Why is River Flow Monitored in Jharkhand?

1. Where is Jharkhand?

Geographical Background

Jharkhand is located in the eastern region of India, approximately between latitudes 21.6°N - 25.5°N and longitudes 83.2°E - 87.6°E. It is a diversified and hilly state, with most of its area composed of the Chota Nagpur Plateau. The plateau consists of rolling hill country, rock outcrops, and long valleys, creating a scenic landscape. The availability of several rivers and streams also contributes to the region's appeal. The rolling hills are interspersed with patches of green forest blocks, which play a significant role in the hydrological cycle and state ecosystem. The plateau's topography and slope govern the flow and pattern of water bodies and define the hydrological properties of the state.

Humanities and culture

Jharkhand has a vibrant and rich cultural heritage of indigenous people tradition, or Adivasis. Such tribal societies with their own languages, arts, music, and dances are the Santhal, Munda, and Oraon. Tribal classical dance of the Chhau type, involving martial arts, music, and dance, is performed during festivals and ceremonies, entrancing the audience through their energetic movement and glittering attire. The state also has a wide range of handicrafts, such as very detailed wood carvings, bamboo crafts, and metal crafts, that reflect the high level of skill of the indigenous artisans.

Religiously, Jharkhand is mostly a region of Hindu, Christian, and tribal religious beliefs. There are several temples and churches throughout the state, some of the temples dedicated to the local deities worshiping the tribal people. Sarhul festival, to welcome the advent of spring and pay tribute to nature, by the tribal people is an integral part of the culture, which reflects the irrevocable link of understanding between the Jharkhand people and the nature around them.

River Overview and Hydrology

Damodar and Subarnarekha are some of the important river systems of Jharkhand. Damodar River, also known commonly as the "Sorrow of Bengal" due to its tragic history in recurring floods, has its origin in the Chota Nagpur Plateau of Jharkhand. It flows east in the state before entering West Bengal and finally joining the Hooghly River. The Subarnarekha River, actually the "River of gold" in Sanskrit, also rises in the Chota Nagpur Plateau and flows east - southeast into the Bay of Bengal.

They are of utmost importance to Jharkhand. They are a major water source for a variety of uses. Agriculture, which is one of the prime driving forces of the state economy, employs the rivers to irrigate rice, maize, and pulses. But run-off during the season of the rivers, especially the Damodar, has also been an issue. The river floods have ruined huge properties, infrastructure, and cropped lands of Jharkhand and West Bengal in the past. The rivers are also sheltering a diverse range of aquatic life, supporting the livelihood of the fishermen. The water of the rivers is also used for industrial purposes and domestic use, by majorly coal-mining and steel industries, which are common in Jharkhand.

2. What is the River Flow Near Jharkhand?

Factors of Influence

Rainfall and Runoff

There is a tropical monsoon climate with Jharkhand. The monsoon season, usually June to September, has the majority of the seasonal rains, typically providing 80% - 90% of the annual rainfall. Heavy and extended rains in these months result in heavy runoff, which is responsible for the sudden increase of rivers through flooding. The quantity and tendency of rain in the state may be varying, with certain areas receiving more rain than other areas and thereby affecting river flows in the different zones. To the contrary, in the October-May dry season, river flows significantly decrease and water levels also decrease, sometimes causing water shortages, especially in distant and far places away from major water sources.

Topography and River Morphology

The hill and hill topography of the Chota Nagpur Plateau has a vast control on river flow in Jharkhand. The steep sloping hills, therefore, cause the rivers to flow with a high erosive capacity, flowing at high speeds and creating very deep gorges and valleys. When the rivers flow over the rather flat terrain, they become slow-moving and lay down sediments. The Damodar River, for example, contains a lot of water in a very narrow and deep channel over the hilly terrain, and this can lead to flash floods during rainfall. The river flows along the plains and its path is regulated by floodplains and natural levees. The Subarnarekha River is also seen with the same trend and its path is regulated by the changing topography as it flows through the state.

Reservoir Operations

There are several dams and reservoirs constructed across the rivers of Jharkhand mainly for flood regulation, irrigation, and power generation. The Damodar Valley Corporation (DVC) has built some dams in the Damodar River and its tributaries, such as the Maithon Dam and the Panchet Dam. They store water during the monsoon season and release it in a regulated way during the dry season for various purposes. But occasionally the operation of these dams prevents the free flow of the rivers, damaging the downstream ecosystem and the economies of communities that rely on the rivers.

Historical Hydrological Events

The Damodar River has a long history of causing immense floods in Jharkhand and its adjacent state, West Bengal. Earlier, before damming, the river would flood almost every year, inundating vast areas of land and displacing thousands of villagers. One of the biggest floods was in 1943, which resulted in huge loss and destruction. According to historical records, the floodwaters flooded large tracts of agricultural land, destroyed houses and other infrastructure, and brought a significant disruption of economic life. In recent times, even though the relief in a way of the issue of floods is given through dams, heavy monsoon rains remain a cause of flood threats. Tracking of these incidents is required for improved flood - mitigation policies and prosperity and security of citizens in Jharkhand.

3. How is River Flow in Jharkhand Tracked?

Traditional Practices

Surface Drift Float Method

Surface drift float method is a basic but primitive method to measure river flow. A float object, e.g., a buoy or wood, is used on the river surface. The time for the float to cover a given distance is measured, and the river's surface speed is approximated by dividing the distance by the time. This technique provides only a measurement of surface flow, and the information is influenced by wind, giving velocity measurements that are not accurate.

Anchored Boat Method (Staff Gauge / Current Meter)

The anchored boat method involves placing an anchored boat at a single location in the river. A current meter is lowered into the river at several distinct depths to obtain the water velocity, and the water level is indicated by a staff gauge. With several velocities taken across the cross-section of the river and the cross-sectional area, the river discharge can be calculated. This method gives more information-bearing data than the surface drift float method but is cumbersome, time-consuming, and unsafe on rivers with strong currents.

ADCP Introduction: Acoustic Doppler Current Profiler (ADCP)

Acoustic Doppler Current Profiler (ADCP) is a significant innovation in river flow measurement technology. Unlike other traditional methods, ADCP current meter is non-intrusive, and it measures water velocity across different depths by employing sound waves. It can also provide concurrent profiles of the bottom-to-top river flow within a relatively short time, and thus it is very effective in approximating the variable and complex river flows in Jharkhand. The technology provides more accurate and qualitative data gathering, which is required for efficient water resources management in the state.

4. How Does ADCP Work on the Doppler Principle?

An ADCP profiler operates on the Doppler principle. It provides sound waves of a particular frequency into the water. When the sound waves travel and strike moving particles within the water, such as sediment, plankton, or water molecules, the frequency of the sound waves that bounce back is shifted. If the particles are moving towards the ADCP, the frequency of the waves coming back will be greater, and if the particles are moving away from the ADCP, the frequency will be smaller. By measuring this frequency change accurately (Doppler shift), the ADCP can calculate the speed of water at different depths. Different transducers of the ADCP are employed to measure different velocities in different directions, making it possible to compute the three-dimensional pattern of flow of the river and providing valuable information on the river's flow dynamics.

5. What is Needed to Obtain High-Quality Measurement of River Flow in Jharkhand?

Equipment Requirements

Credible ADCP measurements of the rivers in Jharkhand can be taken with specific equipment features. Material strength is necessary because of the potentially aggressive river environment, with potential sediment in the water and varying water quality. ADCPs made of corrosion-resistant materials like stainless steel or titanium are suitable for long-term deployment. A light and compact design is also beneficial in the sense that it allows easier transportation and installation, especially in remote or mountainous regions where access can be problematic. Cost savings are also vital since it will enable the technology to be more accessible to be used for overall monitoring of the state's varied river systems.

6. How to Choose the Appropriate Current Measurement Equipment?

Method of Deployment

• Ship - Borne (Moving Boat) ADCP: Ideal for conducting large - scale river surveys, discharge surveying over long reaches, and rapidly mapping river flow patterns. Can cover vast stretches of the rivers in Jharkhand when the boat is in motion, providing an overall sense of the flow characteristics.
• Bottom - Mounted (Fixed) ADCP: A bottom - mounted ADCP can be used to conduct long - term continuous measurement, which can be fixed on the river bed to record data for a long period. This helps in determining long - term flow patterns, seasonal variations, and the impacts of various factors on the river flow.
• Cable - Way ADCP: In cable - way equipped river reaches, one may suspend a cable - way ADCP and travel across a river to take readings at more than one station. It is a convenient alternative in reaches where boat - based measurement will be impractical, e.g., in a narrow or shallow river reach.

Working Frequency

• 600 kHz ADCP: A 600 kHz ADCP provides an appropriate balance of resolution and range and can measure 70 meters in horizontal range. It can be used for the majority of river sections in Jharkhand to accurately measure the flow characteristics.
• 300 kHz ADCP: Providing a wider range of up to 110 meters, a 300 kHz ADCP would be appropriate for deeper and wider segments of the rivers, such as parts of the Damodar River.

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.