How to Measure the Water Current of the Cooper River?

1. Location of the Cooper River

The Cooper River is located in Australia. As a matter of fact, it is one of the important watercourses of South Australia. It originates within the Mount Lofty Ranges. From here, it takes a general south-west course, crossing most varied landscapes.

Thus, the course of the river crosses agricultural areas that become extremely dependent upon its water for irrigation purposes. This, in turn, promotes the growth of crops like grapes for wine, cereals, fruits, and vegetables. The historical and economically connected small towns or settlements are also found on both sides of its banks.

The Cooper River is home to many types of aquatic life, from several species of fish, while its banks provide crucial habitats for various waterbirds, reptiles, and other wildlife. Floodplains and wetlands associated with the river serve an important purpose in ecological balance in this area.

2. Flow Rate Characteristics of the Cooper River

The flow rate of the Cooper River carries quite large seasonal and climatic variation. It really very much depends on Australia's pattern of rainfall. During a wet season, which may be variable every year but generally falls within certain months of austral summer, December through February, the river receives increased flow from increased rainfall in its catchment area.

This rate may reduce considerably during the drought periods or dry season. There is also water abstraction for both irrigation and domestic purposes along the length of this river. The average flow rate of the river varies from some cubic meters per second in very dry conditions to hundreds of cubic meters per second in wet conditions.

For this reason, the volume of water carried by the Cooper River is essential to maintain healthy ecosystems in the areas it passes through as well as for agricultural pursuits that comprise a significant percentage of the local economy.

3. Methods of Measuring Water Current of Cooper River

Velocity Meter Method

This traditional method utilizes mechanical or electronic velocity meters. These devices are installed at locations along a river in order to measure the speed of water flow directly at those places. However, to find an accurate picture of the normal water current, many measurements have to be taken at different depths and across sections of the river. This, considering the length and variable conditions of the Cooper River, is quite labor-intensive and time-consuming.

Acoustic Doppler Current Profiler (ADCP) Method

The ADCP profiler provides a more advanced and convenient way to measure water currents. The movement of the water particles is detected by way of sound waves. Basically, it measures the velocity of water at several depths simultaneously by sending acoustic signals and analyzing the Doppler shift of the reflected signals. Therefore, this offers an orderly profile of the water current, hence allowing a closer approximation to real flow conditions within the river. ADCP meter ​can be deployed from a boat, bridge, or even on buoys for continuous monitoring.

Buoy Method

The buoy method involves placing buoys in the river, which have sensors that measure the movement of water around them. In this instance, buoys float on the water surface and may give an indication of the current of the surface waters. They may not be so accurate in the complexity which the water current has, especially regarding the variations that different velocities have at different levels of depth, as compared to the other methodologies.

Of the methods mentioned in the paper, the ADCP flow meter is a more technologically advanced and efficient way of measuring the current of water in the Cooper River.

4. How the Principle of Doppler Using ADCPs Works

The principle of operation of ADCP current profiler is based on Doppler. When an ADCP emits an acoustic signal into the water, the emitted sound waves travel through the water and scatter off the moving water particles. In relation to the movement of the water particles, the reflected sound waves have a frequency shift due to the Doppler effect.

If the particles of water are flowing towards the ADCP current meter, the reflected wave frequency would be higher than the emitted frequency. In contrast, if the movement of the particles of water happens to be away from the acoustic doppler velocity meter, then obviously the reflected wave frequency would fall lower. By measuring this shift in frequency precisely, the ADCP will be able to find out the velocity of water particles at different depths.

These are then combined by the acoustic doppler flow meter to provide a complete profile of the water current. This therefore gives an insight into how the water is flowing not just at the surface, but throughout the vertical section of the river.

5. Requirements for High - Quality Measurement of the Cooper River Currents

The measurements require the equipment to possess certain qualities for the measurement to be of high quality.

The equipment needs to be highly material reliable. It should be able to put up with adverse conditions in the river, such as those from water and sediment, besides temperature. The varied flow of the Cooper River and the presence of debris during the high-flow periods require durable equipment.

In addition, small size and lightweight with low power consumption is preferred. A device that is compact and light is easy to handle and deploy, whether it sits on a boat or attached to a buoy. Low power consumption ensures that the equipment can operate for long periods without frequent replacements of batteries or access to a continuous power source.

Cost-effectiveness is very important, as the lower the cost, the wider the dispersal of measurement equipment for more thorough monitoring of the river.

Titanium alloy will serve very well in casing the ADCP. Other factors that make the titanium alloy highly competent for the purpose are that it is highly resistant to corrosion, an important issue while dealing with water bodies like the Cooper River; moreover, the equipment constantly comes in contact with water and other corrosive substances. It is also strong, durable, and resistant to physical impacts and pressure changes that may occur during the deployment and operation of the equipment. Besides, the density of the titanium alloy is relatively low, thus helping in the general purpose of keeping the equipment lightweight.

6. Selection of Appropriate Equipment for Current Measurement

In selecting appropriate equipment for measuring the current of the Cooper River, several factors have to be considered.

According to the Purpose of Use

If one is looking to measure the horizontal cross-section of the river current, he wants a horizontal ADCP-the HADCP. The HADCPs are designed to give an excellent degree of accuracy in the measurement of water flow across the horizontal plane, which is vital for ensuring good understanding of the overall movement of water across any particular section of the river.

This would involve measuring the vertical cross-section of the river current, for which a vertical ADCP should be selected. Vertical ADCPs can measure with accuracy the velocity of the water at different depths, providing a detailed profile of how the water is flowing vertically in the river.

Based on the Frequency

Which frequency to choose is a factor of the depth of the water in the Cooper River. For up to 70 meters of water depth, a 600 kHz ADCP would normally suffice. A frequency of 600 kHz offers a very good resolution and accuracy in fairly shallow waters in measuring the water current.

Such a higher frequency would be suitable for waters with more than 70 meters, up to approximately 110 meters, and that can be achieved with a 300 kHz ADCP. The frequency of 300 kHz can penetrate deeper in water for the effective measurement of the water current.

Some well-known brands for ADCPs are Teledyne RDI, Nortek, and Sontek. However, for those seeking a cost - effective option with excellent quality, the China Sonar PandaADCP is worth considering. It is made of all - titanium alloy material, ensuring durability and reliability. With its remarkable cost - performance ratio, it provides a great alternative for measuring the water current of the Cooper River. 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.