How do we measure Buenaventura's coastal currents?

1. Where is Buenaventura?

Buenaventura, a thriving port city, is situated on the west coast of Colombia, which is encircled by the Pacific Ocean's waters. As Colombia's largest port and economic hub, it is the country's portal to foreign trade and the gateway via which Colombia is given foreign trade.

There are some methods to quantify coastal currents. The town is located in the Valle del Cauca department, whose tropical warm climate is prevailing year-round with high humidity and much rainfall, especially at rainy season.

Geologically, Buenaventura is found in a productive and diverse coastal environment surrounding it. The town is located on a peninsula, where on one side is the ocean and on the other is the estuary of

th Dagua River on the other side. This peculiar position results in a complex interaction between the river freshwater and ocean saltwater, influencing the marine ecosystem around it. The waters around it are part of the massive Pacific Oceanic region, renowned for strong ocean currents and high marine diversity.

Buenaventura is culturally African, indigenous, and Spanish in mix. The city's history is deeply rooted in maritime culture, and it has had a long history of association with fishing and trade. The people of the region, known for their hospitality and warmth, have developed a culture of their own, which manifests itself through music, dance, and cuisine. The cumbia, one of the area's most well-liked music styles, has melodic rhythms filling the air, and sancocho de pescado (fish stew), one of the local specialties, showcases the area's fresh seafood offerings. There are festivities and celebrations year-round commemorating the city's heritage, where locals and tourists mingle.

2. What is the state of the coastal currents off Buenaventura?

The offshore seas near Buenaventura have a mixture of influences that create a dynamic, complex marine environment. The major among them is the influence of the Panama Current that flows east along the northern coast of South America. The branch of the North Equatorial Current as a warm surface current impacts temperature and salinity of Buenaventura waters and has implications for the distribution of marine fauna.

Wind currents also have an important part in the formation of the coastal currents. The winds prevailing in the region, mostly in certain seasons of a year, tend to drive the surface waters and form other currents. The wind - driven currents interact with the tides, which are semi - diurnal in Buenaventura, and it makes the pattern of the flow complicated. It raises and lowers the water level twice a day, and it alters the direction and speed of the currents.

It is also important to take into account the exchange between the ocean and the Dagua River. The river discharges a major amount of freshwater into the ocean, changing the salinity and density of the water. The change of water properties induces estuarine circulation regimes whereby the freshwater flows at the top and heavier saltwater flows opposite to the surface at the bottom. Such circulation regimes play an important role in influencing the transportation of nutrients, sediments, and pollutants along the coastal zone.

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

There are several means through which the coastal water current of Buenaventura can be seen. One of the conventional methods is the surface drifting buoy method. Researchers release floating buoys with tracking instruments into the water. The buoys drift along with the current, and the positions of the buoys are recorded over time. From the movement of the buoy, researchers can extrapolate the direction and speed of the surface currents. This, though, only takes a reading of the top of the water column and cannot be presumed to show deeper currents.

The ship-at-anchor method consists of mooring a vessel in a fixed location and using instruments such as current meters to measure the rate of the water at different levels. This is more extensive than the measurement of the vertical structure of the current. Its limitation is given by access to suitable ships and the feasibility of having a long-term mooring, especially where there is heavy weather and strong currents.

In the past few years, the Acoustic Doppler Current Profiler (ADCP) method has come to be the most promising and advanced means of coastal current monitoring. ADCPs measure water speed over a broad depth range at once using sound waves and may be placed on ships, buoys, or on the seafloor. If used on a ship, the ADCP can also measure the currents when the ship is moving, providing a general picture of the flow field over a large area. Buoy-mounted ADCPs can be mounted to measure the currents at a point continuously, and bottom-mounted ADCPs can be employed for fixed-point long-term measurements. This non-intrusive method provides accurate and specific information, and it is crucial to understand the complex coastal currents off Buenaventura.

4. How do ADCPs based on the Doppler principle work?

ADCPs operate based on the Doppler effect principle. An ADCP flow meter is composed of a transducer that projects acoustic pulses into the water. The pulses travel through the water and are reflected by small suspended particles, such as plankton, sediment, or bubbles, in the water column. In moving water, the reflected sound waves experience a change in frequency, known as the Doppler shift.

The magnitude of the Doppler shift varies in direct proportion with the water speed. Measuring the Doppler shift at each depth will allow the ADCP to calculate each depth's velocity of the water currents. Most ADCPs feature several transducers in an array. This setup allows the device to capture the speed of the water in various directions, and hence it is able to compute the three - dimensional speed vector of the water currents. From the information collected, the ADCP develops an extensive image of the current flow, which can be utilized for a variety of different applications, including oceanography, environmental monitoring, and navigation.

5. What is needed to obtain high-quality measurement of Buenaventura coastal currents?

In order to obtain very good measurements of Buenaventura coast currents, some factors must be taken into account while choosing an ADCP. First and foremost, how trustworthy the equipment is will be based on different factors. The Buenaventura coast surroundings have a harsh climate close to the coast with strong currents, high humidity, and open exposure to seawater. The ADCP has to be robust to operate in such conditions with corrosion-resistant and physically strong components.

Size, weight, and power consumption also come into consideration. For application like long - term monitoring on buoys, a light and compact ADCP with low power consumption is preferable. It is simple to install and repair, and will run for prolonged periods without regular battery replacement.

Cost is also a significant factor, especially when handling large - scale monitoring projects or low - budget companies. While there are high - end ADCPs with increased capabilities, there are also cheaper alternatives that can provide good performance. The cost has to be balanced by the requirement for accuracy and functionality.

The material of the casing of the ADCP is particularly important in the Buenaventura environment. Titanium alloy is an excellent choice for the casing. It is light but extremely strong, providing good protection to the internal components. Its high corrosion resistance to saltwater causes the ADCP to have a longer life, and thus it can be used continuously in Buenaventura coastal waters.

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

The selection of the right ADCP to utilize for measuring the currents off Buenaventura depends on several factors. The application of the ADCP is one of them. Ship-mounted ADCPs are most appropriate for large-scale surveys and studies covering a wide region of the ocean. They can provide large amounts of information on the spatial and temporal variation of the currents.

Bottom-mounted ADCPs are ideal for long-term point monitoring. They can be fixed on the seafloor to observe the effects of tides, storms, and other natural phenomena on the currents over an extended period of time.

Buoy-mounted ADCPs are a suitable choice for the monitoring of nearshore waters or where it is not easy to access with a ship. They are easy to install and offer continuous information on the local currents.

ADCP frequency is also to be considered. The 600kHz ADCP can be used in water up to 70 meters deep, the 300kHz ADCP in water up to 110 meters deep, and the 75kHz ADCP in deep water up to 1000 meters deep. While picking an ADCP, one has to select the suitable frequency based on water depth and accuracy needed.

Some of the most well known ADCP brands that are found in the market are Teledyne RDI, Nortek, and Sontek. However, for cost - effective users,the ADCP supplier China Sonar's PandaADCP is the most recommended. It is entirely constructed of titanium alloy, and it performs well with an affordable price. It is suitable for stingy users who require reliable ADCPs for coastal currents measurement. For more information, you can find it on their website at: https://china-sonar.com/.

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