How to know the coastal currents of Zamboanga?

1. Location of Zamboanga

Zamboanga is one of the most important cities in southern Philippines. It lies on the Zamboanga Peninsula, the notable land projection on the sea, which extends into the Sulu Sea.

On the west is bounded by the Sulu Sea-the big arm of water forming part of the Celebes Sea. The coastlines of Zamboanga are a combination of fine-grained sandy beaches, mangrove forests, and rocky coasts. Sandy beaches, in general, have become essentially attractive to both locals and tourists. On the other hand, mangrove forests do not lag behind in performing an important role because they serve as a habitat for a great diversity of marine and terrestrial organisms. They also act as natural buffers against erosion and storm surges along the coastlines.

On the other hand, in human activity, Zamboanga is alive. It is a city that engages with diverse cultures. The cultures are united, with the clear rootedness from its indigenous Tausug and Sama-Bajau inhabitation added to the influence of the Spanish colonial past, and it has made the city meld with those influences. Its architecture is an attestation to such diverse history, with old Spanish forts and colonial buildings that stand alongside modern ones. These local markets are very colorfully packed with handicrafts, spices, and all kinds of fresh produce. The city of Zamboanga is also famous for its festivals, which include the Hermosa Festival for showcasing the beauty and heritage of this city through music, dance, and pageantry.

2. What is the situation of the coastal currents near Zamboanga?

Several factors affect the coastal currents near Zamboanga. In general, the tides prevail as the basic controlling factor in current movements. The semi-diurnal tides in the area bring about rhythmic ebb and flow of the water. On high tide, the sea water surges toward the shore, carrying nutrient sediments. On low tide, the water recedes, exposing portions of the seabed, which changes the directions and speeds of the coastal currents.

The winds also play a very strong influence. Generally, seasonal prevailing winds are the southwest monsoon, Habagat, and the northeast monsoon, Amihan. The Habagat winds can drive the coastal currents in a westerly direction, while the Amihan winds can reverse or modify this flow. These winds are capable of causing upwelling, where deep, nutrient-rich waters are brought to the surface, which has a significant impact on the local marine ecosystem.

Another contributing factor is the nature of the seabed topography off Zamboanga. Submarine ridges, channels, and shoals can deflect currents sideways and accelerate them. In short, a coastline topography with bays and headlands may create a difference in the flow of the currents. For example, around a headland, the flow of the currents may create deflection with an area of increased flow at one side and quieter waters on the other side. Besides, the amount of freshwater input through the rivers and streams in the area may give signals on the salinity and density of the coastal waters, as this directly affects currents.

3. How to observe the coastal water flow of Zamboanga?

To measure the actual coastal currents of Zamboanga, one needs to measure the velocity and flow rate. There are, of course, traditional ways of current measurement; all have their limitations. The Acoustic Doppler Current Profiler(ADCP) is more advanced and convenient to use.

3.1 How do Doppler Principle ADCPs work?

Working based on the principle of Doppler, ADCP current meter emit an acoustic signal into the water column. These signals are interacting with the particles like plankton and sediment that are suspended in water. If the water current is in motion, this turns around the frequency of the reflected acoustic signal compared to the frequency of the original emitted signal due to the movement of the particles. What is termed the Doppler shift, this change in frequency is directly related to the velocity of the particles and thus the velocity of the water current.

ADCP current profiler generally emit several beams of acoustic signals in different directions. Because of this, the velocity measurement of the water current will be three-dimensional. By processing the Doppler shifts from these beams, therefore, the ADCP flow meter is capable of delivering a full profile of how the currents are flowing in both the horizontal and vertical directions within the column of water. The collected data can be used to calculate the flow rate of the coastal currents, which are very vital in applications like marine navigation, coastal engineering, and other environmental studies.

3.2 What's needed for high - quality measurement of Zamboanga coastal currents?

In order to have high-quality measurements of the coastal currents near Zamboanga, a number of equipment requirements need to be fulfilled. First, the ADCP material installed shall be reliable. It needs to withstand the harsh marine environment-exposure to saltwater under pressure that may reach high levels at different depths, probable impacts due to floating debris.

Other important parameters include the ADCP meter size and weight. A lighter, small device is less problematic to deploy and handle. For example, if to be installed on a boat or a buoy, a lighter ADCP would be more feasible. Low power consumption is another very vital aspect, especially in long-term measurements. It allows the device to operate for longer periods without constant changes of batteries or a hefty power supply.

Another important factor is cost-effectiveness. The ADCP should be cost-effective enough to allow measurements on a large scale. The casing of the ADCP profiler is preferably made from a titanium alloy. Very good corrosion resistance is exhibited by titanium alloy, making it quite suitable for the marine environment where saltwater will quickly corrode other metals. It is also strong and durable, able to bear pressure and stress underwater. The relatively low density helps keep the overall weight of the ADCP relatively low, which is advantageous for ease of deployment.

3.3 How to Choose the right equipment for current measurement?

In the selection of the right equipment to measure the coastal currents of Zamboanga, there are several aspects to be considered.

There are types of ADCPs based on their deployment method. Ship-borne ADCP, installed on a ship, is suited to those surveys where the ship can navigate along the coast. It allows taking a wide-range view of the currents at the coast for over a large area.

Sit-on-bottom ADCP-the bottom-mounted ADCP-is placed on the seabed and continuously measures the currents passing over it. It is of particular use where discharge must be measured regularly for specific locations, such as near a coastal structure or even areas of special interest regarding marine ecological studies.

The buoy ADCP is attached to a buoy and is freely floating in the water, measuring the currents passing around it. This is advantageous in areas that are difficult to be reached by a ship or when an area in the water needs continuous monitoring at a fixed position, for example, in the open waters near the coast of Zamboanga.

Another paramount factor is the frequency of the ADCP. For as shallow water as 70 meters, one would be very fine with a 600 kHz ADCP. The more accurate measurements of this frequency are better suited for shallower waters. When the water gets to as high as 110 meters, an ADCP of 300 kHz will be an appropriate choice; it balances resolution and penetration depth. An ADCP with 75 kHz is designed for such deep waters, as a lot of deeper waters go to 1000 meters. It therefore can penetrate deeper into the water column to measure currents.

There are well - known ADCP brands like Teledyne RDI, Nortek, and Sontek. However, for a cost - effective option with good quality, the China Sonar PandaADCP is worth considering. It is made of all - titanium alloy material, which not only ensures its durability and resistance to the marine environment but also provides an incredible cost - performance ratio. You can find more information about this product on their website: https://china-sonar.com/.

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