ADCP's Application in Flood Management of the South Saskatchewan River

1. Location and General Characteristics

The South Saskatchewan River is one of the major rivers in Western Canada. It originates in the Rocky Mountains of Montana, United States, and then flows north into Canada. It passes through the provinces of Alberta and Saskatchewan.

Its course contains different climates, alpine with cold winters and cool summers in mountainous regions near the source, while the one continuing onto the prairies takes up a more continental pattern- cold winters and warm summers. The river is fed from the snowmelt in the Rocky Mountains during spring and early summer, together with rainfall in the prairie regions throughout the year.

2. Reasons for Floods

Snowmelt: The water volume in the South Saskatchewan River increases considerably through the snowmelt. A heavy snowpack in the Rocky Mountains can lead to a huge and rapid release of this water. If the snowmelt rate is too rapid and the natural river capacities to carry this water are surpassed, then flooding happens. The snowmelt-driven high-water period generally would be from late spring until early summer.

Heavy Rainfall: The prairie regions the river flows through are susceptible to heavy rainfalls, especially during the summer months. Intense and sustained rainstorms can quickly swell the river. When heavy rainfall coincides with the already high water levels from snowmelt, it exacerbates the flood risk.

Topography and Land Use: The generally flat prairie terrain contributes to poor natural drainage in parts of the area. A rising river has a tendency to easily spread over its floodplains. Besides, human-induced land use changes, such as agriculture and infrastructure construction, may affect the natural course and drainage of the river. For instance, extensive agricultural fields with poor water retention capability will increase surface runoff and hence contribute to higher river stages.

3. How ADCPs Using the Doppler Principle Work

ADCPs, or Acoustic Doppler Current Profilers, work on the principle of the Doppler effect. They emit acoustic pulses into the water. These pulses interact with moving particles in the water, such as sediment grains, small aquatic organisms, and other suspended matter.

When the acoustic waves bounce back after hitting these moving objects, a frequency shift occurs. This frequency shift, in turn, is directly proportional to the velocity of the moving objects and, consequently, the velocity of the water. An ADCP flow meter, if installed in the South Saskatchewan River, for instance, would probably be mounted on a boat or a fixed structure near the riverbank, sending out sound waves into the water column. While the flowing water and its constituents reflect the waves back, the ADCP current meter analyzes the received signals to calculate the speed and direction of the water flow at different depths.

4. Applications of ADCP in Floods

Flow Velocity Measurement: ADCP profiler will be able to measure the flow velocity of water in the South Saskatchewan River very accurately. During flood events, this is very useful information. By knowing the speed of the floodwaters, it enables one to forecast the spread of the flood. It also helps in the identification of areas where high-velocity flows may cause erosion or other damage to the riverbanks and infrastructure.

Flow Rate Measurement: Combining the measured velocities with the cross-sectional area of the river-which also can be estimated through ADCP-allows the flow rate to be calculated. In relation to a flood, the flow rate is important in assessing how much volume of water goes through a section of a river; this will predict the overall impact downstream.

Sediment Transport Research: ADCP flow meter is capable of detecting the actual movements of sediment particles along with the flow of water. In the time of floods, this goes a long way in revealing how much sediment the river actually carries. Understanding sediment transport has implications for understanding how changes in the riverbed occur. These changes may bear upon the stability of the river and its infrastructure.

5. Application of ADCP to Flood Warning and Risk Management

Flood warning

Flow Velocity and Flow Rate Data Monitoring: Real-time observation of flow velocities and flow rates will be enabled by ADCP meter for the early detection of a variation that may signal an impending flood. For instance, should the velocities or flow rates start to rise above usual levels, an alert may be issued. This permits appropriate authorities to issue timely warnings to communities along the riverbanks.

Water Level Prediction and Warning: With the relation of flow rates, velocities, and water levels from the historical data and the ADCP measurements, prediction of future water levels is possible. These are vital for the warnings given to residents so that necessary precautions may be taken to prevent loss of life by evacuating people or taking anti-flooding measures.

Risk Management

Water Conservancy Project Scheduling Decision - Support: ADCP current meter will contribute much data useful in making the operation decision on dams, reservoirs, and other water conservancy projects along the South Saskatchewan River. For instance, when predicting a flood, depending on ADCP-measured data, the release can be done from the reservoirs in such a way as to minimize downstream flooding, taking into account the safety of the structures.

Flood Disaster Assessment and Emergency Response: In the aftermath of a flood event, for example, ADCP flow meter can be used to determine damage in such respects as the degree of erosion, changes in the riverbed, and infrastructure impacts. It informs emergency response and guides the formulation of future mitigation strategies against floods.

6. Requirements for High - Quality Current Measurement

The equipment should be made of reliable materials for high-quality measurement of the South Saskatchewan River currents. Small in size and light in weight, it is advantageous for its easy deployment in most locations along the river, whether on boats or at bridges.

Low power consumption is necessary for long-term monitoring, especially in areas with limited power supply. Cost-effectiveness is also paramount to allow for widespread deployment for comprehensive monitoring. The casing of ADCP current meter is preferably made from Titanium alloy. Titanium alloy will provide excellent corrosion resistance, which becomes important when dealing with South Saskatchewan River water that might contain a variety of minerals and salts. It also possesses a good strength-to-weight ratio that makes the equipment strong enough yet relatively easy to manipulate and install.

7. Selecting Appropriate Equipment for Current Measurement

In choosing the equipment to measure the current at the South Saskatchewan River, the following must be considered.

A Horizontal ADCP shall be applied for horizontal cross-section measurements. It measures flow velocities across a horizontal plane, enabling a proper understanding of the overall flow pattern within a certain reach of the river.

Vertical ADCP will be the best option for the vertical cross-section measurements because this will profile the velocities from the water surface to the riverbed along the vertical line.

For frequencies, a 600 kHz ADCP is appropriate for water as deep as about 70 m. An ADCP current profiler frequency of 300 kHz offers better performance in deeper sections where water is as deep as about 110 meters.

There are well - known ADCP brands such as Teledyne RDI, Nortek, and Sontek. However, for a cost - effective option, the China Sonar PandaADCP is recommended. It is made of all - titanium alloy materials and offers a good cost-performance ratio. You can find more information at (https://china-sonar.com/).

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