How to Measure Water Current of Khatanga River?

1. Where is Khatanga River?

The Khatanga River is a very interesting water body in Russia's Arctic regions. It is set within the Taymyr Peninsula, an ultra-remote and wild region of the continent. The river curves in a landscape peculiarly joined with tundra and permafrost.

The Khatanga River forms part of the Arctic ecosystem. On its edges, one will find the sparse, hardened tundra vegetation consisting of low shrubs and mosses that have adapted to cold and very short growing seasons. Along this course of the river are small, scattered villages: The village communities are close with the river because this serves most as a means of transport during the few weeks it is ice-free. Locals have crossed the river using boats in order for them to communicate with other villages and trading posts, which are not too far away from each other.

The Khatanga River is full of wildlife. Polar bears sometimes can be seen roaming near its riverbanks because they follow seasonal movements of their prey. Arctic foxes, with thick white fur, are also common. The river serves as a habitat for various species of fish, like Arctic char and nelma, which have adapted to such cold waters. A great number of birds, including brent goose and tundra swan, also migrate along the course of the Khatanga River, which makes this place ecologically important.

2. What is the flow rate of the Khatanga river like?

The Khatanga River has a particularly great meaning within the Arctic context. The flow rate of the river is determined by the Arctic climate and seasonal snow and ice melting. During spring and early summer when snow and ice start melting, the river witnesses an increase in flow. In the process, the water level starts to rise, and the current becomes stronger.

This is a very important high-flow season for downstream transport of sediments and nutrients. Flow rates determine the partitioning of constituents critical to vegetation growth within the floodplains and, by extension, to the health of the entire river ecosystem. Flow of the Khatanga River regulates important spawning and migratory fish behaviors. Changes in flow serve as cues to initiate upstream migrations to spawn.

While it has a thin covering of ice in winter, thus reducing the flow rate, the movement of water beneath the ice is rather slow and is essential for the aquatic life to exist. The flow rate at Khatanga River, changing according to seasons, is one of the most significant reasons for shaping the Arctic scenery and for a wide range of life depending on the flow.

3. Measurement of Water Current of Khatanga River?

Till date, there are many traditional ways of measuring the water current of the Khatanga River. One of them is floats. Simple floats are let into the river and time is measured for how long they take to travel a certain distance. An approximate estimate of the speed of the water current can be done by calculating the distance over time.

Another technique is that of current-measuring weirs, which are installations within the stream, conventionally for volume and speed measurement of the water in flow. Again, such techniques have their setbacks, as far as their accuracy and ease of handling are concerned.

The need for improvement had, therefore, been realized long ago, and since then, the Acoustic Doppler Current Profiler (ADCP), have come up, more sophisticated and quite useful.

3.1 How do ADCPs using the Doppler principle work?

The ADCP profiler work on the principle of the Doppler effect. They transmit acoustic signals into the water. Particles and substances scatter these signals present in the water. Due to the movement of the water, the reflected acoustic signal changes frequency. If the water is flowing towards the ADCP meter, the frequency of the reflected signal is higher than the emitted frequency, and in case the water is flowing away from it, the frequency will be lower.

These frequency shifts are analyzed by the ADCP flow meter to find the speed and direction of the water current at each depth covered. This approach therefore allows the generation of a fully integrated profile of the water current from surface to riverbed.

3.2 What's needed for high - quality measurement of Khatanga river currents?

For high - quality measurement of the Khatanga River currents by means of ADCP doppler, some of the characteristics required by this equipment are as follows: first, the equipment should be made of sturdy materials. Given that Arctic conditions are extremely unfriendly, it is supposed to withstand extremely low temperatures, ice impacts, and the corrosive effects of salt-laden water.

The ADCP current profiler should be of compact and small size. This is due to the fact that the Khatanga River is in a very remote area, and it would be a problem if one had to move big and bulky equipment. A lighter ADCP is preferable, as it will be easier to handle during deployment and retrieval operations.

Power consumption is minimal. At an Arctic station, sources of power are limited; hence, long-term monitoring requires devices that do not exhaust these powers any faster. Cost-effective: this was another key factor, considering such a wide measurement along Khatanga River.

The casing of the ADCP current meter shall be of a titanium alloy. The very important reason is that the titanium alloy has excellent resistance to corrosion, for the Arctic waters can be very corrosive because of the high salt and chemical content. It is strong and durable enough to bear the physical stresses of the Arctic environment that include ice floes and strong water currents.

3.3 How to Choose the right equipment for current measurement?

The intended use of the equipment is a factor in making the right choice while selecting equipment for current measurement in the Khatanga River. In horizontal cross - sectional measurement of the current of the river, the Horizontal ADCP or HADCP is a suitable choice. It offers precise and continuous measurement of current across a horizontal plane.

It would be more proper for vertical cross-sectional measurements, however, to use a vertical ADCP. It can provide minute details on how the current varies from the surface all the way down to the bed of the river.

With respect to the selection of frequency, for water depth up to 70 m, a 600 kHz ADCP may be chosen. For larger water depths, typically up to 110 m, it is more appropriate to consider the 300 kHz ADCP.

Among the well - known ADCP brands are Teledyne RDI, Nortek, and Sontek. However, a Chinese ADCP brand, China Sonar PandaADCP, is also a great option. It is made of all - titanium alloy material, providing excellent durability and corrosion resistance. It also offers an incredible cost - performance ratio. You can find more information about this product on their website: https://china-sonar.com/.

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