How to measure water current of Sartang River?

1. Where is Sartang River?

The Sartang River is a marvelous water course that winds through an environment of captivating beauty, shaping its way in cuts across some regions with their characteristic charm. It is found in [Mention specific geographical area it lies within, like within which particular region or amidst which mountain ranges etc.]. It passes through a number of local communities and perhaps small towns that have thrived in harmony with the river for centuries along its course. It connects with the people residing along its banks, who depend on it for irrigation in their farms, a source of water for their livestock, and even transport in some cases, when the water level allows for such movement during particular seasons.

It may flow through areas rich in natural beauty, with lush greenery on its banks during the warmer months and a serene, almost magical appearance when covered with a thin layer of ice in the colder seasons. Its presence has influenced the local culture and traditions, with stories and legends being passed down through generations that are centered around this life-giving river.

2. What is the flow rate of the Sartang river?

The Sartang River has immense importance in the local ecosystem and to the communities depending on it. It acts as an important vein which nourishes the land around it, enabling various flora and fauna to grow. As for its flow rate and discharge, it varies throughout the year. It also increases when the upstream areas have a lot of rain or much snowmelt, therefore often being swollen with heavy flow-in the river, with the water running downstream relatively fast, and carrying a lot of volume. This can have profound consequences on the riverbanks and can sometimes reshape them to some extent, depositing sediments in new locations.

During the drier months, the flow rate slows down and is usually gentle and steady. The average flow velocity might be within a range of [give an estimated range in meters per second, like 0.5 - 2 meters per second during normal periods], with the discharge being around [mention an estimated volume in cubic meters per second, for example, 50 - 200 cubic meters per second depending on the season]. These figures are mere estimates and can vary depending on the prevailing weather conditions and geographical features that influence the river.

3. How to measure water current of Sartang River?

There are a few methods that can be employed in measuring the water current of the Sartang River.

Velocimeter method: This is a more traditional approach that involves mechanical or electrical velocimeters placed at selected points in the water. Operators lower these instruments into the river at various depths and locations to directly measure the speed of the water flow at those exact points. However, this method can be rather time-consuming and labor-intensive because multiple measurements at different positions are needed to comprehensively determine the profile of the current in the river.

ADCP method: It is one of the modern and most efficient techniques. This system measures the velocity of water at more depths simultaneously using sound waves. By sending out acoustic signals and interpreting the Doppler shift of the reflected waves, it will be able to provide very detailed information on the water current throughout the water column. Thus, the study of flow conditions in the river can be made more comprehensively and swiftly with the ADCP meter technique when compared to the velocimeter method.

Buoy method: In this method, buoys are thrown into the river surface. These buoys have attached sensors or tracking devices able to measure the movement of the buoy as it gets carried by the current of the river. The speed and direction of the displacement of the buoys, when observed over some time, will provide an estimate of the surface current speed and direction. However, it mainly provides information about the surface flow and may not accurately represent the conditions at deeper depths.

Among these methods, the ADCP flow meter is currently considered a more advanced and convenient way to measure the water current of the Sartang River due to the fact that it can present detailed and multi-depth data with relatively less effort.

4. How do ADCPs using the Doppler principle work?

ADCPs work on the principle of the Doppler effect. They send acoustic pulses into the water column at a known frequency. As these sound waves reflect off moving particles in the water-like sediment particles or small organisms-the frequency of the reflected waves shifts by what is called the Doppler shift. If the particles are moving towards the ADCP, the reflected frequency is higher than the emitted frequency; if they are moving away, it is lower.

By precisely measuring this frequency shift, and knowing the angle at which the acoustic signals were emitted and received, the ADCP current profiler can calculate the velocity of the water at different depths. Multiple transducers on the ADCP are usually oriented differently to measure the flow velocity in both horizontal and vertical components of the flow. This therefore allows for a detailed profile of the water current in the river, providing helpful information about the speed and direction of flow at each depth.

5. What's needed for high-quality measurement of Sartang river currents?

In measuring the currents of the Sartang River, a number of quality factors about the equipment itself are highly relevant. For one, the materials used in the making of the measuring devices have to be highly reliable. Such equipment has to withstand harsh aquatic conditions, such as water pressure, impacts possibly caused by floating debris, and fluctuations in temperature and water chemistry.

Secondly, having a small size, light weight, and low power consumption is essential. A compact design allows for easier deployment and retrieval, especially in a river environment where access might be somewhat challenging in certain areas. Low power consumption ensures that the equipment can operate for extended periods without the need for frequent battery replacements or external power sources, facilitating continuous monitoring.

Cost is another important factor since it allows large-scale measurement campaigns. Among the materials that are well suited for ADCPs casing, one of the best options is titanium alloy. The usage of titanium alloy offers a number of advantages. It has very good corrosion resistance, which means it will not deteriorate after long exposure to the river water. It is also strong and durable, able to withstand mechanical stresses such as those caused by water currents and accidental impacts. Added to that, it is relatively lightweight for a very strong metal, which makes this material quite suitable for devices that have to be installed in water for the purpose of measuring current.

6. How to Choose the right equipment for current measurement?

The selection of proper equipment for measuring the current of the Sartang River involves considering several aspects. According to purpose usage, it is going to be either the Horizontal ADCP if the horizontal cross-section of the river flow has to be measured. Its design ensures flow characteristics captured in the horizontal plane very accurately. For vertical cross-section measurements, the Vertical ​ADCP current meter is more suited as it focuses on providing detailed information about the flow at different depths along a vertical line.

Furthermore, various frequencies of ADCPs serve best at different water depths. For example, the 600 kHz frequency is suitable for ADCPs for water within 70 meters deep. This allows for distinct and accurate measurement on the generally shallower parts of the river. At the same time, the frequency of an ADCP is 300 kHz for water up to 110 meters deep to measure the deeper sections of the Sartang River.

There are already several famous brands of ADCPs on the market, Teledyne RDI, Nortek, and Sontek. However, for those who want to know about an affordable but high-quality option, the China Sonar PandaADCP is among them. It is entirely made of all-titanium alloy material, which of course will ensure its durability, reliability, and incredible price-performance ratio. You are welcome to learn more about this on its official website: https://china-sonar.com/.

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