ADCP for Kura River Flood Management

1. Where is the Kura River?

The Kura River is one of the main intake rivers of the South Caucasus. The river flows through Turkey, Georgia, and Azerbaijan. It is 1,515 kilometers in length with a drainage basin area of approximately 188,000 square kilometers.

In its course, it passes through cities such as Tbilisi in Georgia. The climate of the region conditions the water regime of the river. The climate of the area is varied, and there is a variation in precipitation throughout the year. The upper reaches receive more rainfall and snowmelt. The Kura River forms a very important source of water supply for irrigation, hydro - power generation, and domestic water supply in the countries through which it passes. It also forms a major part in the transportation and fishing industries.

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

Flooding on the Kura River happens mainly because of several factors such as heavy rainfall in most cases experienced in the upper catchment area. The water level of the river rises drastically on occasions of heavy precipitation recorded for relatively short periods or when its cumulative rainfall exceeds the average capacities of the river to move with water.

Snowmelt in spring is yet another contributing factor to its flood events. The sudden release of water from snowmelts in mountainous areas around its basin increases the river flow almost overnight. Besides that, the topography of the river valley-this is a very flat flood plain in some areas-allows water to spread out easily during any flood. These factors include land-use changes like deforestation and urbanization, which reduce the natural water-holding capacity of the land and increase surface runoff, therefore aggravating the flood situation. Due to the complexities of the factors causing floods, Acoustic Doppler Current Profiler (ADCP) provides an advanced and efficient way of measuring and managing the flow of the river during flood periods.

3. How do Doppler principle-based ADCPs work?

ADCPs work on the principle of the Doppler effect. The instrument sends acoustic signals into the water. These signals scatter off the moving water particles. When the acoustic waves bounce back after hitting the moving particles, the frequency of the reflected waves changes due to the Doppler effect.

Some are installed with several transducers that make it possible to transmit and receive acoustic signals in many directions, by accurately estimating the shift of frequency of the reflected signal, the water flow speed will have been determined across different river section or depth. It can show velocity measurements from the riverbed all the way up to the surface of the water and through each wide reach across a river.

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

Flow Velocity Measurement: ADCP current meter can measure flow velocity with high accuracy in the Kura River floods. This is very much important to understand the velocity at which water is flowing at different parts of the river. Monitoring flow velocity allows the identification of where water is flowing quickly that could indicate a surge in a flood or a shift in the flood behavior. For example, changes in flow velocity near riverbanks or within the main channel can be monitored closely.

Application of Flow-Rate Measurement: Flow-rate is calculated with the help of the measurement of flow velocity multiplied by the cross-sectional area of the river. In the scenario of the Kura River floods, this is the kind of information that helps in the approximation of the total volume of water passing through a certain section per unit time for flood forecasting and to have an idea about the integral magnitude of the flood.

Sediment-transport Research: In the case of flooding, quite a lot of sediment is moved along the Kura River. ADCP current profiler is able to detect the movement of sediment particles through the analysis of backscattered acoustic signals. It means that researchers can investigate sediment-transport patterns during floods, which is crucial for understanding the long-term evolution of the riverbed and the impact on the river hydrological characteristics.

5. How is the data measured by ADCP helpful in flood warning and Kura River risk management?

Flood Warning Aspect

• Flow-velocity and Flow-rate Data Monitoring: The ADCP flow meter enables monitoring of flow velocity and flow rate continuously to detect abnormal changes. If the flow velocity is more than a certain threshold value or the flow rate increases suddenly, it triggers an early flood warning that can be relayed to local authorities and communities near the river.
• Water - level Prediction and Warning: The flow data obtained from ADCP meter can be used in conjunction with other hydrological models to predict water - level changes. By analyzing the relationship between flow - rate and water - level, more accurate flood warnings can be issued, especially in the flood - prone areas of the Kura River.

Risk Management Aspect

• Water-Conservancy Project Dispatching Decision Support: The precise flow data obtained from ADCP forms a vital input in the functioning of various water-conservancy projects comprising dams and canals along the Kura River. Decisions on whether to release or hold water could be made more efficiently in order to prevent flood disasters in areas further downstream.
• Flood-disaster Assessment and Emergency Response: The ADCP-measured data after the event of a flood provides ways of assessing the flood in terms of area affected and the impact. It allows the formulation of proper strategies for emergency response such as rescue operations and damage assessment surveys.

6. What is necessary to measure Kura River currents with high quality?

High-quality, current measurement of the Kura River can be taken by equipment made from such material, and such other construction shall withstand the harsh aquatic environment through the corrosive action of the water and possible impacts from floating debris and sediment. The small-size light weightedness is also an advantage in installing and deploying them in various locations in the river.

It is also important that power consumption is low to ensure continued operation, particularly in the most remote areas where supply could be limited. Cost-effectiveness is another factor since large-scale deployment may be necessary in order to comprehensively monitor river currents. The casing of ADCP profiler is preferably made of titanium alloy. This material has excellent corrosion resistance, which will be important in resisting the corrosive effects of Kura River water over time. It also provides a good strength-to-weight ratio, making the equipment durable and easy to handle.

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

The measurement purpose should be kept in mind when selecting any equipment for current measurement to be done in the Kura River. For horizontal cross-sectional flow measurement, an H-ADCP would be desirable; it gives flow-velocity information with sufficient resolution across the width of a river. For vertical cross-sections of flow measurement, however, a Vertical ADCP provides more appropriate flow-velocity distribution from bed to water surface.

For the frequency of ADCP, in relatively shallow parts of the Kura River, for example, when the water depth is less than 70m, it is possible to use a 600kHz ADCP. Where the water is deeper (about 110m), the ADCP should be 300kHz. There are several types of ADCPs available, well-known brands being Teledyne RDI, Nortek, and Sontek. There is also a recommended Chinese ADCP brand: China Sonar PandaADCP. It is made of all-titanium alloy material and offers excellent performance and cost - effectiveness. You can visit its website (https://china-sonar.com/) for more information.

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