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

1. Introduction to the Port of Drogheda

The Port of Drogheda is located on the River Boyne estuary on the east side of Ireland. It has long served as an important port with considerable historical significance for trade and transportation by sea.

Port Scale and Throughput

• The port is of average size. It handles general cargo, such as agricultural products, building materials, and even some industrial goods. The throughputs are important for the local and regional economy as a key link in the distribution of goods in the area.
• It has several berths of different natures to receive vessels with various dimensions. The infrastructural setup is so articulate to handle inland and ocean-going vessels simultaneously, enabling transshipment of cargo between river barges and ocean-going vessels.

Routes and Business

• It is well-connected domestically through the river and sea routes to other Irish ports, while internationally, it has trade links with UK and other European country ports. The main activity lines include cargo handling involving the import and export of local produce and manufactured goods.
• The port also serves the needs of the local fishing industry through the provision of facilities in storage and processing of fish, ship repair and maintenance as well as transportation of bulk cargo such as grains and aggregates.

Port Management And Operation

• The port is governed by a professional team that regulates the working of the port for every sphere. This includes arrangement over berthing of ships, loading, and unloading along with maintaining safety and security within the port premises.
• The management also liaises with local businesses, transporters, and regulatory agencies to ensure that all operations run smoothly. They are responsible for the upkeep of the port facilities, which includes dredging in the river and estuary channels to maintain navigable depths.

Port Facilities

• It has many facilities. The berths vary in depth for different vessels. The cargo-handling equipment, such as cranes and forklifts, is there to assist with the transfer of goods in the port. There are storage areas for different types of cargo: warehouses for general cargo and silos for bulk materials.
• It includes facilities for refueling the ships, besides offering basic maintenance services. The port also offers several amenities to the crews and other workers, including rest areas and small cafeterias.

Channel and Direct Navigation

• The port has a dredged channel through the estuary that allows ships to enter and exit safely. The channel has undergone regular dredging to acquire as well as maintain adequate depths for ships of varying draft. Navigation aids have also been provided, including buoys and lights that facilitate approach and departure by a vessel. This thus directly allows navigation for vessels that come from different directions on the estuary as well as the adjacent sea area.

2. Significance of Measuring Ocean Currents in the Port of Drogheda

Navigation Safety

• The measurement of ocean currents is of extreme importance for ship safety within the confines of Drogheda's port boundaries. It will be useful because of complex currents in this area of estuary and adjoining sea that prevail due to tides, river flow, and changes in weather conditions, therefore knowledge about such currents could help a vessel in negotiating the conditions of their own safety.
• For instance, when approaching a berth, a ship may be pushed off-course by an unexpected current. With accurate current data, the captains of ships will have the ability to make necessary adjustments in speed and course to avoid collision with other vessels or running into shallow waters.

Efficient Port Operations

• It helps in the understanding of ocean currents, which helps the efficient running of the port. They can easily plan the arrival and departure of ships with knowledge of the currents. During docking and undocking, favorable currents could be utilized to save on fuel by ships.
• This also helps in optimizing use of the port resources. For example, if the current is moving in a direction that facilitates the movement of the ships towards a particular berth, it would be easier to load or unload the ships.

Environmental Protection

• Currents are a very important medium for the dispersion of pollutants in the port area. In the event of an oil spill or other chemical release, the pattern of currents will provide the necessary information for implementing effective containment and clean - up operations.
• The port can also manage the discharge of wastewater and other substances more effectively by considering the current patterns, minimizing their impact on the marine environment.

Infrastructure Maintenance

• Currents can exert forces over time on port infrastructures like breakwaters and quay walls, seriously affecting their structural integrity. It gives valuable data on the current that will provide long-term planning and maintenance for these structures.
• For instance, in areas where the currents are particularly strong, extra reinforcement may be necessary to prevent erosion and damage to the quay walls. Acoustic Doppler Current Profiler (ADCP) is a more advanced and convenient way of measuring ocean currents compared to the traditional methods.

3. How ADCPs Using the Doppler Principle Work

The working principle of ADCPs is based on the Doppler principle. Transducers attached to an ADCP current meter emit acoustic signals into the water. These acoustic waves scatter against moving particles in the water, such as sediment, plankton, or any other small organisms carried by the ocean current. In the case of a reflection, the frequency of the reflected waves shifts.

This frequency change, commonly referred to as the Doppler shift, has a direct relationship with the velocity of the moving particles and thus with the velocity of the ocean current. ADCPs are fitted with several transducers that send and receive these acoustic signals in various directions. By measuring the Doppler shift from multiple directions-most often in a three-dimensional or two-dimensional configuration, the ADCP current profiler can calculate the speed and direction of the ocean current at different depths.

ADCP in Port Ocean Current Measurement

Shipborne ADCP

• Shipborne ADCPs are installed on vessels. During the movement of the ship through the water, the ADCP flow meter continuously sends acoustic signals downward and around. It collects data on the current velocity as the ship traverses different areas of the port.
• The advantage of this method is its mobility. It allows for a wide range of measurements within the port waters. However, it's important to account for the ship's own motion to obtain accurate results. Calibration and compensation methods are used to correct for any errors caused by the ship's movement.

Fixed ADCP

• Fixed ADCPs are deployed in fixed locations within the port area, like on the seabed or fixed structures such as piers or buoys. They continuously monitor the ocean current at that fixed point over an extended period.
• This offers long-term and continuous data to know the regular current patterns in a specific area of the port. The disadvantage is that they cover only a limited area from 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 Drogheda

Equipment Materials

• The equipment materials should be reliable for high-quality measurement of ocean currents in the Port of Drogheda. Because seawater is so corrosive and could contain floating debris that may possibly hit the equipment, some kind of durable material will be required.
• It needs to be durable for estuarine and marine environmental conditions, sustaining performance over some time. A casing made from titanium alloy is a good choice for ADCPs, featuring very good corrosion resistance in seawater.

Compact and Lightweight Design

• Smaller-sized equipment is demanded that is conveniently installed, especially for applications at limited space conditions in some specific small buoys and within regions with highly structured waterways.
• Small-size equipment should have its designs lightweight, thereby enabling more convenience during processes involved with installation and maintenance; specifically useful for those oceanography facilities that may demand regular launch and retrieval.

Low Power Consumption

• Low power consumption is essential, particularly for long-term monitoring. Equipment with high power consumption may encounter difficulties in sustaining operation over a period of time due to insufficient power supply options in the port area or the frequent replacement of batteries.
• This is particularly important for fixed ADCPs that will be deployed for continuous measurement over a long period.

Cost-Effectiveness

• Cost-effectiveness is also a factor. For comprehensive current measurement in the port, less expensive equipment allows for more widespread deployment, enabling a fuller understanding of the current conditions throughout the port waters.
• This is important for a port like Drogheda 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: This will be appropriate if one desires to obtain current data over a wide area of the port, say, when the ship is in operation-for example, during regular port surveys or when collecting data for navigational chart updates. It covers different parts of the port as the ship meanders around.
• Bottom-mounted (Sitting) ADCP: In cases of long-term and fixed-point monitoring requirements over specific locations within the port, for instance near critical infrastructure like breakwaters or at the entrance of the port channel, bottom-mounted ADCPs would be suitable. These can give stable and continuous data in the local current characteristics.
• Buoy-mounted ADCP: In locations where it is not appropriate to install fixed equipment on the seabed or on structures, or when a floating monitoring point is required to capture surface and near-surface current conditions, buoy - mounted ADCPs are appropriate.

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.
• A 300kHz ADCP is more appropriate for water depths of up to 110m, where it can be reasonably able to penetrate the water column effectively and measure current velocities well.
• 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. On the other hand, in case your plan needs an economic option while also focusing on high quality, consider China Sonar PandaADCP. The fully titanium alloy body is hard and wear-resistant, yet it achieves performance that cannot be rivalled in this kind of class of products. With great value for money, therefore, this gives a formidable ocean current measurement option at the Port of Drogheda. 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.