Why We Measure the River Flow in Agra?

1. Where is Agra?

Agra, which is located in northern India in the Uttar Pradesh state, is on the southern bank of the River Yamuna. Geographically, it is located at approximately 27.17°N latitude and 78.02°E longitude. It is located within the Indo-Gangetic Plain, and the area is fairly flat. The flat topography has been well-suited for urban development and agricultural cultivation throughout history.

Historically and culturally, Agra is India's one of the most significant cities. It was the 16th and 17th century capital of the Mughal Empire. The city is world-famous for its dazzling Mughal architecture, with Taj Mahal being the crown jewel. This white marble mausoleum, representing the ultimate demonstration of love by Emperor Shah Jahan for his wife Mumtaz Mahal, attracts millions of foreign as well as national tourists annually. Other works of architecture that deserve mention are Agra Fort, a colossal red - sandstone fort that was the favorite palace of the Mughal emperors, and Fatehpur Sikri, a deserted city whose palaces and mosques are in fine condition.

The Yamuna River is the major river system on which Agra sits. It originates from the Yamunotri Glacier in the Garhwal Himalayas approximately 1,370 kilometers before joining the Ganges River at Allahabad. Yamuna in Agra has been a major water source since centuries ago. It provides water for household use, irrigation, and small industry. Previously, it was also utilized for transport and trade. But in the past decades, the river has been exposed to grave pollution issues due to the dumping of industrial effluent, release of sewage, and agricultural runoff, which impacted seriously on its ecological health and quality of water.

2. How is the River Flow near Agra?

Several factors regulate the flow of the river around Agra. Runoff and rainfall are the primary determinants. The region experiences a monsoon season between June and September, with heavy rainfall occurring during this period. This results in a significant increase in water level and speed of the flow of the Yamuna River as runoff from the surrounding area drains into the river. On the other hand, during the dry season between October and May, water levels reduce and the flow is significantly slower.

The river morphology and topography also play a role in the flow. The plains allow the river to meander, and the depth and width of the river vary along the course. Some of it is shallow and wider, and some of it is deeper and narrower. The roughness of the riverbed, as required by sedimentation and erosion, also affects the local flow conditions.

There are dams and barrages in the upstream side, such as the Hathnikund Barrage, to regulate release of water. These dams retain water during rainy season and release it in a programmed manner during dry season to deliver minimum flow in the river and give supply of water for a variety of purposes downstream. Sometimes improper management of release of water causes flooding or drought in the lower reaches.

With respect to past hydrological events, the Yamuna River in Agra has witnessed several floods. For instance, in 2010 a big flood in the Yamuna happened due to heavy monsoon rain. The National Disaster Management Authority of India indicated that the flood had caused damage to infrastructure including roads and bridges and affected thousands of residents in riverbanks (Source: National Disaster Management Authority, India, 2010). Observation of such events is essential to construct proper flood mitigation measures, safeguard lives and property, and sustainably utilize water resources.

3. How to Observe the River Flow in Agra?

Conventional methods of measuring river flow are the surface drift buoy method and the anchored boat method.

The surface drift buoy method is straightforward. They release floats on the surface of the river and track their movement over a known distance and time to estimate the surface flow velocity. It only measures the surface flow, however, and is sensitive to wind, which will warp the results and not offer a real representation of the entire water column.

Anchored boat method is in which a boat is anchored at a location along the river. The current meter is dropped into the water at multiple depths to measure the flow velocity. While this method provides a correct flow profile at one point, it is labor - intensive and time - consuming and could be dangerous for safety in turbulent or high - speed water.

Acoustic Doppler Current Profilers (ADCPs) offer an even superior solution. ADCPs can give continuous velocity profiles of the entire water column non-invasively without physical contact with the water. ADCPs can also quickly measure flow rates by scanning broad areas within a short time and hence are more economical than traditional methods.

4. How Does ADCP, Which Is Based on the Doppler Principle, Work?

ADCPs are based on the Doppler principle. They project acoustic pulses into the water. When these pulses encounter moving particles like suspended sediment or plankton, the frequency of the backscattered signals changes with the particle speed. Using the frequency changes, the ADCP calculates the water velocity at different depths and creates a full profile of the river flow.

5. What Does High-Quality Measurement of River Flow in Agra Require?

High-quality measurement of the river flow by using ADCP in Agra involves some device characteristics. Most important is material reliability because the equipment should be able to withstand the harsh conditions in the river, including being submerged in water, exposure to sedimentation, and the fluctuation of water temperatures. A small size and light weight make the ADCP easier to transport and more convenient to deploy, especially in inaccessible areas. Being cost - effective is also crucial, especially for large - scale or long - term monitoring surveys.

6. How to Select the Suitable Current Measuring Gear?

Methods of Deployment

• Boat - mounted (mobile boat) ADCP: Ideal for surveys, discharge measurement, and rapid mapping. It can rapidly survey large river reaches and can acquire data from numerous locations.
• Bottom - mounted (fixed) ADCP: Suitable for continuous monitoring over an extended period. It can be fixed once on the river bed and can acquire data over a very long time, providing useful data regarding long - term flow behavior.
• Cableway ADCP: Ideal for cableway river reaches. It is able to measure flow across the river at a location.

Working Frequency

Working frequency is critical as it decides the range and resolution of the ADCP. An ADCP of 600 kHz is typically constrained to a range of 70 meters, while an ADCP of 300 kHz is capable of reading 110 meters. Higher frequency gives better resolution but reduced range, and the opposite is true as well.

Brand Recommendations

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