How do we estimate the coastal currents of Batangas?

1. Location of Batangas

Batangas is a province in the Philippines and is located on the southern part of Luzon. It is a coastal area with its various terrains and dynamic economic vigor.

Geographically, it is bestowed with a long coastline facing the Verde Island Passage, once recognized as the "Center of the Center of Marine Shorefish Biodiversity" in the world. The place has beautiful beaches, coves, and headlands. In general, the coastal plains are level and fertile, thus appropriate for different agricultural activities. There are volcanic features in the place since Batangas is near some active volcanoes, such as Taal Volcano.

On the human side, fishing is one of the major industries. Its rich marine resources make Verde Island Passage a place that provides livelihood to a wide number of fishermen. It houses several beach resorts and diving spots, attracting local and international tourists alike. Some of the notable tourist spots there are likewise found in the province, including the port of Batangas, an important transportation hub that services trade and travel.

The waters of Verde Island Passage harbor a large number of marine species. In particular, the numerous multi-colored coral reefs host literal thousands of species of fish, crustaceans, and other creatures. The sea condition varies with the seasons and is formed during the monsoon seasons due to the peculiar topography of the area.

2. What are the conditions of the currents along the shores near Batangas?

In the case of Batangas, coastal currents depend on a number of factors, one of which would be tidal current contribution. In general, tidal currents arise due to gravitational forces pulling on the sea by the moon and sun; this causes the tides to ebb and flood. These tidal currents can vary in strength and direction depending on the lunar cycle and the local topography of the coastline and seabed.

The most pronounced effect is by the monsoon winds. During the southwest monsoon, known locally as Habagat, the wind blows from the southwest, pushing the surface waters and creating generally prevailing currents in one direction. Meanwhile, during the northeast monsoon, known locally as Amihan, the northeast winds are variable.

Another decisive factor is the topography of the seabed, especially around the Verde Island Passage. The islands, islets, and underwater ridges will make it accelerate, decelerate, or change directions. The complicated shoreline morphology, bays, and headlands influence the flow of the currents. Inflow of freshwater from local rivers might affect the density of the coastal waters and hence the current patterns.

3. How to Observe Coastal Water Flow of Batangas?

Batangas current could be described in terms of velocity and flow rate. Velocity may range from slow in sheltered bays and lagoons to quite fast in areas where the currents are normally constricted or where stronger winds or tides are acting upon them. The amount of water that actually moves through a given area in a unit time determines the flow rate.

These can be effectively measured by ADCP current meter. In fact, ADCP current profiler can provide very accurate and detailed data about the water flow at varied depths.

3.1 How do ADCPs Based on the Doppler Principle Work?

The working principle of Acoustic Doppler Current Profiler (ADCP) is based on Doppler. ADCPs emit acoustic signals into the water. These signals tend to scatter against moving particles in the water, such as sediment, plankton, and small organisms. As a result of the moving particles, the acoustic waves are reflected back, the frequency of the reflected waves changing.

This frequency shift is linearly proportional to the velocity of the moving particles and, therefore, the water velocity. Because they emit multiple acoustic beams in various directions, ADCP flow meter have been able to measure the three-dimensional velocities of water, with components of both horizontal and vertical. After processing, the data collected is converted into useful information about the coastal currents.

3.2 What is required for high - quality measurement of Batangas coastal currents?

For the high-quality measurement of Batangas's coastal currents, the equipment used has to meet the certain requirements. First, the material of the equipment must be reliable enough to protect it from the harsh marine environment. The material of the equipment must be resistant against the corrosion caused by saltwater, and it has to remain resistant against various levels of humidity and temperature.

This equipment should be compact, light, with low power consumption, and should be able to provide cost-effective large-scale measurements. The casing of ADCP doppler would preferably be made from Titanium alloy. It is for this reason that titanium alloy has excellent corrosion resistance, an important feature in salt water, and is strong and durable enough to resist mechanical stresses in the marine environment. Besides, this relatively low-density material helps to reduce the weight of the equipment. It has good thermal stability that is useful in variable temperature conditions in the sea.

3.3 How to choose the right equipment for current measurement?

Choosing the equipment to measure current in a given site in Batangas requires consideration of the method for its deployment. There are different types of ADCP profiler with variation in different applications.

In the case of ship-based measurements, it can be done by a ship-mounted ADCP meter. It could measure the current the ship is experiencing while running in the water.

If the measurement has to be done from the seabed itself, then a bottom-mounted ADCP is ideal. It would be placed on the seabed and would measure the currents that pass over it.

If the measurements are done with the help of a floating platform, then it would be a buoy-mounted ADCP.

The 600kHz ADCP will provide high-resolution measurements for water depths up to 70m. For waters somewhat deeper, ranging from 70-110m, a 300kHz ADCP is more appropriate, while for very deep waters of up to 1000m, a 75kHz ADCP will be quite appropriate since it can penetrate deeper to measure currents with good accuracy.

Among the ADCP brands, well - known ones include Teledyne RDI, Nortek, and Sontek. However, for a cost - effective option with excellent quality, the China Sonar PandaADCP is a good choice. It is made of all - titanium alloy and offers an excellent price - performance ratio. You can visit https://china-sonar.com/ for more details.

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