ADCP in Warburton River Flood Management

1. Where is the Warburton River?

The Warburton River is located in Australia. It is considered a major river passing through arid and semi-arid parts of the country.

It flows geographically through the topography of deserts and plains. This topography and climate typical of Australia tends to moderate the course taken by the Warburton River. The Warburton River features in the most fundamental aspects of the local water cycle and supplies the limited vegetation and wildlife with a vital amount of water.

Based on the climatic factor and rainfall, the region that the Warburton River is located in tends to fit into the arid to semi-arid category of climate. The rainfall is periodic and so irregular. In fact, when it rains, the flow of the river dramatically shifts. Usually, the river is dry all the time, and flooding, in turn, generally occurs when heavy rain comes, which is very rare to occur. They can be severe due to the volumes of water that run off the dry terrain to the river channels.

2. Why does the flooding of the Warburton River take place?

Heavy and Erratic Rainfall: Heavy rainfall in generally dry catchments is the primary cause of the flooding in the Warburton River. During the dry season, the soil in the catchments is normally hard-baked and has low infiltration capacity. In these cases, when heavy rain falls, most of the water runs off quickly into the river and raises its water mark almost instantly.

Flash Flooding from Upland Areas: Similarly, the upland areas of catchment may contribute to flash floods. The steep slopes of such catchments allow rainstorm water to run off very fast. It ultimately focuses quickly into the river channels and thus causes sudden and violent flood downstream.

Lack of Vegetation and Soil Conditions: The nature of the region, being arid and semi-arid, restricts vegetation to intercept and/or slow down rainfall. Besides, the soil texture is usually sandy or clay-like, which causes the area to either provide a quick runoff opportunity or get impermeable upon saturation, thus accentuating the flood situation.

It is in this regard that the ADCP profiler can play an important role in understanding and managing the flow of a river during flood events.

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

ADCPs rely on the principle of the Doppler effect. First, a certain acoustic signal is sent by the device into the water. Since the latter is flowing, the released signal interacts with the moving particles of the water. Consequently, when the acoustic signal is reflected back to the ADCP flow meter, its frequency changes owing to the Doppler effect.

It measures the shift in frequency between the emitted signal and the received signal. It can translate this frequency shift to the velocity of water at various depths. The more common devices have multiple transducers, which send and receive acoustic signals in multiple directions. This allows them to build up a profile of the water velocity across a section of the river.

For example, if the water is moving towards the ADCP meter, then the frequency of the reflected signal will be higher compared to the emitted signal. In contrast, if the water is flowing away from the ADCP, then the reflected signal frequency will be low. By measuring these frequency shifts with a great degree of accuracy, and thereby applying the right mathematical algorithms, the ADCP doppler can obtain the water velocity at many points within its measurement range.

4. What are the applications of ADCP in the Warburton River flood?

Velocity Measurement

Acoustic Doppler Current Profiler (ADCP) will play a significant role during Warburton River flooding in the accurate measurement of the velocity of the flowing water. With its tender for continuous monitoring of the velocity of the water at different depths and locations, it presents real-time information on the speed at which water moves. This will be crucial to understand the dynamics of the flood by describing the direction that the flood waters take and the intensity of flow that the flood water would have.

Flow Measurement Application

Acoustic Doppler Current Profiler (ADCP) is also capable of measuring the flow rate of the Warburton River. Using the measured water velocities at many points across a section, along with the river's known cross-section area, it can calculate the total volume of water that is flowing through the section per unit time, known as the flow rate. This is fundamental information to quantify the amount of water in all flood stages, and for decision-making processes regarding flood control and regulation, as well as management of water resources.

Application in Sediment Transport Research

Among other functions, ADCP current profiler could be useful in sediment transport studies across the Warburton River during flooding. While the water is flowing, it transports sediments. The ADCP is able to detect the variation in the backscattered acoustic signal generated by the presence of sediments. From these changes, researchers can estimate the quantity and motion of sediments, crucial in the comprehension of the long-term evolution of the riverbed and the action of floods on the river's sedimentary environment.

5.What is the possible use of ADCP measured data for flood warning and for the management of the Warburton River?

Warning of Floods

Monitoring Velocity and Flow Data: In this respect, the ADCP flow meter collects real-time data on velocity and flow and continuously monitors it. If the measured water velocity exceeds the threshold value, or the flow rate increases abnormally, this may indicate the approaching of a flood peak or a potential flood situation. Such an early warning enables relevant authorities to take precautionary measures, like relocating people in low-lying areas, or reinforcing flood defenses.

Water Level Prediction and Warning: Measured flow data, when correlated with historical data of water level and appropriate hydrological models, can enable the ADCP data to predict the future water levels. If the predicted water level is above the flood warning level, timely warnings can be issued to the public, enabling them to prepare for the flood.

Risk Management

Water Conservancy Project Scheduling Decision Support: Accurate flow and velocity information can be used to make decisions on how water conservancy projects like dams and sluices are operated. The amount of water to be released from the dam, for instance, can be regulated with the actual measured flow of water so that the water level in the Warburton River is controlled and its consequences of flooding are minimal.

Flood Disaster Assessment and Emergency Response: The data collected by ADCP meter during the flood event will be useful in analyzing the magnitude of the flood with respect to the extent of inundation, the velocity of the floodwater, and the quantity of sediment deposition. This will be highly important in formulating an emergency response plan and in carrying out post-flood reconstruction and rehabilitation work.

6.What is needed to have high-quality measurement of the currents of the Warburton River?

There are a lot of factors that should be considered for high-quality measurement. First of all, one should use equipment made of reliable materials. The casing of the ADCP flow meter is very important. Given the harsh and often sandy or silty water environment, the casing is recommended to be made from some durable and corrosion-resistant material like a titanium alloy. With high strength, it will be able to enable equipment to bear such pressure and impulse caused by water flow in the river.

Besides material reliability, the size and weight of the equipment shall also be small and lightweight. The ADCP doppler will be easily installed and operated at various points of the river, including places not so accessible. The low power consumption is important; hence, it can work continuously for a long period without frequent battery replacement or connection to a power source. Also, the cost of equipment should be relatively low to enable large-scale measurement. Lower cost allows deploying more ADCPs down the Warburton River for more extensive and detailed data in flood management.

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

Equipment selection for current measurement at the Warburton River will depend on a number of factors that include the type of measurement required, whether it be for a horizontal cross-section measurement, in which case one would select a Horizontal ADCP flow meter, or a vertical cross-section measurement, for which the right kind will be the Vertical ADCP meter.

Different frequencies are suitable for different water depth. For instance, a 600 kHz is suitable for water depths in the range of 70 m. So, if the water depth in Warburton River lies within this range and it also meets the requirements of measurement, then it can be considered for a 600 kHz ADCP. The 300 kHz ADCP would be more suited for deeper waters, say over 70 m up to 110 m, for better measurements.

There are several well-known brands of ADCPs available in the market. These are Teledyne RDI, Nortek, and Sontek. But the most cost-effective one is 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.