ADCP in The Desna River Flood Management

1. Where is The Desna River?

The Desna River is an important river in Eastern Europe.

Geographical Location and Course It lies predominantly in Ukraine and Belarus. The Desna River arises in the hilly country east of Valdai in Russia, while it generally flows south-west for some 1,130 kilometers, or 702 miles. It is one of the most extensive Dnieper River tributaries and forms part of the area's water arteries.

Cities and Settlements Along the River There are several cities and towns that stand on both sides of one or another bank of the Desna River, including in Ukraine, such cities as Chernihiv, and in Belarus, towns like Novozybkov, among others. Such cities and villages use the river for water supply purposes, fishing, and transport. In some places of the river, boating and swimming can also be accessed for recreational means.

Rainfall and Water Conditions The climatic condition of the Desna River basin is temperate - continental. Precipitation is relatively well distributed within a year, with an annual average of about 500 - 700 millimeters. The snowfall is also high during the winter months. Rainfall and snowmelt account for variations in water levels along the river. During springtime, the melting of snow in its catchments and the local rains result in a rise in its water levels.

2. What are the causes of flooding in The Desna River?

Spring Snowmelts The most striking cause of flood occurrences is the snowmelt in spring. The snow accumulated in large amounts during winter starts melting as the temperature rises. The water from the melted snow quickly flows into the river, raising its water volume up to a great extent. If this thawing out happens too quickly, such as with a rapid warming trend, the river may not be able to accept the heightened volume of water and flooding over the banks will result.

Heavy Rainfall While rainfall is generally evenly distributed throughout the year in the Desna River basin, intense precipitation events are possible. Intense rainstorms may produce a very rapid increase in the water level of the river. High water from snowmelt, combined with heavy rainfall, is one of the factors that increases the flood risk. Heavy rainfall from a succession of intense rainstorms falling during late spring or early summer can produce a more major flooding event.

River Ice Jams During the spring breakup of ice, the Desna River has a tendency to be subject to ice jams. As the ice begins to move downstream, it can get stuck in narrow sections of the river or at bends. These would block the normal flow of water, causing the upstream areas to flood by the back-up of water. The force of the backed-up water can also cause damage to the riverbanks and any infrastructure located nearby.

With all these flood-related challenges, ADCP offers an advanced and convenient measurement method for the better management of floods.

3. How do ADCPs using the Doppler Principle Work?

In general, Acoustic Doppler Current Profiler(ADCP) work based on the principle of the Doppler effect. First, an ADCP sends out an acoustic pulse into the water with a well-known frequency. Typical frequencies would be either 300 kHz or 600 kHz depending on the depth of the water and the measurement requirements.

Transmitting and Receiving Signals The acoustic pulses are sent out in a fan-shaped pattern. As the pulses travel through the water, they interact with moving water particles and any suspended sediment. Where pulses strike the moving objects, part of that energy is reflected back to the ADCP current meter.

Detecting the Doppler Shift Due to the Doppler effect, reflected signals have a different frequency from those that were transmitted. Where the water particles or sediment are moving towards an ADCP current profiler, the frequency of the reflected signal is higher than the originally transmitted one; otherwise, this frequency is lower if they are moving away from it. These changes in frequency are detected with high precision by sensors on an ADCP doppler.

Calculating Velocity and Other Parameters These internal algorithms of the ADCP flow meter calculate the Doppler shifts it detects, hence the velocity of the water currents at a range within the column of water. It can also integrate the velocity data over the cross-sectional area of the river and hence compute the flow rate of the water passing through any given point. Additionally, the ADCP meter can provide information about the movement and concentration of suspended sediment in the water.

4. What are the applications of ADCP in floods of The Desna River?

Velocity Measurement

The ADCP profiler come in handy during the flood events to calculate the velocity of the water flow in currents of Desna River. They measure, in real time, the speed of the water at various depths. This helps to understand the dynamic behavior of floodwaters; for instance, whether the current is stronger at the surface or at the bottom. The information of the velocity may also show how the current changes with time and space, which again is very important for predicting the spread and impact of flood diffusion.

Flow Measurement Application

The ADCP will also carry out proper flow rate calculations corresponding to the Desna River in cases of flooding. Because they take into consideration the velocities measured across the cross-sectional area of the river at the measurement point, they give an estimate of the volume of water that flows downstream. This is very important data when it comes to flood forecasting and understanding the magnitude of the flood. It helps identify how much water will reach the different areas along the riverbanks and how much damage is likely to be caused.

Application of Sediment Translocation Research

Floodings in the Desna River contribute to sediment transport. ADCPs can be applied to investigate sediment translocation by measuring the Doppler shifts produced by suspended sediment particles. It would thus be able to analyze sediment distribution along the bed and banks during floods-a result of floods. It also enables one to simulate the possible future variations of the river morphology and sedimentation consequences for constructions such as bridges and dams.

5. How does the ADCP data measured could be used in flood warning and risk management in general for The Desna River?

Flood Warning

Data Monitoring of Velocity and Flow: ADCPs are useful in the provision of real-time velocity and flow rate data, which are critical in flood warning. Basically, continuous monitoring of these parameters will enable the authorities to identify sudden rises either in speed or volume of water flowing in the river. As an example, if the flow rate goes beyond a threshold value associated with past events of flooding, early warning can be issued. This helps in evacuating the people well in advance in the flood-prone areas and making necessary preparations for various emergency responses.

Water Level Prediction and Warning: Acoustic doppler flow meter data can also be used to predict water levels. Since the velocity and flow rate are related with water level, analyzing the trends in the measured data will predict how the water level will change in the near future. With this, water level warnings can be issued to the communities along the river with ample time taken in advance to take precautions such as relocating valuable possessions to higher grounds or reinforcing flood defenses.

Risk Management

Water Conservancy Engineering Scheduling Decision Support: Data obtained from ADCPs allow decision-makers to schedule water conservancy engineering operations. Or, to rephrase it, if the flow rate and velocity data indicates a large flood might well be in its way, then accordingly, the operators of the dams can release water from the dams to reduce the impact downstream. Either hold back more, if possible, to reduce the peak flood flow or release the water in a controlled manner so that sudden surges would not damage the structure downstream.

Assessment of Flood Disaster and Emergency Response: In the event of floods, acoustic doppler velocity meter ​measures the flow or velocity at various instances of the flow. Analysis would therefore provide where the maximum flooding occurred and which areas have the worst situations. This information is very important in organizing the work of rescue teams, sending them to the most affected areas, and delivering relief supplies to people who need them. In conclusion,

6. What's needed for high - quality measurement of The Desna River currents?

Material Reliability

Reliability of materials is a must for the equipment to obtain correct and regular measurement of the currents of the Desna River. Above all, the casing of the acoustic current meter should be resistant to the hard conditions that occur in the river, as well as to water, sediment, and impacts that might take place.

Small Size, Light Weight, and Low Power Consumption

The ADCP should be compact in size, light in weight, and low power-consuming to enable its easy deployment and use along Desna River for large-scale measurements.

A small and lightweight gadget is easy to install on boats, buoys, and other platforms used for measurement. Low power consumption allows operation for extended terms without frequent replacement of batteries or the need for access to a continuous power supply, with the ability to operate in remote areas where the power supply may be limited.

Low Cost for Large-Scale Measurement 

When monitoring large-scale current conditions in the Desna River using acoustic doppler current meter, the equipment cost is to be within a reasonable range. A very high cost restricts the number of devices that can be deployed and hence restricts the comprehensiveness of data to be collected.

Advantages of Using Titanium Alloy for Casing

Water conditions of the Desna River provide the perfect environment for the housing of ADCPs using a titanium alloy. This would be very important because of the excellent corrosion resistance it has and due to the fact that river water might contain several corrosive substances.

It is also strong and durable, able to withstand physical stresses and impacts which the device may encounter during deployment and operation.

Apart from that, the relatively low density contributes to the low weight of the device itself and hence meets the requirement for the equipment to be lightweight in order to be easily deployed.

7. How to Choose the right equipment for current measurement?

Based on Measurement Orientation If the measurement is focused on the horizontal cross-section currents, then Horizontal ADCP - HADCP should be chosen. The HADCPs measure with great accuracy water flow across a horizontal plane across the river. On the other hand, if one's measurement refers to vertical cross-sectional currents, then the Vertical ADCP is just for that. Vertical ADCPs can provide information concerning the velocity profile from the surface to the bottom.

Based on Frequency Selection The measured needs and water depth also depend on the type of frequency applied. For instance, an ADCP of 600 kHz frequency works in water to a depth of about 70 meters. This frequency can resolve better in rather shallower waters.

An ADCP of 300 kHz is even more suited for deeper waters, like those that may be encountered in parts of the Desna River where the depth exceeds 70 m. In such situations, the equipment will have deeper water column penetration and thus be able to offer good measurements of currents. There exist several popular brands of ADCPs on the market, including Teledyne RDI, Nortek, and Sontek. However, for those looking for a cost - effective option with high quality, the China Sonar PandaADCP is a great choice. It is made of all - titanium alloy material, which ensures its durability and performance in various river environments. It also offers an incredible cost - performance ratio.

You can learn more about it on its official website: https://china-sonar.com

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