ADCP in Flood Management of Zeya River

Explore Zeya River, its flood causes, ADCP's working principle, applications in flood management, and equipment selection.

1. Where is the Zeya River?

The Zeya River is located in the Heilongjiang Province of China. It is a major tributary of the Amur River. The source of the river is in the mountains of Inner Mongolia.

Geographically, it passes through a deeply contrasting landscape, with mountainous regions on its upper reaches and then opening into plains and valleys as it moves on to its confluence with the Amur. Along its course, it touches parts of rural areas and smaller towns. The Zeya River represents an important part of the local water system and thus provides the region with water for agricultural activities and domestic purposes.

The Zeya River falls under the area of continental monsoon climate. The normal feature of such a type is a well-defined wet period-the three summer months of June, July, and August. During this period, heavy rainfall remarkably increases the water volume of the river. Apart from rain, the water source for the river comes from snow melting during the spring period in surrounding mountains, but it is much smaller compared to the rainfall season.

2. What are the causes of flooding in the Zeya River?

Flooding of the Zeya River emanates from a number of causes. The first is heavy rainfall experienced in this region during the wet season. In the case of heavy rains that come continuously in a short period, it easily surpasses the carrying capacity of the river. In heavy rainstorms, the amount of water flowing into the river from its catchment may be so high compared to the rates at which the river discharges this water. Such a situation, especially in a short period, would result in the rise of water levels in the river with consequent flooding.

Except for this, the melting of snow in spring contributes much to the cause of flooding. If the temperature rises rapidly and causes quick melting of snow in mountains, then a large volume of water enters the river. This sudden volume of water is not perhaps handled by the river. As such, the water level rises.

The topography of the river basin also plays a role. In areas along the river, of course, its topography allows water to hold longer, like on grounds with relatively flat terrains. Besides, human activities such as deforestation and improper land use in the upper catchments of a river increase the erodibility of its soil particles. Deposits of the eroded soil in the bed of the channel reduce its carrying capacity, hence making it flood easily.

The ADCP current profiler has, therefore, become more sophisticated and handy for the measurement of the flow conditions of the river during flood events.

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

Acoustic Doppler Current Profiler(ADCP) work on the principle of a frequency shift, which is generally known as the Doppler principle. When an ADCP sends an acoustic signal into the water, this signal scatters by moving particles in the water. Since the water is flowing, the frequency of the reflected acoustic signal would be shifted, also called a Doppler effect.

The ADCP measures the difference between the emitted frequency and the received frequency of the acoustic signal. From this shift in frequency, it is able to calculate the velocity of the water at different depths. The device usually has multiple transducers, capable of emitting and receiving acoustic signals in various directions; thus, the profile it usually attains is that of the water velocity across a section of the river.

For example, if the water is flowing towards the ADCP current meter, then its reflected signal will be of a higher frequency than the emitted one, and vice versa when the water is flowing away. It is by precisely measuring these changes in frequency and applying the appropriate mathematical algorithms that the ADCP flow meter can determine with accuracy the velocity of the water at various points within the measurement range.

4. What applications does the ADCP have in floods of the Zeya River?

Measurement of Velocity

During flood events in the Zeya River, an important role will be played by ADCP meter through the provision of accurate measurements of the velocity of water flow. It continuously monitors the water velocity at different locations and depths; hence, it supplies data in real time on the speed at which the water is traveling. This shall be important in understanding dynamics such as the direction and intensity of floodwater movement.

Flow Measurement Application

ADCP profiler is also capable of measuring the flow rate of the Zeya River. By integrating the water velocities measured at several points over a cross-section with the known cross-sectional area of the river, it will provide the total volume of water flowing through the section per unit time, which is the flow rate. This information is crucial to assess the general water volume within any given flood, and it becomes really helpful for making decisions regarding flood control and regulating water resources.

Application in Sediment Transport Research

Besides flow and velocity measurements, acoustic doppler flow meter will be helpful in studying sediment transport in the Zeya River during flooding. While in motion, the water will carry sediments, and when it does, this acoustic doppler velocity meter shall detect changes in the backscattered acoustic signal caused by the presence of sediments. By analyzing these changes, the researchers can estimate the amount and movement of the sediments. This is important for further understanding of long-term evolution of the riverbed and the impact of floods on the river's sedimentary environment.

5. How can the ADCP-measured data be used in flood warning and risk management of the Zeya River?

Flood Warning

Data from ADCPs continuously monitor the real-time velocity and flow data. Therefore, in case water velocity is above the threshold value or there is a sudden increase in the flow rate, that may indicate that a flood peak is approaching or there is a potential flood situation developing. It thus provides an early warning for the relevant authorities to adopt necessary precautionary measures such as evacuation of people residing in low-lying areas or consolidating the flood defenses.

Water Level Prediction and Warning: Measured flow data can be correlated with the historical water level data to predict future water levels by using appropriate hydrological models. Further, if the predicted water level is expected to exceed the flood warning level, timely warnings can be issued to the public for preparation for flood.

Risk Management

Water Conservancy Project Scheduling Decision Support: The precise flow and velocity data provided by the ADCP can help in deciding on the operation of the water conservancy project, such as dams and sluices. Based on the water flow, the release of water from the dam can be controlled to allow for the control of water level in the Zeya River in events of floods. • Flood Disaster Assessment and Emergency Response: The ADCP data after the event can be used for appraisals of the extent of flood, speed of flood water, and sedimentation. It is very valuable data when determining and planning the scope of emergency operations and any further construction or rehabilitation work after the flood event.

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

High-quality measurement of the Zeya River currents can be achieved with several key factors. First of all, the device used in the measurement process should possess credible materials. The casing of the acoustic current meter plays a very important role here. The casing must be made from titanium alloy. There are numerous advantages to using titanium alloy. It has high strength that allows the equipment to resist the pressure and impact of running water in the river. It is also highly resistant to corrosion, which is one of the main requirements taking into account the probable content of different corrosive matters in the Zeya River's water.

Besides reliability in the material, the size and weight of the equipment should be small and light. That makes installation and operation in the most varied locations along the river much easier, especially in places that are not easily accessible. Low power consumption is relevant as well since longer continuous operation without the frequent replacement of batteries or junction to a power source becomes possible. The cost of the equipment must be relatively low, too, in order to make large-scale measurement possible. A lower cost means that more ADCPs can be deployed along the Zeya River, providing more comprehensive and detailed data for flood management.

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

Various elements must be considered when choosing appropriate equipment for current measurement at Zeya River. If it is to be used for horizontal cross - section measurement, then HADCP - Horizontal ADCP needs to be selected. In cases of vertical cross - section measurement, ADCP Vertical is to be chosen.

Second, different frequencies are suitable for different water depths. For instance, a 600 kHz ADCP is suitable for water depths within 70 m. If the water depth of the Zeya River is within the range, besides matching the measurement requirements, a 600 kHz ADCP can be considered. For deeper waters, this would be more appropriate at 110 m from 70 m because it can give better measurements at this depth.

There are known brands such as Teledyne RDI, Nortek, and Sontek. For those looking to have an affordable alternative, it would be China Sonar PandaADCP. It is made of all - titanium alloy material, which ensures its durability and reliability in the water environment. Moreover, it offers an incredible cost - performance ratio. You can find more information about it on its official website: (https://china-sonar.com/).

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

Brand model
Teledyne RDI Ocean Surveyor ADCP, Pinnacle ADCP, Sentinel V ADCP, Workhorse II Monitor ADCP, Workhorse II Sentinel ADCP, Workhorse II Mariner ADCP, Workhorse Long Ranger ADCP, RiverPro ADCP, RiverRay ADCP, StreamPro ADCP, ChannelMaster ADCP, etc.
NORTEK Eco, Signature VM Ocean, Signature, AWAC, Aquadopp Profiler, etc.
SonTek  SonTek-RS5, SonTek-M9, SonTek-SL, SonTek-IQ, etc.
China Sonar PandaADCP-DR-600K, PandaADCP-SC-300K, PandaADCP-DR-300K,PandaADCP-SC-600K, PandaADCP-DR-75K-PHASED, etc.
Jack Law November 14, 2024
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