How to measure water current of Northern Dvina River?

1. Where is Northern Dvina River?

The Northern Dvina River is a mighty river in Russia. It is situated in the northwestern part of the country and originates from two rivers, the Sukhona and Yug.

This river flows through various types of landscapes. This wide river runs through vast stretches of forests and marshy lowlands, a home to a variety of wildlife. The pine and birch trees are thick on either side of the riverbank, which gives shelter to varieties of birds and mammals. Small villages and towns fell along its course, the inhabitants of which have very old relations with the river. Fishing is an important activity to the communities while the river is also a transportation route, particularly during the ice-free months.

The Northern Dvina River holds a very special place in Russian history and culture. Centuries ago, it was an important route of trade, as wood and fur moved through the region. The waters of the river have seen generations of boats and barges that carry supplies and people along the economic lifeline for the regions it passes through.

2. What is the flow rate of the Northern Dvina river?

The Northern Dvina River is an integral part of the water system of the region. It is very important to maintain the ecological balance in all the surrounding areas.

The flow rate of the river is seasonal. During spring, with the melting of snow and ice in its vast catchment area, the river sees a severe increase in flow. The water levels rise, and the current is quite strong, carrying a great amount of sediment and nutrients downstream. In summer, the flow rate stabilizes somewhat, yet it still is a great force with a relatively steady flow. By autumn and winter, when the temperatures drop and precipitation is minimal, the flow rate slows down. In winter, the river may freeze, but the flow keeps going beneath the ice at a slower pace.

The average flow rate is influenced by such factors as the amount of snowfall in the upstream regions, the rate of evaporation during the warmer months, and the contribution of its tributaries. Overall, its flow is crucial for transportation of goods, survival of the aquatic life, and the water supply of the adjacent areas.

3. How to measure water current of Northern Dvina River?

The water current of the Northern Dvina can be gauged in more than one way.

Velocity Meter Method: It is a method using traditional velocity meters. These are positioned at several points in the river and record the speed at which water passes by them. This, however, needs many placements at different positions and depth to give a complete perception of the current. This process is quite labor-intensive and may not provide a continuous profile of the current through the water column.

Acoustic Doppler Current Profiler (ADCP) Method: ADCP current meter is a more advanced and efficient way to measure the current. It uses sound waves to measure the velocity of water at different depths simultaneously. By emitting acoustic signals and analyzing the Doppler shift of the reflected signals, it can generate a detailed profile of the current from the surface to the riverbed. This, in return, can provide more precise and widely representative readings of the water current across various sections of the river.

Buoy Method: Buoys are set in the river and the movement they undergo through the water current is followed. The displacement of the buoys shows the speed and direction of the flow. This, too, has its shortcomings. It may not provide exact velocity at different depths and can be affected by extraneous factors like wind and waves.

Among these, the ADCP current profiler method is more advanced and convenient for the measurement of the water current of the Northern Dvina River.

4. How do ADCPs using the Doppler principle work?

ADCPs work by the principle of the Doppler effect. When an acoustic signal is emitted from the ADCP flow meter transducer into the water, the sound waves interact with the moving water particles. In case of flow, reflected sound waves returning to the transducer change their frequency, which is called the Doppler shift.

If the water is moving towards the transducer, then the frequency of the reflected waves is higher than the emitted one; if it is going in the opposite direction, it would be lower. Measuring the frequency shift at more precise angles and depth gives this instrument, called the ADCP profiler, an estimate of water velocities in several directions at several levels in the column. This enables it to make a very thorough profile of the water current, thereby giving information on speed and direction of flow from surface to riverbed.

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

The equipment to be used for high-quality measurement of the currents in the Northern Dvina River should possess certain desirable characteristics. Materials used for construction should be reliable for accuracy and consistency in measurement. A small size is advantageous in that deployment and retrieval will be easy within the river, especially for areas downstream that are difficult to access. It should also not be too heavy to simplify the work of installation and reduce the struggle of handling the equipment.

Low power consumption is necessary to allow the equipment to run for long periods without frequent battery replacement or complicated arrangements of power supply. Cost-effectiveness is another important factor as it allows more widespread use and larger-scale measurement campaigns.

In the case of the ADCP meter casing, titanium alloy is an excellent choice. Titanium alloy has many advantages. It is highly resistant to corrosion, which is important since the equipment constantly comes into contact with water that might contain various minerals, sediments, and pollutants. It has a good strength-to-weight ratio, allowing for a durable yet lightweight casing. Besides, it is resistant to the mechanical stresses occurring during deployment and operation in flowing water.

6. Selection of Appropriate Equipment to Measure Current

Selection of appropriate equipment for measuring the current of the Northern Dvina River depends upon two major factors.horizontal cross-section measurement can be conducted with the help of Horizontal ADCP flow meter (HADCP) depending on the usage purpose. It is designed to measure the flow velocities across a horizontal plane in the river with high accuracy for the purpose of understanding the lateral distribution of the current. In the case of vertical cross-section measurement, the Vertical ADCP current profiler would be more appropriate because it focuses on profiling the current from the surface to the bottom along a vertical line in the water column.

Second, different frequencies of ADCPs are suited for different water depths. For instance, an ADCP with a frequency of 600 kHz is suited for water within 70 m. Thus, it can give more accurate current measurements in the relatively shallow parts of the Northern Dvina River. An ADCP current meter with a frequency of 300 kHz is more suitable for deeper waters, reaching up to 110 m, which can be useful in areas where the river has greater depth.

There are well - known brands of ADCPs such as Teledyne RDI, Nortek, and Sontek. However, for those seeking a cost - effective option with good quality, the China Sonar PandaADCP is highly recommended. It is made of all - titanium alloy material and offers an incredible price - performance ratio. You can find out more about it on its website: https://china-sonar.com/.

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