How to measure water current of Sukhona River?

1. Where is Sukhona River?

The Sukhona River is a significant watercourse in north - western Russia. It is within Vologda Oblast and Arkhangelsk Oblast. The river flows through an area dominated by forests, meadows, and pieces of agricultural land. Its two banks are dotted with villages and small towns in scores. The local communities have a long - standing relationship with the river. It is used for fishing, providing a source of food and livelihood for many. The Sukhona River also serves as a transportation route in some areas, especially in the past when river transport was more prevalent. Many other wild creatures, like beavers, otters, and lots of birds that depend on the river, also inhabit areas around it.

2. What is the Sukhona river like in terms of flow?

The flow of the Sukhona River varies by season. During spring, when snowmelt from upstream regions occurs and rain is more voluminous, the flow is significantly greater. The water is surging downstream with a relatively high velocity, and the discharge can be quite substantial. The high-flow period may see velocities reaching an estimated range of 0.6-1.5 meters per second and discharges in the range of an estimated volume of 30-100 cubic meters per second.

The rate of flow would be low during summer and fall as water is removed for agriculture and other purposes due to evaporation. The average stream velocity could be in a range from 0.1 - 0.5 meters per second, and this discharge can go as low as 10 - 30 cubic meters per second over the months of low precipitation. In winter, because of partial freezing of ice, the flow beneath would be greatly reduced.

3. How to measure the Sukhona River water current?

There are a number of ways by which the Sukhona River water current is measured.

Velocimeter method: This traditional technique applies mechanical or electrical velocimeters. These instruments are placed at different depths and locations along the river. The speed of the water flow at these points is directly measured, thus giving an idea about the current. 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): This is more modern and effective. ADCP current meter emits acoustic signals into the water column and analyzes the reflected waves for the Doppler shift, which allows the measurement of water velocity at more than one depth simultaneously. It can present a more detailed picture of flow conditions of the river in front of the transit in less time than is possible with the velocimeter method.

Buoy method: Buoys equipped with sensors or tracking devices are placed on the surface of the Sukhona River. By observing the movement of the buoys over time, an estimate of the surface current speed and direction can be made. However, this method is focused on the surface flow mainly and may not represent conditions at greater depths.

Among these methods, the ADCP flow meter is currently considered a more advanced and convenient way to measure the water current of the Sukhona River due to its ability to provide detailed, multi-depth data with relatively less effort.

4. How do ADCPs using the Doppler principle work?

ADCPs operate based on the principle of the Doppler principle. They emit acoustic pulses at a known frequency into the water. These sound waves return at a shifted frequency when those pulses come into contact with any moving particles in the water, like sediment particles or other small organisms. This shift of frequency is called the Doppler shift.

If the particles are moving towards the ADCP meter, the reflected frequency is higher than the emitted one, and if they are moving away, it is lower. With the exact measurement of this shift in frequency, and with consideration of the angle at which the acoustic signals were emitted and received, the ADCP profiler is able to calculate the velocity of the water at different depths. Usually, several transducers on the ADCP current profiler are set up in various orientations and measure the flow velocity in a number of directions, including both horizontal and vertical components. This allows a detailed profile of the water current to be made of the river.

5. What's needed for high - quality measurement of Sukhona river currents?

High-quality measurement of Sukhona River currents can be performed by equipment that would possess certain characteristics. The materials used to build up the measuring devices should be of good quality and reliable. Equipment should sustain all those harsh conditions such as possible impacts from the floating parts, changes in water temperature, and quality fluctuations.

The equipment design should also be of small size, light in weight, and low power consumption. In such a compact design, deployment is easier and retrieval can be better accomplished, particularly in the region where access to the river may be somewhat challenging due to terrain or lack of infrastructure. The low power consumption ensures that the equipment can work for extended periods without requiring frequent battery replacements or other external power sources.

Another important factor for large-scale measurement is the cost. Titanium alloy is an excellent choice as the casing material for the ADCPs. The advantages of using it are many. It has excellent resistance to corrosion, which means it may endure long-term exposure with the river water without having significant damage. It is strong, tough, and resistant to mechanical stresses such as water currents and impacts in case of accidents. Besides, it is relatively light in weight compared to a lot of metals, hence suitable for making equipment to be used in water current measurement.

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

With the view to select proper equipment for the measurement of the Sukhona River current, the following should be considered. In general, for measuring the horizontal cross-section of flow, the Horizontal ADCP-HADCP-would be appropriate because it is specially designed to accurately capture the horizontal plane flow characteristics. This would, however, be more appropriate in measuring vertical cross-sections since detailed information about flow in different depths along a vertical line is acquired.

Besides, ADCPs of different frequencies are suitable for different water depths. For example, an ADCP with a frequency of 600 kHz is well-suited for water depths within 70 meters. It can provide clear and accurate measurements in the relatively shallower parts of the Sukhona River. In the meantime, an ADCP of 300 kHz would suit water depths of up to 110 meters and therefore will serve the deeper parts 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.