Drainage - Googlecloud12/new-first- GitHub Wiki

Drainage For the medical term, see Drainage (medical). See also: Storm drain and Stormwater

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Deep inside a Sydney drain in New South Wales, Australia Drainage is the natural or artificial removal of surface and sub-surface water from an area. Many agricultural soils need drainage to improve production or to manage water supplies. Geotextiles Modern drainage systems incorporate geotextile filters that retain and prevent fine grains of soil from passing into and clogging the drain. Geotextiles are synthetic textile fabrics specially manufactured for civil and environmental engineering applications. Geotextiles are designed to retain fine soil particles while allowing water to pass through. In a typical drainage system they would be laid along a trench which would then be filled with coarse granular material: gravel, sea shells, stone or rock. The geotextile is then folded over the top of the stone and the trench is then covered by soil. Groundwater seeps through the geotextile and flows within the stone to an outfall. In high groundwater conditions a perforated plastic (PVC or PE) pipe is laid along the base of the drain to increase the volume of water transported in the drain. Alternatively, prefabricated plastic drainage systems made of HDPE called SmartDitch, often incorporating geotextile, coco fiber or rag filters can be considered. The use of these materials has become increasingly more common due to their ease of use which eliminates the need for transporting and laying stone drainage aggregate which is invariably more expensive than a synthetic drain and concrete liners. Over the past 30 years geotextile and PVC filters have become the most commonly used soil filter media. They are cheap to produce and easy to lay, with factory controlled properties that ensure long term filtration performance even in fine silty soil conditions. 21st century alternatives Seattle's Public Utilities created a pilot program called Street Edge Alternatives (SEA Streets) Project. The project focuses on designing a system "to provide drainage that more closely mimics the natural landscape prior to development than traditional piped systems".[3] The streets are characterized by ditches along the side of the roadway, with plantings designed throughout the area. An emphasis on non curbed sidewalks allows water to flow more freely into the areas of permeable surface on the side of the streets. Because of the plantings the run off water from the urban area does not all directly go into the ground but can also be absorbed into the surrounding environment. According to the monitoring by Seattle Public Utilities, they report a 99 percent reduction of storm water leaving the drainage project[3] Drainage has undergone a large-scale environmental review in the recent past in the United Kingdom. Sustainable Urban Drainage Systems (SuDS) are designed to encourage contractors to install drainage system that more closely mimic the natural flow of water in nature. Since 2010 local and neighbourhood planning in the UK is required by law to factor SuDS into any development projects that they are responsible for. Drainage manufacturers that are showing a commitment to SuDS in pioneering improved environmental drainage options in the United Kingdom include Alumasc Exterior Building Products, Aco Technologies and Polypipe.

Slot drainage has proved the most breakthrough product of the last twenty years in the as a drainage option. As a channel drainage system it is designed to eliminate the need for further pipework systems to be installed in parallel to the drainage, reducing the environmental impact of production as well as improving water collection. Both stainless steel and concrete channel slot drainage have become industry standards on construction projects. Reasons for artificial drainage

An agricultural drainage channel outside Magome, Japan after a heavy rain. Note that protuberances create turbulent water, preventing sediment from settling in the channel. Wetland soils may need drainage to be used for agriculture. In the northern United States and Europe, glaciation created numerous small lakes which gradually filled with humus to make marshes. Some of these were drained using open ditches and trenches to make mucklands, which are primarily used for high value crops such as vegetables. The largest project of this type in the world has been in process for centuries in the Netherlands. The area between Amsterdam, Haarlem and Leiden was, in prehistoric times swampland and small lakes. Turf cutting (Peat mining), subsidence and shoreline erosion gradually caused the formation of one large lake, the Haarlemmermeer, or lake of Haarlem. The invention of wind powered pumping engines in the 15th century permitted drainage of some of the marginal land, but the final drainage of the lake had to await the design of large, steam powered pumps and agreements between regional authorities. The elimination of the lake occurred between 1849 and 1852, creating thousands of km² of new land. Coastal plains and river deltas may have seasonally or permanently high water tables and must have drainage improvements if they are to be used for agriculture. An example is the flatwoods citrus-growing region of Florida. After periods of high rainfall, drainage pumps are employed to prevent damage to the citrus groves from overly wet soils. Rice production requires complete control of water, as fields need to be flooded or drained at different stages of the crop cycle. The Netherlands has also led the way in this type of drainage, not only to drain lowland along the shore, but actually pushing back the sea until the original nation has been greatly enlarged. In moist climates, soils may be adequate for cropping with the exception that they become waterlogged for brief periods each year, from snow melt or from heavy rains. Soils that are predominantly clay will pass water very slowly downward, meanwhile plant roots suffocate because the excessive water around the roots eliminates air movement through the soil. Other soils may have an impervious layer of mineralized soil, called a hardpan or relatively impervious rock layers may underlie shallow soils. Drainage is especially important in tree fruit production. Soils that are otherwise excellent may be waterlogged for a week of the year, which is sufficient to kill fruit trees and cost the productivity of the land until replacements can be established. In each of these cases appropriate drainage carries off temporary flushes of water to prevent damage to annual or perennial crops. Drier areas are often farmed by irrigation, and one would not consider drainage necessary. However, irrigation water always contains minerals and salts, which can be concentrated to toxic levels by evapotranspiration. Irrigated land may need periodic flushes with excessive irrigation water and drainage to control soil salinity.

Indian Rivers Inter-link From Wikipedia, the free encyclopedia The Indian Rivers Inter-link is a proposed large-scale civil engineering project that aims to link India's rivers by a network of reservoirs and canals and so reduce persistent floods in some parts and water shortages in other parts of India.[1][2] The Inter-link project has been split into three parts: a northern Himalayan rivers inter-link component, a southern Peninsular component and starting 2005, an intrastate rivers linking component.[3] The project is being managed by India's National Water Development Agency (NWDA), under its Ministry of Water Resources. NWDA has studied and prepared reports on 14 inter-link projects for Himalayan component, 16 inter-link projects for Peninsular component and 37 intrastate river linking projects.[3] The average rainfall in India is about 4,000 billion cubic meters, but most of India's rainfall comes over a 4-month period – June through September. Furthermore the rain across the nation is not uniform, the east and north gets most of the rain, while the west and south get less.[4][5] India also sees years of excess monsoons and floods, followed by below average or late monsoons with droughts. This geographical and time variance in availability of natural water versus the year round demand for irrigation, drinking and industrial water creates a demand-supply gap, that has been worsening with India's rising population.[5] Proponents of the rivers inter-linking projects claim the answers to India's water problem is to conserve the abundant monsoon water bounty, store it in reservoirs, and deliver this water – using rivers inter-linking project – to areas and over times when water becomes scarce.[4] Beyond water security, the project is also seen to offer potential benefits to transport infrastructure through navigation, as well as to broadening income sources in rural areas through fish farming. Opponents are concerned about knowledge gap on environmental, ecological, social displacement impacts as well as unseen and unknown risks associated with tinkering with nature.[2] Others are concerned that some projects create international impact and the rights of nations such as Bangladesh must be respected and negotiated History British colonial era The Inter-linking of Rivers in India proposal has a long history. During the British colonial rule, for example, the 19th century engineer Arthur Cotton proposed the plan to interlink major Indian rivers in order to hasten import and export of goods from its colony in South Asia, as well as to address water shortages and droughts in southeastern India, now Andhra Pradesh and Orissa.[7] Post independence In the 1970s, K.L. Rao,[8] a former irrigation minister proposed “National Water Grid”. He was concerned about the severe shortages of water in the South and repetitive flooding in the North every year. He suggested that the Brahmaputra and Ganga basins are water surplus areas, and central and south India as water deficit areas. He proposed that surplus water be diverted to areas of deficit. When Rao made the proposal, several inter-basin transfer projects had already been successfully implemented in India, and Rao suggested that the success be scaled up.[8] In 1980, India’s Ministry of Water Resources came out with a report entitled “National Perspectives for Water Resources Development”. This report split the water development project in two parts – the Himalayan and Peninsular components. Congress Party came to power and it abandoned the plan. In 1982, India financed and set up a committee of nominated experts, through National Water Development Agency (NWDA)[1] to complete detailed studies, surveys and investigations in respect of reservoirs, canals and all aspects of feasibility of inter-linking Peninsular rivers and related water resource management. NWDA has produced many reports over 30 years, from 1982 through 2013.[1] However, the projects were not pursued. The river inter-linking idea was revived in 1999, after a new political alliance formed the central government, but this time with a major strategic shift. The proposal was modified to intra-basin development as opposed to inter-basin water transfer 21st century

Drought affected area farm lands in Karnataka. By 2004, a different political alliance led by Congress Party was in power, and it resurrected its opposition to the project concept and plans. Social activists campaigned that the project may be disastrous in terms of cost, potential environmental and ecological damage, water table and unseen dangers inherent with tinkering with nature. The central government of India, from 2005 through 2013, instituted a number of committees, rejected a number of reports, and financed a series of feasibility and impact studies, each with changing environmental law and standards.[9][10] In February 2012, while disposing a Public Interest Litigation (PIL) lodged in the year 2002, Supreme Court (SC) refused to give any direction for implementation of Rivers Interlinking Project. SC stated that it involves policy decisions which are part of legislative competence of state and central governments. However, SC directed the Ministry of Water Resources to constitute an experts committee to pursue the matter with the governments as no party had pleaded against the implementation of Rivers Interlinking Project.[11] Plan The National perspective plan envisions about 150 million acre feet (MAF) (185 billion cubic metres) of water storage along with building inter-links.[14] These storages and the interlinks will add nearly 170 million acre feet of water for beneficial uses in India, enabling irrigation over an additional area of 35 million hectares, generation of 40,000 MW capacity hydro power, flood control and other benefits. The total surface water available to India is nearly 1440 million acre feet (1776 billion cubic meters) of which only 220 million acre feet was being used in the year 1979. The rest is neither utilized nor managed, and it causes disastrous floods year after year. Up to 1979, India had built over 600 storage dams with an aggregate capacity of 171 billion cubic meters. These small storages hardly enable a seventh of the water available in the country to be utilized beneficially to its fullest potential.[14] From India-wide perspective, at least 946 billion cubic meters of water flow annually could be utilized in India, power generation capacity added and perennial inland navigation could be provided. Also some benefits of flood control would be achieved. The project claims that the development of the rivers of the sub-continent, each state of India, as well as its international neighbors stand to gain by way of additional irrigation, hydro power generation, navigation and flood control.[14] The project may also contribute to food security to the anticipated population peak of India.[14] The Ganga-Brahmaputra-Meghna is a major international drainage basin which carries more than 1,000 million acre feet out of total 1440 million acre feet in India. Water is a scarce commodity and several basins such as Cauvery, Yamuna, Sutlej, Ravi and other smaller inter-State/intra-State rivers are short of water. 99 districts of the country are classified as drought prone, an area of about 40 million hectare is prone to recurring floods.[14] The inter-link project is expected to help reduce the scale of this suffering and associated losses. The National Perspective Plan comprised, starting 1980s, of two main components:

1. Himalayan Rivers Development, and
2. Peninsular Rivers Development An intrastate component was added in 2005. Himalayan Rivers Development envisages construction of storage reservoirs on the main Ganga and the Brahmaputra and their principal tributaries in India and Nepal along with inter-linking canal system to transfer surplus flows of the eastern tributaries of the Ganga to the West apart from linking of the main Brahmaputra with the Ganga.[14] Apart from providing irrigation to an additional area of about 22 million hectares the generation of about 30 million kilowatt of hydro-power, it will provide substantial flood control in the Ganga-Brahmaputra basin. The Scheme will benefit not only the States in the Ganga-Brahmaputra Basin, but also Nepal and Bangladesh, assuming river flow management treaties are successfully negotiated.[14] The Himalayan component would consist of a series of dams built along the Ganga and Brahmaputra rivers in India, Nepal and Bhutan for the purposes of storage. Canals would be built to transfer surplus water from the eastern tributaries of the Ganga to the west. This is expected to contribute to flood control measures in the Ganga and Brahmaputra river basins. It could also provide excess water for the Farakka Barrage to flush out the silt at the port of Kolkata. Fourteen (14) inter-links under consideration for Himalayan component are as follows, with feasibility study status identified:[15] • Ghaghara–Yamuna link (Feasibility study complete) • Sarda–Yamuna link (Feasibility study complete) • Yamuna–Rajasthan link (Feasibility study complete) • Rajasthan–Sabarmati link (Feasibility study complete) • Kosi–Ghaghara link • Kosi–Mechi link • Manas–Sankosh–Tista–Ganga link • Jogighopa–Tista–Farakka link • Ganga–Damodar–Subernarekha link (Feasibility study complete) • Subernarekha–Mahanadi link (Feasibility study complete) • Farakka–Sunderbans link (Feasibility study complete) • Gandak–Ganga link (Feasibility study complete) • Chunar–Sone Barrage link (Feasibility study complete) • Sone dam–Southern tributaries of Ganga li The Indian Rivers Inter-link project is similar in scope and technical challenges as other major global river inter-link projects, such as:
3. Rhine–Main–Danube Canal – completed in 1992, and also called the Europa Canal, it inter-links the Main river to the Danube river, thus connecting North Sea and Atlantic Ocean to the Black Sea. It provides a navigable artery between the Rhine delta at Rotterdam in the Netherlands to the Danube Delta in eastern Romania.[20] It is 171 km long, has the summit altitude (between the Hilpoltstein and Bachhausen locks) is 406 m above sea level, the highest point on Earth reachable by ships from the sea. In 2010, the inter-link provided navigation for 5.2 million tonnes of goods, mostly food, agriculture, ores and fertilizers, reducing the need for 250,000 truck trips per year.[21] The canal is also a source for irrigation, industrial water and power generation plants.[22]
4. Illinois Waterway system consists of 541 kilometers of interlink that connects a system of rivers, lakes, and canals to provide a shipping connection from the Great Lakes to the Gulf of Mexico via the Mississippi River. It provides a navigation route; primary cargoes are coal to powerplants, chemicals and petroleum upstream, and agriculture produce downstream primarily for export.[23] The Illinois waterway is the principal source of industrial and municipal services water needs along its way; it serves the petroleum refining, pulp and paper processing, metal works, fermentation and distillation, and agricultural products industries.[24]
5. Tennessee–Tombigbee Waterway is a 377 kilometer man-made waterway that interlinks the Tennessee River to the Black Warrior-Tombigbee River in the United States.[25] The Tennessee–Tombigbee Waterway links major coal producing regions to coal consuming regions, and serves as commercial navigation for coal and timber products. Industries that utilize these natural resources have found the Waterway to be their most cost-efficient mode of transportation.[26] The water from the Tenn-Tom Waterway is a major source of industrial water supply, public drinking water supply, and irrigation along its way.[27]
6. Gulf Intracoastal Waterway, completed in 1949, interlinks 8 rivers, and is located along the Gulf Coast of the United States. It is a navigable inland waterway running approximately 1700 kilometers from Florida to Texas.[28] It is the third busiest waterway in the United States, handling 70 million tonnes of cargo per year,[29] and a major low cost, ecologically friendly and low carbon footprint way to import, export and transport raw materials and products for industrial, chemical and petrochemical industries in the United States.[30] It has also become a significant source for fishing industry as well as for harvesting and shipping shellfish along the coast line of the United States. Other completed rivers inter-linking projects include the Marne-Rhine Canal in France,[31][32] and the All-American Canal and California State Water Project in the United States.[33] Ecological and environmental issues Some activists and scholars have, between 2002 and 2008, questioned the merits of Indian rivers inter-link projects, and questioned if appropriate study of benefits and risks to environment and ecology has been completed so far. Bandyopadhyay et al. claim there are knowledge gaps between the claimed benefits and potential threats from environment and ecological impact.[2] They also question whether the inter-linking project will deliver the benefits of flood control. Vaidyanathan claimed, in 2003, that there are uncertainty and unknowns about operations, how much water will be shifted and when, whether this may cause waterlogging, salinisation and the resulting desertification in the command areas of these projects.[46] Other scholars have asked whether there are other technologies to address the cycle of droughts and flood havocs, with less uncertainties about potential environmental and ecological impact.[47] Displacement of people and fisheries profession Water storage and distributed reservoirs are likely to displace people – a rehabilitation process that has attracted concern of sociologists and political groups. Further, the inter-link would create a path for aquatic ecosystems to migrate from one river to another, which in turn may affect the livelihoods of people who rely on fishery as their income. Lakra et al., in their 2011 study, claim[48] large dams, interbasin transfers and water withdrawal from rivers is likely to have negative as well as positive impacts on freshwater aquatic ecosystem. As regards to the impact on fish and aquatic biodiversity, there could be positive as well as negative impacts. Poverty and population issues India has a growing population, and large impoverished rural population that relies on monsoon-irrigated agriculture. Weather uncertainties, and potential climate change induced weather volatilities, raise concerns of social stability and impact of floods and droughts on rural poverty. The population of India is expected to grow further at a decelerating pace and stabilize around 1.5 billion by 2050, or another 300 million people – the size of United States – compared to the 2011 census. This will increase demand for reliable sources of food and improved agriculture yields – both of which, claims India's National Council of Applied Economic Research,[4] require significantly improve irrigation network than the current state. The average rainfall in India is about 4,000 billion cubic metre, of which annual surface water flow in India is estimated at 1,869 billion cubic metre. Of this, for topological and other reasons, only about 690 billion cubic metre of the available surface water can be utilised for irrigation, industrial, drinking and ground water replenishment purposes. In other words, about 1,100 billion cubic metre of water is available, on average, every year for irrigation in India.[4] This amount of water is adequate for irrigating 140 million hectares. As of 2007, about 60% of this potential was realized through irrigation network or natural flow of Indian rivers, lakes and adoption of pumps to pull ground water for irrigation. 80% of the water India receives through its annual rains and surface water flow, happens over a 4-month period – June through September.[4][5] This spatial and time variance in availability of natural water versus year round demand for irrigation, drinking and industrial water creates a demand-supply gap, that only worsens with India's rising population. Proponents claim the answers to India's water problem is to conserve the abundant monsoon water bounty, store it in reservoirs, and use this water in areas which have occasional inadequate rainfall, or are known to be drought-prone or in those times of the year when water supplies become scarce.[4][49] International issues Misra et al. in their 2007 report,[6] claim inter-linking of rivers initially appears to be a costly proposition in ecological, geological, hydrological and economical terms, in the long run the net benefits coming from it will far outweigh these costs or losses. However, they suggest that there is a lack of an international legal framework for the projects India is proposing. In at least some inter-link projects, neighboring countries such as Bangladesh may be affected, and international concerns for the project must be negotiated. Political views BJP-led NDA government of Atal Bihari Vajpayee had mooted the idea of interlinking of rivers to deal with the problem of drought and floods afflicting different parts of the country at the same time.[10] The congress general secretary Rahul Gandhi said in 2009 that the entire idea of interlinking of rivers was dangerous and that he was opposed to interlinking of rivers as it would have "severe" environmental implications. BJP MP Rajiv Pratap Rudy suggested that Gandhi should do some research on the interlinking of rivers and its benefits and then arrive at a conclusion. Jairam Ramesh, a cabinet minister in former UPA government, said the idea of interlinking India's rivers was a "disaster", putting a question mark on the future of the ambitious project.[50] Karunanidhi, whose DMK has been a key ally of the Congress-led UPA at the Centre, wrote that linking rivers at the national level perhaps is the only permanent solution to the water scarcity problem in the country.” Karunanidhi said the government should make an assessment of the project’'s feasibility starting with the south-bound rivers. DMK for 2014 general elections added Nationalisation and inter-linking of rivers to its manifesto. Kalpasar Project is an irrigation project which envisages storing Narmada River water in an off-shore fresh water reservoir located in Gulf of Khambhat sea for further pumping to arid Sourashtra region for irrigation use. It is one of the preferred project for implementation by the newly elected Prime Minister of India, Narendra Modi.[51] Geography of India The Geography of India describes the geographic features of India, a country in South Asia. India lies largely on the Indian Plate, the northern portion of the Indo-Australian Plate, whose continental crust forms the Indian subcontinent. The country is situated north of the equator between 8°4' and 37°6' north latitude and 68°7' and 97°25' east longitude.[2] It is the seventh-largest country in the world, with a total area of 3,166,414 square kilometres (1,222,559 sq mi).[3] India measures 3,214 km (1,997 mi) from north to south and 2,933 km (1,822 mi) from east to west. It has a land frontier of 15,200 km (9,445 mi) and a coastline of 7,517 km (4,671 mi).[4] On the south, India projects into and is bounded by the Indian Ocean – in particular, by the Arabian Sea on the southwest, the Laccadive Sea to the south, and the Bay of Bengal on the southeast. The Palk Strait and Gulf of Mannar separate India from Sri Lanka to its immediate southeast, and the Maldives are some 400 kilometres (250 mi) to the southwest. India's Andaman and Nicobar Islands, some 1,200 kilometres (750 mi) southeast of the mainland, share maritime borders with Myanmar, Thailand and Indonesia. Kanyakumari at 8°4′41″N and 77°32′28″E is the southernmost tip of the Indian mainland, while the southernmost point in India is Indira Point on Great Nicobar Island.[4] India's territorial waters extend into the sea to a distance of 12 nautical miles (13.8 mi; 22.2 km) from the coast baseline.[5] The northern frontiers of India are defined largely by the Himalayan mountain range, where the country borders China, Bhutan, and Nepal. Its western border with Pakistan lies in the Punjab Plain and the Thar Desert. In the far northeast, the Chin Hills and Kachin Hills, deeply forested mountainous regions, separate India from Burma. On the east, its border with Bangladesh is largely defined by the Khasi Hills and Mizo Hills, and the watershed region of the Indo-Gangetic Plain.[clarification needed] India is entirely contained on the Indian Plate, a major tectonic plate that was formed when it split off from the ancient continent Gondwanaland (ancient landmass, consisting of the southern part of the supercontinent of Pangea). The Indo-Australian is subdivided into the Indian and Australian plates. About 90 million years ago, during the late Cretaceous Period, the Indian Plate began moving north at about 15 cm/year (6 in/yr).[6] About 50 to 55 million years ago, in the Eocene Epoch of the Cenozoic Era, the plate collided with Asia after covering a distance of 2,000 to 3,000 km (1,243 to 1,864 mi), having moved faster than any other known plate. In 2007, German geologists determined that the Indian Plate was able to move so quickly because it is only half as thick as the other plates which formerly constituted Gondwanaland.[7] The collision with the Eurasian Plate along the modern border between India and Nepal formed the orogenic belt that created the Tibetan Plateau and the Himalayas. As of 2009, the Indian Plate is moving northeast at 5 cm/yr (2 in/yr), while the Eurasian Plate is moving north at only 2 cm/yr (0.8 in/yr). India is thus referred to as the "fastest continent".[7] This is causing the Eurasian Plate to deform, and the Indian Plate to compress at a rate of India's borders run a total length of 15,106.70 km (9,386.87 mi).[1] Its borders with Pakistan and Bangladesh were delineated according to the Radcliffe Line, which was created in 1947 during Partition of India. Its western border with Pakistan extends up to 3,323 km (2,065 mi), dividing the Punjab region and running along the boundaries of the Thar Desert and the Rann of Kutch.[1] This border runs along the Indian states of Jammu & Kashmir, Rajasthan, Gujarat, and Punjab.[8] Both nations delineated a Line of Control (LoC) to serve as the informal boundary between the Indian and Pakistan-administered areas of Kashmir. According to India's claim, it also shares a 106 km (66 mi) border with Afghanistan in northwestern Kashmir, which is under Pakistani control.[1] India's border with Bangladesh runs 4,096.70 km (2,545.57 mi).[1] West Bengal, Assam, Meghalaya, Tripura and Mizoram are the States which share the border with Bangladesh.[9] There are 92 enclaves of Bangladesh on Indian soil and 106 enclaves of India are on Bangladeshi soil.[10] The Teen Bigha Corridor is a strip of land formerly belonging to India on the West Bengal–Bangladesh border which has been leased indefinitely to Bangladesh so that it can access its Dehgram–Angalpota enclaves.[citation needed] The Line of Actual Control (LAC) is the effective border between India and the People's Republic of China. It traverses 4,057 km along the Indian states of Jammu and Kashmir, Uttarakhand, Himachal Pradesh, Sikkim and Arunachal Pradesh.[11] The border with Burma (Myanmar) extends up to 1,643 km (1,021 mi) along the southern borders of India's northeastern states viz. Arunachal Pradesh, Nagaland, Manipur and Mizoram.[12] Located amidst the Himalayan range, India's border with Bhutan runs 699 km (434 mi).[1] Sikkim, West Bengal, Assam and Arunachal Pradesh are the States, which share the border with Bhutan.[13] The border with Nepal runs 1,751 km (1,088 mi) along the foothills of the Himalayas in northern India.[1] Uttarakhand, Uttar Pradesh, Bihar, West Bengal and Sikkim are the States, which share the border with Nepal.[14] The Siliguri Corridor, narrowed sharply by the borders of Bhutan, Nepal and Bangladesh, connects peninsular India with the northeastern states The Northern Mountains

Map of the hilly regions in India. A great arc of mountains, consisting of the Himalayas, Hindu Kush, and Patkai ranges define the northern Indian subcontinent. These were formed by the ongoing tectonic collision of the Indian and Eurasian plates. The mountains in these ranges include some of the world's tallest mountains which act as a natural barrier to cold polar winds. They also facilitate the monsoon winds which in turn influence the climate in India. Rivers originating in these mountains flow through the fertile Indo–Gangetic plains. These mountains are recognised by biogeographers as the boundary between two of the Earth's great ecozones: the temperate Palearctic that covers most of Eurasia and the tropical and subtropical Indomalaya ecozone which includes the Indian subcontinent, Southeast Asia and Indonesia. The Himalayan range is the world's highest mountain range, with its tallest peak Mt. Everest (8,854 metres (29,049 ft)) on the Nepal–China border.[15] They form India's northeastern border, separating it from northeastern Asia. They are one of the world's youngest mountain ranges and extend almost uninterrupted for 2,500 km (1,600 mi), covering an area of 500,000 km2 (190,000 sq mi).[15] The Himalayas extend from Jammu and Kashmir in the north to Arunachal Pradesh in the east. These states along with Himachal Pradesh, Uttarakhand, and Sikkim lie mostly in the Himalayan region. Numerous Himalayan peaks rise over 7,000 m (23,000 ft) and the snow line ranges between 6,000 m (20,000 ft) in Sikkim to around 3,000 m (9,800 ft) in Kashmir. Kanchenjunga—on the Sikkim–Nepal border—is the highest point in the area administered by India. Most peaks in the Himalayas remain snowbound throughout the year. The Himalayas act as a barrier to the frigid katabatic winds flowing down from Central Asia. Thus, North India is kept warm or only mildly cooled during winter; in summer, the same phenomenon makes India relatively hot. The Peninsular Plateaus • The Vindhya range runs across most of central India, extending 1,050 km (650 mi).[15] The average elevation of these hills is from 300 to 600 m (980 to 1,970 ft) and rarely goes above 700 metres (2,300 ft).[15] They are believed to have been formed by the wastes created by the weathering of the ancient Aravali mountains.[18] Geographically, it separates Northern India from Southern India. The western end of the range lies in eastern Gujarat, near its border with Madhya Pradesh, and runs east and north, almost meeting the Ganges at Mirzapur

Dry deciduous and thorny forests of plateau regions in India • The Malwa Plateau is spread across Rajasthan, Madhya Pradesh and Gujarat. The average elevation of the Malwa plateau is 500 metres, and the landscape generally slopes towards the north. Most of the region is drained by the Chambal River and its tributaries; the western part is drained by the upper reaches of the Mahi River. • The Deccan Plateau is a large triangular plateau, bounded by the Vindhyas to the north and flanked by the Eastern and Western Ghats. The Deccan covers a total area of 1.9 million km² (735,000 mile²). It is mostly flat, with elevations ranging from 300 to 600 m (980 to 1,970 ft). The average elevation of the plateau is 2,000 feet (610 m) above sea level. The surface slopes from 3,000 feet (910 m) in the west to 1,500 feet (460 m) in the east.[19] It slopes gently from west to east and gives rise to several peninsular rivers such as the Godavari, the Krishna, the Kaveri and the Mahanadi which drain into the Bay of Bengal. This region is mostly semi-arid as it lies on the leeward side of both Ghats. Much of the Deccan is covered by thorn scrub forest scattered with small regions of deciduous broadleaf forest. Climate in the Deccan ranges from hot summers to mild winters. • The Chota Nagpur Plateau is situated in eastern India, covering much of Jharkhand and adjacent parts of Odisha, Bihar and Chhattisgarh. Its total area is approximately 65,000 km2 (25,000 sq mi) and is made up of three smaller plateaus — the Ranchi, Hazaribagh, and Kodarma plateaus. The Ranchi plateau is the largest, with an average elevation of 700 m (2,300 ft). Much of the plateau is forested, covered by the Chota Nagpur dry deciduous forests. Vast reserves of metal ores and coal have been found in the Chota Nagpur plateau. The Kathiawar peninsula in western Gujarat is bounded by the Gulf of Kutch and the Gulf of Khambat. The natural vegetation in most of the peninsula is xeric scrub, part of the Northwestern thorn scrub forests ecoregion. • The Satpura Range begins in eastern Gujarat near the Arabian Sea coast and runs east across Maharashtra, Madhya Pradesh and Chhattisgarh. It extends 900 km (560 mi) with many peaks rising above 1,000 m (3,300 ft).[15] It is triangular in shape, with its apex at Ratnapuri and the two sides being parallel to the Tapti and Narmada rivers.[20] It runs parallel to the Vindhya Range, which lies to the north, and these two east-west ranges divide the Indo–Gangetic plain from the Deccan Plateau located north of River Narmada. • The Aravali Range is the oldest mountain range in India, running across Rajasthan from northeast to southwest direction, extending approximately 800 km (500 mi).[21] The northern end of the range continues as isolated hills and rocky ridges into Haryana, ending near Delhi. The highest peak in this range is Guru Shikhar at Mount Abu, rising to 1,722 m (5,650 ft), lying near the border with Gujarat.[22] The Aravali Range is the eroded stub of an ancient fold mountain system.[23] The range rose in a Precambrian event called the Aravali–Delhi orogen. The range joins two of the ancient segments that make up the Indian craton, the Marwar segment to the northwest of the range, and the Bundelkhand segment to the southeast.