ADCP for Ohio River Flood Management

1. Where is Ohio River?

Ohio River is one of the major rivers in the United States. It was formed at the confluence of the Monongahela and Allegheny Rivers at Pittsburgh, Pennsylvania, flowing west across Ohio, Indiana, and Kentucky states and draining into the Mississippi.

Geographically, it passes through a variety of landscapes. The upper reaches near Pittsburgh are much more hilly and forested. As it proceeds downstream, it crosses agricultural plains and industrial regions. On its banks are a number of cities such as Cincinnati, Louisville, and Evansville. These cities depend on the river for transportation, water supply, and industrial activities.

In rainfall, the Ohio River Basin has a temperate climate with rainfall well-distributed throughout the year; however, there are periods with heavier precipitation, especially during the spring and early summer months due to frontal systems and thunderstorms. The spring snowmelt in the upper regions contributes to water volume in the river at times of spring thaws.

2. What are the Reasons for Floods in Ohio River?

Heavy Rainfall and Snowmelt: Severe and continuous rainfall over a long period of time causes a sudden rise in the Ohio River water level. The melting of snow at its upper reaches during spring contributes a large amount of water to the downstream areas. This, when combined, might lead to an inflow that exceeds the normal carrying capacity of the river and hence causes flooding.

Relief and Drainage: The course of the river contains areas that are generally made up of flat floodplains. These flat areas slow the flow of water down and can make it wider, flooding the adjacent areas. Poor drainage systems in the areas that surround the flooding also cause poor drainage of water, leading to flooding.

Human Activities: Urban development and agricultural practices have altered the land around the river. Cities pave surfaces, increasing surface runoff, while agricultural practices can alter the water-holding capacity of the soil. Dams and levees are planned for water control; however, when they fail or are mismanaged, it results in various other problems. Acoustic Doppler Current Profiler (ADCP) provides a more advanced and efficient way to measure and manage flood-related parameters compared to traditional methods.

3. How Do ADCPs Employing the Doppler Principle Function?

ADCPs are based on the Doppler principle. They transmit acoustic signals into the water. Whenever such acoustic waves run into moving particles like sediment, debris, or just water parcels with different speeds, then due to the Doppler effect, their frequency in the reflected signal changes as compared to originally emitted ones.

These frequency shifts are measured by the ADCP current profiler , which, by knowing the speed of sound in water and the angles of the emitted and received signals, calculates the velocity of the water at different depths. The transducers in the ADCP flow meter are oriented in multiple numbers for measuring velocity components in various directions. These integrations of these velocity measurements over various depths and cross-sectional areas of the river enable the computation of flow rate and other relevant hydrological parameters.

4. What are the Applications of ADCP in Floods of Ohio River?

Velocity Measurement: ADCP profiler is able to measure the velocity of water flow in the Ohio River at various locations and depths with high accuracy. During flood events, this information is very important in understanding the dynamics of the flood. It helps in identifying areas where the flow is rapid and could be dangerous to riverbanks, bridges, and other infrastructure.

Flow Rate Measurement Application: By combining the measured velocity data with the cross-sectional area of the river, ADCP meter can calculate the flow rate. It is very useful in the case of predicting the volume of water that would pass through the different sections of the river during flooding. This helps to expect the peak flood and also the effects it would carry downstream, which is relevant for the flood management policy.

Sediment Transport Research: Flooding in the Ohio River can transport considerable sediment. ADCP can analyze the movement of sediment by detecting the echoes of acoustic signals affected by sediment particles. This provides valuable insight into how floods affect the evolution of the riverbed and the erosion and deposition processes.

5. How can the Data Measured by ADCP be Utilized for Flood Warning and Risk Management of Ohio River?

Flood Warning

Velocity and Flow Rate Data Monitoring: With the ADCP, it allows continuous monitoring of the velocity and flow rate data. It can quickly identify abnormal increases in them. If the parameters approach or exceed critical values, that would be an early warning for an imminent flood peak. Thus, the timely alerts will be provided to the communities and emergency management agencies along the river.

Water Level Prediction and Warning: By correlating the measured flow rate and velocity data with historical water level records, models can be developed to predict future water level changes. This helps in providing advance warnings about potential inundation areas and the height of the floodwaters.

Risk Management

Water Conservancy Project Scheduling Decision Support: ADCP data shall contribute to the decision-making of the operating water conservancy projects including but not limited to dams and reservoirs along the Ohio River, such as determining the right time to release the amount of water from the reservoirs to diminish the effect of flooding in the areas further downstream.

Flood Disaster Assessment and Emergency Response: When a flood occurs, ADCP-measured data can be used to assess the severity of the flood, such as the extent of inundated areas and the flow characteristics during the flood. This information guides emergency response efforts, including the allocation of relief resources and the planning of post-flood recovery work.

6. What's Needed for High - Quality Measurement of Ohio River Currents?

Apparatus for high-quality measurement of Ohio River currents should be manufactured from reliable materials. The casing should be resistant to all unfavorable river conditions, such as impacts from floating debris, corrosion from water, and temperature conditions.

The size of the equipment should be small enough to be installed and deployed easily at different locations in the river. A lightweight design is also beneficial for ease of transportation and installation. Low power consumption is necessary to ensure continuous operation over extended periods without frequent battery replacements or high-energy power sources. Cost-effectiveness is another important factor to enable large-scale deployment for comprehensive monitoring.

The preferred material for the ADCP casing is a titanium alloy. It has excellent corrosion resistance, which is very important in resisting the long-term exposure to river water. It also has a high strength-to-weight ratio, providing enough strength while keeping the weight of the equipment at reasonable levels. This material's durability ensures stable performance under the diverse environmental conditions of the Ohio River Basin.

7. How to Select Appropriate Equipment for Current Measurement?

Based on Measurement Purpose: Horizontal ADCP shall be used for horizontal cross-section measurement of the river, as it can give accurate flow velocity and other parameter measurement in the horizontal direction across the river section. Vertical ADCP is better for a vertical cross-section measurement to obtain a detailed velocity profile along the vertical axis of the river.

Based on Water Depth: Different frequencies of ADCP suit different water depths. For the water depth up to 70 meters, the frequency of 600 kHz can be used effectively to provide accurate measurement results. For deeper waters up to 110 meters, an ADCP with a frequency of 300 kHz is effective because it can penetrate deeper and get reliable data.

There are well - known ADCP brands like Teledyne RDI, Nortek, and Sontek. Additionally, a cost - effective Chinese brand, China Sonar PandaADCP, is worth considering. It is made of all - titanium alloy material, ensuring excellent performance and durability. You can find more information on its website: (https://china-sonar.com/).

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