ADCP's Application to Ocean Current Measurement in Aparri Port

1. Where is Aparri Port

Aparri Port is located in the municipality of Aparri in the province of Cagayan, Philippines. It is one of the major ports in the northern part of the country and is a vital gateway for maritime activities in the region.

Port Scale and Throughput

• The port is moderately to largely scaled. It handles a variety of cargo, inclusive of agricultural products from the Cagayan Valley, which is a major agricultural region. These products include rice, corn, and tobacco. It also manages fishery products as the area has a productive fishing ground. The throughput is considerable, especially during the peak agricultural and fishing seasons.
• Aparri Port serves as a lifeline for delivery to and from Northern Luzon and other parts of the country. It has berthing facilities for medium-sized cargo ships and fishing boats that serve the important means in the local and regional trade network.

Routes and Business

It connects with other domestic ports through shipping routes. Its significant businesses are fishing and cargo handling. Fishing boats use the port as a central point of their operations. They unload and refuel with supplies. For cargo, it ships in agricultural and any other local products to other markets.

• In addition, the port can facilitate small-scale tourism activities that involve trips around the Cagayan River or its nearby coastal areas.
• The port is managed by regional port authorities. Their jobs specifically include keeping order within the vessels and ensuring order while berthing and mooring processes are carried out. These are in charge of activities concerning loading and unloading cargo for them not to get damaged and also, that handling is done with speed.
• They also work on security measures to safeguard the port and its assets. This includes collaborating with local law enforcement agencies and implementing safety protocols to protect the ships, the port facilities, and the people working in and around the port.

Port Facilities

Aparri Port has several berths that may allow for various types of vessels. There are areas in the docking with piers and quays suitable for fishing boats and cargo ships. It would also have storage facilities, both perishable-like fish and produce-and non-perishable goods.

Basic facilities would include a fish market for the local fishery trade and facilities for refueling vessels and fresh water. There may also be some simple workshops for minor repairs and maintenance to boats.

Channel and Direct Navigation

Aparri Port has a well-defined channel for safe navigation. The channel is kept at an adequate depth by the tides. Buoys and beacons are installed to help ships entering and leaving the port. These marks help the mariners navigate in a straight course thus enabling them to avoid all types of dangers such as shallow waters and undersea obstacles.

2. Aparri Port Importance of Measuring Ocean Currents

Safe Vessel Operations

Measuring ocean currents is crucial for the safe operation of vessels in Aparri Port. The knowledge of the current's direction and speed allows precise berthing and mooring. From this viewpoint, the understanding of currents would be very useful to port operators for the best positioning of vessels during docking in order to minimize the risks of hitting the port infrastructure or other vessels. This is indeed quite crucial, considering that both fishing and cargo vessels make use of the port. Currents can also have implications for the stability of vessels when moored. Precise current measurements enable corrections to be made for the proper tensioning of mooring lines and other measures so that ships will not be in jeopardy.

Fishing Benefits

• For fishing locally, the understanding of currents is of paramount importance. Nutrients carried by currents ensure proper dispersion of fish and other organisms. Accurate measurement of current will indicate where the concentration of fish could be higher, thereby increasing productivity.
• The direction and speed of currents can, additionally, affect travel time and fuel consumption by fishing vessels. Such information helps fishermen in better tour planning with regard to time and economic factors.

Infrastructure and Environmental Considerations

Current measurements from an infrastructure viewpoint provide valuable data on maintenance and future planning of the port structures. Such currents will make the quay walls, piers, and other facilities exposed to their hydrodynamic forces less stable and durable. In possession of proper current data, port authorities would be able to design more resistant infrastructure and plan preventive maintenance activities that extend the life of structural elements.

Knowledge of the currents in this regard helps predict the dispersion of pollutants within the port waters. This helps in the event of an oil spill or other contaminant release to implement effective containment and cleanup strategies. It also assists in monitoring the impact of port activities on the surrounding marine ecosystem.

The Acoustic Doppler Current Profiler(ADCP) represents an advanced and convenient method compared to the traditional techniques in the measurement of ocean currents. It can provide real-time, detailed information about the current profile, which allows for more precise and efficient monitoring of ocean currents in the port area.

3. How ADCPs Using the Doppler Principle Work

In principle, ADCPs are based on the Doppler principle, sending acoustic signals into the water where they encounter moving particles in the water, which reflect waves whose frequency has shifted through a phenomenon known as the Doppler effect.

It measures the frequency shift of the reflected signals. From these, with the use of specific algorithms and calibration, it determines the velocity of the moving particles. As the movement of those particles is principally from the ocean current, this ADCP can calculate the current's velocity.

ADCP in Port Ocean Current Measurement: Shipborne ADCP

Shipborne ADCPs are mounted on ships operating in the port area. Accordingly, the ship-mounted ADCP transmits acoustic pulses in different directions-often downwards and sideways-while the vessel cruises along, continuously measuring the velocity of the currents at various depths across its track. Data acquired while the ship cruises can be combined to generate a detailed map of the current field over the entire port area, thus portraying thorough understanding of the pattern of currents to be encountered during the voyage of the vessel.

Fixed ADCPs are deployed in strategic locations within the port on the seabed or on fixed structures like piers or breakwaters. These ADCPs monitor steady-state ocean currents occurring at the same site over time. Data from fixed ADCPs is useful in developing a long-term and consistent current condition at hotspots in the port. This information will serve as a benchmark for port operations, research, and infrastructure planning.

4. Requirements for High - Quality Measurement of Aparri Port Currents

Equipment Requirements

The equipment should be made of reliable materials that can withstand the harsh marine environment, including the corrosive effects of seawater, high pressures at different water depths, and potential impacts from floating debris, for high-quality measurement of the ocean currents in Aparri Port.

Other considerations are the size and weight of the equipment, where smaller size and lighter weight is advantageous, particularly when installation on vessels or in locations on fixed structures where space may be limited. In such cases, there is more flexibility in the placement of equipment.

The other critical aspect is the power consumption. It should be low-power-consuming so that it can run on a wider scale without necessarily changing batteries now and then or requiring a lot of energy supply. This is particularly crucial for fixed ADCPs, as sometimes accessing continual power may be no easy task.

Advantage of Titanium Alloy Casing

The ADCPs whose casing is of titanium alloy are unrivaled. Excellent corrosion resistance of the alloy means a long resistance to seawater corrosion, which goes a long way in the maintenance of the integrity and performance of the ADCP. Besides, it has a high strength-to-weight ratio that allows durability but with lightweight; this is useful for both installation and operation. In addition, the titanium alloy can bear higher pressure at greater depths; hence, it is suitable for application in variant water depth conditions in a port area.

5. Selection of Appropriate Equipment on Current Measurement

Depending on Usage

• Shipborne ADCP: If the concern is to gain a very comprehensive understanding of the currents in the port during vessels' movements, then shipborne ADCPs would be a good solution. It can cover most areas of the port since the ship would sail along the areas that need mapping, creating a wide-ranging view of current conditions.
• The bottom-mounted ADCP, sitting on the seabed, is more appropriate for long-term and continuous monitoring of current conditions at specific fixed locations, such as near key port structures or areas where the current characteristics are of particular interest for research or operational reference. They can provide stable and consistent data over a long period.
• Buoy-mounted ADCP: In instances where the currents have to be measured in areas unreachable either by fixed installations or by ship operations, ADCPs mounted on buoys are used. These are allowed to drift with the currents to a certain extent while measuring and thus provide information on the current fluctuations in those areas.

Based on Frequency

• For water of depths within 70 meters, a frequency of 600 kHz is often the best option. It offers detailed, accurate current measurements in the rather shallow parts of the port.
• For water to a depth of 110 meters, a 300 kHz ADCP would be more suitable. Its deeper water column penetration capability will serve well in obtaining dependable current data at such depths.
• For deeper areas, especially those with water depth up to 1000 meters, one should use the ADCP with a frequency of about 75 kHz. It will be capable of covering such huge depth range and still measure the ocean currents with reasonable accuracy.

There are several well - known ADCP brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, it's worth mentioning a cost - effective Chinese ADCP brand - China Sonar PandaADCP. It is made of all - titanium alloy material and offers an impressive price - performance ratio. You can visit its website at (https://china-sonar.com/) for more information.

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