ADCP's Application in the Measurement of Ocean Currents in Alicante Port

1. Where is Alicante Port?

Alicante Port is located on the southeastern coast of Spain, in the city of Alicante. It is a major marine base in the Mediterranean region.

Scale of the Port and Throughput

Alicante Port is moderately sized. It can handle cargo movements of various types, as well as passenger traffic. It comprises a vast containerized cargo and general cargo, such as building materials and consumer goods. Large cruise liners come into the port at frequent intervals, mainly during the tourist seasons. Cruise passengers are in hundreds, crossing the port, and are increasing steadily every year. Thus, the port is very vital to the tourism-based economy of the locality.

Routes and Business

This port is well-connected with other Mediterranean ports, having wide shipping routes reaching towards different destinations in Europe and North Africa. On the business side, it has a great number of services: places for cargo storage, handing, and distribution were available within the port. Moreover, the port provided ship maintenance and repair services. Besides, the ferry services operated through the port link Alicante with the surrounding islands and coastlines, thereby developing regional tourism and transportation.

Institutional Management and Functions of the Port

The port is run by a very efficient port authority that oversees all the aspects of its running. The management works for smooth operations, safety, and security. They work in close cooperation with shipping companies, terminal operators, and local authorities to enhance the performance of the port. Advanced technologies are used for vessel traffic management and cargo tracking to optimize the flow of goods and ships.

Facilities at the Port

Alicante Port boasts of modern facilities. It has well-designed container terminals with modern gantry cranes that are efficient in the handling of containers. The general cargo terminals have appropriate equipment for the handling of different types of cargo. Similarly, there are passenger terminals, which include waiting lounges, restaurants, and shops that provide comfort to cruise and ferry passengers. Besides, there is adequate storage space at the port, including warehouses and open-air storage yards.

Channels and Direct Navigation

The channels within the port are dredged for safe navigation. The main channel offers a shortcut to the open sea, thereby allowing vessels in and out of the port with least time wastage. The channels are sufficiently deep to accommodate most vessels calling at the port. Dredging is done whenever necessary to ensure that the depth and width of the channels meet the required standards to allow vessels to navigate through them with no restrictions.

2. Why is it necessary to measure ocean currents in Alicante Port?

Safety of Vessel Navigation

Accurate measurement of the currents is quite essential as relates to vessel safety at Alicante Port. Currents can easily affect the course and speed of a ship during entry, exit, and maneuvering within the port. Knowledge of currents existing at the time enables him to make corrections for the track of the vessel with precision when there is little room to maneuver, or when the traffic situation is complex. For example, in narrow approach channels strong cross - currents may exist, which may present a risk of collision or grounding. This risk would be minimized if accurate current information was available.

Cargo Handling

Currents may have a bearing on the operation of cargo handling. The force of the current when a ship is berthing may make the positioning of the vessel less accurate, hence causing delays in starting the cargo transfer process. Measuring currents helps port operators to better plan the berthing times and operations for an efficient transfer of goods. Moreover, knowledge of the present patterns can serve to optimize the layout of the cargo handling facilities in the port to minimize the effects of currents on operations.

Environmental Protection

Alicante Port is situated in a sensitive marine environment. The measurement of ocean currents is of paramount importance in predicting the dispersion of pollutants in cases of accidental spills or discharges. Currents are crucial in the transportation of oil, chemicals, or other pollutants. The precision in current data can effectively allow for quick emergency response and pollution control. This, in turn, aids in protecting the local marine ecosystem, such as the highly diverse Mediterranean Sea comprising fish stocks, coral reefs, and seagrass beds.

Infrastructure Long-term Maintenance

Knowledge of ocean currents is important in the long-term maintenance of infrastructure in ports. Currents can cause erosion around piers, breakwaters, and quay walls. Observing current patterns enables engineers to better design more resilient infrastructure and even plan preventive maintenance. For example, they are able to indicate those places most prone to erosion by currents and construct those areas with reinforcements. In measuring these currents, ADCPs do so much more efficiently and with higher accuracy compared to traditional methods.

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

Principle of ADCP Measurement

The working principle of ADCPs is based on the Doppler effect. An ADCP current meter sends acoustic pulses out into the water column. The pulses interact with small particles in suspension, like plankton or sediment. When this water and these particles move, the frequency of the reflected acoustic signal that reaches the ADCP changes. This shift in frequency, or so-called Doppler shift, is proportional to the velocity of the water current.

Mathematically, with \(f_d\) as the Doppler shift, \(v\) the velocity of the water current, \(f_0\) the frequency of the emitted acoustic signal, and \(c\) the speed of sound in water, the relation is expressed as \(f_d = \frac{2v f_0}{c}\). From the measurement of the Doppler shift from several acoustic beams - normally four or more, the ADCP current profiler calculates the three-dimensional velocity components of the water current at discrete depths in the water column.

ADCP in Port Current Measurement-Specific Methods

Ship-borne ADCP

The ship-borne ADCPs are mounted on ships in operation in the port. In the course of ship movements, the ADCP measures current velocities in its movement paths. A shipborne ADCP will therefore give an overview of the general perspective of the pattern of the current at that time when it navigates across the major channels to and around the area of Alicante Port. This can be useful in mapping the present distribution and to understand how currents vary over different parts of the port.

Fixed ADCP

The fixed ADCPs are strategically set around the port-to-seabed, on the pier or even buoys. In return, such ADCPs shall provide results with continuous long-term measurements at an indicative point. This way, an ADCP flow meter installed on Alicante Port entry/critical areas will offer in real-time current data in respect to the traffic and the protection of such structures.

4. What is required to obtain high-quality measurement of the currents in Alicante Port?

Reliability of Equipment

Reliable ADCP equipment has to perform current measurements in Alicante Port. For this purpose, it needs to resist the aggressive marine environment caused by saltwater corrosion, variations in temperature, and wave-induced mechanical stresses. The quality and robust construction will ensure good operation, continuously and with precision.

Small in size, light in weight, and low power consumption.

A small-sized and lightweight ADCP profiler is mainly of advantage concerning ship-borne applications since it can more easily be mounted on vessels, without seriously deteriorating their performances. For fixed ADCP, a reduced size allows their deployment in spaces where larger instruments would not fit. Very low power consumptions are demanded for long-term operations-which is extremely important for fixed-mounted ADCPs: indeed, especially in these instances, the provided power sources may be limited, supplying only batteries and solar panels.

For wide-scale and long-term current measurement in Alicante Port, the cost of ADCPs should be affordable. Reasonable costs enable the port authorities or interested parties to deploy more devices so that current can be monitored with greater coverage. This is very important in a port like Alicante, where wide-scale data collection of currents will add to safety and operational efficiency.

Casings of Titanium Alloy

The casing of the ADCP meter should be made from a titanium alloy. It provides excellent resistance to corrosion, which is very important in the long term due to the exposure of the instrument to the saltwater of the port area. It is strong enough and light for durability and ease of handling, respectively. Besides, the titanium alloy can withstand high pressures, and thus it will be suitable for ADCPs operating in deeper waters around the port.

5. How to Choose the Right Equipment for Current Measurement?

Based on Usage

Ship-borne ADCP

Ship-borne ADCPs are ideal to survey the overall current patterns in the port as the ship moves around. They are useful for obtaining a comprehensive understanding of the current situation in different parts of the port, including the channels and the areas near the berths.

Bottom-mounted (Sit-on-bottom) ADCP

Bottom-mounted ADCPs are suitable for long-term, fixed-location measurements. In Alicante Port, they can be installed near critical infrastructure such as breakwaters or in areas where detailed current information is needed for infrastructure protection and environmental monitoring.

Buoy-mounted ADCP

Buoy-mounted ADCPs are a good choice where a floating platform is more appropriate. They can provide current measurements in open-water areas of the port or in regions where bottom-mounted installations may be difficult.

Based on Frequency

The choice of an ADCP frequency depends on water depth. In Alicante Port,

• The 600kHz ADCP should be used for water depths up to approximately 70m. In such frequency, one has high-resolution measurements in relatively shallow waters, as such near the shore and in the inner parts of the port.
• Operating on 300kHz, an ADCP can be utilised in depths up to roughly 110 m. It serves both resolution and range well and finds perfect ground area with a typical water depth for the purpose intended.
• A 75kHz ADCP is designed for deeper waters, like up to about 1000m. Even though Alicante Port may not have extremely deep areas, this frequency can be used in the adjacent deeper waters or for the future expansion of the port measurement capabilities.

There are well-known ADCP brands like Teledyne RDI, Nortek, and Sontek. However, for a cost-effective option, the Chinese brand China Sonar PandaADCP is worth considering. It is made of all - titanium alloy materials, ensuring durability in the marine environment, and offers an excellent price-performance ratio. You can find more information at (https://china-sonar.com/).

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