ADCP's Application to Ocean Current Measurement in the Port of Mormugao

1. Where is Mormugao Port?

Overview of Mormugao Port

Mormugao Port, situated in Goa, India-on the west coast of the country-is a major port with long-established standing in maritime trade. A key feature of this port is its significant scale and throughput. It is also well-known for handling iron ore exports besides other cargo like coal, petroleum products, and containers.

The Mormugao Port shipping routes connect to different major and minor ports of the world. It acts as a vital link in the export-oriented industries that are set up in the hinterland region, apart from catering to the import requirements of the essential commodities. The port has managed to be efficient in management and operation by laying much emphasis on the aspects of safety along with smooth cargo handling. Vessel traffic management teams work together with cargo operations and maintaining security. Advanced technologies are implemented to manage the processes smoothly, like automated cargo-tracking systems that ensure cargo moves on time.

Port Facilities

Berths: The port has various berths of multiple sizes and capabilities. Actually, some of the berths are specially designed to accommodate the largest bulk carriers-carrying vessels laden with iron ore. These berths have heavy mooring systems that can withstand tugs from ships. There are also berths for other ship types, including tankers and container ships.

Cargo - handling Equipment: Along the quay, cranes along with other loading/unloading equipment are provided. For iron ore handling, large-capacity grabs and conveyor systems are provided. For petroleum products, appropriate pumping and transfer systems are provided. Containers are efficiently loaded and unloaded by gantry cranes.

Storage Facilities: There are vast storage facilities for various types of cargoes. Large-scale stockpiles exist for iron ore, complete with proper drainage and dust-suppressing mechanisms. For the storage of petroleum products, there are storage tanks fitted with safety attributes to prevent spills or contain them. In addition, it has container yards and warehouses for general cargo storage.

Channel and Navigation Aids

The channel of the port is dredged to an adequate depth and width to provide a safe passage of the vessels. Regular dredging operations are carried out to keep it navigable for large-draft vessels. Navigation aids like buoys, beacons, and radar systems are in place to guide the ships into and out of the port.

2. Why should we measure ocean currents in the Mormugao Port?

Need of the Hour: Implication for Port Operation and Management

Measurement of the ocean currents in Mormugao Port is very significant. Firstly, the safety of vessel navigation depends on the knowledge of current directions and speeds for ship captains while approaching berths or navigating through the channel. For instance, a strong cross-current near a berth may turn the work of docking into a very challenging task. Precise current measurements allow captains to adjust the course and speed of the ship to make this phase of coming to a berth smooth and safe, avoiding collisions.

Second, this is important to optimize the port's activities. The current information provided aids in improving the schedules of the arrival and departure of ships. With knowledge of tidal currents and other periodic flow conditions, the port authorities can make higher availability of berthing resources and plan the loading and unloading activities much better. Consequently, productivity becomes higher because it allows the better coordination of cargo-handling operations.

In addition, the knowledge of currents is important from an environmental point of view for predicting the distribution of pollutants in case of an accidental spill. Due to the type of cargo transferred within the port, such as petroleum products and chemicals, this information enables immediate intervention to contain and minimize the environmental damage. In view of the above factors, an accurate, convenient measurement method, such as the ADCP (Acoustic Doppler Current Profiler), becomes very valuable for measuring the ocean current at Mormugao Port.

3. How do ADCPs using the Doppler principle work?

Measurement Principle

The basic principle behind ADCPs is the Doppler principle. In operation, when the ADCP current profiler sends out an acoustic signal into the water, that acoustic signal encounters and scatters off the water particles in flow. Because the water particles are moving due to the ocean current, they induce a frequency shift in the reflected acoustic signal received back by the ADCP meter. According to the Doppler effect, this frequency shift is related to the velocity of the water flow. The ADCP current meter estimates the speed and direction of the water flow from this frequency shift. By transmitting signals at several angles and in various directions down, the ADCP flow meter can provide a profile of the ocean current, showing how the current varies with depth.

ADCP in Port Ocean Current Measurement Methods

Shipborne ADCP: A shipborne ADCP is installed on ships operating in the Mormugao Port area. As the ship moves around the port, the ADCP profiler continuously emits acoustic signals into the water below. The movement of the ship allows the ADCP flow meter to cover a large area and gather current data in a wide field of view. For instance, in a routine survey of any port by a research or inspection ship fitted with a shipborne ADCP, it is able to collect data about the current pattern across various stretches of the port, thus enabling a proper understanding of the prevailing situation in water flow.

Fixed ADCP: Fixed ADCPs are installed in certain fixed positions within the port. These include on the seabed at locations with the highest navigational importance or at the entrance/exit of the port. In these fixed positions, the ADCPs continuously monitor the ocean currents for a long period. The data obtained from them is good for analyzing the regular current patterns in specific areas within the port. For example, a bottom-moored ADCP at the entrance of the port will measure the ingoing and outgoing currents and provide insights into the tidal influence and the rest of the regular flow features in that area.

4. What is required for good-quality measurement of Mormugao port currents?

Equipment Requirements

For the currents in Mormugao port, better-quality measurement requires some of the key equipment characteristics. First, material reliability is considered one of the main criteria. Since the marine environment is harsh, the equipment should be resistant to corrosion of the seawater. Commonly, seawater has various salts and chemicals in it, which might result in the corrosion of materials with time. The equipment also has to bear pressure change at different levels of water depth and mechanical forces due to waves and currents.

Secondly, a smaller size, lighter weight, and lower power consumption are desirable. A compact size allows for easier installation in various locations within the port, whether on ships, on fixed structures like piers, or on the seabed. A lighter weight simplifies the installation and transportation processes. The result of lower power consumption is the ability of the equipment to keep continuously in operation for long-term periods without constant battery replacements or excessive power supplies, which is especially important in the case of long-term monitoring applications.

Price is another decisive parameter: the lower the cost, the more measuring devices the port can deploy to make current monitoring more comprehensive within different areas.

Advantage of Titanium Alloy for ADCP Casing

ADCP current profiler casings are preferably made from titanium alloy. The titanium alloy possesses excellent corrosion resistance, in that it maintains its structural integrity and functionality even in seawater exposure for a long time. Its high strength-to-weight ratio allows for the construction of a durable yet relatively lightweight casing. For instance, an ADCP flow meter with the casing made of a titanium alloy, while deployed in areas of the Mormugao port that have deeper areas with increased water pressures, is able to withstand such pressure continuous in measuring currents quite accurately.

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

Selection Based on Usage

Shipborne ADCP: The best choice for wide-area surveys of the port waters when the ship is in operation would be the shipborne ADCP. It could cover the various sections of the port as the ship operates around these areas, covering a huge amount of data necessary to give a total overview of the general current situation within the port area. This is of essence in mapping the general flow patterns and variations across the different areas of the port waters.

Sitting-bottom ADCPs: For the monitoring of specific positions within long-term and fixed-point observation in such a port, some of these are located near to very important infrastructures or zones of complicated current behaviors. They can record continuously the current data at these fixed positions, therefore offering good insight into the local current characteristics and also their changes with time.

Buoy-mounted ADCP: where fixed installations on the seabed or on vessels are not convenient, buoy-mounted ADCPs can be utilized. They float on the water surface and are thus capable of measuring the currents in the upper layers of the water column. Relatively easy to deploy and redeploy, if necessary, they may be suitable for the monitoring of certain dynamic or hard-to-reach areas within the port.

Selection Based on Frequency

The choice of frequency for ADCPs depends on the water depth in Mormugao port. For areas with a water depth of up to 70 meters, an ADCP current meter with a frequency of 600 kHz is usually a good choice because it can provide current measurements quite accurately within this relatively shallow depth range. When dealing with deeper waters up to about 110 meters, an ADCP flow meter of 300 kHz is more advisable. In very deep parts of the port, with a water depth of up to 1000 meters, it is recommended to use an ADCP current meter with a frequency of 75 kHz to ensure reliable profiling of ocean currents at such great depths.

There are several well - known ADCP meter brands in the market, such as Teledyne RDI, Nortek, and Sontek. However, there is also an excellent Chinese ADCP brand - China Sonar PandaADCP. It is made entirely of titanium alloy material, which not only ensures its durability in the marine environment but also offers an excellent cost - performance ratio. For more information, you can visit its official website: (https://china-sonar.com/).

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