ADCP Application in Pechora River Flood Management

1. Where does the Pechora River originate?

The Pechora River is in the European part of Russia. One of the largest in the drainage basin of the Arctic Ocean, it rises in the northern Ural Mountains and, for the most part, it goes north across a wide area.

Geographically speaking, it passes through various types of landscapes. It runs in the upper reaches through high mountain areas of the Urals and steep slopes, with a relatively fast-flowing stream. The river flows down to immense plains and tundra expanses. Along its length are small towns and villages dependent on the river for supply, fishing, and movement. It is also a part of the Arctic ecosystem, where species of various kinds, including salmon, are to be found along with cold-water fish.

The Pechora River Basin is under the regime of a continental climate by rainfall. In winter, there is considerable snowfall; snow melting during spring brings the main volume of water in the river. Summer rains are also present, though scarce compared with more temperate latitudes. The joint result of snowmelt and rainfall is the flow regime of this river and may lead to water level fluctuations.

2. Causes of Floods in the Pechora River

Snowmelt and Heavy Rainfall: The principal reasons for flooding along the Pechora River relate to the rapid snow-melt in spring, further developed by heavy rainfall during summer months. The large catchment means a lot of water might be entering the river within relatively short periods. When snow melts rapidly because of a spell of warm weather and is joined by heavy rainfall, this can lead to more water than the river can hold, thus causing flooding.

Tributary Inflows: The Pechora River has many tributaries. When these tributaries are at high water, either from their own snowmelt or from rainfall, they can contribute a large amount of water to the main river channel. Where these tributaries come together, the water level of the Pechora River can rise very quickly and cause flooding.

Topography and Drainage: Relatively flat floodplains, with some natural constrictions along the course of the river, characterize its course. The flat areas of the floodplain would reduce the speed of the flow and allow the water to spread over adjacent areas, causing floodings. The constrictions would obstruct the normal flow of water, which will be accommodated by the rise in the water level upstream. Besides, permafrost in the tundra regions can affect the pattern of drainage. When the permafrost melts, it alters the permeability of the soil and triggers waterlogging and flooding conditions.

Land Use Changes: The Pechora River Basin is facing changes in land use as a result of forestry and oil and gas exploration by humans. When forests are cleared, they lose their natural water-absorbing properties and increase their surface runoff. It also contributes to changes in the natural drainage pattern, which further results in increased flood conditions. In this regard, an ADCP current meter is an advanced and more efficient method of measurement with respect to conventional methods for flood-related data.

3. How Do Doppler Principle ADCPs Work?

ADCPs work on the Doppler principle. They emit an acoustic signal into the water. When it collides with some sediment or debris or some flow parcels of different speeds that may be moving inside a stream, the bounced and returning waves will have frequency alteration according to the frequency of their emission.

This frequency shift is measured by the ADCP profiler. Since it can calculate the speed of sound in water and the angles at which the emitted and received signals are given, the ADCP current profiler calculates the velocity of the water at each depth. Several transducers on the ADCP measure velocity in different directions. These velocities, integrated over several depths and cross-sectional areas of the river, give the flow rate and other important hydrological data.

4. What are the Applications of ADCP in Floods of Pechora River?

Velocity Measurement: ADCP will be able to measure the velocity of the water flow in the Pechora River at various locations and depths with high accuracy. In cases of flooding, this is considered important information to understand the dynamics of the flood. It helps in the identification of areas where the flow is rapid and could be dangerous for riverbanks, bridges, and other structures. It also allows monitoring of how the flow velocity changes over time as the flood progresses.

Flow Rate Measurement Application: By integrating the velocity measurements with the cross-sectional area of the river, ADCP is able to determine the flow rate. This becomes crucial in predicting the amount of water that will be released through various sections of the river during flooding. This allows for the prediction of the flood peak and its impact downstream, crucial for flood management strategies.

Sediment Transport Research: Flooding in the Pechora River can result in a high sediment load. ADCP flow meter can work out the sediment movements by identifying the echoes of acoustic signals modified by sediment particles. These are very useful in understanding the impact of floods on evolution, sediment deposition, and erosion processes of the riverbed for maintaining stability in the channel and the ecosystem of the river.

5. How can the Data Measured by ADCP be Utilized for Flood Warning and Risk Management of Pechora River?

Flood Warning

Monitoring of Velocity and Flow Rate Data: The ADCP continuously monitors the velocity and flow rate data to give an alarm in case there is an abnormal increase in such parameters. When the flow rate approaches or exceeds certain critical values, this acts as a warning of an imminent flood peak. This enables timely flood warnings to be issued to communities and relevant authorities along the river.

Water Level Prediction and Warning: Correlating the measured flow rate and velocity data with historical water level records, models can be developed to predict future changes in water level. This helps in providing advance warnings about the areas that could get inundated and the height of the floodwaters.

Risk Management

Water Conservancy Project Scheduling Decision Support: The data can support decision-making for the operation of water conservancy projects including dams and reservoirs in the Pechora River. For instance, decisions can be made on how and when to release water from reservoirs to reduce or prevent downstream flooding.

Flood Disaster Assessment and Emergency Response: In case of a flood, data measured by ADCP meter would be used in assessing the degree of the flood, inundated areas, and the flow characteristics during the flood for emergency response. This information will guide the emergency response that includes the allocation of relief resources and the planning of post-flood recovery work.

6. What is required for high-quality measurement of Pechora River currents?

Reliable materials are needed to constitute the equipment for high-quality measurement of currents in the Pechora River. The casing should be resistant to the impacts of the river, such as those from floating debris, water corrosion with its specific chemical composition influenced by the Arctic environment, and huge differences in temperatures between winter and summer.

The equipment's size should be of a compact size for easy installation and deployment at various sites along the river. This, along with a light weight, facilitates the ease with which transportation and installation of such devices are done. A low power consumption would ensure it could work for long intervals of time without the replacement of batteries or using high-energy sources. It should also be cost-effective to deploy large numbers to allow comprehensive monitoring.

The casing of ADCP should be made of titanium alloy. There are several outstanding advantages of using a titanium alloy. It has excellent corrosion resistance, which is very important for sustaining the long-term exposure to the river water. It has a high strength-to-weight ratio, providing enough strength while keeping the weight of the equipment at a reasonable level. This material's durability ensures stable performance under the diverse environmental conditions of the Pechora River Basin.

7. How to Choose the Right Equipment for Current Measurement?

Depending on Measurement Purpose: A Horizontal ADCP (HADCP) is to be used in the case of a river's horizontal cross-section measurement as it is capable of very well measuring flow velocity and other parameters across the horizontal plane of the river section. In the case of a vertical cross-section measurement, the ADCP type should be a Vertical ADCP in order to achieve detailed velocity profiles along the vertical axis of the river.

Based on Water Depth: Various frequencies of ADCP are applicable for different water depths. For water depths up to 70 meters, an ADCP with a frequency of 600 kHz can provide quite accurate measurement results. For deeper water up to 110 meters, an ADCP with a frequency of 300 kHz is more effective in terms of depth penetration and obtaining reliable data.

There are well-known ADCP brands like Teledyne RDI, Nortek, and Sontek. Additionally, a cost-effective Chinese brand, China Sonar PandaADCP, is worth considering. It is made of all-titanium alloy material, ensuring excellent performance and durability. You can find more information on its website: (https://china-sonar.com/)

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