ADCP Application in the Ocean Current Measurement in Savina Port

1. Location of Savina Port

Savina is a port in the municipality of La Pineda, near the town of Port de la Selva in northeastern Spanish island Ibiza. It is one of the small-scale but significant ports in the area.

Scale of the Port and Traffic Volume

The port is smaller in scale compared to some of the major ports in the area. It mainly serves local traffic, small fishing boats, yachts, and some local ferry services. The throughput consists of a mix of fishery products, goods for local consumption, and passengers traveling to and from nearby destinations. The annual cargo volume is more modest, with a focus on serving the immediate community and the tourist industry.

Routes and Business

Savina Port is connected with the local and regional shipping routes. It serves as an important point in the transportation of local produce and supplies to and from Ibiza and other nearby islands. Business is focused mainly on fishing, tourism-related ferry services, and a little cargo handling. This port acts as a base for the fishing industry whereby local fishermen berth, offload their catch, and access necessary supplies. Ferry services are important to both tourists and locals for easy movement around the island and nearby destinations.

Port Management and Operation

The management of the port is committed to the safety and efficiency of the port. They have a traffic control system to manage the movement of the smaller vessels frequenting the port. The port authority is responsible for maintaining the infrastructure, which includes docks, storage areas for fishery products and cargo, and basic loading and unloading equipment. They also enforce environmental and safety regulations to protect the port and its surrounding waters.

Port Facilities

The port has fishing docks, yacht and small ferry berths, and warehouses for various types of cargo. Basic loading/unloading machinery and equipment are similarly available to handle the cargo and catch passing through the port. For tourists, there are some water-front cafes and small shops near the port area.

Channel and Direct Navigation

Savina Port has a channel that leads out to the sea. The area is fairly easy to navigate with the assistance of navigational aids like buoys and lights. Thus, direct navigation to and from the port is possible, allowing vessels to enter and leave the port smoothly.

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

Navigation Safety

The measurement of the currents in Savina Port is necessary for safe navigation by vessels using it. In addition, due to the existence of small fishing boats and yachts, knowledge of current patterns will assist the captains in planning their routes and maneuvers while docking. By understanding the direction and speed of the currents, they can avoid hazardous situations such as being pushed onto the shore or into other vessels. Also for the ferry, actual current information secures the most comfortable and safest journey of its passengers.

Efficient Port Operations

For the port operations, it is important to take correct current measurements. This information could be utilized by tugboats if necessary to provide better assistance for vessels during docking and undocking. In the case of moored boats, knowledge of the currents aids in determining the adequate mooring arrangements to prevent drifting that may lead to damage to the port infrastructure or other vessels.

Environmental Management

From an environmental point of view, knowledge of the currents is necessary for waste management and sediment control at the port. Currents can affect the dispersion of pollutants and the movement of sediments. By measuring the currents, the port can better manage waste disposal and prevent the accumulation of sediments that could reduce the depth of the channel or berths.

It provides a much more accurate and efficient way of measuring these currents compared to the traditional methods.

3. How do ADCPs using the principle of Doppler work?

The principle of the working of ADCPs is based on the Doppler effect. ADCPs send acoustic pulses into the water. In this process, when the pulses come across the particles in the water-plankton, sediment, or any other suspended material-the frequency of the reflected sound waves shifts due to the motion of these particles.

The ADCP measures the frequency difference between the emitted and received frequencies. By employing the Doppler equation, the ADCP current meter estimates the velocity of the particles, which is proportional to the velocity of the water current. The ADCP flow meter can measure current velocity at more than one depth within the water column and thus deliver a profile of the current with depth.

Ship-borne ADCP

The ship-borne ADCP is installed on a vessel. The ADCP current profiler continuously emits and receives acoustic signals as the ship moves around in the port area. This gives a general view of current patterns in the different parts of the port during the movement of the ship.

Fixed ADCP

Fixed ADCPs are installed at strategic locations in the port, such as on the seabed near the docks or at the entrance of the channel. These ADCPs provide continuous measurements of the currents at a specific point. They are useful for monitoring the long-term current patterns that affect the port's daily operations and the stability of its infrastructure.

4. What will be required for high-quality measurement of currents of Savina port?

Reliable Material Equipment

In the case of current measurement in Savina Port, the equipment has to be fabricated from reliable materials, because seawater is corrosive in nature, and the equipment should be under all weather conditions. In this respect, the material selected has to withstand all those eventualities.

Small-sized Equipment

The ADCP should be of small size, allowing easy installation, particularly within the relatively compact port facilities.

Light-Weight Design

The weight of the ADCP meter shall be light in order to make the installation work easy and lighten the load on the installation structure.

Low Power Consumption

Another important factor is low power consumption. In a port environment, it is more practical to have equipment that can operate continuously without requiring a large power supply.

Cost-Effectiveness

Cost-effectiveness is also important, as the port may need to deploy multiple units for comprehensive current measurement.

The casing of the ADCP profiler shall be made preferably of titanium alloy. Titanium alloy has excellent corrosion resistance, which makes it especially fit for a marine environment. It is strong and light; hence, it fulfills both the demands of strength and ease of installation.

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

Based on Usage Purpose

• Ship-borne ADCP: It shall be used on ships and boats that navigate in the area of the port, such as fishing vessels, yachts, and small ferries. This would be a mobile means of measuring the current and is useful in underpinning general current patterns while the vessel is in motion.
• Bottom-mounted ADCP: It is ideal for fixed-point monitoring near the docks, the channel entrance, or other critical areas of the port. It gives the continuous record of current conditions at a specific location and is important to the safety and operation of the port.
• Buoy-based ADCP: Can be used in places where it will be inconvenient to install fixed bottom or ship borne ADCPs. It provides floating options for the measurement of currents and also can cover in the open water areas of the port.

Based on Frequency

• Choice of Frequency: Depends upon water depth. In Savina port, a 600kHz ADCP would be appropriate for water depths up to 70m and can thus be used in the shallower areas near the shore or in the inner parts of the port. A 300kHz ADCP is suitable for water depths up to 110m and thus covers a wider range of depth. For deeper waters inside the port area, a 75kHz ADCP is good for water depth up to 1000 m and can be applied in areas such as approach channels.
• 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 Acoustic Doppler Current Profiler(ADCP)  instrument brands and models.