ADCP's Application in Flood Management of Guaporé (Itenez) River

1. Where is Guaporé (Itenez) River?

The Guaporé (Itenez) River is in South America. It forms part of the border between Brazil and Bolivia. The river rises in the Brazilian state of Rondônia and flows generally northward through a region rich in tropical rainforests and diverse ecosystems.

Geographically, it cuts through a dense vegetation landscape characterized by numerous species of hardwood trees, lianas, and epiphytes. It is inhabited by a number of wildlife, such as jaguars, tapirs, several species of monkeys, and a host of fish species. The riparian indigenous communities have a very long-standing relationship with this river for fishing, transport, and water for household use.

The Guaporé (Itenez) River Basin has a tropical rainforest climate, which means that the rainfall is copious throughout the year, and there is no well-marked dry season. This heavy and sustained rainfall provides a continuous water volume in the river but makes the area very flood-prone in case of rising water levels due to extreme weather conditions or other factors.

2.What are the reasons for floods in Guaporé River-Itenez?

Heavy Rainfall: The Guaporé River is one of the rivers in the tropical rainforest that continuously receives a lot of rain. This can lead to the sudden rise in the water level of the river when it rains heavily and for longer periods. The large catchment area means that the water coming from a wider region converges into it, quickly overwhelming its capacity and leading to flooding.

Tributary Overflow: The Guaporé (Itenez) River has many tributaries. When these feeding rivers also receive heavy rain and swell, they will overflow and release a lot of water into the main stream. This can exacerbate the flood situation and cause the water levels to rise even further.

Topography and Drainage: The topography of the riverbanks is level enough in some places to easily allow spreads of water into the adjoining areas. Besides this, the usual intricacy in the pattern of waterways and natural obstructions or constrictions occurring in the river course obstruct the normal flow of water and force it to back up and create floods.

Deforestation and Land Use Changes: Despite the fact that the Amazon rainforest is widespread, deforestation in the Guaporé-Itenez River Basin could give some influence. When forests are removed, the area's capability to absorb and retain water decreases. The result of this is a greater amount of surface runoff, subsequently flowing into the river, increasing the water volume and the possibility of flooding. Use of ADCP profiler guarantees that measuring and managing floods, linked with their occurrences in rivers and estuaries, could become much easier than compared methods so far applied.

3. How Do ADCPs Using the Doppler Principle Work?

The ADCPs work on the principle of Doppler. They emit acoustic signals into the water. These acoustic waves interact with moving particles in the water, such as sediment, debris, and different-velocity water parcels. When the emitted waves bounce back after hitting these moving objects, the frequency of the reflected waves changes due to the Doppler effect.

It measures the Doppler frequency shift, while knowing the speed of sound in water and the angles at which the signal is emitted and received. This allows for a calculation of the velocity at different water depths. More than one transducer of ADCP measures the velocity in more than one direction. Such velocity, integrated over variable depths and cross-sectional area of the river, leads to a determination of flow rate and other important hydrological information.

4. What are the Applications of ADCP in Floods of Guaporé (Itenez) River?

Velocity Measurement: ADCP can measure the actual velocity of the water flow in the Guaporé-Itenez River at various locations and depths. During flood events, this information is important to know the dynamics of the flood. It helps identify the areas where the flow is rapid and may be dangerous for riverbanks, bridges, and other infrastructure. It also allows monitoring how the flow velocity changes with time as the flood progresses.

Flow Rate Measurement Application: ADCP meter will be able to estimate the flow rate by using the measured velocity data in conjunction with the cross-sectional area of the river. This helps in understanding the volume of water that will pass through every section of the river in case of a flood. This helps in the prediction of the flood peak and its effects further downstream, which is crucial for the adoption of flood management strategies.

Sediment Transport Research: During floods, the Guaporé (Itenez) River can transport a great amount of sediment. The ADCP flow meter can analyze sediment transport by acquiring echoes of acoustic signals altered by sediment particles. Such information is relevant for the understanding of the flood effect on bed evolution, sediment deposition, and erosion processes, in order to guarantee the river channel stability and the general ecosystem.

5. How Can Data Measured by ADCP Be Used for Flood Warning and Risk Management in the Guaporé River (Itenez)?

Flood Warning

Velocity and Flow Rate Data Monitoring: The ADCP current profiler provides an opportunity for real-time observation of abnormal rises in both velocity and flow rate by continuously monitoring them. It would also indicate that this is a flood peak whenever the flow rate approaches or reaches these critical values. This allows adequate flood warnings to be provided to the indigenous communities and other settlements downstream of the river, besides the relevant authorities.

Water Level Prediction and Warning: Historical correlation with water level records should make a model possible that projects what will be the likely alteration of the level in days or time ahead, which aids much in issuing warnings to anticipate inundation areas with or without warning of their level of flooding. Therefore, enabling one to go against it effectively.

Risk Management

Water Conservancy Project Scheduling Decision Support: The ADCP data can help in making decisions related to the operation of small dams and reservoirs in the Guaporé (Itenez) River Basin. For instance, it will assist in deciding the appropriate time and quantity of water that should be released from reservoirs to minimize the downstream flood impact.

Flood Disaster Assessment and Emergency Response: After a flood, the data collected by ADCP can be used to assess the severity of the flood in terms of inundated areas and flow characteristics during the flood. It helps to guide emergency response efforts in terms of the distribution of relief resources and planning for post-flood recovery works.

6. What is needed to accomplish high-quality measurements of currents of the Guaporé River (Itenez)?

In high-quality measurement, it should possess reliable materials, resistance from a casing to unfavorable field conditions of the river to resist impacts caused by possible floating debris, chemical structure of water (sometimes under conditions of the surrounding rainforest), and the hot humid climate.

This will allow it to be small in size for easy installation and deployment at different locations in the river, especially in locations that are deep in the rainforest.

Such a design makes it easier to transport and install lightweight equipment. It should be designed to be of low power consumption so that the devices can stay running continuously for long hours without running out of power or having to use very high-energy sources. Cost-effectiveness is another important factor to enable large-scale deployment for comprehensive monitoring.

The casing of an ADCP current meter is preferably to be made of titanium alloy. Several outstanding advantages are found with a titanium alloy. The excellent corrosion resistance is necessary in guaranteeing the long-time exposure to river water. Also, it has a high strength-to-weight ratio, offering good strength while keeping the equipment weight at reasonable levels. It is durable to give stable performance under all the varied environmental conditions that come along with the Guaporé-Itenez River Basin.

7. How to Choose Right Equipment for Current Measurement?

In the choice of right equipment for current measurement on the Guaporé-Itenez River, some criteria should be followed. The first choice is related to the use purpose; when it concerns horizontal section measurement, Horizontal ADCP-HADCP, it would serve the very purpose, for it correctly measures the flow velocity in the horizontal direction across the river section and also the other parameters of flow. In the case of vertical cross-section measurement, the Vertical ADCP is more suitable because it can gain detailed velocity profiles along the vertical axis of the river. Besides, different frequencies should be selected according to the actual water depth.

For water depths within 70 meters, an ADCP with a frequency of 600 kHz is usually a pretty good choice because it may provide relatively accurate measurement results within this depth range. An ADCP of 300 kHz would be more suitable for water masses with a depth of up to 110 meters because it is capable of effective penetration into great depths with reliable data. There are various ADCP brands available in the market, such as Teledyne RDI, Nortek, and Sontek. However, it is worth highlighting a high - quality and cost-effective Chinese ADCP brand-China Sonar PandaADCP. 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.