The canal-carrying capacity of Farakka is

1. The Ganga River System: Distributaries and Bifurcation (basic)

To understand the Ganga River system, we must first look at its journey’s end. After traveling nearly 2,525 km across the northern plains of India, the Ganga reaches a critical turning point near the Rajmahal Hills in West Bengal Geography of India, Majid Husain, The Drainage System of India, p.12. Here, the river undergoes bifurcation—a process where a single river channel splits into two or more independent branches that do not rejoin. These branches are known as distributaries.

At the Farakka Barrage in the Malda district of West Bengal, the Ganga ceases to flow as a single unit and divides into two main streams:

• The Padma: This is the main continuation of the river that flows eastward into Bangladesh.
• The Bhagirathi-Hooghly: This is the western distributary that flows south through West Bengal, passing through Kolkata and Haora before merging into the Bay of Bengal near Haldia Geography of India, Majid Husain, The Drainage System of India, p.12.

A crucial engineering component here is the Farakka Feeder Canal. This canal was designed to divert a specific volume of water from the main Ganga into the Bhagirathi-Hooghly branch. The goal is to ensure enough water flow to flush out silt and keep the Kolkata Port navigable. This feeder canal has a significant design carrying capacity of approximately 40,000 cusecs (cubic feet per second), which is roughly equivalent to 1,132 m³/s.

Feature	Tributary	Distributary
Direction	Flows into a larger main river.	Flows away from the main river.
Example	The Yamuna joining the Ganga at Prayagraj.	The Hooghly splitting from the Ganga at Farakka.
Occurrence	Usually found in the upper/middle reaches.	Usually found in the delta region (lower reach).

Sources: Geography of India (Majid Husain), The Drainage System of India, p.12; INDIA PHYSICAL ENVIRONMENT (NCERT 2025 ed.), Drainage System, p.21

2. Multipurpose River Valley Projects (MPRVPs) and Barrages (basic)

Imagine a river as a wild, seasonal force of nature—surging with floods during monsoons and trickling during summers. To harness this force for a growing nation, India developed Multipurpose River Valley Projects (MPRVPs). These are not merely walls of concrete; they are integrated systems designed to solve several problems simultaneously: providing water for crops (irrigation), generating electricity (hydropower), preventing floods, and even enabling inland navigation. Jawaharlal Nehru famously called these projects the 'temples of modern India' because he believed they would bridge the gap between rural agriculture and urban industrialization NCERT, Contemporary India II: Textbook in Geography for Class X, p.56.
The first major leap in this direction was the Damodar Valley Corporation (DVC), established in February 1948. Modeled after the Tennessee Valley Authority (USA), it transformed the 'Sorrow of Bengal'—the Damodar River—into a source of prosperity through a series of dams like Tilaiya, Konar, Maithon, and Panchet Majid Husain, Geography of India, Energy Resources, p.20. While some projects like the Gandak or Chambal projects focus primarily on power and irrigation, others like the Kosi and DVC include flood control as a critical objective Nitin Singhania, Indian Economy, p.367.
In your studies, you will encounter two main types of structures: Dams and Barrages. While they look similar, they serve different primary functions:

Feature	Dam	Barrage
Primary Purpose	Storage: Creates a large reservoir to hold water for long-term use.	Diversion: Uses gates to raise the water level slightly and divert it into canals.
Example	Bhakra Dam: Stores water for the Bhakra canals and power Majid Husain, Geography of India, Energy Resources, p.21.	Farakka Barrage: Diverts Ganga water into the Hooghly river for navigation Nitin Singhania, Indian Economy, p.367.

Beyond storage and diversion, these projects often include a Feeder Canal—a specialized channel that carries a specific volume of water (discharge) from a barrage to another location to maintain water levels or supply irrigation. For instance, the Farakka Barrage utilizes a feeder canal to ensure the Hooghly river remains navigable for the Kolkata port.

Sources: NCERT, Contemporary India II: Textbook in Geography for Class X, Water Resources, p.56; Majid Husain, Geography of India, Energy Resources, p.20; Majid Husain, Geography of India, Energy Resources, p.21; Nitin Singhania, Indian Economy, Irrigation in India, p.367

3. Siltation and Preservation of Kolkata Port (intermediate)

The Kolkata Port is unique in India as it is a riverine port, situated about 126 miles inland on the banks of the Hooghly River. Unlike deep-sea ports, its survival depends entirely on the health of the river. The primary threat to this port is siltation—the gradual accumulation of sediment on the riverbed. As noted in Geography of India, Majid Husain, Transport, Communications and Trade, p.24, the silting of riverbeds reduces the depth of water, creating significant obstacles for large ocean-going vessels trying to reach the docks. Without a strong, consistent flow of water to 'flush' this silt out into the Bay of Bengal, the shipping channel would eventually choke, rendering the port useless. To address this, the Farakka Barrage was constructed in West Bengal. The core strategy for the preservation of Kolkata Port involves diverting a massive volume of water from the main Ganga stream into the Bhagirathi-Hooghly system via a Feeder Canal. This canal has a specific design capacity of approximately 40,000 cusecs (cubic feet per second), which is roughly equivalent to 1,132–1,135 cumecs (cubic meters per second). This extra volume of water increases the velocity of the Hooghly, providing the necessary 'head' to push sediment downstream and maintain the required draft (depth) for navigation. However, managing this flow is a complex balancing act. India's rivers face a fluctuation regime where water discharge decreases substantially during the lean summer and winter months Geography of India, Majid Husain, Transport, Communications and Trade, p.24. During these dry periods, ensuring the 40,000 cusecs for the Hooghly becomes a point of hydrological and diplomatic sensitivity, as the water is also needed for downstream requirements in Bangladesh. As INDIA PHYSICAL ENVIRONMENT, Geography Class XI, Drainage System, p.24 highlights, the uneven distribution of water in time and space makes such management projects essential for the nation's economic infrastructure.

Feature	Deep-Sea Port (e.g., Vizag)	Riverine Port (Kolkata)
Location	Directly on the coastline	Located inland on a river bank
Major Challenge	Cyclones and tidal surges	Siltation and shifting sandbars
Maintenance	Minimal dredging needed	Requires constant flushing/dredging

Sources: Geography of India (Majid Husain), Transport, Communications and Trade, p.24; INDIA PHYSICAL ENVIRONMENT (NCERT), Drainage System, p.24

4. International Water Diplomacy: India-Bangladesh Relations (exam-level)

When we discuss International Water Diplomacy between India and Bangladesh, we are essentially looking at the challenge of managing 54 shared rivers. The centerpiece of this relationship is the Farakka Barrage, located in West Bengal. Commissioned in 1975, its primary objective was to divert water from the Ganga into the Hooghly River via a 38.38 km long feeder canal to flush out silt and keep the Kolkata Port operational. This feeder canal has a specific design capacity of 40,000 cusecs (approximately 1,133 cumecs). However, this diversion created a classic 'upper riparian vs. lower riparian' conflict, as Bangladesh (the lower riparian) feared reduced flows during the dry season would harm its agriculture and ecology.

To resolve this, the landmark Ganga Water Sharing Treaty was signed on December 12, 1996, for a duration of 30 years Geography of India, Majid Husain, The Drainage System of India, p.39. The treaty focuses on the lean season (March 1 to May 10), where water is shared in 10-day cycles. If the flow at Farakka is 70,000 cusecs or less, both countries share it 50:50. If it is between 70,000 and 75,000 cusecs, Bangladesh receives a fixed 35,000 cusecs, and India receives the rest. If it exceeds 75,000 cusecs, India keeps 40,000 cusecs (matching the feeder canal's capacity) and Bangladesh receives the remainder.

Flow at Farakka	India's Share	Bangladesh's Share
< 70,000 cusecs	50%	50%
70,000 – 75,000 cusecs	Balance flow	35,000 cusecs
> 75,000 cusecs	40,000 cusecs	Balance flow

Beyond the Ganga, diplomacy extends to sub-regional cooperation involving Bhutan. One ambitious plan involves diverting 12,000 cusecs from the Sankosh River in Bhutan to the Teesta and then to the Farakka Barrage to augment the Ganga's flow Geography of India, Majid Husain, The Drainage System of India, p.40. Another proposed solution is the Brahmaputra-Ganga Link Canal, a 320 km feeder linking Dhubri in Assam to Farakka Geography of India, Majid Husain, The Drainage System of India, p.43. While these projects offer benefits like irrigation and navigation, they remain sensitive due to environmental concerns and the need for absolute political concurrence between New Delhi and Dhaka.

Sources: Geography of India (Majid Husain), The Drainage System of India, p.39; Geography of India (Majid Husain), The Drainage System of India, p.40; Geography of India (Majid Husain), The Drainage System of India, p.43; Geography of India (Majid Husain), India–Political Aspects, p.42

5. National Waterway-1 (NW-1) and Inland Navigation (intermediate)

Inland water transport is one of the most cost-effective and environment-friendly modes of transport, yet it currently handles less than 1% of India's total cargo movement Indian Economy, Nitin Singhania, Infrastructure, p.459. To revolutionize this sector, the government established the Inland Waterways Authority of India (IWAI) in 1986, headquartered in Noida. While the National Waterways Act of 2016 expanded the list of national waterways to 111, National Waterway-1 (NW-1) remains the most significant and developed artery of this system INDIA PEOPLE AND ECONOMY, NCERT, Transport and Communication, p.81.

National Waterway-1 stretches 1,620 km from Prayagraj (Allahabad) to Haldia. It utilizes the Ganga-Bhagirathi-Hooghly river system, passing through the states of Uttar Pradesh, Bihar, Jharkhand, and West Bengal. Its navigability varies by vessel type: while ordinary boats can reach as far upstream as Haridwar, the waterway is navigable by larger mechanical boats primarily up to Patna INDIA PEOPLE AND ECONOMY, NCERT, Transport and Communication, p.81. To support this infrastructure, specialized facilities like the National Inland Navigation Institute in Patna and India's first 'freight village' (a specialized industrial estate for logistics) in Varanasi have been developed Geography of India, Majid Husain, Transport, Communications and Trade, p.23.

A critical engineering component of NW-1 is the Farakka Barrage in West Bengal. A major challenge for navigation in the lower reaches (the Hooghly river) is siltation, which can choke the port of Kolkata. To counter this, a Feeder Canal approximately 38.38 km long was constructed. This canal has a design carrying capacity of about 40,000 cusecs (cubic feet per second), which translates to roughly 1,132–1,135 m³/s. This controlled diversion of water from the Ganga into the Bhagirathi-Hooghly system ensures sufficient depth (draft) for large vessels to navigate year-round toward the Haldia and Kolkata ports.

Feature	Details for National Waterway-1 (NW-1)
Stretch	Prayagraj to Haldia (1,620 km)
River System	Ganga-Bhagirathi-Hooghly
Key Infrastructure	Farakka Barrage & Feeder Canal (40,000 cusecs capacity)
Major Hubs	Varanasi (Freight Village), Patna, Kolkata/Haldia

Sources: Indian Economy, Nitin Singhania, Infrastructure, p.459; INDIA PEOPLE AND ECONOMY, NCERT, Transport and Communication, p.81; Geography of India, Majid Husain, Transport, Communications and Trade, p.23

6. Technical Specifications of Farakka Feeder Canal (exam-level)

To understand the Farakka Feeder Canal, we must first look at its purpose: it is the lifeblood of the Hooghly river system. The canal was designed to divert sediment-free water from the Ganga into the Bhagirathi-Hooghly river to flush out silt and maintain the navigability of the Kolkata Port. This artificial canal takes off from the right bank of the Ganga at the Farakka Barrage in Murshidabad and runs for a length of approximately 38.38 km before outfalling into the Bhagirathi river. This stretch is a critical component of National Waterway 1 (NW-1), which connects Haldia to Prayagraj INDIA PEOPLE AND ECONOMY, NCERT 2025, Transport and Communication, p.81.

The most vital technical specification for an aspirant to remember is its carrying capacity. The feeder canal is designed to carry a discharge of 40,000 cusecs (cubic feet per second), which translates to approximately 1,133 to 1,135 cumecs (cubic meters per second). This volume is significant when compared to the natural lean-season flow of the Ganga. For instance, while the mean maximum discharge of the Ganga at Farakka can soar to 55,000 cusecs, the minimum can drop significantly, making the managed diversion of 40,000 cusecs through this canal a point of intense hydrological and diplomatic focus Majid Husain, Geography of India, The Drainage System of India, p.23.

From a classification perspective, the Farakka Barrage Project is categorized as a Major Irrigation Project. In the Indian administrative context, any project with a Culturable Command Area (CCA) of more than 10,000 hectares falls into this category Nitin Singhania, Indian Economy, Irrigation in India, p.367. Although its primary role is navigational flushing rather than field irrigation, the sheer scale of the engineering and the volume of water managed place it in the highest tier of Indian water infrastructure projects.

Sources: INDIA PEOPLE AND ECONOMY, NCERT 2025, Transport and Communication, p.81; Majid Husain, Geography of India, The Drainage System of India, p.23; Nitin Singhania, Indian Economy, Irrigation in India, p.367

7. Solving the Original PYQ (exam-level)

Now that you have mastered the geographical significance of the Ganga-Brahmaputra system and the socio-political importance of the Farakka Barrage, this question tests your ability to apply technical specifications to functional outcomes. The core purpose of the Farakka Barrage is to divert water into the Hooghly River to prevent siltation at the Kolkata Port. When we discuss "carrying capacity," we are specifically referring to the Feeder Canal, which acts as the lifeline for the downstream navigation channel. By connecting your understanding of river management and water diversion projects, you can see that the capacity must be significant enough to flush out heavy sediment while remaining within the limits of the 1996 Indo-Bangladesh Water Sharing Treaty.

The correct answer is (C) 40,000 cusecs. As a candidate, you should recognize this figure as the design capacity mentioned in official documentation such as the Farakka Barrage Project (FBP) official records. In technical terms, this converts to approximately 1,133 cumecs (cubic meters per second). Reasoning through the data, this volume was specifically engineered to provide the necessary hydraulic force to keep the Hooghly navigable throughout the year, ensuring that the draft for ships at Kolkata remains adequate even during the lean summer months.

UPSC often uses plausible-sounding numbers to create traps for the unprepared. Options like (A) 75,000 and (B) 70,000 cusecs are likely intended to confuse you with the total discharge of the Ganga during certain seasons, which is significantly higher than what a single feeder canal is designed to handle. Conversely, (D) 35,000 cusecs is a figure often debated during dry-season negotiations regarding minimum water release. Remember, the question specifically asks for the canal-carrying capacity (an engineering limit), not the seasonal flow variations or political minimums. Sticking to the static design limit of 40,000 cusecs allows you to bypass these distractors confidently.