ADCP Application in Chulym River Flood Management

1. Where is Chulym River?

Chulym River is in Siberia, Russia; it is a tributary of Ob River. It covers an enormous and sparsely populated area with landscape domination by taiga forests and extensive wetlands.

Geographically, it passes through areas with a continental climate. The river's course is an important part of the local ecosystem, providing a habitat for a variety of wildlife such as moose, beavers, and many species of fish. Along its banks are small settlements of indigenous people and some isolated villages that rely on the river for fishing and transportation.

The Chulym River Basin has intensive snowfall during winter months. The snowmelt in spring, along with the relatively moderate summer rainfall, forms the main contribution to the river's water volume.

2. What are the Reasons for Floods in Chulym River?

Snowmelt and Heavy Rainfall: Flooding along the Chulym River was primarily due to rapid spring snowmelt combined with heavy summer rainfall. Since the catchment area was big, it meant much water could enter the river in a very short period. When snow melts fast because of a sudden warm spell and if it is accompanied by intense rainfall, the river has a chance to overflow beyond its capacity and cause a flood.

Tributary Inflows: The Chulym River has many tributaries. When any of them are at high water from their snowmelt or from rain off the surrounding countryside, these could add a large volume of water to the main river channel. Confluences of such tributaries cause rapid rises in the water level of the Chulym River and create floods.

Topography and Drainage: The course of the river comprises relatively flat floodplains with some natural constrictions. Where the floodplains are flat, the water may be retarded in its flow and spread over adjoining areas, causing floods. Constriction to the normal flow of water will make it back up and raise the water level upstream. Wetlands along the course of the river modify the drainage pattern and create waterlogging and flooding.

Vegetation and Land Cover Changes: Man-induced or natural changes in vegetation cover may alter the water balance of the river. For instance, forest fires or logging in the taiga forest can reduce the landscape's infiltration capacity. The result is an increase in surface runoff that can contribute to higher levels and flooding. The Acoustic Doppler Current Profiler has a more advanced and effective measuring solution in regard to flood-related data than traditional methods provide.

3. How Do ADCPs Using the Doppler Principle Work?

ADCPs work on the principle of the Doppler effect. They transmit acoustic signals into the water. As these acoustic waves interact with moving particles in the water-sediment, debris, or simply water parcels with different velocities-the frequency of the reflected signals, compared to the emitted signals, changes through the Doppler effect.

It measures the Doppler frequency shifts, using the known velocity of sound in water and angles of transmitted and received signals to calculate water velocity at a series of depths. Several transducers on the ADCP profiler are oriented to obtain velocity components from different directions. These velocity records integrated with records of velocity over variable depth and different cross-sectional areas of the stream yield flow rate and other useful hydrological quantities.

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

Velocity Measurement: ADCP current meter can measure the actual velocity of the water flow in the Chulym River at various locations and depths. During flood events, this information is critical to understand the dynamics of the flood. It helps in identifying areas where the flow is rapid and could be dangerous to riverbanks, bridges in case of any, and the local settlements. It also allows for monitoring how the flow velocity changes with time as the flood progresses.

Flow Rate Measurement Application: By combining the measured velocity data with the cross-sectional area of the river, ADCP flow meter can estimate the flow rate. This becomes crucial in predicting the amount of water that will be passing through different sections during a flood. It allows one to predict the flood peak and its consequences downstream, which is important for strategies in managing floods.

Sediment Transport Research: There is the possibility of big sediment loads being transported by any flood in the Chulym River. ADCP might analyze the sediment movement based on the echo of acoustic signals modified by the sediment particles. Therefore, ADCP meter can provide helpful information on how floods contribute to the evolution of the riverbed topography, with deposition and erosion processes for the stability of the river channel and its entire ecosystem.

5. How can the data measured by ADCP be utilized for flood warning and risk management in the case of the Chulym River?

Flood Warning

Velocity and Flow Rate Data Monitoring: ADCP continuously monitors the velocity and flow rate data, which allows for the early detection of abnormal increases in these parameters. When the flow rate approaches or exceeds certain critical values, it serves as an indication of an impending flood peak. This enables timely flood warnings to be issued to the local communities and relevant authorities.

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

Risk Management

Water Conservancy Project Scheduling Decision Support: The data from ADCP can help in making decisions regarding the operation of water conservancy projects such as small dams or reservoirs, if any, along Chulym River. For example, the timing and amount of water released from the reservoirs in order to minimize the consequences of floods downstream.

Flood Disaster Assessment and Emergency Response: In the aftermath of a flood, ADCP-measured data can be used to assess the severity of the flood in terms of the extent of inundated areas and the flow characteristics during the flood. This information guides emergency response efforts, including the allocation of relief resources and the planning of post-flood recovery work.

6. What’s Needed for High-Quality Measurement of Chulym River Currents?

The equipment for high-quality measurement of the Chulym River currents should be made of reliable materials. The casing should sustain all the possible impacts from the river: impacts of floating debris, which can be more significant during floods; corrosion from water with its unique chemical composition influenced by the surrounding environment; and extreme temperature differences between winter and summer.

The size of the equipment must be small enough to be installed and deployed easily at different locations along the river, particularly those that are difficult to reach due to the remote location of the area. It should also be lightweight in design for easy transportation and installation. Low power consumption is necessary for continuous operation over a long period of time, without the need for frequently changing batteries or high-energy power sources. Cost-effectiveness for large-scale deployment to provide comprehensive monitoring is another critical factor.

The ADCP current profiler casing is preferably made from a titanium alloy. This type of material offers several outstanding advantages: It provides excellent corrosion resistance, necessary to withstand the long-term action of the river water, and it has a high strength-to-weight ratio that supplies sufficient strength while keeping the weight of the equipment at reasonable levels. Such durability of the material provides stability of performance in the different environmental conditions of the Chulym River Basin.

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

While selecting the appropriate equipment for current measurement in the Chulym River, there are a few aspects to consider. First of all, depending on the purpose of usage, if the horizontal cross-section measurement is of focal interest, then HADCP will be suitable because it can measure the flow velocity and other parameters in the horizontal direction across the river section with good accuracy. For vertical cross-section measurement, the Vertical ADCP would be more appropriate because it can get more detailed velocity profiles along the vertical axis of the river.

Secondly, different frequencies shall be chosen according to actual water depth. In case of water depths within 70 meters, an ADCP with 600 kHz is generally good as this class of ADCPs provides quite good measurement results within such depth. For deeper water areas, up to 110 meters deep, an ADCP frequency of 300 kHz is more suitable because it can penetrate the water more effectively at greater depths and return data successfully.

There are various ADCP brands available in the market, such as Teledyne RDI, Nortek, and Sontek. However, it is worth highlighting a high-quality and cost-effective Chinese ADCP brand-China Sonar PandaADCP. 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.