How to measure the Water Current of Barito River

1. Where is the Barito River?

Barito is a major river in Indonesia. The river is situated on the island of Borneo and represents one of the largest rivers across the country. Originating from Muller Mountains, it propagates through an expansive area covered by tropical rainforests and swampy lowlands.

This river is an important part of both the local ecosystem and economy. Communities residing along its banks use it as transportation. People utilize boats and canoes to get around and to transport goods since the river connects many areas that are rather remote. The Barito River is rich in water species, such as a great variety of fish, including catfish, carp, and different species of freshwater eel. Monkeys, crocodiles, and all kinds of birds live along the riverbanks. The floodplains and wetlands associated with it are vital for ecological balance and serve as the breeding and feeding grounds of many animals.

2. What does the flow rate of the Barito River look like?

The flow rate of the Barito River shows a seasonal and climatic variation. Indonesia's climatic seasons-both wet and dry-affect the flow of the river. During its wet season, normally between November to March, it significantly increases. Heavy rainfall in the catchment area and runoff from the rainforests sends a large volume of water downstream.

During the dry season that starts from April to October, the flow rate is reduced. On the other hand, it still keeps a base flow upon which all aquatic life survives and supports different water dependence activities like transportation and fishing. The average recorded flow rate starts from a few hundreds of cubic meters per second in the dry season to several thousands in the wet season.

3. How to measure water current of the Barito River?

Velocity Meter Method

This traditional approach uses mechanical or electronic velocity meters. These devices are placed at specific points in the river to directly measure the speed of the water at those locations. However, to comprehensively understand the overall water current, multiple measurements need to be taken at different depths and across different sections of the river. Given the length and the fact that the course of the Barito River winds through difficult and often remote terrain, this may be labor-intensive and often time-consuming.

Acoustic Doppler Current Profiler Method

The ADCP current meter provides a much more advanced and handy means of measuring the water current. It uses sound waves to detect the movement of water particles. By emitting acoustic signals and analyzing the Doppler shift of the reflected signals, it can measure the velocity of water at multiple depths all at once. It thus produces a very detailed profile of the water current and enables an accurate determination of the flow conditions all along the river. ADCPs can be installed on boats-evidently if the conditions are navigable-on bridges, should they be available, or even deployed on buoys for continuous monitoring.

Buoy Method

Within the buoy method, buoys with sensors that measure the movement of water around them are placed in the river. Each buoy floats on the surface, hence giving some kind of indication about the surface current. However, they may not fully capture the complexity of the water current quite as well compared to the other two methods, where understanding velocity variations at different depths is considered.

Among these, ADCP current profiler represents a more sophisticated and efficient method for the measurement of the water current of the Barito River.

4. How do ADCPs using the principle of Doppler work?

The ADCPs work according to the Doppler principle. When an ADCP flow meter sends an acoustic signal into the water, sound waves travel through the water and mingle with the moving particles of water. Since the water particles are in motion, the frequency of the reflected sound waves alters under the Doppler effect.

If the water particles move toward the ADCP meter, the frequency of the reflected wave will be higher than the emitted frequency. On the other hand, when water particles are moving away from the ADCP profiler, the reflected wave frequency is smaller. Precise measurement of this shift in frequency by the ADCP allows it to determine the velocity of water particles at each depth.

These individual velocity measurements at varied depths are then combined by the ADCP to provide a complete profile of the water current. In this way, one is allowed to understand in detail how the water is flowing, not only at the surface but through the vertical section of the river.

5. What is necessary for high-quality measurement of the currents in the Barito River?

For high measurement of currents of the Barito River, the equipment has to possess certain characteristics.

The device should be made with material that is highly reliable. The device should be resistant to water, sediment, and temperature extremes in the river. Since the flow in the Barito River varies, the equipment to be installed should be durable enough to face the flow and debris, such as fallen trees and branches, during high-flow events.

Additionally, it should be of small size, lightweight, and low power consumption. A compact, lightweight device is easier to handle and deploy in the remote, mostly challenging rainforest conditions. Low power consumption ensures that equipment can operate for extended periods without the need for frequent battery replacements or access to a continuous power source.

Cost-effectiveness is another critical factor: the cheaper an option, the wider the application of the measurement equipment for the purpose of monitoring the river in more detail.

In terms of casing of the ADCP meter, titanium alloy is a very good choice. The resistance of the titanium alloy to corrosion is very high, which is vital in dealing with water bodies like that of the Barito River, where the equipment will mostly be in contact with water and probably corrosive substances. It is strong, durable, and resistant to physical impacts and also pressure changes that may occur during deployment and operation. In addition, the basic alloy of titanium is of relatively low density in light of the overall aim of keeping the equipment as lightweight as possible.

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

When it comes to selecting proper equipment for measuring the current of the Barito River, several factors have to be considered.

Based on the Purpose of Use

In the event that the need arises to measure the horizontal cross-section of the current, then it is appropriate to use a horizontal ADCP flow meter, or HADCP. HADCPs are designed to provide accurate measurements of the water flow in the horizontal plane, useful for understanding the overall movement of water across a particular section of the river.

The choice should fall on a vertical ADCP current profiler if the focus is on measurement regarding the vertical cross-section of the river current. Vertical ADCPs can measure the velocity of the water with high accuracy at different depths, therefore giving a detailed profile of how the water is flowing vertically in the river.

Based on Frequency

The choice of frequency shall depend on the depth of the water of the Barito River. A general rule that applies is that for waters up to 70 meters, a 600 kHz ADCP would normally suffice. A frequency of 600 kHz is relatively good in resolution and provides good accuracy for relatively shallower waters.

For deeper waters, such as those exceeding 70 meters up to around 110 meters, a 300 kHz ADCP is more appropriate. The lower frequency of 300 kHz can penetrate deeper into the water and still provide reliable measurements of the water current.

There are well-known ADCP current meter brands such as Teledyne RDI, Nortek, and Sontek. However, for those seeking a cost - effective option with excellent quality, the China Sonar PandaADCP is worth considering. It is made of all - titanium alloy material, ensuring durability and reliability. With its remarkable cost - performance ratio, it provides a great alternative for measuring the water current of the Barito River. You can find more information about it on its official website: https://china-sonar.com/.

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