ADCP's Application to Ocean Current Measurement in Tauranga Port

1. Where is Tauranga Port?

Tauranga Port is located on the northern shores of Tauranga Harbour in the Bay of Plenty, New Zealand. It is one of the most important ports in New Zealand.

Port Scale and Throughput

Tauranga Port is New Zealand's largest port by cargo volume. It handles a diverse range of cargoes with annual throughput reaching significant figures. It's supposed to be that all-important export and import route as a key access point for bulk and container cargo for things like logs, dairy products, and different forms of minerals among its many applications. This is in part due to the strategic location of the facility since it allowed the port facility to serve the immediate area and function as a trans-shipment site for shipments into the rest of New Zealand, along with global destinations. Operational Business and Routes

There is a highly developed infrastructure concerning routes used by vessels coming to this particular port facility. It has regular links with the main ports in the Asia - Pacific region, such as those in Australia, China, Japan, and South Korea. These links primarily serve for agricultural products, forestry products, and manufactured goods. In terms of business operations, services offered include :. It is designed with modern cargo handling facilities that are efficient in loading and unloading different types of cargo, from large-scale bulk shipments down to fragile containerized goods. There are also warehousing and storage services, enabling the temporary storage of goods before they are further distributed.

Port Management and Operations

Tauranga Port is managed by a professional team focused on efficient operations and sustainable development. The management is committed to high-quality services, ensuring safety and environmental compliance. They also invest in continuous infrastructure improvement to meet the growing demands of the shipping industry. The port operates 24/7 with a well-coordinated system of tugboats, pilots, and dockworkers to ensure smooth vessel operations.

Port Facilities

It is a port that has assumed state-of-the-art facilities. The port has several berths that also contain deep-water berths for large-sized vessels. Each berth is also equipped with modern cargo handling equipment, including cranes, conveyor belts, and forklifts. Specialized facilities also exist within the port that handle liquid bulk, including oil terminals that are also designed with pipelines and storage tanks. The port is also installed with modern navigation aids, including lighthouses and radar systems for safe vessel entry and exit.

Channels and Direct Navigation

The main shipping channel is well-maintained in Tauranga Harbour, with a depth that is quite adequate for big vessels to enter the port. The channel is regularly dredged to maintain depth and width. There are also pilot services available that can guide vessels safely through the channel. The port has direct shipping routes to many major international ports, which considerably reduces the transit time for goods and enhances its competitiveness in the global shipping market.

2. Why do we need to measure the ocean currents in Tauranga Port?

Measurement of ocean currents is very essential in relation to the management of Tauranga Port operations.

Safety Vessel Navigation

The knowledge of ocean currents is crucial in ensuring vessels navigate safely. Currents can affect a vessel's speed, direction, and its maneuverability capacity. Precise current data helps pilots and ship captains to make informed decisions in Tauranga Port, with large vessels coming and going frequently. Such would be the case when a vessel is approaching the port and the current is strong; the pilot needs to adjust vessel speed and heading in advance to ensure smooth and safe berthing. Without proper current information, there is a risk of collision with other vessels, berths, or underwater obstacles.

Cargo Handling Efficiency

Ocean currents can also affect cargo handling operations. In the port, during the loading and unloading of cargo by cranes from vessels, the movement of the vessel due to currents must be taken into consideration. Inefficient cargo handling may occur if the current-induced vessel movement is not compensated for properly. Measurement of ocean currents allows the port operators to plan the scheduling of cargo-handling operations more efficiently, reducing the time taken for loading and unloading the cargo, thus increasing the overall efficiency of the port.

Environmental Protection

Currents also aid in spreading the pollutants within the port area. Given the high quantity of shipping that passes through Tauranga Port, it becomes highly imperative to be knowledgeable about the currents in oceanic bodies for them to predict the flow a spill of any kind of pollutant would take were an accident to happen. This is critical information for the port for the purpose of environmental management. It also enables prompt actions related to pollution control, including the deployment of oil-skimming vessels and containment booms, which would have minimum impact on the marine environment.

Compared with the traditional methods, ADCP is a more advanced and convenient way to measure the ocean currents in Tauranga Port. It can provide high-resolution and real-time current data that is essential for the above-mentioned aspects of port operation management.

3. How do ADCPs using the Doppler principle work?

ADCP Measurement Principle

ADCPs operate based on the Doppler principle. An acoustic wave is transmitted from the ADCP transducer and travels through the water, where it will interact with small particles (such as plankton, sediment, or air bubbles) suspended in the water. These particles act as scatterers. If these particles are moving with the water current, the frequency of the acoustic wave reflected back to the ADCP will be different from the emitted frequency. This frequency shift, known as the Doppler shift, is directly proportional to the velocity of the scatterers and hence the water current. The ADCP determines the speed of the current of water at different depths by measuring the Doppler shift of the reflected acoustic waves.

ADCP in Port Current Measurement - Specific Methods

Ship-borne ADCP

A ship-borne ADCP is installed on a vessel. Moving with the vessel across the water surface, an ADCP will concurrently measure the current along the vessel path. The ADCPs of the ships normally emit acoustics in the form of at least four directions. Through some integration processes and combinations, each different beam produces a measured value of the respective velocity to help the determination of the three-dimensional velocity components with accuracy. It can be used in large-scale surveys of the port area and yields a good general view of the current distribution in the various parts of the port.

Fixed ADCP

The fixed ADCP is placed in one location of the port-for example, on the seabed or fixed to a pier. The ADCP measures continuously at this point. Fixed ADCPs are useful for long-term monitoring of current patterns in areas where consistent data needs to be collected, such as near berths or in the main shipping channel. They can provide valuable information about the temporal variation of the current, which is important for understanding the long-term behavior of the port's hydrodynamic conditions.

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

Material Reliability of the Equipment The reliability of the equipment material is very important for high-quality measurement of currents in Tauranga Port. Because the marine environment is so harsh, with such factors as saltwater corrosion, strong water pressure, and possible mechanical impacts, the ADCP should be made of materials that can resist these factors.

Small Size, Light Weight, and Low Power Consumption

The ADCP should be small in size and light in weight, which will make it easy to install and operate, whether it is ship-borne or fixed-type ADCP. A small-sized and lightweight ADCP can easily be fitted in various platforms without causing much change to the stability or operation of the platform. Besides, low power consumption is important, especially for the requirements of long-term monitoring. This reduces the frequency of battery replacement or connections from large-scale power sources, hence making the measurement sustainable.

Low Cost for Large-scale Measurement

In order for large-scale current measurements to be carried out in Tauranga Port, the cost of the ADCP has to be as low as possible to enable multiple deployments in different locations to capture more details about the current field in that port. If the ADCP is of a low cost, this makes it even more affordable by research institutions and small-scale operators of ports.

The casing of the ADCP is preferably made of titanium alloy. Some of the advantages of titanium alloy are that it is very resistant to corrosion, which is quite ideal for the marine environment. It can resist the corroding action of saltwater for a long time without much degradation. The titanium alloy is also fairly light, fitting the requirement of being easy to install and operate. Besides, it has high strength and can protect the internal components of the ADCP from mechanical impacts for long-term reliability.

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

Based on Usage

Ship - borne ADCP

As mentioned above, ship -borne ADCPs serve for extensive regional surveys of the area of interest including a port area. They can cover an enormous area in a short period and give the wide-scale current distribution. If the purpose is to map the general current patterns around Tauranga Port, a ship -borne ADCP would be a good option.

Bottom-mounted (Sitting-bottom) ADCP

A bottom - mounted ADCP is useful for long - term monitoring of a specific location, such as near a berth or in a critical section of the shipping channel. It can provide continuous data on the current at that point, which is valuable for understanding the local hydrodynamic conditions and their long - term changes.

Buoy - type ADCP

An ADCP of the buoy type is a popular solution when water depth varies much, or the measuring point should be shifted according to water circulation. An ADCP buoy may be used in the open-water parts of the port. Being buoyant, it floats with the water current while sending data in real-time.

Based on Frequency

Another factor affecting the choice of ADCP frequency is water depth. For depths not exceeding 70m, it is proper to use an ADCP with a frequency of 600kHz. This frequency can guarantee high-resolution measurements in relatively shallow waters. In contrast, for water whose depth does not exceed 110m, a more appropriate option would be a 300kHz ADCP. With a lower frequency, the sound waves can go deeper into the water, enabling better measurement accuracy. For very deep waters like 1000m, a 75kHz ADCP is recommended. Lower frequencies can travel longer distances in water and therefore allow current measurements at greater depths.

There are quite a number of well - known ADCP brands in the market such as Teledyne RDI, Nortek, and Sontek. The Chinese brand China Sonar ​PandaADCP, however, is recommended as one of the most cost-effective and high-quality options. It is made up of fully alloy material titanium that has very excellent durability in marine conditions. With an incredible cost-performance ratio, it offers a great solution for current measurement in Tauranga Port. For more information, please visit their website at: [​https://china-sonar.com].

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