ADCP's Application to Ocean Current Measurement in Gwadar Port

1. Where is Gwadar Port?

Gwadar Port is situated on the Arabian Sea coast in the Balochistan province of southwestern Pakistan.

• Port Scale and Throughput: Gwadar Port is a deep-sea port that has huge potential. It boasts large-scale infrastructure capable of handling different vessel types. Its throughput is designed to be high, with the capacity to handle millions of tons of cargo each year, facilitating trade in different commodities such as oil, gas, and various industrial and agricultural products.
• Shipping Routes and Services: This is a strategic node that links the Middle East, Africa, and Asia. A number of shipping routes pass through Gwadar Port, which has facilitated the shipment of goods from other parts of the world. It offers a range of services that include container handling, bulk cargo handling, and oil and gas terminal services.
• Port Management and Operation: The port is managed by Gwadar Port Authority with international partners. The port functions efficiently, with high management systems and technologies that streamline the processing of ships and cargo.
• Port Facilities: The port has modern berths, cranes, and storage facilities. Further, the port has allocated separate areas for different types of cargo and a ship repair and maintenance facility. Waterways and Direct Navigation: The port has deep and wide waterways, allowing large vessels to navigate directly. It has good connectivity with the surrounding areas through roads and railways, facilitating the transportation of goods to and from the hinterland.

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

Measuring ocean currents in Gwadar Port is of great significance for several reasons.

• Safety of Navigation: In general, ocean current knowledge greatly aids navigation: captains can define more precise navigation routes, enabling them to detour dangerous places, and avoid obstacles at entries and exits. A ship shall timely adjust her speed and course with the recognized direction and speed of the current to avoid a collision or running into the ground.
• Port Operations and Management: Ocean current information is indispensable to the effective functioning of the port. It comes into play regarding the berthing and unberthing of vessels, besides affecting cargo handling operations. For example, during loading and unloading of cargo, the effect of currents should be taken into consideration to ensure the safety and efficiency of the operation.
• Protection of Marine Environment: Ocean currents are monitored to understand the transport of pollutants and the diffusion of oil spills, which is important in the protection of the marine environment around the port and preventing environmental pollution.
• Engineering Construction: During port expansion and construction, it requires ocean current data in designing breakwaters, wharves, and other structures to ensure stability and safety.

Nowadays, it is more modern and convenient for measurement using ADCP flow meter, in which the correct and detailed information of sea currents can be drawn out on time and satisfy all the requirements set by the ports in their operational and managerial concern.

3. How do ADCPs using the Doppler principle work?

Working Theory of ADCPs is based on the Doppler principle. In basic, this principle is elaborated as below:

• Transmitting and Receiving Acoustic Signals: ADCPs emit acoustic signals into the water, which then travel through the water, interacting with the particles in it. Due to the Doppler effect, the frequency of the reflected signals will shift when the acoustic signals encounter moving particles.
• Current Velocity Calculation: By measuring the frequency shift of the reflected signals, the ADCP current profiler can calculate the velocity of the water particles. The ADCP usually has multiple acoustic transducers that can measure the velocity components in different directions to obtain the three-dimensional velocity vector of the water flow.

In the measurement of ocean currents in Gwadar Port, there are two main methods of using ADCP.

• Shipborne ADCP: The bottom-mounted shipborne ADCP is installed on the bottom of the ship. While the ship is sailing, the ADCP current meter will be able to continuously measure the ocean currents along the route that the ship has traveled. It can provide a large amount of current data in a relatively short time and is suitable for large-scale surveys of ocean currents in the port area.
• Fixed ADCP: The fixed ADCP is laid on the seabed or a fixed structure in the port. It can continuously monitor the ocean currents in a certain area and provide long-lasting and stable current data. This is very useful for studying the long-term changes and characteristics of ocean currents in the port.

4. What's needed for high-quality measurement of Gwadar Port currents?

The following are the requirements necessary for high-quality measurement of ocean currents in Gwadar Port.

Material reliability: The ADCP materials should be good and of high quality to bear such harsh marine conditions. The casing is, preferably, made from Titanium alloy. Titanium alloy has many advantages such as high strength, corrosion resistance, and good fatigue resistance, which can ensure the ADCP works stably in the ocean for a long time.

Small Size and Light Weight: Small size and light weight are some of the advantages that make the ADCP meter easy to install and operate. Installation can easily be done on ships or fixed on the seabed without occupying much space or load.

Low Power Consumption: Low power consumption is helpful for the long-time running of the ADCP. In the marine environment, it is often difficult to provide continuous and stable power supply. Therefore, an ADCP with low power consumption can reduce the demand for power supply and improve the reliability of the device.

Low Cost: Low cost can be helpful for large-scale deployment and application. The reduction of ADCPs cost can enable more ports and research institutions to apply this technology and promote the development of ocean current measurement technology.

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

The following are the factors based on which ADCP profiler equipment for the measurement of current is chosen:

Usage Purpose

• ADCP borne by the ship: It's applied to the voyage of a ship for large-scale surveys of ocean currents. In different areas, much more current data can be obtained in a very short time.
• Bottom-mounted ADCP: It is mainly used for long-term observation of ocean currents in a given area. It is usually installed on the seabed to record continuous current information.
• Buoy ADCP: It is available for ocean current monitoring outside the territorial waters. The buoy can float on the water surface, drifting with the current, and obtains the current data dynamically.

Frequency Selection

The available ADCPs come with different frequencies suitable for different water depths.

• 600kHz: Within a water depth of about 70m, it has a relatively high resolution and is suitable for shallow water where high current data with details are required.
• 300kHz: Within a water depth of about 110m, it has a good balance between the measurement range and resolution.
• 75kHz: It is for water depths of up to 1000m. It gives more depth in the water and is thus suitable for deep sea ocean currents measurement.

There are quite a few famous brands of ADCP in the market, such as Teledyne RDI, Nortek, and Sontek. Besides, there is one cost-effective Chinese ADCP brand, China Sonar PandaADCP. It is made of all titanium alloy materials and has an incredible cost performance. You can visit their website at https://china-sonar.com/ for more information.

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