ADCP's Application to Ocean Current Measurement in the Port of Wicklow

1. Location and General Features of the Port of Wicklow

The Port of Wicklow is located on the east coast of Ireland. It is a port that has long been integral to the local maritime activities and trade.

Port Scale and Throughput

• The port is relatively small to medium scale. Its throughput mainly consists of agricultural products, building materials, and fishing-related goods. It serves as a base for local fishing vessels and also handles cargo ships that transport goods to and from other Irish ports and some international destinations.
• The infrastructure is designed to manage a moderate volume of traffic. There are a number of berths with different depths and lengths to accommodate various types of vessels, from small fishing boats to medium - sized cargo ships.

Routes and Business

• Domestically, the port is well-connected with other Irish ports, enabling easy transportation of local produce like grains, livestock feed, and construction aggregates. Internationally, it has some trade connections with the UK and other European countries, mainly in products specific to the region, such as Wicklow-sourced granite and other minerals.
• The principal port activities are fishing, handling of cargo and storage. It offers berthing facilities for the fishing vessels to land their catches as well as machinery and plants to handle and store a wide range of cargoes. There are small quantities of ship-related activities including simple repair work and bunker supply services.

Management and Operation of Port

• The port is run by a team of experts who control its affairs in all respects. These include berthing arrangements, coordination of cargo loading and unloading in ships, and the security and safety of the entire port area.
• It also liaises with the local fishermen, farmers, and other businesses relying on the port. They maintain the port facilities, including dredging the channel so that the ships can come in and go out with no problem.

Port Facilities

• It is equipped with basic port facilities. There are berths with appropriate depths for various vessels. The port does have cargo-handling gear, including cranes and forklifts that help in the transfer of consignments. Storage of different types of cargo, like fish in cold storage and other building materials in dry warehouses, is also possible there.
• The other facilities include ship refueling and basic maintenance facilities. The port also has some facilities for local fishermen and visiting sailors.

Channel and Direct Navigation

The port has a maintained channel for safe entrance and exit. It is dredged regularly to ensure that ships of different drafts have the required depth of the channel. Navigation aids such as buoys and lights are installed to guide ships during approach and departure. This enables direct navigation for vessels coming from different directions along the Irish Sea.

2. Importance of Measuring Ocean Currents in the Port of Wicklow

Navigation Safety

• Measurement of ocean currents is critical for the safety of vessels in the Port of Wicklow. The Irish Sea exhibits complex current patterns with different tidal and weather conditions. Such information helps vessels to maneuver in a safer way, particularly during berthing and unberthing operations.
• For instance, if a strong lateral current exists, and a ship is not aware of this, it might be pushed off-course, possibly colliding with other vessels or running aground. This can be avoided if the captain of the ship has the current data with him, thus making changes in speed and course.

Efficient Port Operations

• Understanding the ocean currents helps in the smooth running of the port. If the current is known, then the port authorities can schedule the arrival and departure of ships accordingly. The ships can use the favorable currents to their advantage for economizing on fuel while docking and undocking.
• This also helps in optimizing the use of port resources. For instance, if the current is flowing in a direction that assists the movement of ships to a particular berth, the loading and unloading process can be more efficient.

Environmental Protection

• Currents help in the dispersion of the pollutants in the port area; however, in the event of an oil spill or a chemical release, understanding of the current patterns would become crucial for the deployment of effective containment and clean - up operations.
• Similarly, the port can effectively plan the discharge of wastewater and other products by accounting for the current patterns so as to minimize their impact on the marine environment.

Infrastructure Maintenance

• The forces that result from currents over a certain period will act on and impact the structural soundness of structures such as breakwaters and quay walls. By measuring these currents, extremely useful data are acquired relevant to long-term planning and maintenance.
• For instance, in places with very strong currents, additional reinforcement may be necessary to prevent erosion and damage to quay walls. Acoustic Doppler Current Profiler (ADCP) offers a more sophisticated and convenient measurement of ocean currents compared to the more conventional methods.

3. How ADCPs Using the Doppler Principle Work

ADCPs operate based on the Doppler principle. They emit acoustic signals into the water. These acoustic waves interact with moving particles in the water (such as sediment, plankton, or other small organisms carried by the ocean current). When the waves bounce back, the frequency of the reflected waves changes.

This frequency shift, called the Doppler shift, is proportional to the velocity of the moving particles and, hence, the velocity of the ocean current. ADCPs have multiple transducers that transmit and receive these acoustic signals in various directions. By measuring the Doppler shift from several directions-usually in a three-dimensional or two-dimensional configuration-the ADCP can determine the speed and direction of the ocean current at different depths.

ADCP in Port Ocean Current Measurement

Shipborne ADCP

Shipborne ADCPs are fitted on ships. As a ship cruises through waters, the ADCP current meter travels downwards and around, repeatedly sending acoustic signals and gathering the current velocity information as a ship covers different regions of the port.

The advantage of this method is that it is mobile. A wide range of measurements can be done within the port waters. However, the ship's own motion needs to be accounted for in order to get the results accurately. Calibration and compensation methods are used to correct for any errors due to the movement of the ship.

Fixed ADCP

Fixed ADCPs are deployed in fixed locations of the port, either on the sea bottom or on fixed installations like piers or buoys. They continually measure the ocean current at that fixed point over some extended period.

This provides long-term and consistent data for understanding the regular current patterns in a specific area of the port. The disadvantage is that they only cover a limited area around their installation location, but they are very useful for establishing reference current data for particular regions within the port.

4. Requirements for High - Quality Measurement of Currents in the Port of Wicklow

Equipment Materials

• The materials used in this equipment for quality measurement of currents in the ocean in Port Wicklow are of vital importance. As seawater is corrosive and has floating debris with the potential to cause an impact, it needs a hardy material.
• The equipment must be able to resist the marine environment of the Irish Sea and keep up performance for the long term. For ADCPs, a casing in titanium alloy is suitable, since it offers very good resistance to corrosion in seawater.

Compact and Lightweight Design

• The size of the equipment should be small to facilitate easy installation, especially in areas with limited space such as on small buoys or in regions with complex underwater structures.
• A lightweight design is also beneficial as it simplifies the installation and maintenance processes. This is particularly important for equipment that may need to be deployed and retrieved frequently.

Low Power Consumption

• Low power consumption is essential mainly for long-term monitoring; high power devices may experience difficulty in being continuously kept running due to the insufficient number of powers available in the port area, or continuous replacement of expensive batteries will be required;
• This becomes an important criterion for bottom-mounted ADCP, as they are put in operation and supposed to keep running over a long, uninterrupted period of time.

Cost-Effectiveness

• Cost - effectiveness is also a factor. For comprehensive current measurement in the port, affordable equipment allows for more extensive deployment, enabling a more thorough understanding of the current conditions throughout the port waters.
• This is important for a port like Wicklow to optimize its resources and make informed decisions about current measurement strategies.

5. How to Choose the Right Equipment for Current Measurement

Based on Usage Purpose

• Shipborne ADCP: If the aim is to obtain current data over a wide area of the port while the ship is in operation-for example, during regular port surveys or while collecting data for navigational chart updates-shipborne ADCPs are a good choice. They can cover different parts of the port as the ship moves around.
• Bottom-mounted (Sitting) ADCP: Bottom-mounted ADCPs would be more appropriate where there is a requirement for the long-term, fixed-point monitoring of particular locations within the port area, especially those near or at the entrance of the port channel. They have the added advantages of very stable and continuous data recording in the establishment of the local characteristics of the currents.
• Buoy-mounted ADCP: For areas where it is not convenient to install fixed equipment on the seabed or on structures, or when a floating monitoring point is needed to capture surface and near-surface current conditions, buoy-mounted ADCPs are the way to go.

Based on Different Frequencies

• For water depths within 70m, a 600kHz ADCP is often a good option. It can provide relatively high-resolution current profiles in shallower areas, suitable for many parts of the port where the water depth is not extremely deep, such as near the quay walls or in the inner harbor.
• ADCPs of 300kHz can go through waters as deep as up to 110m; at this depth, water-column penetration is effective with more reasonable current velocity measurements.
• For much deeper areas, such as in the approach channel of the port where the water depth may exceed 1000m, a 75kHz ADCP is recommended. Its lower frequency allows it to reach greater depths and still obtain useful current information.

There are well-known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, the China Sonar PandaADCP will be a good option for those who are seeking a cost-effective but excellent option. It is made of all-titanium alloy material, which can combine durability and good performance. With an incredible cost-performance ratio, it provides an excellent choice for ocean current measurement in the Port of Wicklow. You can learn more about it on its official website: (https://china-sonar.com/).

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