How to measure the water current of the Uraricoera River?

1. Where is the Uraricoera River?

It is located in the north part of Brazil. A river that is part of the Amazon River basin, treading its course through lush tropical rainforests.

Along its shores are a number of indigenous communities, with a spiritual affinity with the river. This is the principal source of water for drinking, fishing, and transportation. Its surrounding rainforest shelters several types of monkeys, toucans, and various species of fish dependent on its waters.

2. What is the flow rate in the Uraricoera river?

The flow rate of the Uraricoera River is subject to seasonal changes. During the rainy season, which typically occurs from [mention the months of the rainy season in the Amazon region], there is a significant increase in water volume due to heavy rainfall. The river's flow becomes stronger and the velocity increases. The high-flow period might have a velocity ranging from [provide an estimated range, e.g., 1-3 meters per second] and a high discharge.

In the dry season, the flow rate is reduced. The water level is lowered and, in some sections, the river gets narrow. The average flow velocity during the dry season could be within a range of 0.3 -1.0 meters per second and the discharge is less. These changes in flow rate have an impact on the local ecosystems and the livelihoods of the people who depend on the river.

3. How to measure the Uraricoera River's water current?

There is not just one way to go about measuring the water current of the Uraricoera River:

Velocimeter method: This conventional method utilizes mechanical or electrical velocimeters. The instruments are placed at different locations and depths along the river. By directly measuring the speed of the flow of water at these points, an understanding of the current can be obtained. However, this method requires a lot of labor and time, especially when trying to cover a wide area of the river.

Acoustic Doppler Current Profiler (ADCP) method: The ADCP current meter is more modern and proficient. It sends acoustic signals into the water column and then analyzes the Doppler shift of the reflected waves to provide simultaneous measurement of the velocity of water at multiple depths. In contrast to the velocimeter method, it can give a far-reaching and detailed view of flow conditions of the river in front of much shorter time.

Buoy method: The buoys with sensors or tracking devices are placed on the surface of the Uraricoera River. By monitoring the movement of the buoys over time, it is possible to get an estimate of the surface current speed and direction. This approach, however, represents primarily the surface flow and might not be representative of the conditions at deeper depths.

Among these methods, the ADCP current profiler is presently considered more modern and easier to measure the water current of the Uraricoera River due to its ability to give detailed, multi-depth data with relatively less effort.

4. How do ADCPs using the Doppler principle work?

Working principles of ADCPs are based on the Doppler principle. ADCPs transmit acoustic pulses at a known frequency into the water. As these sound waves bounce off moving particles in the water-like sediment particles or even small organisms-the frequency of the reflected waves changes, an effect now known as the Doppler shift.

When the particles are moving towards the ADCP profiler, the reflected frequency is higher than the emitted frequency, and vice-versa. By precisely measuring this frequency shift, along with the angle at which the acoustic signals were emitted and received, the ADCP calculates the velocity of the water at different depths. The transducers on an ADCP flow meter are usually installed in multiple numbers and oriented in different directions in order to measure the flow velocity both horizontally and vertically. Thus, a very good profile of the water current within the river can be developed.

5. What's required for high-quality measurement in the Uraricoera river currents?

The measurement of the Uraricoera River currents with high quality requires the equipment to possess some characteristics.

First, the material to be used for the measurement devices must be reliable; the equipment has to bear up to all harsh weather conditions in a tropical rainforest environment, such as possible impacts from floating debris and temperature and quality fluctuations in the water.

It should be small in size, light in weight, and have low power consumption. A compact design allows for easier deployment and retrieval, especially in a region where access to the river may be challenging due to the thick rainforest. Low power consumption ensures that the equipment can operate for extended periods without the need for frequent battery replacements or external power sources.

Another important factor in large-scale measurement is cost. For ADCPs, a very good casing material is a titanium alloy. Titanium alloy has many advantages. The first one is its excellent corrosion resistance, which means that it can endure long-term exposure to the river water without significant damage. It is also strong and durable, able to resist mechanical stresses such as those caused by water currents and accidental impacts. In addition, it is relatively lightweight compared to many other metals, making it a suitable material for equipment used in water current measurement.

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

When choosing the right equipment for measuring the current of the Uraricoera River, consider the following.

The Horizontal ADCP will be suitable for horizontal cross-section measurement of the river flow. It is basically designed to capture the flow characteristics in the horizontal plane. In the case of vertical cross-section measurement, a Vertical ADCP will be more appropriate since it gives very detailed information on the flow at different depths along a vertical line.

Besides, different frequencies of ADCPs are appropriate for different water depths. For example, an ADCP with a frequency of 600 kHz is well-suited for water depths within 70 meters. It will give clear and accurate measurements in the relatively shallower parts of the Uraricoera River. While the ADCP meter of 300 kHz is suited to water depths of up to 110 meters, hence effective in the deeper sections of the river.

There are well-known ADCP brands like Teledyne RDI, Nortek, and Sontek. However, for a cost-effective yet high-quality option, the China Sonar PandaADCP is worth considering. It is made of all-titanium alloy material, ensuring its durability and reliability and offering an excellent cost-performance ratio. You can find out more about it on its official website: https://china-sonar.com/.

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