ADCP's Application to Ocean Current Measurement in Sagunto Port

1. Where is Sagunto Port?

Sagunto Port is on the eastern coast of Spain. It is an important port for serving local and regional maritime activities.

Port Scale and Throughput

The port has average productivity. Its main throughput consists of bulk cargo like ore, coal, and building material, as well as a small share of general cargo and container traffic. Its annual cargo output is determined by the local industry and commerce. That is, it mainly supplies the nearby industries with raw materials and exports their produce to overseas.

Lines and Commerce

The Sagunto Port is well connected with regional shipping routes. The involvement pertains to transporting goods from or to other Spanish and some international destination ports. The core business encompasses activities involving bulk cargo handling and the allied logistical activities pertaining to such. In addition, services are rendered concerning warehousing and transferring of cargo.

Management and Operation of the Port

The mission of the port management is to ensure that all the operations are running safely and efficiently. They have a traffic control system for the movement of ships. The port authority is responsible for the maintenance of the infrastructure that includes the docks, storage areas, and cargo-handling equipment. They are also responsible for the implementation of various environmental and safety regulations.

Port Facilities

Facilities within the port are appropriate for bulk cargo handling. Deep-water berths for large bulk carriers, along with cranes for loading and unloading, are available, besides storage areas for different cargo, open-air storage of ores, and covered storage for other materials. 

Channel and Direct Navigation

The Sagunto Port has a channel opening into the sea. The navigation conditions in the area are not too complex and, with the support of aids to navigation, like buoys and lights, direct navigation towards and from the port is possible. The ships smoothly enter and leave the port.

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

The measurement of the ocean currents is very important and for many reasons, including in Sagunto port. The knowledge of the current patterns helps the captains to control their vessels in a better way while performing the maneuvers of docking and undocking. Understanding the direction and speed of the currents allows ships to adjust their courses and speeds to avoid collision and smoothly approach the berths.

Bulk cargo handling, being one of the mainstays of the commercial operations of the port, relies on precise current measurement. This is mainly to inform the tugs that would assist in transferring large bulk carriers efficiently. Knowledge of currents helps in managing the moored ships to prevent them from drifting and causing damage to the port infrastructure or other vessels.

Besides, knowledge of ocean currents is very important for environmental management at the port. Currents can take part in the dispersal of pollutants and in the transport of sediments. Current measurements enable the port to dispose of waste more effectively and prevent sedimentation, which may lead to loss of depth both in the channel and at the berths. The Acoustic Doppler Current Profiler (ADCP) does the job much more accurately and more efficiently than other methods applied earlier.

3. How do ADCPs using the Doppler principle work?

An ADCP current meter basically works on the principle of Doppler. ADCPs send acoustic pulses into the water. Interaction of these pulses with the particles in water-plankton, sediment, or other suspended matter-changes the frequency of the reflected sound waves owing to the movement of these particles.

This frequency difference between the emitted and the received signal is measured by the ADCP meter. By utilizing the Doppler equation, it calculates for the velocity of the particles, which is proportional to the velocity of the water current. The ADCP current profiler can measure the current velocity at different depths within the water column, creating a vertical profile of the current.

Ship-borne ADCP

Ship-borne deployment mounts an ADCP on a vessel. In the conduct of rounds around the port area, the ADCP flow meter repeatedly transmits and then receives the acoustic signals it transmits. Here, in such a situation, data collected when the ship moves provides wider views of the current patterns throughout the different sections of the area covering the port.

Fixed ADCP

Fixed ADCPs are installed in strategic positions within the port, such as on the seabed near the docks or at the entrance of the channel. These ADCPs continuously measure the currents at a single point. They serve to monitor long-term current patterns that influence daily operations and the stability of infrastructure in the port.

4. What do the measurements of Sagunto port currents need?

The equipment to realize high-quality current measurement in Sagunto Port should be made of reliable materials, considering seawater is corrosive and the device should be exposed to such elements. The ADCP meter to be used should be of a small size, which would mean relatively easier installation, especially within the somewhat compact facilities of the port.

The weight of an ADCP profiler has to be lightweight to ease and simplify the installment process and relieve the structures of buoyancy. One more important condition is low power consumption. Not all vessels operating in a port like Sagunto may have plentiful power supply onboard, so there is a need for a low-power consumption ADCP for uninterrupted operation. Finally, cost-effectiveness is another paramount factor, due to the potential need for many units to adequately measure currents throughout the port area.

The ADCP casing is preferably made of titanium alloy. First, titanium alloy has excellent corrosion resistance, making it well-suited for marine applications. Besides, it is strong enough and light, which meets the requirements of durability and ease of installation.

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

Based on Usage Purpose

• Ship-borne ADCP: This is for ships that are always moving within the area of the port, for example, bulk carriers and general cargo ships. It provides a mobile way of measurement of currents, hence useful in understanding overall current patterns that the vessel travels.
• Bottom-mounted ADCP: It is suitable for fixed-point observation near the docks, the entrance, or other critical areas within the port. It yields a continuous record of current conditions at a specific location and forms an important part of the safety and operation of the port.
• Buoy-based ADCP: Can be applied in situations where it is not convenient to install the fixed-bottom and ship borne ADCPs. It offers the floating option in the current measurement and may range from an area over the open water inside the port limit.

Based on Frequency

Depending on water depth:. In Sagunto port, a 600kHz ADCP would be appropriate for water depths up to 70m and could be used in the shallower areas near the shore or in the inner parts of the port. A 300kHz ADCP is appropriate for water depths up to 110m and can cover a wider range of depths. In deeper waters of the port area, the 75kHz ADCP is suitable for up to 1000m of water depth. It can be installed in areas like an approach channel.

There are well-known ADCP brands like Teledyne RDI, Nortek, and Sontek. However, a Chinese brand, China Sonar PandaADCP, is also a great option. It is made of all-titanium alloy material, providing excellent durability and a high level of corrosion resistance. It also offers an attractive cost-performance ratio. You can visit their website (https://china-sonar.com/) for more details.

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