ADCP's application in flood management of Argun River

1. Where is Argun River?

The Argun River is in Northeast Asia. It constitutes a part of the border between Russia and China. The river has its source in the Khingan Mountains.

The river makes its course through rich landscapes dotted by forests, grasslands, and some marsh areas. It forms an important water resource for the local ecosystems and communities. It provides water supplies for activities such as fishing and limited agricultural use.

The climate and rainfall in these regions, through which the Argun River flows, represent the continental type. The winters can be cold with snowfall, while summers are comparatively warm. Snow melting in spring and summer and autumn rains make up the volume of water in this river. Considering the variations in the volume of snow melt and rainwater, the level of water may vary; this could lead to the risk of flooding in case of heavy precipitation or faster melting of snow.

2. What are the reasons for floods in the Argun River?

Snowmelt and Heavy Rainfall: The primary causes of floods in the Argun River are rapid snowmelt in spring and heavy rainfall. The large amounts of water from melting snow in the Khingan Mountains and the catchment area, along with additional rainwater, can quickly increase the river's volume. The mountainous terrain near the source accelerates the runoff process, sending a significant amount of water downstream.

Topography: The coming of floodplains and low-lying areas along its course provides space for water to spread and accumulate. The essentially flat areas reduce the speed of the flow, which automatically increases the chance of flooding. Meeting with other tributaries can also add more water at times of high flow, leading to worse flood conditions.

Human - Induced Changes: The flood patterns can sometimes be influenced by certain human activities. For instance, any deforestation around the catchment area may reduce the forest's capacity to intercept and retain the rainwater. This therefore can increase the surface runoff and the volume of water reaching the river faster, hence increasing flood risk.

The Acoustic Doppler Current Profiler (ADCP) can be a useful tool to understand the flow regime of the Argun River during flood events.

3. How do ADCPs using the principle of Doppler work?

An ADCP current profiler operates based on the principle called the Doppler principle. The tool emits an acoustic signal into the water. As the water is flowing, the signal interacts with the moving water particles. When the acoustic signal is reflected back to the ADCP current meter, the frequency of the reflected signal changes due to the Doppler effect.

The ADCP measures the differential frequency between the emitted signal and the received signal. From this frequency shift, it calculates the velocity of the water at different depths. Most ADCPs have several transducers that send and receive acoustic signals in various directions. This allows them to build up a profile of the water velocity across a section of the river.

For instance, if the water is flowing towards the ADCP flow meter, the reflected signal would have a higher frequency compared to the emitted one. In contrast, when water flows away from the ADCP meter, the frequency of the reflected signal becomes lower. Precise measurement of such frequency changes, combined with relevant mathematical algorithms, enables the ADCP flow meter to accurately calculate the velocity of water at different measurement points.

4. What are the uses of an ADCP in Argun River floods?

Measurement of Velocity

Acoustic Doppler Current Profiler (ADCP) plays an important role in the Argun River during flood events by measuring the velocity of the water flow with high accuracy. It continuously provides real - time data of water velocity at different locations and depths of the area, showing the travel rate of the water. Such information is critically needed for understanding the dynamics of the flood, which helps predict the direction and intensity of the moving floodwaters.

Flow Measurement Application

It can also measure the flow rate of the Argun River. Since ADCP measures the water velocities at individual points across a section of the river, combining with the known crosssectional area of the river, it can be used to calculate the total volume of water flowing through the section per unit time-that is, the flow rate. This information is crucial in the estimation of the total volume of water in a flood and in further decisions related to flood control and water resource management.

Application in Sediment Transport Research

Besides flow and velocity measurements, ADCP current profiler has an application in sediment transport research during floods in the Argun River. While flowing, water carries sediments. The ADCP flow meter is able to detect, within the backscattered acoustic signal, changes in the backscatter that vary with the presence of sediments. By analyzing these changes, researchers can estimate the amount and movement of sediments, which is of paramount importance in understanding the long-term evolution of the riverbed and the impact that floods have on the sedimentary environment of the river.

5. How could the data measured by ADCP be applied for flood warning and risk management of the Argun River?

Flood Warning

Velocity and Flow Data Monitoring: In real time, the velocity and flow data obtained from ADCP current meter are continuously monitored. If the velocity of water flow is over a certain threshold or the flow rate increases significantly, it could be a signal that a flood peak is approaching or that there is likely to be a flood. As a result, this can enable the relevant department in the government to take necessary steps in advance, such as relocating people in low-lying areas or taking effective measures to protect the embankment. Water Level Prediction and Warning: Measured flow data correlated with historical water level data using appropriate hydrological models can be used to predict future water levels from ADCP data. If the predicted water level is above the flood warning level, timely warnings can be issued to the public to prepare for the flood.

Risk Management

Water Conservancy Project Scheduling Decisions: Accurate flow and velocity data from ADCP current profiler can support decisions concerning the operation of water conservancy projects such as dams and sluices. For instance, according to the measured water flow, it is possible to adjust the release of water from a dam and thus control the water level in the Argun River in order to try to minimize any damage due to floods.

Assessment of Flood Disaster and Emergency Response: The data gathered from ADCP profiler during and after a flood will be useful in assessing the intensity of the flood. This information will include the extent of inundation, the velocity of the floodwaters, and the quantity of sediment deposits. This is quite important for formulating emergency response plans and also for carrying out post-flood reconstruction and rehabilitation work.

6. What is necessary to ensure high-quality measurement of the Argun River currents?

What is necessary for high - quality measurement of Argun River currents is as follows. First of all, high-quality and reliable materials should be used. In this respect, the casing of the ADCP meter is especially important. For instance, the casing of the ADCP current profiler is recommended to be made of a titanium alloy. The high strength of the titanium alloy can withstand the pressure and impact caused by water flow in the river. It is also highly resistant to corrosion, which is of utmost importance considering the water environment of the Argun River, which may contain various corrosive substances.

Besides material reliability, the size and weight of the equipment should be as small and light as possible. It enhances the ease of installation and operation of the ADCP profiler in various parts of the river; particularly, regions that may be very inaccessible. Low power consumption is also an important factor, as this enables longer continuous measurement without changing batteries frequently or connecting to a power source. The cost of equipment must be relatively low for enabling large-scale measurement. Lower costs allow for more ADCPs to be deployed along the Argun River, hence more comprehensive and detailed data from which flood management can be derived.

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

The selection of proper equipment for the current measurement in the Argun River has to be done with consideration for several aspects. First, based on the type of measurement required, if it is for horizontal cross - section measurement, then HADCP - Horizontal ADCP should be selected. If it is for vertical cross - section measurement, then the Vertical ADCP will be appropriate.

Secondly, different frequencies suitable for various water depths. The 600 kHz ADCP is suitable for water depth within 70 m. If the water depth in the Argun River is within this range and matched with the measurement requirements, then a 600 kHz ADCP should work. In cases of deeper water, where water depths are over 70 m and up to 110 m, a 300 kHz ADCP would be more appropriate because it can provide more accurate measurement for such depth.

There are quite a few well-known ADCP current meter brands in the market, including Teledyne RDI, Nortek, and Sontek, just to name a few. These three are the major ones. If one wants to find something economic in this category, they can look at China Sonar PandaADCP. It's made of all-titanium alloy material, ensuring that it withstands the harsh water environment with reliability and endurance. It offers an unparalleled cost-to-performance ratio. You can know more about it on its official website: (https://china-sonar.com/).

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