ADCP in Flood Prevention Management of the Aras River

I. Where is the Aras River?

Natural and Geographic Features

The Aras River is located in Western Asia. It borders Armenia, Azerbaijan, Iran, and Turkey. The course of the river is very long, meandering from mountainous landscapes to valleys and plains. It is fed by snowmelt from surrounding mountains and rainfall in the region. A considerable portion of the length of the Aras River has a rather wide and shallow channel, and the flow may be seasonal.

Cities and Settlements Along the River 

There is a number of cities and towns on the Aras River, such as Julfa in Azerbaijan and Meydan - e - Sharq in Iran. The urban settlements draw a very good amount of water from the river for their use, irrigation, and to some small extent for transportation. The river forms part of the boundary between some of these countries through which it flows.  

Rainfall and Snowmelt Situation 

The Aras River basin has a climate that includes snowfall within the mountains during winter and rainfall throughout the entire year. Snowmelt-especially during spring-is one of the major contributors of volume to the water in the river. On the other hand, rainfall can be more intensive at times and distributed variably, with wetter and drier seasons. This combination might cause actual oscillations in the level of the water, at times flooding it.

II.What are the causes of the flooding in the Aras River?

Causes

1. Heavy Rainfall and Spring Snowmelt: This happens to be the major reason for flood occurrences. The leading factor is intensive rainfalls in the rainier months, together with spring snowmelt in the upper reaches of the basin, which contribute to its flooding. The large volume of water input into the river increases rapidly and can develop into sudden flooding over the low-lying area.
2. Tributary Contribution: Aras has a number of tributaries, each draining a subregion. Whenever this contribution increases either because of a local rainfall or snowmelt in the primary tributaries, it is poured into the main course, raising the volume of water and possible levels of flooding.
3. Geographic Features: Flat floodplains along the river and meandering may cause water back-up and flooding. In high-water events, the river may overtop or breach its natural levees and spread out into the surrounding lands.

Frequency and Magnitude of Flooding 

Flooding of the Aras River occurs within a certain periodicity, more often in spring and during heavy rainfall. The scale of flooding varies from minor floods that affect only the riverbanks and small parts of the adjacent areas to major floods capable of flooding broad areas of floodplains and causing disruptions in cities and transport. 

Flood Effects

1. Infrastructure Damage: Floods can affect bridges, roads, and water-supply and sewage systems. This results in jammed transportation and disrupted essential services supplies in urban cities such as Julfa and Meydan-e-Sharq.
2. Impact on Agriculture: The floodplains of Aras are primarily utilized for agriculture. Hence, flooding may have an impact on agriculture by causing crop damage, soil erosion, and disruption in farming activities.
3. Displacement of People: When the flooding is extreme, people may be evacuated from low-lying areas. This could lead to temporary displacement of people and emergency sheltering as well as emergency supplies. In other cases, flooding triggers economic losses brought about by disrupted trade, infrastructural damage, and loss of agricultural production.

While ADCP doppler provides a more advanced and convenient measuring method, it is greatly needed for Aras in terms of flood prevention management.

III. Principles of Operation of Doppler-Based ADCPs

The Acoustic Doppler Current Profiler(ADCP) work off of the Doppler principle. They send out acoustic pulses-cosound waves-into the water. These sound waves, since the water particles are in motion, are reflected back to the ADCP. The frequency of the sound waves reflected back changes due to the Doppler effect. This change in frequency is directly related with the velocity of the water particles.

When applied to the Aras River, ADCP meter can be installed on boats, fixed platforms near the banks, or even buoys. The instrument sends out a succession of sound pulses at a predetermined frequency. The received and reflected signals are then processed by the internal electronics of the ADCP flow meter. The determination of the frequency shift of the reflected signals from different depths makes it possible to calculate water column velocity at various depths. After processing, this information may be given in real time and provide the essentials in terms of data on the flow of the Aras River.

IV. Application of ADCP in floods of the Aras River

Velocity Measurement 

It is very efficient in the ADCP current profiler to measure the velocity of the water flow in the Aras River. Precise determination of actual velocity at various locations and depths provides critical insights into the flow dynamics. This information shall be paramount in predicting the flow of floodwaters downstream and assessing the erosive power of the water. For example, high-velocity water during flooding can easily cause more severe erosion of riverbanks and levees. 

Application of Flow Measurement 

Flow rate measurement by ADCP current meter is very important in the Aras River for flood control. By calculating the amount of water passing through a certain cross-section, the authorities in charge of flood management will be able to estimate how much water may eventually cause flooding. The data help to manipulate the operating floodgates, dams, and other structures that control water levels and prevent over-flooding. 

Application in Sediment Transport Research 

During flooding, the Aras River carries a high amount of sediment. ADCP profiler can measure sediment concentration and the rate of sediment transport. Knowledge of sediment movement is very important in maintaining the health of the river and associated ecosystems. Data obtained may lead to the prediction of sediment deposition important for channel management and floodplains stability.

V. How does the data measured by ADCP apply to flood warning and risk management for the Aras River?

Flood Warning

1. Velocity and Flow Data Monitoring: The acoustic doppler velocity metercontinuously monitors the velocity and flow rate within the Aras River. By setting thresholds for such parameters, the flood management agencies would be warned when the water flow indicates an abnormal rise. For example, it can give an indication of the flood that is about to happen in case of higher velocity or flow rate than the specified one. These warnings provide an early indication of evacuating people in advance in areas that are subject to floods and turning on all flood protection measures.
2. Water Level Prediction and Warning: Integration of acoustic doppler flow meterdata with other hydrological data on rainfall measurements and snowmelt estimates provides more accurate water level predictions. Comparing these predicted levels against historical flood levels will provide timely warnings to the communities along the river, including cities like Julfa and Meydan-e-Sharq.

Risk Management

1. Decision Support for Water Conservancy Project Scheduling: ADCP data becomes useful in operating and scheduling different water conservancy projects along Aras River. For example, flow rate and velocity information may serve useful in deciding on the optimum release from dams and reservoirs with a view to balancing flood control and supply needs. It also helps design and maintains levees and other flood-protection infrastructure.
2. Flood Disaster Evaluation and Emergency Response: Immediately after a flooding incident, ADCP data can be used to assess the level of damage that might have been inflicted. Analysis of the velocity and water depth after the occurrence of flooding gives the rescue team the critical area affected by the flood. This information aids in planning the rescue operation, distribution of relief supplies, and long-term recovery and rehabilitation works.

VI. For what purpose high-quality measurement of the currents of the Aras River is required?

Reliability of Equipment Materials 

The equipment for measuring the Aras River currents should be made from reliable materials. This is most preferably made from casing made of a titanium alloy. The strength in the titanium alloy is great and seminal to hold up against the pressure and physical forces transmitted in the Aras River. Besides this, the alloy has great resistance to corrosion from the water and sediment, which secures the long-term durability of the equipment. 

Small Size 

The small-sized ADCP is preferred for deployment in the Aras River. This makes the instrument relatively easy to install on various platforms, including small boats and buoys, or at riverbank monitoring stations, with no significant obstruction to river flow. Placement can thus be more flexible to obtain comprehensive current measurements. 

Light Weight 

Smaller and lighter ADCPs are easier to carry and install, especially in remote parts of the Aras River. The ADCPs can easily be taken by field technicians to various locations and set up to start the measurement. This is very important during situations that deal with emergency flood monitoring. 

Low Power Consumption 

For long-term monitoring of the Aras River, low-power-consumption ADCPs are highly desirable. Considering the length of the river, equipment that works on longer duration without breakdown of power supply or too frequent battery change is urgently sought.

 Low Cost 

In addition, in order to carry out a large-scale measurement along the Aras River, the cost of ADCP equipment needs to be relatively less expensive. In this way, several units would be fitted at various points on the river in order to give an appropriate insight regarding current patterns and flood risk involved.

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

Choose by Usage

1. Horizontal Cross - Section Measurement: To measure horizontally across the section of the Aras River, it is best to use an HADCP. The HADCP will be able to measure the velocity and flow rate across the width, giving a full picture of the flow characteristics at that particular cross-section. This is very important to understand in terms of the spread of water across the river in cases of flood-plain management.
2. Vertical Cross - Section Measurement: In the case of vertical cross-section measurement, a vertical ADCP would be more suitable. It measures the velocity and flow rate at various depths with the purpose of analyzing the vertical structure of the river flow. This becomes important for learning stratification of water and sediment movements.

Choose Different Frequencies 

However, the frequency of choice will depend on the depth of the Aras River. For shallow depths up to 70 meters, an ADCP high-frequency type can be appropriate, the 300 kHz type will do a better job.

Finally, there are several well - known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, for cost - effective and high - quality ADCPs, the Chinese brand ChinaSonar PandaADCP is highly recommended. It features an all - titanium alloy material construction and offers excellent value for money. You can visit (https://china-sonar.com/) for more information.

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