ADCP's Application to Ocean Current Measurement in Beira Port

1. Where is Beira port?

Beira Port is located on the northern bank of the Pungwe River estuary in Sofala Province, Mozambique. It is one of the most important ports in Mozambique.

Scale and Throughput

Beira Port is of a relatively large scale: it is an important transportation node for the inland countries in southern Africa and transports a lot. Its yearly throughput includes minerals, agricultural products, and manufactured goods. The number of berths is more than a few; some of them can allow vessels of large sizes, which contributes to its large volume of import and export.

Routes and Business

The port has an extensive shipping route system, linking it with most of the major international ports in the world. It is a vital link in the trade of Mozambique and its neighbors, especially Zimbabwe, Malawi, and Zambia. Major businesses undertaken by the port include general cargo handling, container handling, and bulk cargo handling. For example, it exports a large quantity of coal mined from the nearby mines and imports consumer goods and industrial equipment for both local and regional markets.

Port Management and Operations

The port is run by a professional management team known as the Port Authority, responsible for the day-to-day running of activities that relate to the port. This will involve vessel berthing, cargo handling, and port security. Management is focused on high-quality services with the aim of attracting more shipping lines and cargo. In terms of operation, the port has a well-organized loading and unloading system, which includes modern cranes and other handling equipment for efficient performance.

Port Facilities

The Beira Port has various facilities. There are warehouses for storing different goods, such as dry goods and refrigerated products. The container yards have stacking areas and handling equipment to handle the containers in the port efficiently. Besides all the above, fueling is available in order to supply vessels with fuel during their stop-overs.

Waterways and Direct Navigation

It has a well-maintained channel through which vessels can enter and leave safely. Besides, the dredging of the channel depth was made to enable big draft vessels to access the port. It connects to direct shipping routes that connect major ports in Europe, Asia, and other parts of Africa, which helps in easier international trade.

2. Why should we measure the ocean currents in the Beira port?

The measurement of ocean currents in Beira Port is very important for several aspects of port operation and management.

Safety of Vessel Navigation

Knowledge of ocean currents with good accuracy is a vital component for safe navigation of vessels. Currents can affect the speed and direction a ship can travel. In Beira Port, where there is a considerable volume of vessel traffic, the current patterns will help the captains to plan their routes more effectively. For example, through strong ebb or flood currents, vessels may have to change course and speed to avoid collision with other vessels, port structures, or to remain within the channel. This reduces the occurrence of maritime accidents, hence protecting the vessels and the valuable cargo they carry.

Cargo Handling Efficiency

Currents can impact the process of cargo handling. In case such a current is too strong, cranes cannot position the cargo on or off the vessels with high accuracy. By measuring ocean currents, port operators are able to schedule cargo handling operations during relatively calm currents. It increases the efficiency of the whole process of loading and unloading, cutting down the time which vessels spend in the port and increasing the overall productivity of the port.

Coastal Erosion and Sedimentation

The information on the currents, on the other hand, is valuable in understanding the physical processes of coastal erosion and sedimentation. In the Beira Port area, for example, bed sediments shifted around by currents could impact channel depth and the stability of the port structure. With proper current monitoring, a given port authority can resort to effective and timely application of, say, beach nourishment or construction of breakwaters to prevent possible impacts due to coastal erosion and sedimentation.

While these traditional methods are employed, the ADCP method has, in more recent times, developed as a more advanced and convenient way of measuring ocean currents in Beira Port. Real-time and high-resolution data can be given which is then indispensable in the above-mentioned aspects of port management.

3. How do ADCPs using the Doppler principle work?

ADCP Measurement Principle

ADCPs work on the principle of the Doppler principle. When an acoustic wave is emitted from the ADCP transducer and contacts moving particles in the water-such as suspended sediment or plankton-the frequency of the reflected wave changes. It is this change in frequency, or Doppler shift, that is directly related to the velocity of the moving particles relative to the ADCP. By measuring the Doppler shift of the reflected acoustic waves, the ADCP is able to compute the velocity of the water at various depths.

ADCP in Port Current Measurement - Methods Specific

Ship - borne ADCP

A ship-borne ADCP is mounted on the hull of a vessel. While the vessel cruises in the water, the ADCP measures the ocean currents along the track the ship has travelled. It sends acoustic signals down into the water column below. Reflections from the moving water particles produce a Doppler shift in these signals, and the ADCP processes these changes to obtain velocity profiles of currents at different depths. This instrument is helpful to obtain an overall view of large-scale current patterns in the port area. For example, it can be used to chart the general distribution of currents in the main fairways and in the vicinity of the port entrances.

Fixed ADCP

Fixed ADCPs are seabed-mounted or structure-mounted in the port. Fixed ADCPs have fixed positions, and they keep continuous measurements at one location only. These instruments are occasionally used for monitoring long-term data on current velocities and directions at key locations around the port-for example, in the vicinity of the berths or where strong currents might affect erosion or deposition. The bottom-moored ADCPs are able to capture high-frequency oscillations that will be relevant when understanding small-scale ocean current turbulence.

4. What is required for carrying out quality measurements of the currents in the Beira Port?

Equipment Material Reliability The material of the ADCP will be an important factor in making high-quality measurements of currents in Beira Port. Due to the harsh conditions found in the marine environment, the equipment will need to be constructed of many generally reliable varieties of materials. In Beira Port, the main characteristics of the marine environment will include saltwater corrosion, strong currents, and impacts from debris potentially.

Size, Weight, and Power Consumption

The ADCP should be compact in size and light in weight. A smaller and lighter device is easier to install, either a ship-borne or fixed ADCP. Besides, it minimizes the impact on the host platform-for example, on a ship or seabed structure. Moreover, the ADCP should have low power consumption. That's all the more critical in fixed ADCPs depending on battery-powered or solar-powered systems, requiring low power consumption to keep devices running over long intervals without frequent battery replacements or complicated arrangements for a power supply.

Cost-effectiveness

Another important consideration, particularly when measurements over an extended area in the port, is the cost of the ADCP. It becomes viable to deploy multiple units with the view of gaining an overall understanding of the current patterns when the ADCP is rather cost-effective.

Titanium Alloy Casing

The casing of the ADCP is preferably made of titanium alloy. Titanium alloy has several advantages. It has excellent corrosion resistance, which is quite important for a saltwater environment such as Beira Port. The internal components of the ADCP will not get corroded to extend the life of the instrument. Compared to some other kinds of corrosion-resistant materials, Titanium alloy is rather light and has met the requirements of the lightweight ADCP. Besides, it has high strength and thus protects the internal components from mechanical impacts.

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

Based on Usage

Ship - borne ADCP

As mentioned previously, ship-borne ADCPs have the ability to obtain current data over vast coverage while the vessel is on its journeys. They will be perfect for determining the general pattern of currents in and around the port. For example, if a vessel travels across the major shipping lanes, or if it explores new areas for the expansion of the port, it will be of much use.

Bottom-mounted (Sit-on-the-bottom) ADCP Bottom-mounted ADCPs are designed for long - term placement on the seabed. They are very good for continuous current monitoring over a prolonged period at one location. In Beira Port, they can be used to monitor currents near the berths where accurate knowledge of the current is crucial for safe berthing and unberthing of vessels.

Buoy - mounted ADCP

Buoy-mounted ADCPs are attached to floating buoys. These are good for measuring the surface-layer currents and can move with the flow of water. An ADCP will be able to provide data with respect to surface-level current patterns, which is very important for understanding the overall circulation in the port area at least in areas where surface currents may be substantial enough to influence vessel operations.

Based on Frequency

The choice of ADCP frequency is dictated by water depth. For water within 70m, a 600kHz frequency ADCP will be suitable, which offers high-resolution data in relatively shallow waters. Where the water is up to 110m, a 300kHz ADCP will be a better choice because it can give deeper penetration within the water column with a reasonable resolution. If the depth is approximately 1000m, for instance, then a 75kHz ADCP is preferred since it has a wider range and can cover bigger current measurements.

Some of the well-known brands in ADCPs are Teledyne RDI, Nortek, and Sontek. However, for anyone looking for more budget-friendly but good-quality ones, one should really try the Chinese brand called China Sonar ​PandaADCP. It is made of all - titanium alloy material, which offers excellent durability and performance. With its incredible cost - performance ratio, it is an ideal choice for ocean current measurement in Beira Port. You can visit their website at [​https://china-sonar.com]or more information.

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