How to Measure Water Current of the Kolyma river?

1. Where is the Kolyma?

The Kolyma River is one of the most important rivers in the far-east part of Russia, flowing through vast and cold landscapes of Siberia. Originating in the Kolyma Highlands, this river passes through a site of extreme cold with peculiar tundra and taiga types of vegetation.

The Kolyma cuts through the natural wonder of permafrost lands. The upper reaches are filled with mountainous terrain, snow-capped peaks which feed the river during summer months with glacial melt. It meanders through the taiga forests, providing a source of water for the sturdy coniferous trees and the very numerous species of wildlife that thrive in this region. Moose, lynx, and an abundance of species of migratory birds can be found in the vicinity of the river.

The river holds a mill of human history, too. Small settlements and mining towns spread down the banks. The Kolyma once saw frenetic gold mining activity. Harsh conditions have shaped the resilient spirit of the people who lived and worked here. It was used as a transport route, though very hazardous due to the ice-clad winters and the inaccessibility of the region.

2. What is the Flow Rate of the Kolyma River like?

The discharge of the Kolyma River is highly seasonal. In the spring and early summer, snow and ice in the Kolyma Highlands start to melt. A high-flow period then occurs, with a great increase in the river's volume. The current is strong, with water surging down along the channel and stirring sediment and nutrients-albeit very important downstream.

This flow rate decreases drastically during the long and cold winter. During this time, the river freezes, and at places, it may be used as an ice road. However, the average flow rate changes along the length of the river. In the upper reaches, closer to its source, the gradient may lead to a faster flow. While passing through flatter regions before reaching the Arctic Ocean, it slows down, and the river widens.

Human activities such as mining and water diversions also affect the flow of the Kolyma. These activities may interfere with the natural pattern of flow and even affect the general health of the ecosystem within the river.

3. How to Measure Water Current of the Kolyma River?

There is quite a number of ways to measure the water current of the Kolyma River.

Traditional Methods

Float Method 

A simple traditional method for estimating water current is through the use of a float. Submerged into the river, a buoyant object - essentially any catch-all object such as a block of wood or a plastic container - is employed. It gives an approximation to the surface current speed-the time of travel of a float over a known distance. Quite sensitive to wind and surface disturbances, this method provides information on the surface current alone and not on the deeper layers. 

Current Meters

Mechanical or electrical current meters may be deployed to record water speed at a point. These meters are placed in the water at a particular depth and record the speed of the water passing through them. They will provide more detailed measurements than floats at a single point but do not give the profile of the current through the water column.

Advanced Method - Acoustic Doppler Current Profilers (ADCPs) ADCPs are the more advanced and efficient way to measure the water current of the Kolyma River.

3.1 How do ADCPs using the Doppler Principle Work?

The ADCPs work on the principle of the Doppler effect. The instrument sends acoustic pulses into the water. If there are suspended particles in the water, such as sediment and small organisms, the pulses will scatter from them. If the water is moving, then the frequency of the reflected acoustic signals will change. 

This frequency shift is measured by the ADCP and the Doppler formula is applied to determine the velocity at the varying depths of the water. Since the ADCP emits pulses in multiple directions and at multiple frequencies, this results in a rather high-resolution profile throughout the water column. This is an improvement on older methods, such as that described above, which was able to only measure current structure.

3.2 What is needed regarding quality measurement of the Kolyma River currents? 

High-quality measurement of Kolyma river currents requires that equipment must be reliable. The climate is extremely cold, and possible ice damages require that measuring devices function properly.

 It should be compact and lightweight equipment. This is of importance for ease in deployment, especially in remote areas along the river that may be difficult to reach. Low power consumption is also desired so that the equipment may run for quite a long time without needing to change so many batteries or using any external sources of power. Cost-effectiveness is also a vital issue that needs consideration because, in general, large-scale measurements will be required. 

Using a titanium alloy for the casing is of great benefit in ADCPs. A titanium alloy is so important in a water-rich environment, like the Kolyma River, since corrosion in it is minimal. This material is also strong and durable to resist physical forces from river current and possible impacts. The light weight also offers convenience during installation and transport.

3.3 How to choose the correct equipment for current measurement? 

To choose the appropriate equipment for current measurement, one must carefully consider the peculiarities of the measurement at hand-for example, that of the Kolyma River. 

For Horizontal Measurements

HADCP stands for horizontal ADCP, which refers to horizontal measurements across a section of a river. It provides a broad view of the current flow in a horizontal plane that is useful to understand the overall flow patterns of the river. 

Vertical Profile Measurements: In the case of vertical profile measurements of current, an ADCP in a vertical setup would be more apt. It can provide critical detail on the water velocity at different depths that becomes again very important to study stratification and mixing of the water column. 

Frequency Selection: For relatively shallower parts of the Kolyma River, up to about 70 meters, one of the possible choices in frequency may be a 600 kHz ADCP. In cases of deeper parts, up to about 110 meters, the more suitable choice will be the 300 kHz ADCP.

There are well - known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, for a cost - effective option with good quality, the China Sonar PandaADCP is a great choice. It is made of all - titanium alloy, providing durability and resistance to the Kolyma River's environment. It also offers an excellent price - performance ratio. You can visit https://china-sonar.com/ for more information.

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