ADCP's Application to Ocean Current Measurement in London Port

1. Where is the location of London Port?

London Port is situated along the River Thames in London, England, and represents a complex of docks and terminals that have been vital to the history of trade and commerce in the city and the country as a whole.

Port Scale and Throughput

Large-scale, although of a changed nature. It now handles everything from containers, although not on the same scale as some of the larger dedicated container ports, to a good deal of bulk cargo such as construction materials, aggregates, and fuels. The throughput is impressive, given its importance for the local and regional economy. It acts as the main entry point for goods that are being delivered to the London area and also distributed further afield throughout the UK.

Routes and Business

The port is linked with different domestic and international shipping routes. It engages in a wide variety of businesses. Import businesses that are handled by the port include consumer goods, food products, and industrial supplies. The exports handled by the port include manufactured goods and waste materials to be recycled. It is also used for the transportation of vehicles and acts as a useful link in the supply of goods to industries and construction businesses of London.

Port Management and Operation

The port is managed through a combination of public and private entities. They are responsible for tasks such as berth allocation, ensuring the efficient movement of vessels, and overseeing the handling of cargo. Given the port's location in a major urban area, there is a particular emphasis on safety, security, and environmental management. Regular maintenance and upgrading of port facilities go on to make them satisfactory to meet the requirements of modern trade and fulfill regulative requirements.

Port Facilities

London Port has a range of facilities. There are various types of berths, which enable ships of different sizes, from small barges to medium-sized cargo vessels, to come in. It has cranes and other handling equipment for loading and unloading cargo. There are also storage facilities, such as warehouses and open-air yards, which hold merchandise in temporary storage. In addition, there are places for customs clearance and other administrative activities related to trade.

Channel and Direct Shipping

The River Thames provides a natural waterway to the port, and this channel is maintained to accommodate ships that enter the port and those that leave. It does have a link with all other UK and European ports with which transhipment of goods can take place. However, due to its being located upstream, access by larger-sized ships remains somewhat limited compared with deep-sea ports.

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

Navigation Safety

It is important to measure the currents in London Port for safety reasons of ships. The position of the port in the River Thames makes the ships susceptible to tidal currents and other movements in the water. For instance, when a vessel approaches a berth, it may be subjected to strong cross-current that could veer the vessel off-course, thereby increasing the possibility of collision with other vessels or port structures. Precise current measurements allow ship captains to make precise adjustments to the navigation to ensure a safe process for docking.

Operational Efficiency

Knowledge about ocean currents helps the overall operational efficiency of the port. Ships can make use of advantageous currents to minimize fuel consumption and stay out on the sea for shorter periods of time. For instance, with the help of a following current, ships can leave the port and reach their destinations faster and more economically. Understanding the current patterns also helps optimize the scheduling of vessel arrivals and departures, thereby ensuring that resources are put to the most efficient use.

Infrastructure Maintenance and Planning

Understanding of ocean currents is crucial for long-term maintenance and planning of port infrastructures. Currents may cause erosion in the long term and influence the stability of structures like piers and breakwaters. By monitoring the currents, port authorities can anticipate potential damage and take proactive measures such as timely maintenance and reinforcement. This knowledge also helps in designing future infrastructure projects to better withstand the forces exerted by the ocean currents.

Acoustic Doppler Current Profiler (ADCP) is an advanced and convenient approach in current measurements. It is a device that can provide high-resolution, real-time information on the currents' velocities and directions at various depths with large area coverage, hence giving quite detailed insight into the water flow conditions in the port, as compared to the traditional methods.

3. How do the Doppler Principle-based ADCPs work?

ADCPs work off the Doppler principle. They send acoustic signals into the water. These signals get scattered by moving particles in the water, such as suspended sediments or small organisms. When the acoustic waves get reflected back from these moving particles, due to the Doppler effect, the frequency of the reflected waves changes.

Shipborne ADCP

The ADCP current profiler is fitted on a vessel in London Port. The ADCP continuously sends acoustic signals down underneath and sideways when the ship sails in the port area. In this way, with the movement of the ship in different routes in the port, the ADCP profiler has measured the velocity of ocean currents at different depths and locations. This is a wide-area survey of the water currents during the operation of the ship.

Fixed ADCP

Fixed ADCPs are installed in fixed positions in the port at certain locations, like on underwater structures close to the entrance or along the quay walls. These are usually stationary and work continuously at a fixed position of the ocean currents. They give long-term, consistent data about the current conditions at that spot. This is very useful for understanding the regular patterns and variation of the currents in those key areas of the port.

4. What’s needed for high - quality measurement of London Port currents?

Material Reliability

The equipment used for current measurement, especially the casing of ADCP flow meter, should be made of reliable materials. Titanium alloy is a preferred material for the casing. Titanium alloy has excellent corrosion resistance, which is essential for withstanding the harsh marine environment. The corrosive effect of seawater can quickly damage equipment with less - resistant materials. With a high strength-to-weight ratio, the titanium alloy can give excellent protection to the ADCP meter internal components without making the equipment very heavy. This, of course makes installation at sea, either on a ship or from a fixed underwater location, much easier. Besides that, this is a good thermal stability, which is advantageous for an instrument in the variable temperature conditions of the marine environment.

Size, Weight, and Power Consumption

The size should be small and it should be lightweight. A compact and lightweight ADCP profiler is easier to install and less likely to interfere with the water flow during measurement. It also simplifies the installation process, whether it is on a ship or at a fixed position in the port. Small power consumption is also very important. Low power consumption in the case of fixed ADCPs ensures that for long-term monitoring, the equipment can operate continuously without frequent battery replacements or power supply problems.

Cost-Effectiveness

Cost is one important factor for large-scale measurement. If the equipment is too expensive, that will limit how many ADCPs can be deployed in the port. Cost-effectiveness allows higher coverage of current measurements to have a better understanding of ocean currents throughout the port area.

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

Based on Usage

Shipborne ADCP: Where the general purpose of carrying out current measurements during the movement of the ship within the port area is required, the shipborne ADCP will be quite suitable. It will be able to cover a reasonably big area by navigating the ship around the port and present an overall view of the current situation in different port areas. 

Bottom-mounted ADCP: The bottom-mounted ADCP would serve best for fixed-point monitoring of preselected locations in the port, near critical infrastructure, or places that possess special current characteristics. It stays in one position and continuously records current conditions in that location-a contribution to the knowledge about the long-term behavior of the currents.

Buoy-mounted ADCP: In cases where one needs to monitor certain surface area currents or in open waters within the port, buoy-mounted ADCP can be availed. It floats on the water surface, measuring the currents in its vicinity, which is good to get an idea of the surface current pattern.

Based on Frequency and Depth

Different water depth should select different frequencies of ADCPs. For the water depth within 70m, 600kHz is recommended due to the fact that it can provide a quite accurate current measurement in a relative shallow area. It shall be 300kHz for water depth up to 110m and 75kHz for the area with water depths reaching as deep as 1000m.

There are well - known ADCP flow meter brands such as Teledyne RDI, Nortek, and Sontek. However, a Chinese brand, China Sonar PandaADCP, stands out. It is made of all - titanium alloy material, ensuring high durability and reliability in the marine environment. Moreover, it offers an incredible cost - performance ratio. You can learn more about it through its official website: https://china-sonar.com/.

In the end, Acoustic Doppler Current Profiler (ADCP)  is crucial in the measurement of ocean currents in the Port of London. Selecting appropriate equipment considering a specific need-one that will provide appropriate and useful current data to support efficient operation and management-is very important.

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