Drainage

Drainage

Drainage

Describes the river system of an area

What is a Drainage Basin?

The area drained by a single river system called a drainage basin.

Origin of Brahmaputra River System

Tibet; near Lake Mansarovar, close to Indus and Sutlej.

Course of Brahmaputra RIver

1. Mostly out of India

2. East flow parallel to the himalayas

3. Namcha Barwa - takes a U-Turn and enters India at Arunachal Pradesh.

4. High volume of water and silt due to heavy rain channels shift quickly

5. Arunachal - called dihang, joined by dibang and dohit.

6. Assam - Large Riverine Islands - a small piece of land that is located in the middle or on the banks of a river (Majuli)

Origin of Indus river system

Tibet, near Lake Mansarovar

Course of Indus River System

1. Moves from origin towards the west, enters Ladakh and forms gorges.

2. Flows via gilgit baltistan and emerges from mountains and attock

3. Jhelum, Chenab, Ravi, Beas, and Sutlej join together at Mithankot, Pakisthan

4. Meets the Arabian Sea

Tributaries of Indus System

Zaskar, Nubra, Shyok, Hunza - gentle slope of river

Length of the Indus River System

• 2900 km (longest in the world)

• 1/3rd of basin in india (irrigation in ladakh, jammu and kashmir, himachal pradesh, punjab)

• 2/3rd of basin in pakistan

• Indus water treaty - 20% used by india (no dams) - upper riparian state

Course of the Ganga River systems

• bhagirathi - headwaters of ganga

• alaknanda - joined at derprayag, uttarkhand at haridaw - moves from mountains to plains

• flows east till farraka in west bengal (the northernmost point of ganga delta)

• bifurcate into bhagirathi hoogly and meghna

• hoogly - southward flow of the bay of bengal

• meghna - mainstream joined in bangladesh with brahmaputra

• mainstream - forms the sunderbhands delta

Tributaries of the Ganga river system

Yamuna (origin - yamuokri glacier) runs parallel to allahabad, ghagra, ghandhak, khosi (often floods - originates from nepal himalayas)

tributaries (from peninsular uplands) chambal, betwa and son - shorter courses.

Length of the Ganga river system

2500km. ambala - between indus and ganga 100km forms large meanders.

Course of Peninsular rivers

• main water is divided by western ghats (runs north to south)

• flows east and drains into the bay of bengal - forms deltas

• narmada and tapi flow east

Narmada Basin

• origin - amarkanta hills, madhya pradesh

• course - flows towards west from a rift valley formed via faulting

• marble rocks, dhuandhar falls

• short tributaries join at 90 degrees

• madhya pradesh, gujarat

Tapi Basin

• origin - satpura range, betul

• course - rift valley parallel to narmada

• rivers - sabarmati, mahi, brahmaputra, periyar

• madhya pradesh, gujarat, maharashtra

Godavari Basin

• origin - western ghats, masik, maharashtra (dakshin ganga)

• length - 1500km

• drains into the bay of bengal

• river - purna, wardha, pranhita, manjira, wainganga, penganga

• madhya pradesh, odisha, andhra pradesh, maharashtra

• largest peninsular river

Mahanadi Basin

• origin - highland of chhattisgarh

• lentgh - 860 km

• maharashtra, chattisgarh, jharkand, odisha

Kaveri Basin

• origin - bhramagiri range

• tributaries - amaravati, bhavani, hemavathy, kabini

• length - 760km

• drains in bay of bengal - south of cuddalore, tamil nadu

• karnataka, tamil nadu, kerala.

• shivasamudram falls and hydroelectric project

Smaller Rivers flowing to the east

• The Damodar

• The Brahmani

• The Baitarni

• The Subarnrekha

Lakes characteristics

1. Most lakes are permanent

2. Some contain water only during the rainy season

3. Some lakes are the result of the action of glaciers and ice sheets

4. Some have been formed by wind, river action and human activities

Different Types of Lakes

• A meandering river across a floodplain forms cut-offs that later develop into ox-bow lakes.

• Spits and bars form lagoons in the coastal areas. Eg, the Chilika Lake, the Pulicat Lake and the Kolleru Lake.

• Lakes in the region of inland drainage are sometimes seasonal. For example, the Sambhar Lake in Rajasthan is a saltwater lake which is used for producing salt.

• Most of the freshwater lakes are in the Himalayan region. They are of glacial origin. The Wular Lake in Jammu and Kashmir is the result of tectonic activity, which is the largest freshwater lake in India. Some other important freshwater lakes are Dal Lake, Bhimtal, Nainital, Loktak and Barapani.

Importance of Lakes

1. Lakes help to regulate the flow of a river.

2. During heavy rains, these lakes prevent flooding.

3. During the dry season, these lakes help to maintain an even flow of water.

4. Lakes can also be used for developing hydel power.

5. Lakes moderate the surrounding climate, maintain the aquatic ecosystem, enhance natural beauty, and provide recreation.

Role of Rivers in the Economy

• Rivers have been of fundamental importance throughout human history.

• Water from rivers is a basic natural resource, essential for various human activities.

• Rivers are used for irrigation, navigation, hydropower generation etc.

River Pollution

The growing domestic, municipal, industrial and agricultural demand for water from rivers is affecting the quality of water. Rivers are getting polluted as a heavy load of untreated sewage and industrial effluents are getting emptied into the rivers. Concern over rising river pollution led to the launching of various action plans to clean the rivers.

National River Conservation Plan (NRCP)

The river cleaning programme in the country started w/ Ganga Action Plan (GAP) in 1985. Expanded to cover other plans in 1995. Improve water quality of rivers (major water source in India)