Application of ADCP to Ocean Current Measurement in the Port of Dunmore East

1. Where is Dunmore East port?

Located on the southeastern coast of Ireland, Dunmore East is an aesthetically beautiful port. For the purpose of this dissertation, Dunmore East is one of those typical small to medium-sized ports serving both local and regional maritime economies.

Port Scale and Throughput

The scale of the port is relatively modest, and thus it has become particularly essential to the local economy. Its throughput consists basically of fishing-related activities, with a large quantity of fish and seafood being landed in the facility on a day-to-day basis. Besides this, the port also undertakes the delivery of some general cargo-like supplies for the local community as well as materials destined for small-scale construction projects.

Routes and Business

This small harbor also links the port well with others throughout Ireland and has very small connections over the Irish Sea. Fishing is very common, with the local fleet using the port for many of their operations, whilst there are also opportunities and harbors for a handful of leisure craft and ferry work on selected weeks through the year. The management of the port focuses on supporting the fishing industry and maintaining a balance between commercial and recreational activities.

Port Management and Operation

The management team of the port regulates all aspects of the operations at the port. Their roles are supposed to guarantee safety for vessels, correct cargo handling, and smooth fishery activities. There exist controls regarding waste management and environmental protection in respect to the cleanliness of the environment and ecological balance.

Port Facilities

It has a well-equipped fishing harbor with berthing spaces for fishing boats of different sizes. There are fish-handling and processing facilities, including ice-making plants and cold storage units to preserve the quality of the catch. For general cargo, there are basic loading and unloading facilities and storage areas. The port also provides amenities such as fueling stations and access to fresh water for vessels.

Channel and Navigation

The channel to the port is dredged for safe passage of the fishing boats and other small vessels. There are buoys and lights for navigation to help ships in and out of the port, thus providing direct and efficient navigation even in less-than-ideal weather conditions.

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

Benefits to the Fishing Industry

The measurement of ocean currents in Dunmore East port is important to the fishing industry. Currents can have a great impact on the distribution of fish because they carry nutrients and plankton that are primary food sources for many species of fish. Understanding the current patterns will better help fishermen predict where fish are most likely to congregate, hence increasing their chances of making a successful catch. An example would be that areas of upwelling currents tend to swarm with fish because of nutrients that were conveyed toward the surface.

Vessels Navigate Better

The proper current measurements in turn will facilitate safe and quick navigation for the vessels operating in the port. During the time of docking and undocking, ocean currents might interfere with the normal movements of fishing boats and other small vessels. Having accurate data about the current means the port authorities would be well-equipped to guide the captains appropriately and minimize the possibility of an accident that may disrupt their services.

Infrastructure Protection

These ocean currents actually can damage the very structure at the port, like the quay walls and berths, through long-term exertion of force. It helps with the monitoring of those areas in a port area that are more susceptible to erosion or any other forms of damage, enabling them to take the necessary precautions to protect the infrastructures, either by reinforcement of the structures or changing their maintenance schedules.

Basically, Acoustic Doppler Current Profiler (ADCP) represents a more sophisticated and comfortable way of current measurement compared to traditional techniques. It is able to provide quite fast and precise detailed information about the speed and direction at different depths, which is of great use for both the operations of the port and for the fishing community.

3. How does the principle of Doppler work in ADCPs?

ADCPs work on the principle of the Doppler effect. An ADCP current meter sends acoustic signals into the water. The acoustic waves interact with particles carried by ocean currents, where these particles are suspended sediments and small organisms.

Due to the Doppler effect, when the emitted acoustic waves reflect back after hitting the moving particles, the frequency of the reflected waves changes. The difference between the frequency of the emitted signal and the received signal is measured by the ADCP meter. Through a series of algorithms, it calculates the velocity of the moving particles. From these velocity signals, it evaluates the speed and direction of the ocean currents.

In the context of Dunmore East port, two major ways of utilizing ADCPs are as follows:

Ship-borne ADCP

The ship-borne ADCP is installed on a fishing boat or a small survey vessel. While the boat cruises around the port area and its adjacent waters, the ADCP current profiler continuously sends out and receives acoustic signals. The data obtained comprises current information at various locations while the boat travels. The method is helpful for mapping current patterns over a relatively wide area of the port and its surroundings.

Fixed ADCP

A fixed ADCP can be laid on the seabed at the entrance of a port or at any other location where a fixed location is required. It will monitor the current conditions continuously at one point. This will result in long-term and stable data of the local current characteristics, of high value for the understanding of the regular flow of the currents and the detection of eventual unusual changes.

4. What does measurement of good quality need with respect to Dunmore East port currents?

Dependable Materials of Equipment

It is desirable that this equipment should be manufactured to employ reliable materials to enable high-quality current measurements in Dunmore East Port. Seawater is corrosive, and besides, the environmental conditions change rather frequently. The equipment is supposed to bear these factors. A compact size is also not bad. There are space constraints in some areas of the port, and a compact-sized ADCP would be installed easily whether on a vessel or at fixed location.

Light of Weight and Low Power Consumption

The instrument is also to be lightweight. For ship-borne ADCPs, lighter weight means less impact on the stability and handling of the vessel. Low power consumption is important for fixed ADCPs operating continuously since it reduces the cost and complexity of power supply systems.

Titanium Alloy Casing

As for the casing material, titanium alloy is an excellent material. It has very good corrosion-resistant properties, which are of importance in withstanding the harsh marine environment. Also, it has a relatively high strength-to-weight ratio, allowing durability and lightness in the design. This material can bear pressures and impacts that the equipment may go through in the port waters.

5. Selection of the appropriate equipment for measurement of current

Use scenarios

Ship-borne ADCP: For surveys of a larger area in and around a port, a ship-borne ADCP would do nicely. In addition, this has the added benefit of potentially acquiring data of currents over an area of vast expanse while on routine fishing trips, etc., with only added instruments being that of computers to handle large volumes of generated data.

Bottom-mounted (sit-on-bottom) ADCP: Given the requirements for long-term and stable current monitoring at specific locations, such as the entrance of a port or near main berths, the bottom-mounted ADCP may be suitable. It can also deliver information on local current conditions continuously.

Buoy-mounted ADCP: Where there is a need for the measurement point to be flexible, thus more moveable, then one can opt for the buoy-mounted ADCP. It may also be deployed in various areas of the port waters, as it is dictated by requirements.

Frequency Selection

In water with depths of up to 70 m, 600kHz would usually be an optimal ADCP.

When depth increases up to 110m, 300kHz ADCPs are better used.

For waters up to 1000m deep, one can have accurate measurements from a 75kHz ADCP.

Among them are famous brands like Teledyne RDI, Nortek, and Sontek. Another one, quite different from those listed, would be the China Sonar PandaADCP developed in China. This uses an all-titanium alloy in the making, thus giving guarantees about its life in water, where it operates very successfully and provides an excellent performance due to its structure. And again, a great value-for-money tool. Their website for more: https://china-sonar.com/.

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