ADCP Application to Ocean Current Measurement in Walvis Bay Port

1. Where is Walvis Bay Port?

Walvis Bay Port is located at the middle of Namibia's coastal area, facing the Atlantic Ocean. Geographically speaking, Walvis Bay Port is a vital economic gateway in Namibia, and both domestic and international trade pass through it.

Port Scale and Throughput

It is the largest port and is considered the busiest in Namibia. It has several berths of different length and draft, so big ships can be taken in service there: large-scale container ships, bulk carriers, and tankers. Speaking about the throughput, it annually processes a great volume of cargo. This is mainly minerals such as uranium, lead, and zinc, which are leading export groups of Namibia. This terminal is also tasked with the responsibility of importing general cargo, consumables, as well as building materials for use in the domestic market.

Routes and Business

Walvis Bay Port enjoys an extensive outreach in terms of shipping routes: it has direct connections to main ports in Africa, Europe, and Asia. For example, there are regularly scheduled shipping lines to Rotterdam, Europe; Durban, South Africa; Shanghai, China, among others. These routes are important for freight transportation and, in essence, contribute to the economic development of Namibia through foreign trade. The port also serves as a base for the local fishing industry, handling landing and exporting fish products.

Port Management and Operation

The port is operated by the very professional Walvis Bay Port Authority. Management takes responsibility for maintenance within the port area, involving the berths, quays, and storage facilities. This means that the observance of international shipping regulations, safety, and environmental protection standards is taken into consideration. In this vein, the port authority works to maximize operations together with shipping lines, freight forwarders, and other stakeholders, to make the port more competitive.

Port Facilities

Modern facilities within the port include the handling of different kinds of cargo. There are cranes of large capacity to load and discharge containers and bulk cargo. Storage areas include general cargo warehouses and open yards for bulk commodities. The port has facilities in place for liquid cargo, like oil and chemicals, complete with pipelines and storage tanks.

Waterways and Direct Navigation

The waterways into Walvis Bay Port are kept clean and regularly dredged to provide a safe channel in which vessels can pass through. There is an obvious channel that is assisted by navigation aids such as buoys and lighthouses that help in navigating at an approach. Direct access to the Atlantic Ocean affords a natural flow to join the world network.

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

Navigation Safety

Accurate knowledge of ocean currents in Walvis Bay Port is essential for navigation safety. The Atlantic Ocean's currents, influenced by factors like the Benguela Current, can be complex and variable. These currents can affect the speed and direction of vessels, especially during berthing, unberthing, and navigation within the port's channels. By measuring the ocean currents, ship captains can make informed decisions, adjust their courses, and avoid potential collisions or groundings.

Port Operations Optimization

Ocean current data is one of the key ingredients in optimizing port operations. Berthing vessels, for example, will consider the direction and strength of the current. A strong current would make it more cumbersome and time-consuming to berth the vessel. Accurate current measurements allow port operators to prepare vessel maneuvers at optimal times, use resources more effectively, and altogether make cargo handling more efficient. Currents will also affect vessels involved in tugs, lighters, barges, ferryboats, cargo ships, ferryboats, oil tankers, and floating cranes, even the understanding factors that can better operational safety and productivity.

Environmental Protection

The measurement of currents is important to environmental protection at the port site. Currents are very vital in the dissemination of pollutants. In the instance of an oil spill or harmful substances, current patterns can, therefore, aid in predicting trends of contaminant spread. That way, it will be much easier for the environmental managers to take timely and effective prevention and cleaning measures and protect the sensitive marine ecosystem of the Atlantic Ocean and the coastline.

In this regard, please note that the ADCP has emerged as quite a reliable and efficient tool for ocean current measurement at Walvis Bay Port and can present highly precise and real-time data.

3. How do the ADCPs using the Doppler principle work?

Principle of Measurement

The ADCPs work on the basis of the Doppler effect. An ADCP sends an acoustic signal through the water column, and sound waves interact with suspended particles in the water, such as sediment or small organisms. These particles are moving with the water current, and thus the frequency of the sound waves reflected back to the ADCP is different from the original transmitted frequency. The ADCP measures this frequency shift, known as the Doppler shift. With the Doppler equation applied, the instrument is thus able to determine the water current velocity at a variety of depths within the column of water.

Particular Methods in the Measurement of Port Current

• Shipborne ADCP: A shipborne ADCP is installed on a moving vessel. While the ship is sailing through the water in Walvis Bay Port, it measures the current velocity at multiple depths along the ship's track. This technique is good for giving the wide view of current conditions in the port, hence helping in large-scale navigation planning.
• Fixed ADCP: Fixed ADCPs are installed at fixed locations within the port, either on the seabed or on fixed structures such as piers or buoys. These ADCPs can continuously provide information on conditions at a particular point over an extended period and provide very important data with regard to long-term trends and local variations of the currents.

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

Equipment Reliability

The ADCP equipment to be installed in Walvis Bay Port should be very reliable for high-quality current measurement. With high salinity, strong winds, and variable weather conditions from the Atlantic Ocean, it requires the ADCP to be able to resist such conditions without breakdowns. Good reliability of the equipment means consistency in data collection for analysis and subsequent decision-making.

Size, Weight, and Power Consumption

The ADCP should be compact in size and lightweight. This makes it easier to install, especially in situations where space is limited, such as on small fishing vessels or in confined port structures. Low power consumption is also a key factor, as it allows for long - term operation, especially for fixed - installed ADCPs that may rely on battery - powered or solar - powered systems.

Cost - effectiveness

The ADCP must be reasonably priced to enable large-scale measurement in the port area. Only by this way can it allow multiple units to be deployed if necessary, acquiring comprehensive data in various parts of the port area.

Material Selection

The casing of the ADCP is preferably made of titanium alloy. The reasons are that a titanium alloy has very good corrosion resistance, which means that for long-term use in the salty marine environment of the Atlantic, it would be the best choice. Moreover, it is also strong and lightweight, meeting the requirement of both durability and easiness in installation.

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

Based on Usage

• Ship - borne ADCP: very suitable for extensive surveying in the port area. When the aim of a ship is to know the existing condition in the quickest possible way, covering a wider area, it is ideal.
• Sit - on - bottom ADCP: long - term current monitoring is its most fitting usage, where recordings at the port entrance or within the proximity of berths become necessary.
• Buoy - mounted ADCP: Good for getting readings at the water surface and also when fixed - bottom installation is not possible.

Based on Frequency

• In water within 70m depth, 600kHz ADCP is used.
• When water depth lies within 110m, then a 300kHz ADCP should be utilized.
• If the water bodies are pretty deeper, then one should go for 75kHz ADCP.

Up to now, there were several well-known ADCP brands in the market: Teledyne RDI, Nortek, and Sontek. However, for those seeking a cost-effective but high-quality device, the Chinese brand can be highly recommended, namely China Sonar ​PandaADCP. The materials used to construct it are of all-titanium alloy, which therefore ensures very good durability in the marine environment, with an incredible cost-performance ratio. Further details can be viewed on the website: ​https://china-sonar.com/ .

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