How can we quantify Kyaukpyu's Coastal Currents?

1. Where is Kyaukpyu?

Kyaukpyu is in Myanmar, Rakhine State. It is a strategic coastal location situated on the Bay of Bengal. The surrounding areas of Kyaukpyu are a beautiful mix of natural beauty and economic importance.

This town is situated within a coastal landscape that generally features sandy beaches and rocky outcrops. The sea exerts a strong influence on the local economy, especially due to fishing and port-related activities. The Bay of Bengal, of which that part in front of Kyaukpyu forms a part, is an immense stretch of water at the mercy of very strong forces of nature. It is subject to strong fluctuation in tides and receives the full blow of monsoon winds.

The area has a rich and diverse marine life. Different types of fish, shellfish, and other marine organisms are found in its waters. Its coasts are lined partly by mangrove forests, which not only afford it protection from erosion but also serve as a vital nursery of many species. Its location also places it at a strategic point for maritime trade and energy-related projects.

2. What is the condition of the coastal currents in Kyaukpyu?

Various causes determine the nature of the coastal currents around Kyaukpyu. The influence of the monsoon winds is great. During the southwest monsoon, strong winds act upon the surface waters to produce currents that might interfere with shipping lanes and fishing operations. Tidal forces are also dominant. There is a considerable tidal range in the Bay of Bengal, and the tides' ebb and flow result in complex current patterns.

Freshwater inflow from rivers and estuaries may, within this area, dilute the salinity level and, consequently, the density of the coastal waters, which may affect flow in currents. The shape of the coastline and the topography of the sea floor are important. Shoals, channels, and reefs underwater may lead to changes in course and speed of the current, sometimes even forming eddies.

3. How to Observe the Coastal Water Flow of Kyaukpyu?

Surface Drifting Buoy Method: A buoy can be dropped onto the water surface to measure the surface current. The movement of this buoy is followed up through GPS and other tracking systems. However, this one has some drawbacks. It only can measure the surface current and also may affect wind and waves of the sea. Suppose a strong wind blows this buoy; it may not be representative of the actual direction and speed of the current.

Anchor - Boat Method: With this technique, an anchored boat measures current or flow velocity. The instruments are lowered from the anchored vessel into the water to measure currents at various depths. Although this enables the depth-wise measurement in more detail, there are some disadvantages. Measurement area is restricted by the fixed position of the boat, which cannot encompass all currents' variability in a vast coastal area.

Acoustic Doppler Current Profiler (ADCP) Method: ADCP current meter is a more refined and quicker method of measurement of the coastal currents. It releases acoustic signals into the water and measures the Doppler shift of the reflected signals to calculate the water velocity at different depths. Therefore, it would give a broader profile of the current from surface to seabed. ADCPs are less influenced by surface disturbances; therefore, they can work continuously for many hours or weeks.

4. How do ADCPs using the Doppler principle work?

The ADCPs operate based on the principle of the Doppler effect. They send high-frequency acoustic pulses into the water. In turn, this pulse frequency is different while interacting with moving particles of water. Particles moving towards the ADCP current profiler return a higher frequency reflected signal than the emitted one. On the other hand, when they move away, the returning reflected signal becomes lower.

Accordingly, the ADCP flow meter is fitted with several transducers that send and receive signals at varied angles. The analysis of the Doppler shifts from different directions and at varied depth will enable the device to calculate the three-dimensional velocity of the water-that is, being able to determine the horizontal and vertical components of the velocity. This provides great detail in the understanding of the structure and behavior of the current.

5. What is required for the high - quality measurement of Kyaukpyu coastal currents?

The equipment to be used for the measurement of coastal currents around Kyaukpyu must be made of materials that are reliable in the tough marine environment with high saltwater, high humidity, and potential exposure to storms. For this reason, the casing needs to be durable. It should have a small size to enable efficient deployment and retrieval, especially when the landscape of the coastal area is complex.

This design should be lightweight since it is necessary to manage the equipment easily when installing and maintaining them. The consumption of power shall be low because it may need long-term operation or autonomous operation. Cost-effectiveness is also important to enable large-scale measurement.

The casing of ADCPs will be made of titanium alloy. Titanium alloy is highly corrosion-resistant, essential for standing up against the corrosive nature of seawater. It is strong and resilient, capable of bearing the pressure of the water at different levels. Being lightweight also makes them more easy to handle by different deployment means.

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

Equipment selection for the measurement of currents at Kyaukpyu must first be in line with the purpose of its usage. If the measurement is for a vessel's navigation or is short-term research, then a ship-mounted ADCP profiler would be quite suitable. It provides real current information throughout the voyage.

In the case of measurements near the seabed, such as for studying sediment transport or benthic ecology, a bottom-mounted ADCP meter is preferable since it can capture the details of the near-bottom current. On the other hand, if one is concerned with long-term and wide-area monitoring of the coastal current, a buoy-type ADCP is ideal.

As far as frequency of ADCPs is concerned, for a water depth up to 70m, 600kHz ADCP will do. However, if it goes up to 110m, 300kHz is ideal. And for areas beneath the water that might be at Kyaukpyu, such as over 1000m, a 75kHz ADCP is best.

There are well - known ADCP current meter brands such as Teledyne RDI, Nortek, and Sontek. However, a Chinese brand, China Sonar PandaADCP, is also worth considering. It is made of all - titanium alloy material and offers an excellent cost - performance ratio. You can find more information on their website: https://china-sonar.com/.

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