ADCP's Application to Ocean Current Measurement in the Port of Londonderry (Foyle)

1. Where is the Port of Londonderry (Foyle)?

The Port of Londonderry (Foyle) is situated on the River Foyle in Northern Ireland. This is a big port with a long maritime history.

Port Scale and Throughput

It is of considerable scale and throughput. It deals in a wide variety of cargo, which includes containers, dry bulk, and liquid bulk. The container traffic has been on the increase and has facilitated the importation and exportation of many goods, such as consumer goods, machinery, and agricultural produce. The throughput of the port is a factor in the economic development of the region, as it serves as a gateway for trade with other parts of the UK and international destinations.

Routes and Business

It is well-connected through shipping routes to various ports in the UK, Europe, and beyond. The port is involved in a range of maritime businesses. Ferry services operate from here, taking passengers and vehicles across to Scotland and other places. In addition, it is an important place for freight shipping. Because of its unique position around the River Foyle, the port acts as a supply center for its goods within the surrounding vicinity.

Port Management and Operation

The port management is responsible for efficient and safe operations. A team of professionals oversees the berthing of vessels, ensuring that ships are allocated the appropriate docking space according to their size and requirements. The cargo handling process is carefully coordinated to minimize delays and maximize the flow of goods. Safety and security are top priorities, with strict regulations and security measures in place to protect the port infrastructure, vessels, and cargo.

Port Facilities

The port is a modern and well-equipped facility. There are several deep-water berths capable of accommodating large ocean-going vessels and smaller coastal ships. The quay sides are furnished with advanced cargo handling equipment, such as cranes of different capacities for loading and unloading containers and bulk cargo. Large storage areas are also available, including warehouses and open - air storage yards for the storage of various types of cargo before and after transportation.

Channel and Direct Shipping

The natural channel is provided by the River Foyle. Nevertheless, maintenance and dredging operations are usual in order to make the channel deeper and wider for shipping. The port operates direct shipping links that give fast and efficient transportation of goods. These links are also crucial in the supply chain as they facilitate smooth retransmission of goods across and between regions and countries.

2. Why should we measure the ocean currents in the Port of Londonderry (Foyle)?

Measuring ocean currents in the Port of Londonderry (Foyle) is of utmost importance. Firstly, for the safety of vessel navigation, knowledge of current patterns is essential. The port's location on the river and its connection to the sea mean that ships are subject to the influence of various currents. Unpredictable currents can seriously threaten the safety of ships during docking, undocking, and while navigating the channel. The port will be able to give more precise navigational information to the ships by measuring the currents accurately, thus reducing the chances of accidents and ascertaining the safety of crew and cargo.

Current measurements are also a basis for ensuring efficient port operations. Currents can affect the speed and the accuracy of cargo handling operations, such as loading and unloading a ship, where the position of the vessel may be highly dependent on the current. With more accurate current data, the port will be able to undertake better scheduling of these operations and optimize the use of the berths, hence raising the overall efficiency of cargo handling.

Lastly, from an environmental point of view, understanding the currents is essential in managing any potential pollution incident. Currents can determine the spread of pollutants such as oil spills or other hazardous substances. By measuring the currents, the port can take proactive measures to minimize the environmental impact and protect the delicate aquatic ecosystem of the River Foyle and the surrounding coastal areas. The Acoustic Doppler Current Profiler (ADCP) offers a more advanced and convenient way of current measurement than the earlier methods available.

3. How do Doppler principle-based ADCPs work?

ADCPs work according to the Doppler principle. First, they emit an acoustic signal into the water. These signals interact with the moving particles in the water-suspended sediments or even small organisms. When the reflected acoustic signals return to the ADCP meter, a frequency shift, consistent with the Doppler effect, occurs. The frequency shift is measured by the ADCP profiler and translates into the velocity of the water particles to produce the velocity of the ocean current.

Ship-borne ADCP

Ship-borne ADCPs are mounted on vessels. While the ship navigates through the port area and adjacent waters, the ADCP current meter sends acoustic pulses in multiple directions, usually upwards and sideways. The device can measure current velocity at different depths along its travel. In this manner, it will give an elaborative profile of current conditions throughout its journey, yielding an in-depth view of the pattern of currents across areas that the vessel would cover.

Fixed ADCP

Fixed ADCPs are deployed within the port at predefined positions, either on the seafloor or quay wall. These ADCPs record, without interruption, the series of current measurements at a fixed position over a long time period. The time-series data acquired on location will be of essential use in the analysis of long-term current characteristics at certain hot spots within the port, like channel entrance and vicinity around the berths.

4. What is required for high-quality measurement of Londonderry (Foyle) port currents?

For high-quality measurement of ocean currents in the Port of Londonderry (Foyle), the equipment needs to be made from reliable materials. Considering that seawater is corrosive and that physical damage from the marine environment may occur, the device needs to be resistant. A small size, low weight, and low power consumption are also advantageous. A compact and lightweight ADCP is easier to install and operate whether on a ship or at a fixed location. Low power consumption allows for continuous operation without frequent battery replacement or high energy demands. Cost-effectiveness is also a key factor to enable wide-scale deployment in the port.

The casing of the ADCP current profiler is preferably made from titanium alloy. Titanium alloy has excellent corrosion resistance in seawater, ensuring the long-term integrity of the device. In addition, it has a high strength-to-weight ratio, which means being strong and durable while holding a relatively low weight. Besides that, titanium alloy is biocompatible, reducing the possibility of negative impacts on marine life.

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

Depending on the specific requirements of measurement, the right equipment choice in the Port of Londonderry (Foyle) varies.

Ship-borne ADCP

This is suitable when a broad overview of the current conditions in different parts of the port is needed. As the ship sails around the port, the ship-borne ADCP can collect data from various locations, providing a wide - range view of the current patterns in the port waters.

Bottom-mounted (Sitting on the seabed) ADCP

This type of ADCP flow meter is suitable for long-term and fixed-point monitoring. It can be installed at strategic points in the port, such as at the entrance of the channel or near the berths, to continuously monitor the current conditions in those specific areas.

Buoy-mounted ADCP

Buoy-mounted ADCPs find their application in areas where the installation of a fixed device on the seabed or on a ship is not practical. They can be deployed in the open water areas within the port and measure the currents at different depths.

Regarding frequency selection, different frequencies are suitable for different water depths. A 600 kHz ADCP is appropriate for water depths up to 70 meters, a 300 kHz ADCP for depths up to 110 meters, and a 75 kHz ADCP for much deeper waters up to 1000 meters.

There are well-known ADCP brands like Teledyne RDI, Nortek, and Sontek. However, there is also a Chinese ADCP brand, China Sonar PandaADCP. It is made of all-titanium alloy material, which ensures its durability in the marine environment and offers an excellent cost-performance ratio. You can find more information on its website: (https://china-sonar.com/).

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