How to measure water current of Lower Tunguska?

1. Where is Lower Tunguska?

The Lower Tunguska River is one of the main rivers in Siberia, Russia. It is located in a very vast and far-away area of the most natural region, highly preserved in its form. The river meanders through heavy taiga forests, housing many animals such as bears, wolves, and several bird species.

It continues to play a major role in the local ecosystem, with plentiful water and a huge variety of flora and fauna living upon it. The surrounding landscape has lots of small settlements with traditional Siberian architecture. The local villages have lived alongside this river for generations, depending on it for everything from fishing and transportation to other needs pertaining to their livelihoods. It may be mysterious, too, since it winds its way through an area steeped in history and folklore. In fact, the Lower Tunguska serves as an artery that connects disparate parts of the Siberian wilderness. The waters have a unique character because of the cold climate and geology of the region.

2. What kind of flow does the river of Lower Tunguska have?

The Lower Tunguska River has a highly seasonal flow rate. During the spring months, when snow and ice from the surrounding areas melt, the river has a high flow. The water volume can surge tremendously, with a fairly strong current.

During the summer period, the flow somewhat stabilizes, but it is still comparatively strong considering the incessant influx of water from its tributaries and groundwater sources. In autumn, while the temperatures are gradually starting to fall, the flow rate also decreases correspondingly. In winter, the flow in the river is considerably less, and in places, the river might be totally frozen.

Its course means that the average flow rate of the Lower Tunguska has to be different in its respective sections, and with a more pronounced gradient in its upper reaches, the flow can be faster in those areas, while it would be flatter in the lowland area. Precipitation in the watershed, including the water-holding capacity in soils and snowpack around, modulates the general flow rate.

3. Measurement of water current of Lower Tunguska?

There are several traditional and modern ways of measuring the water current of the Lower Tunguska River. The use of a current pole is one of the most straightforward traditional methods. A pole, with markings on it, is inserted into the water, while an observer notes the deflection of the pole caused by the current. It gives only an approximate idea of the speed of the surface current.

Another method involves a float. A buoyant object is dropped into the river and its time across a known distance is measured; from that time and distance, the speed of the current can be determined. All these methods, however, have serious drawbacks in that their readings are generally restricted to the surface current and therefore may not be an indication of the whole current profile accurately.

In recent years, advanced techniques have made ADCP current meter popular. They offer a more comprehensive and correct way to measure the current of water.

3.1 How do ADCP using the principle of Doppler work?

Acoustic Doppler Current Profiler(ADCP) work on the principle of the Doppler effect. The instrument emits acoustic pulses into the water. The pulses interact with particles and other substances that are in suspension in the water. Due to the fact that water is in motion, reflected acoustic signals have changed frequency.

This frequency shift is measured by the doppler current profiler. It can deduce, by using the Doppler formula, the water velocity at different depths. The ADCP current profiler can send out multiple pulses in different directions and at different frequencies to build an extremely detailed profile of the water current throughout the water column. This gives a much better view of the current structure of the river, compared to traditional methods.

3.2 What is necessary for high-quality measurement of Lower Tunguska river currents?

The equipment to be used for the high-quality measurement of Lower Tunguska River currents has to be highly reliable since the area condition, which might be icy as well, and the measuring devices have to be able to work under those conditions.

It should also feature small size and lightweight to allow it for easy transport to the remote locations along the river. Power consumption should be low to make the equipment operate long, not requiring many battery replacements or external sources of power. For large-scale or longtime measurement, cost-effectiveness would also be considered important.

The casing of the equipment can be made from the titanium alloy; an example is ADCP doppler. Being in a water-rich environment, say a river, requires high resistance to corrosion, hence the material to be used is quite essential. It's very strong and able to stand the physical forces that the river current creates, or any impacts. Its light weight makes the equipment easy to handle and install at different locations along the river.

3.3 How to Choose the right equipment for current measurement?

The current of the Lower Tunguska River should be measured with equipment selected with due consideration for the measurement requirements. The horizontal ADCP is one suitable choice for current measurements across a section in the horizontal direction, thus giving a broad view of current flow in the horizontal plane, which will be useful to understand the overall pattern of flow in the river.

For vertical profile measurements of the current, a vertical ADCP would suffice. It can provide detailed information on the speed of water at different depths, which is important in various studies of stratification and mixing of the water column.

Different frequencies are adequate, depending on the water depths: for relatively shallow stretches of the Lower Tunguska River, an ADCP flow meter of relatively higher frequency (like 600 kHz) could be used, while for deeper stretches (up to greater depth), it would be more appropriate to use an ADCP of 300 kHz frequency.

There are several brands of ADCP available in the market. Brands like Teledyne RDI, Nortek, and Sontek are well - known for their quality. However, for a cost - effective solution with good quality, the China Sonar PandaADCP is worth considering. It is made of all - titanium alloy, which provides durability and resistance to the harsh river environment. It also offers an excellent price - performance ratio. You can visit https://china-sonar.com/ for more details.

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