ADCP's Application to Ocean Current Measurement in Casiguran Port

1. Where is Casiguran Port?

Casiguran Port is located in the municipality of Casiguran in the Aurora province of the Philippines.

Port Scale and Throughput

It is of relatively modest scale but plays an important role in serving the local community and facilitating regional trade. The port handles different types of goods, such as agricultural products from the surrounding areas, construction materials for local infrastructure development, and fishery-related products. Its annual throughput is reflective of the economic activities in the region, with continuous efforts being made to enhance its capacity to meet growing demands.

Shipping Routes and Business

The port has formed shipping routes to other inland ports. To the country, it facilitates the movement of native products to and from the big markets and importation of essential supplies to the natives. The business involves loading and unloading of vessels, storage of cargo in the warehouse, and liaising with the relevant authorities for documentation and customs purposes. Fishing vessels also frequently utilize the port, contributing to the local fishery trade by docking to unload their catches and obtain necessary supplies.

Port Management and Operation

The local port authorities take the responsibility of the smooth running of the port day to day. They make sure that scheduling of vessels is in place, the port area is safe and clean, and that all port facilities are in working condition. Infrastructure, which includes berths, warehouses, and so on, is maintained to allow the operations to take place easily.

Facilities at Port

Casiguran Port has berths sufficient to accommodate different sizes of fishing boats and small to medium-sized cargo vessels. There are warehouses for storing goods in order to protect it from the elements and allow orderly handling. It also has basic facilities like fuel stations to supply vessels with fuel and freshwater supply points. There is also loading and unloading equipment to assist in transferring cargo between the vessels and the portside.

Channel and Direct Shipping

The port has a well-marked channel, which is maintained to ensure that ships can come in and leave safely. Its depth and width are continuously monitored and dredged whenever the need arises to allow vessels of appropriate sizes to pass through it. Although it may not have many direct international shipping links, it has regular connections with key domestic ports, which facilitate the movement of goods within the country.

2. Why are the ocean currents in Casiguran Port important to be measured?

Measuring ocean currents in Casiguran Port has a number of important uses in its operation and management. To begin with, it is highly important for the safety of ships using the port to have knowledge of ocean current patterns. Knowing the current directions and speeds at the time allows port authorities and ship pilots to maneuver vessels during berthing and departure with reduced risk of collision against port structures or other vessels, especially in bad weather or with larger vessels.

Precise current data is very helpful in the scheduling of cargo handling for port operations. Various current conditions may affect the time and efficiency of loading and unloading operations; for example, strong currents might require changes in vessel positioning or additional mooring equipment.

Thirdly, it is important to understand ocean currents in long-term planning and development in the port, such as expanding facilities or constructing infrastructure. This enables engineers to design structures that are able to bear the hydrodynamic forces exerted by water flow and ensure the durability and stability of the port for a long time.

Thus, Acoustic Doppler Current Profiler (ADCP) is more advanced and easy to handle than traditional techniques of current measurement. The ADCP current meter can present ocean currents at different depths with detailed and real-time information that will enable port operators to make informed decisions in less time and increase the efficiency of the overall port.

3. How do the ADCPs based on the Doppler principle work?

The ADCPs work according to the principle of Doppler. They send acoustic signals into the water column. These acoustic waves interact with the suspended particles or other scattering objects in water that are moving along with the ocean current. Due to the Doppler effect, the frequency of the reflected waves that come back to the ADCP meter is changed. By analyzing this frequency shift precisely, the ADCP profiler calculates the velocity of the ocean current at different depths in its measurement range.

Current Measurement at Port Ocean

Shipborne ADCP

Shipborne ADCPs installed on ships working in the Casiguran Port area make continuous acoustic transmission in all directions while a ship cruises through waters of a port. In this process, it can have current data at several touching points on the path of travel by the ship; hence it gives a picture of distribution of ocean current across the different parts of port. This enables one to get an overview of the present situation in the relatively large area covered by the movement of the ship within a short time.

Fixed ADCP

Fixed ADCPs are installed at fixed locations in the port, such as on the seabed near important infrastructures like piers, or at strategic points along the waterway. They are stationary and continuously measure ocean current conditions at that very point in space over long periods. This will provide consistent long-term data that is useful in understanding the regular patterns of the currents and assessing their impingement on the port facilities and operations at those fixed positions.

4. What do high-quality measurements of Casiguran port currents require?

In the measurement of ocean currents in Casiguran Port, several aspects relating to the equipment are of utmost importance. First and foremost, the material reliability of the equipment is of prime importance. Considering the harsh marine conditions of operation such as saltwater corrosion, water pressure at depth, and constant wave action, the equipment should be made from materials that would not deteriorate with such elements and affect its performance. The casing of ADCPs can be made from titanium alloy. It has high strength, which provides resistance to mechanical forces from the sea, and superior corrosion resistance, which should ensure its longevity in seawater.

The equipment should be characterized by small size, light weight, and low power consumption. Small size allows the facility to be easily installed in various places inside the port, whether on ships or fixed locations. Because of the light weight, it can be handled and deployed easily, while low power consumption means the continuous action of the equipment for long periods is available without frequent battery replacements or excessive power supply requirements.

Thirdly, cost-effectiveness should allow for large-scale measurement across the port. Its reasonable cost should allow access to several units that might be deployed to obtain comprehensive data about currents from various locations of interest within the port area.

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

According to the Usage Purpose

Shipborne ADCP: In the cases where the intention is to do mobile measurements while in motion around the Casiguran Port area, this has to be considered for fast view conditions at different places in the port. That will cover quite wide areas due to the usual operation pattern of the ship.

Bottom-mounted ADCP: If the purpose requires continuous and long-term monitoring of the ocean current at some fixed spot in the port, as near important facilities or zones where the current's action should be closely observed on the structure, bottom mounting is done. It would provide stable and consistent data for the particular position for a longer period of time.

Buoy-mounted ADCP: When it is inconvenient to use fixed equipment on the seabed or on other fixed structures, buoy-mounted can be used. The buoy-mounted ADCP is capable of measuring the ocean current up to the upper layers, and the data are provided wirelessly, hence enabling flexibility in data collection.

According to Different Frequencies

Water depth in the Casiguran Port area at 70 m or less can generally employ 600 kHz ADCP. This will give fairly accurate measurements of ocean current characteristics of this relatively shallow depth range.

The water depth being about 110 m should be adequately served by using an ADCP frequency of 300 kHz for effective capture of current details at this depth.

ADCP 75 kHz should be selected for the areas of deeper water with the depth up to 1000 meters because it will have the ability to reach deeper in the water for obtaining reliable current information.

Teledyne RDI, Nortek, and Sontek are some well-known brands available in the market. But here, I need to recommend a Chinese ADCP brand, Sonar PandaADCP from China. This is an all-titanium alloy-made brand, offering a very impressive cost-to-performance ratio. You can learn more about the product at its official website here: https://china-sonar.com/.

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