can meet the needs of general port water depth measurement.
• 75kHz: It is suitable for water depths of 1000m, which is suitable for measuring deep sea currents outside the port.

There are many well-known ADCP meter brands in the world, such as Teledyne RDI, Nortek, and Sontek. In addition, there is a cost-effective Chinese ADCP brand, China Sonar PandaADCP. It is made of all-titanium alloy material and has 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.