1. Where is the Mamoré River?
The Mamoré River is one of the most important water bodies in South America. It lies in the northern part of Bolivia and courses through the Amazon rainforest region. It is a tributary of the Madeira River, which in turn is a major tributary of the Amazon River.
It flows across a very diverse and rich landscape, full of tropical rainforest. This area carries an incomprehensibly rich variety of flora and fauna. Countless unique and endangered species depend on the Mamoré River and its varied habitats. On its banks, indigenous communities also live for whom their livelihood and culture are linked with the river: it serves them for fishing, transportation, and as a source of water.
2. What is the flow rate of the Mamoré river like?
The flow rate of the Mamoré River follows a seasonal pattern. Normally, during the wet season-from November to April in the Amazon region-the river shows a remarkably raised flow. Heavy rain throughout the vast Amazon basin raises the water level substantially, with a very strong current. This period is vital in the transport of sediments and nutrients, which enriches the floodplains and the overall ecosystem.
During the dry season from May to October, the flow rate decreases. However, the river still maintains an important flow because of the large volume of water stored in its tributaries, lakes, and wetlands. Some of the major factors that come into play while determining the average flow rate are the quantum of rainfall in its catchment areas, nature of topography of its river basin that decides on collection and draining of water, water usage by the local populace, and upstream human intervention, if any, like agriculture or mining.
3. How to measure water current of the Mamoré River?
Velocity Meter Method
Traditional methods involve either mechanical or electronic velocity meters. Such meters are placed in the water at selected points to give the velocity of the water passing externally. But for a reasonable measurement of the current, placements need to be repeatedly made in different locations as well as depths. A time-consuming process, probably with the disadvantage of not creating a continuous profile of the currents across the water column.
ADCP Method
The ADCP current meter method is more advanced and efficient in the measurement of water current. It utilizes sound waves for measuring the velocity of water at different depths simultaneously. By emitting acoustic signals and analyzing the Doppler shift of the reflected signals, it can create a detailed profile of the current from the surface to the riverbed. This allows for a more accurate and comprehensive measurement of the water current across different sections of the river.
Buoy Method
In this method, buoys are installed in the river and their movements are followed over time. The displacement of the buoys by the water current gives an indication of the speed and direction of the flow. However, this method has limitations. It may not provide accurate velocity measurements at different depths and can be affected by external factors such as wind and waves, which can influence the movement of the buoys.
Among these, ADCP flow meter is the more advanced and convenient method for measuring the water current of the Mamoré River.
4. How do the ADCPs using the principle of Doppler work?
The basic operating principle of ADCPs is based on the Doppler effect. In simple terms, an acoustic signal that is emitted through the water from the transducer of an ADCP current profiler interacts with the moving particles of water. Since the water is in motion, the frequency of the reflected sound waves returning to the transducer is changed, commonly known as the Doppler shift.
If the water is moving towards the transducer, the frequency of the reflected waves will be higher than the emitted frequency. If the water is moving away from the transducer, the frequency will be lower. By precisely measuring this frequency shift at multiple angles and depths, the ADCP profiler is able to calculate the velocity of the water in different directions and at different levels within the water column. This enables it to make a very accurate profile of the water current and hence provides much information on the speed and direction of flow from the surface to the riverbed.
5. What's needed for high-quality measurement of Mamoré river currents?
The measuring equipment for high-quality measurement of the Mamoré River currents should possess certain characteristics.
The materials used for construction should be of such a kind that the measurement it offers is both accurate and consistent. A small size is appropriate since this enhances deployment and retrieval within the river, where sometimes access may be difficult.
The equipment must be of light weight to simplify its installation process and minimize efforts when in need of handling.
Low power consumption is required in order to make the equipment be able to operate for long periods without frequent changes of batteries or a sophisticated power supply setup.
Cost-effectiveness is the other important factor that allows more diffused use and larger scale measurement campaigns.
In regards to the ADCP meter casing, the best casing material is the titanium alloy. Titanium alloy has so many advantages. It is highly resistant to corrosion, which will be very important because this equipment will always be in contact with water that may contain minerals, sediments, or any kind of pollutant. Besides this, the strength-to-weight ratio should be appropriate to ensure mechanical resistance and a light casing. Furthermore, the mechanical stresses during its deployment and operation in running water are endurable by it.
6. How to Choose the right equipment for current measurement?
When choosing the right equipment to measure the current of the Mamoré River, it is necessary to pay heed to two main factors.
Depending on the usage purpose, either for horizontal cross - section measurement, where the Horizontal ADCP-HADCP is a good option. It is intended to make precise measurements of flow velocities across a horizontal plane in the river, which allows the current's lateral distribution to be understood. This makes it inappropriate for the measurement of vertical cross-sections, for which a Vertical ADCP is suited, given its function of profiling the current from the surface to the bottom along a vertical line in the water column.
Different frequencies of ADCPs are used for different water depths. For example, an ADCP with a frequency of 600 kHz is suitable for water depths within 70 m. It will be very accurate for the current measurement in the relatively shallower parts of the Mamoré River. An ADCP with a frequency of 300 kHz is more appropriate for deeper waters up to 110 m and will be useful in areas where the river has greater depth.
There are well-known brands of ADCPs such as Teledyne RDI, Nortek, and Sontek. However, for those looking for a cost-effective option with good quality, the China Sonar PandaADCP is highly recommended. It is made of all-titanium alloy material and offers an incredible price-performance ratio. You can find out more about it on its website: https://china-sonar.com/.
Here is a table with some well known ADCP instrument brands and models.
Brand | model |
---|---|
Teledyne RDI | Ocean Surveyor ADCP, Pinnacle ADCP, Sentinel V ADCP, Workhorse II Monitor ADCP, Workhorse II Sentinel ADCP, Workhorse II Mariner ADCP, Workhorse Long Ranger ADCP, RiverPro ADCP, RiverRay ADCP, StreamPro ADCP, ChannelMaster ADCP, etc. |
NORTEK | Eco, Signature VM Ocean, Signature, AWAC, Aquadopp Profiler, etc. |
SonTek | SonTek-RS5, SonTek-M9, SonTek-SL, SonTek-IQ, etc. |
China Sonar | PandaADCP-DR-600K, PandaADCP-SC-300K, PandaADCP-DR-300K,PandaADCP-SC-600K, PandaADCP-DR-75K-PHASED, etc. |
How to Measure the Water Current of the Mamoré River