Why Do We Measure River Flow in Lucknow?

1. Where is Lucknow?

Geographical Background

Lucknow, the capital of Uttar Pradesh state in India, is situated in north India at approximately 26.83°N latitude and 80.92°E longitude. The city lies in the fertile Gangetic Plain, where it has a predominantly flat terrain, which has resulted from centuries of riverbank deposition through alluvium from rivers passing through the region. This flat land has been conducive for urban growth and farming surrounding the city. Though the city is largely urban, the outskirts join the expansive plains with fields and small bodies of water, the most notable being the Gomti River.

Humanities and culture

Lucknow is rich in its history and culture. The city is famous for its lush Nawabi culture. Under Nawab rule, the city was a center of music, dance, art, and architecture. The city boasts monuments such as the Bara Imambara, which demonstrate unique forms of architecture, with massive halls and intricate maze-like corridors. The city's cuisine, which is famous for its delicacies like kebabs and biryanis, comprises rich blends of Mughlai and Awadhi tastes. Urdu, spoken with distinctive Lucknowi flavor, adds to cultural elegance, as the city is the hub of poets, writers, and painters. The celebrations and cultural functions annually pay tribute to its high tradition by attracting international tourists.

Hydrology and River Overview

The lifeblood of Lucknow is the Gomti River. The river starts in Gomat Taal, situated in the Pilibhit district of Uttar Pradesh, and runs south-easterly through the state to merge with the Ganges River at Kaithi. The Gomti River winds its path through the city of Lucknow, cutting its way through and sustaining the livelihood of the populace and creating the landscape within.

To the people of Lucknow, the Gomti is a principal freshwater source for domestic use, although in recent years it has come under pressure due to industrial pollutants and domestic sewage discharge. In agriculture, which is still significant at the edges of the city, the river serves as irrigation water. The river and riverbanks support a variety of flora and fauna ecologically. However, pollution and urbanization have put pressure on this sensitive ecosystem, and conservation and monitoring therefore become the need of the hour.

2. What is the River Flow Near Lucknow?

Influencing Factors

Rainfall and Runoff

Lucknow experiences a tropical savanna climate with distinct wet and dry seasons. The monsoon season between June and September provides the majority of the precipitation in the year, and often this comes to approximately 75 - 80% of the total precipitation. Heavy rains during monsoon times lead to increased runoff, rapidly filling the Gomti River and triggering increases in water levels. The velocity of flow in the river is directly affected by rainfall intensity and duration at this time. During dry periods, river flows are much reduced and sometimes cause water shortages within the city. Urbanization has altered runoff patterns too; increases in impervious surfaces like roads and buildings reduce groundwater infiltration, leading to more surface runoff and sudden surges in rivers during heavy rainfalls.

Topography and River Morphology

Flat topography of Gangetic Plain over which Lucknow is located means that the Gomti River flows relatively slowly with low gradient. This allows sediment to accumulate along the bed as well as banks of the river with time. The width of the river varies, widening in some sections and narrowing in others, mostly as the river navigates through the urban region. River depth also changes, with deeper middle channels and zones diminishing in proximity to the banks. Meandering results in regions of faster-flowing water on the outer bends that result in erosion and the slower flow on the inner bends with deposition of sediment.

Reservoir Operations

There are dams and reservoirs in the upper catchments of the Gomti River basin, such as the Matatila Dam. These regulate water flow by storing water in excess during the monsoon and allowing it to flow out when there is a lean season. This provides a minimum stream flow in the river in order to ensure a regular supply of water to downstream areas such as Lucknow. But excess or mismanagement of rainfall, or unusual weather conditions, can upset this balance, and the region can experience either flooding or drought.

Historical Hydrological Events

There was a large flood in the Gomti River in Lucknow in 1978. Monsoon rains were heavy, and the river overflowed its banks, covering vast areas of the city. According to records of historical documents from news providers and local government documents, thousands of people were displaced and agricultural fields in the surrounding environment were severely impacted. Another significant event was the 2009 drought, which affected the river flow severely. As per the Central Water Commission, this drought affected the water supply in the city too, and resulted in shortages for home use and agriculture, and for the local ecosystem. Monitoring such occurrences is important for developing well-planned flood - control and drought - management strategies for Lucknow.

3. How is the River Flow in Lucknow Monitored?

Traditional Methods

Surface Drift Float Method

Surface drift float is a straightforward technique of observing river flow. A body floating on the surface of the river, like a buoy or wood, is placed on the surface of the river and the time taken to travel a measured distance is noted. If the distance is measured and divided by the time, the surface velocity of the river is found. This is a measure of surface flow only, and the wind can affect it immensely, giving false readings.

Anchored Boat Method (Staff Gauge / Current Meter)

In anchored boat method, there is an anchored boat at a reference point in the river. A current meter is dropped at varying depths into the river to measure water speed, and the water level is measured by a staff gauge. By taking a number of measurements of velocity through the cross - section of the river and calculating the cross - sectional area, the river discharge can be determined. However, the process is time - consuming, laborious, and dangerous, especially in rivers with strong currents.

ADCP Introduction: Acoustic Doppler Current Profiler (ADCP)

The Acoustic Doppler Current Profiler (ADCP) offers a fresh, more cost-effective means of river flow measurement. Non-invasive in nature, it measures water velocity at more than one depth with sound waves. Unlike earlier methods, ADCP can deliver continuous profiles of the river flow between the river bottom and surface within a short time, a consideration making it ideal to monitor the complex flows of the Gomti River at Lucknow.

4. How Does ADCP Function on the Doppler Principle?

An ADCP flow meter functions on the Doppler principle. It emits sound waves of a specific frequency into the water. As the sound waves travel through particles moving in the water, such as sediment or plankton, the frequency of the reflected sound waves changes. If the particles are approaching the ADCP, the frequency of the backscattered waves increases; if they are receding, the frequency decreases. By measuring this change in frequency (the Doppler shift), the ADCP can calculate water velocities at different depths. Multiple transducers measure velocities in different directions so that the three-dimensional flow structure of the river can be defined.

5. What is Needed for High - Quality River Flow Measurement in Lucknow?

Equipment Requirements

In order to have accurate ADCP current meter measurement for the Gomti River, the system should possess material reliability to endure the river's often - harsh environment, e.g., corrosion because of pollutants. Light weight and compactness are helpful for easy deployment, especially in the urban setting where access is restricted. Cost - effectiveness is also desirable so that the technology can be employed more extensively in monitoring the river flow in Lucknow.

6. How to Choose the Right Current Measuring Equipment?

Method of Deployment

• Ship - Based (Mobile Boat) ADCP: Most appropriate for conducting river surveys, approximating discharge over a wide area, and delineating flow patterns quickly. It can span the entire width of the Gomti River in Lucknow as the boat moves along, providing complete information.
• Bottom - Fixed ADCP: For continuous long - term observation, the ADCP can be installed on the riverbed to capture information on long - term trends and seasonal changes in flow.
• Cable - Way ADCP: Where cable - way facilities already exist, cable - way ADCP offers a scope of making measurements at several points in the river, which is useful in regions of complex geometry or difficult boat access.

Working Frequency

• 600 kHz ADCP: It is a balanced choice between range and resolution with a range of up to 70 meters horizontally, and it can be applied to most sections of Lucknow's Gomti River.
• 300 kHz ADCP: With increased range up to 110 meters, it would be ideal for deeper and broader river sections.

Brand Recommendations

Proven and tried international ADCP brands such as Teledyne RDI, Nortek, and SonTek are highly reputable for their quality and reliable products utilized in various hydrological researches and monitoring operations. A good alternative at a low cost is the ADCP supplier Chinese company’s "China Sonar Panda ADCP". Made of all - titanium alloy, it possesses superior strength and dependability and is especially well - adapted to withstand the harsh river conditions along Srinagar. It is a "budget ADCP" with high - class performance at budget prices, hence an excellent choice for monitoring the river flow along Srinagar without digging deep into the pockets in terms of equipment costs. To know more, visit https://china-sonar.com/.

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