The development of water resources projects in the Ganga basin has a long history. There are a large number of water resources development projects in the basin. A few projects are also being planned in collaboration with the Government of Nepal. In order to boost the utilization of waterways, some segments of the Ganga River have been declared as national waterways. A description of the major works is given in what follows.

A remarkable work that includes many great civil engineering structures is the Upper Ganga Canal system whose construction was initiated by the then British government in the 1840s to ward off drought and famine in the western part of the current the Uttar Pradesh state. Northern India experienced a famine in 1837 and 1840 when, according to estimates, the population of the area fell by 20%. Completed in 1854, UGC was to irrigate an area of 0.7 million ha. This canal was the reason why the first engineering college in India, the Thomason College of Civil Engineering was set up at Roorkee, close to Haridwar. In due course of time, this college was upgraded to an engineering university and then converted into an IIT. Today, Roorkee is the home to a number of engineering organizations dealing with water.

At the time of commencement of UGC Project, there was no science of soil mechanics and hydraulic engineering was also in its primitive stages. There was no existing large extensive canal system in the country and the world by that time. In formulation and execution of the project and in projecting the layout and design of main canal and its major structures, Sir Proby Cautley adopted the simple scheme of taking the help of nature and maintaining a compromising attitude, specially in taking the canal across the powerful streams and rivers coming in the alignment and also used his engineering skill in producing simple and bold designs with locally available material (brick, lime and surkhi). Although in the first project report, UGC was proposed as a navigation canal, finally it was constructed as an irrigation canal.

UGC draws its supply from the Ganga River at Haridwar. Prior to the construction of the permanent head works, water was being forced into the canal by means of temporary weirs constructed of wooden crates filled with boulders. Originally, the width at the head was 61 m and the depth at full supply level nearly 3.3 m. Sir Cautley placed the head of the canal at Mayapur, a place well settled and safe from the attack of Ganga River. Currently, the head works are situated at Bhimgoda.

The reach of the canal from the head works to 32^nd km may well be classified among the greatest feats of irrigation engineering in India. The alignment traverses numerous drainages track and the arrangements for negotiating these drainages are complicated by the fact that the canal bed is at places far below and at other far above the general level of surrounding country. Four large torrents are crossed in this reach while several smaller ones are admitted into the canal. The steep slope of the country moreover necessitates the negotiation of over 18 m of bed fall in those first 32 km. UGC flows in deep cutting up to the 19^th km. In the 10^th km, it encounters the Ranipur torrent which is carried over it on a masonry super-passage. The Pathri torrent is passed over the canal on second super passage.

At the 21^st km, the Ratmau torrent is passed across the canal, being admitted directly into the channel on one side and escaped again through a weir. At the 30^th km comes the Solani aqueduct which is the finest work on the canal (see Figure 8.13). Solani aqueduct was constructed with the special inspiration of the great work of Alcantara aqueduct in Portugal, constructed during the years 1,713 to 1,732 and universally accepted to be a stupendous monument of modern art and engineering in Europe. At the time of commissioning Ganga canal in 1854, Solani Aqueduct was ranked as one of the most remarkable massive structure of brick masonry in the whole world.

It cannot, however, be pretended that the design of UGC was perfect by any means. Indeed no sooner was the full supply of the channel first admitted, several serious faults became apparent. In many places, the bed slope was too steep, the masonry falls generated excessive velocities below them, causing heavy scour in bed and banks, and the general layout of the distributary system had some drawbacks. Considerable amount of remodelling was necessary before these defects were removed, but in other respects, the work even now remains substantially as Cautley built it. Noteworthy is the fact that at the time it was constructed, experience of artificial canals was limited to works of only about a third the size of the Ganga Canal. But the mistakes appear to be insignificant when compared with the enormous advances in hydraulic engineering, which the scheme represented. The engineering judgment of planners and designers of UGC was truly marvelous.

The Upper Ganga Canal system is a leading irrigation system in India. It extends over an area of 24,000 sq. km bounded by natural or man made water courses. The Ganga River is on the eastern side, the Hindon River and the Yamuna River on the western side, and the lower Ganga canal on the southern side. The Upper Ganga Canal takes off from the Ganga at the Bhimgoda weir near Haridwar. The main canal is 290 km long and is one of the most exquisitely constructed civil engineering structures. In view of expansion of the command area, the discharge capacity of the canal was recently augmented to 297 m³/s. The command area of the canal is now about 0.924 million ha.

The command area of the system is located between 27° N and 30° N latitudes and 77°15’E and 78°40’E longitudes covering the districts of Saharanpur, Muzaffarnagar, Meerut, Ghaziabad, Bulandshahar, Aligarh, Mathura, Agra, Etah, and Mainpuri. A major project to revitalize the head reaches of the canal was completed in 2003. A parallel canal has been constructed upstream of Roorkee and a new aqueduct has been constructed over the Solani River.

A number of small rivers, such as Kali, Karwan, Solani and West Kali, flow and interact with the ground water system in the canal command. The Upper Ganga Canal system has a large expanse and the main canal as well as its branches are an important source of recharge as they all are unlined. The extraction from ground water is through pumping by public and private tubewells.

UGC system is fed through a headwork complex with a regulation at Mayapur and a diversion weir at Bhimgoda across the Ganga River. The important branches of the system are the Deoband branch (taking off on the left bank at 35 km), the Anupshahr branch (taking off on the left bank at 80 km), the Mat branch (taking off on the right bank at 177 km), and the Hathras branch (taking off from the Mat branch on the left bank at 80 km). The system is unlined and has a network of 115 distributaries. The canal system is connected with natural drains/rivers to discharge the surplus water of the canal.

Climatically the area belongs to a dry sub-humid to moist-humid category. The normal annual rainfall varies from 1050 mm in the north to 650 mm in the south. Around 90% of annual rainfall occurs in the monsoon season (June to October). The annual pan evaporation for the area is about 150 cm. The temperature varies from 3°C to 4°C in January to 43°C to 45°C in May or June.

The scope of the system has been considerably altered since it was first constructed. The Lower Ganga Canal (LGC) which was opened in 1878, intersected by the main branches of the UGC, the Etawah and Kanpur branches and the tail portions of these are now officially included in the LGC system. In their place, however, three new important branches, the Deoband, Mat branches have been added to UGC. In the length of its channels, the UGC is still largest in

India

. The system comprises 910 km of main canal and branches and 5,280 km of distributaries or 6,190 km of channels in all.

There are many small hydropower plants on UGC which utilize its falls to generate power. A hydroelectric power station was built on the Ganga canal at Bahadrabad, 16 km from the site of the head works, where a fall of 5.8 m was available. Incidentally, a famous research station is situated at Bahadrabad which is involved in model studies of WRD projects. Another station is situated at Mohammadpur near Roorkee.

Madhya Ganga Canal

The Madhya Ganga Canal takes off from the Ganga at the Raoli Barrage, about 11 km east of Bijnor in the U.P. state. Raoli Barrage, completed in 1994, is 583 m long; the normal water level of the pond is 221.5 m. The capacity at the head of this 115 km long canal is 234 m³/s and its distributaries are 1466 km long. The usage of water is: Anupshar branch 25.5 cumec, Lakhaoti Branch 63 cumec, Upper Ganga Canal 58 cumec, Parallel Mat Feeder 74 cumec, and losses 13.5 cumec. Madhya Ganga Canal provides irrigation to paddy crop in 114,000 ha as well as augments supply to the UGC system. The Lakhoti branch canal takes off at chainage 82 km from the Madhya Ganga Canal. Its discharge at the head is 63 cume and it is 74 km long. Minors from this canal provide irrigation over about 192,000 ha land in Neem-Kali Doab in Aligarh and Bulandshahar Districts.

Rivers in many parts of India carry enormous water during rainy season which can be used for irrigation for Paddy and to recharge ground water aquifers. This gave rise to the concept of Monsoon canals. Several such canals have been planned and constructed, viz., (i) the Eastern Ganga Canal (ii) the Madhya Ganga Canal, and (iii) the Parallel Lower Ganga Canal. These canals are examples of conjunctive use of water.

To irrigate the lower portion of Ganga -Yamuna doab, a project was sanctioned in 1872. Work commenced in that year for constructing a new canal from the Ganga River with head further down the river. LGC system comprises a weir across Ganga at Narora (near Aligarh), some 6 km below Rajghat, and the canal takes off from the right bank of the river. The weir, which is 1,158 m long, is fitted with falling shutters and enables the level of the normal cold weather supply of the Ganga to be raised by 3.05 m to feed the canal. Under sluices, consisting of 42 vents each of 2.14 m span are provided on the right flank of the weir. The canal head which is set at right angle to the sluices has 30 bays of equal width.

The main canal is 100 km long and irrigates 0.5 million ha. The Lower Ganga Canal has a discharge capacity of 156 m³/s. It was completed in 1879. It serves the districts of Mainpuri, Etah, Farrukhabad, Etawah, Kanpur, Fatehpur and Allahabad in central U.P. These canal systems are irrigating a large area of the Ganga-Yamuna Doab. But, of course, there are still large tracts of culturable area which do not have irrigation facilities.

The LGC system has 1,060 km of main canal and branches and 5,015 km of distributaries. In fact UGC and LGC form a single system. A considerable proportion of channel comprised in the lower system belonged originally to the upper and a supply of water is regularly passed from the later to the former. Viewed in this light, the Ganga canals form the largest irrigation system in the world. The length of the channel, contained in it, is no less than 12,240 km and it irrigates an area of the size of one million ha.

Agra Canal

The committee which proposed the construction of LGC, also suggested that a canal should be taken off from the Yamuna at or near its junction with the Hindan river below Delhi, to irrigate some more area in the Ganga-Yamuna watershed. Investigation showed, however, that the district lying on the left bank of river Yamuna were already or could be fairly commanded by the Ganga canal through Mat branch, whereas on the right bank, there existed a very precarious tract which was greatly in need of irrigation. The site chosen for the head works was at Okhla, 11 km below Delhi and upstream of the junction of the Yamuna and Hindan. To make the water of the Hindon available for the canal, a regulating weir, consisting of 39 vents each of 3.2 m span, was constructed across that river, by means of which its discharge can be diverted through an artificial channel, known as Hinan cut into the Yamuna immediately above the Okhla weir. A further supplementary volume can be obtained from the Ganga canal via the Jani escape, which connects the Ganga Canal with Hindan at point 48 km above the site of the diversion works.

The canal was constructed for a cold weather full supply discharge of 30.8 m³/s with a depth of 2.13 m and for a discharge of 56.0 m³/s during the rainy season with a depth of 3.05 m, the width at the head being 21.4 m. It terminates at its 116^th km at which point the Agra Navigation channel, 25 km long, connected it with Yamuna at Agra. The distribution system comprises of 1,440 km of distributaries.

In the first 13 km of its course, the canal crosses three important torrents, which bring down to the Yamuna the drainage of the rocky hills on the right bank of the canal. The floods from these hills rise rapidly but are of short duration. To obviate the necessity of large drainage crossing, embankments are provided for two of them on the right of the canal. These reservoirs have storage of 4.5 MCM. The floods are received by them and the water stored until it can be passed out gradually. The third torrent is carried under the canal through a large siphon.

The East Ganga Canal Project envisages the utilization of surplus water of the Ganga River during the Monsoon season from the existing Barrage at Bhimgoda Haridwar for providing irrigation to 105,000 ha of paddy crop, mainly in the Bijnor district (99.64 thousand ha), the Haridwar district (360 ha), and the Moradabad district (5,000 ha). The gross command area of the project is 3.01 lakh ha, out of which 2.33 lakh ha is cultivated. The proposed intensity of irrigation in Kharif is 45% which will produce an additional amount of 36.0 lakh quintals of paddy crop.

Before introduction of this project, the area was being irrigated by perennial supplies and by the Upper Ganga and Lower Ganga Canals. The original project was planned in the year 1976 for an estimated cost of Rs. 48.46 crore and the construction work was started in the year 1980-81.

The soil in the command of the East Ganga canal is generally light loam, except in northern areas of the Malin-Chhoya, Chhoya-Ban, Ban-Ganga and Ganga-Kho doabs falling in the Najibabad, Kiratpur and Kotwali blocks. The loamy soil in most of the blocks is highly suitable for rice cultivation and similar soils in the Mirzapur and Saharanpur districts produce bumper harvests of paddy. Irrigation can develop easily as soon as water is made available in abundance. At present the existing sources of irrigation in the Bijnor district are mainly the state tube wells, private tube wells and a small canal system called the Bijnor canal group.

The East Ganga Canal command has monsoonal climate. Monsoon generally starts in the last week of June and lasts up to September. The mean annual precipitation at Bijnor is 1,073 mm. About 90% of the total annual rainfall is received during June to September and the rest 10% in the remaining months. The winter rains are insufficient to meet the water requirement of crops in the area and there is always a need for irrigation water to grow Rabi crops. Uncertain irregular rain causes floods in the area.

YAMUNA CANAL SYSTEMS

The Yamuna River emerges from the hills near Tajewala where water is diverted for irrigation by the Western and Eastern Yamuna Canals. The Yamuna flows further 280 km down to Okhla near Delhi from where the Agra Canal takes off.

The earliest canals in Northern India of which any record exists are the old canals that take off from both banks of the Yamuna. The Eastern Yamuna canal was originally constructed during the Mughal dynasty, probably in the reign of Muhammad Shah (1719-1748 A.D.), and a Royal preserve at Ranup, on the left bank of the Yamuna, is said to have received water from the canal. The works were, however, soon abandoned. They were partially restored by one of the Rohilla Chiefs in about 1780 A.D. and water was brought to Saharanpur. Probably the extended canal ran during one season at most. It was not provided with masonry works and its excessive bed slope would have led to total retrogression. The canal was later realigned by the British early in the 19^th century. As was the usual practice in the case of old works of this nature, the courses of rivers and drainage lines had been utilized as much as possible and all high ground carefully avoided. The alignment of the canal, as remodeled by the British, followed this old practice to a considerable extent but a large number of masonry works were introduced.

The canal has its head on the Yamuna on its eastern bank, a point not far from the head of the Western Yamuna canal. Originally, the supply required was directed by means of temporary spurs into the eastern channel of the river and delivered at Naushera, where the excavated canal commenced and where arrangements were made for surplusing any water not required back in the river. When the canal was opened in 1830, it was realized that the gradient was too much steep, rapids forming in the bed at many points seriously threatening the masonry works. To reduce the slope, masonry falls were constructed at suitable intervals and channel was in part realigned. The distribution system had also a faulty design and was operated and had gradually to be remodelled. Many of the evils experienced in the Western Yamuna Canal repeated themselves in the Eastern Yamuna Canal system such as:

The construction of the weir for the Western Yamuna canal at Tajewala in 1875-79 resulted in a modification of the methods adopted for obtaining the supply for the Eastern Yamuna canal. A new head and regulator for the latter was built in connection with the weir and supply channel excavated from Tajewala to Naushera, the volume in the river was divided between the two canals in fixed proportions, the Government of the United Provinces making an up-keep of the weir and its connected works.

Emperor Feroz Shah Tughlaq constructed the Western Yamuna Canal (WYC) to divert water to the hunting grounds in Hansi-Safidon area in Haryana in 1355 A.D. After the death of Emperor Tughlaq in 1388, the canal fell in disuse. Mughal Emperor Akbar got the canal renovated in 1568. It was further improved by Emperor Shahjahan in 1628. Note that the Hasli canal was also constructed at the same time to bring Ravi water to Lahore; it was later extended by the Sikhs to bring water to the sacred tank at Amritsar (CBIP 1965). During the British period, the canal was realigned and repaired from 1821 onwards. After a long lull in fresh water development, GW development in the area began in 1960s. It was noticed that there is decline in GW level as well as decline in river discharge. Conjunctive use of SW & GW is being practiced in the area by completion of augmentation canal project.

Upper Yamuna Basin covers an area of 25,000 sq. km. In the canal area, tropical climate dominates. In summers, temperature can rise as high as 47°C; during winters, they can go as low as –1 °C. The average rainfall in the area is 746 mm/year; 84% of it falls during summer monsoon. WYC command area is located between the north latitudes 28°20’ & 30°28’ and east longitudes 75°48’ & 77°35’.

The total length of the WYC with all its branches is 325 km. In addition, there are about 32 distributaries and 95 minors, the combined length of which is 1,220 km. To augment canal supplies and prevent water logging in adjacent tract, a large number of augmentation wells were constructed along WYC. Further, to prevent seepage losses along WYC and to further augment its supply, a lined augmentation canal, 69 km in length was constructed recently, taking off from Yamuna Nagar and out falling in WYC at Munak. Heavy-duty wells constructed along this canal direct about 14-15 cumec of ground water to surface water canal system. In addition, there are similar augmentation wells constructed along Delhi parallel Branch and the Narwana Branch Karnal link.

In the entire reach between Tajewala to Wazirabad the river behaves as a mature river and meanders within the flood plains, the width of which increases as the slope decreases. The maximum width of the flood plain is around 3 km. In order to protect the habitations and cultivated area from flood protection, embankments have been constructed along the river, more of them along the right bank.

Ground Water Situation

The area of mountainous sub-basin is underlain by Siwalik and older formations which are semi-consolidated and consolidated in nature and are composed of sand rocks, shale and boulder conglomerates. These are poor repositories of ground water and effectively make no ground water contribution to sub-basin. The plain tract lying south of the Siwalik zone forms a part of Indo-Gangetic alluvial plains of recent origin. The thickness of the alluvial deposit (as deduced from geophysical evidence) is small along the fringe of peninsular mass but progressively increases towards northwards and is maximum in the foredeep area lying immediately south of the Himalayan zone. The alluvial plains are underlain by loose unconsolidated river borne sediments and form very good repository of ground water. Below a particular level, not far below the land surface, the alluvium is saturated with ground water. Water table occurs between 10 to 60 m BGL in the sub-mountainous tract but generally lies between 3 m to 10 m BGL in rest of the area. The aquifer system lying closest to the land surface is in unconfined condition. At deeper levels, particularly below regionally or sub-regionally extensive poorly permeable layers, the ground water occurs in semi-confined to confined conditions. It is expected that with increasing depth, the alluvium could get more and more consolidated because of the increasing over burden and hence have reduced porosity and permeability. The unconfined aquifer, which is quite potential, generally bears an effluent relation with the surface drainage.

Major Aquifer systems

Aquifers have been demarcated in this area based on exploratory drilling and bore-hole logging. Except in areas close to Delhi where the bedrock occurs at a shallow depth, four distinct groups of permeable horizons were identified.

The Aquifer Group 1 (AG1) (composed of different sand and clay layers) extends from water table to 167 m below ground level (BGL). This is composed of relatively coarser sediment and contains fresh formation water. In general, this aquifer behaves as unconfined aquifer displaying delayed yield phenomenon. The effects of leakage are negligible. AG1 is underlain by a clayey horizon 10 to 15 m which is regionally extensive except around sites Nagal, Tikaula, Labhkari, Newal and Ambheta. At these sites, AG1 seems to be directly in contact with Aquifer Group 2 (AG2). AG2, composed of different sand and clay lenses occurring at variable depths (ranging from 65 to 283 m BGL) has distinguishing characteristics of its own at places and at others is separated because of distinguishing features of the overlying and underlying groups. The sediment of this group is less coarse and kanker is encountered at sites located west of river Yamuna. The quality of water is reasonably fresh except in south-western parts. Seven successful long duration pumping tests with observation wells were conducted. The aquifer behaved as confined at 3 sites and as semi-confined at rest 4 sites.

AG2 is underlain by another clayey horizon which is considerably thick at places and appears to be regionally extensive except around sites Sikka and Kheri. A local aquifer group of limited thickness is found enclosed within thin clay around sites Nitli and Baleri. Aquifer Group 3 (AG3) comprises of thin sand layers alternating with thicker clay layers occurring at variable depths varying between 197 m to 346 m BGL, underlies the above groups. The granular material of this group is generally finer in texture and more so in southerly direction. Kankar occurs in southern parts.

AG3 is underlain, in turn, by a thick clayey horizon which in turn is underlain by another permeable granular horizon. Aquifer Group 4 was not fully penetrated.

Behaviour of Ground water

The master slope of water table is from north to south with lateral slopes away from the ground water ridges. There is a prominent ground water trough roughly along the river Yamuna, but this departs Westwards in areas between Panipat to Delhi. A general down-valley shift of contours in post-monsoon period in response to recharge can be observed.

The area between the Eastern Yamuna and Western Yamuna canals south of latitude 30º behaves as a hydro-geological unit with no flow across boundaries but some inflow from north. The piezometric levels of the lower portions of the AG1 show similar behavior to that of the phreatic surface with minor departures. It appears that there is flow in the vertical direction within AG1; and in parts between Yamuna and WYC this is found to be upwards. No GW flow occurs in AG1 from across the eastern boundary but generally outflow takes place from Western boundary. Substantial vertical leakage is expected to be occurring between AG1 and AG2 and much of the flow converging towards the trough may be leaking upwards to AG1.

In general in the submontaneous tract and the areas along the major canals and part of the central area in the south, AG1 has potentiometric head of 0 to 4 m above the AG2. All the observations fit well with the fact that both AG1 and AG2 receive recharge in Bhabhar tract and areas along the major canals and discharge the same to Yamuna drainage.

In major part of the area between the canals, AG3 and AG4 have a higher head over AG2. However, only in southern parts of AG3 and AG4 are likely to provide leakage to AG2 above. The study of daily hydrographs of river levels along with those of ground water levels in the river tract for one year indicate a general sympathetic behavior and a good hydraulic connectivity of the river with ground water storage along the banks. It was concluded from the study that influent -effluent relation of river with the areas in immediate vicinity of the two banks changes with places and times and may not always coincide with the regional relation of ground water body with the river, on either bank.

The soils in sub-mountainous region are classified as reddish soils. South of this zone roughly up to Panipat the soils are classified as 'Tropical Arid Brown'. In area south of Panipat the soils are arid brown soils. The soils in the basin, west of Yamuna River are mostly sandy loam to loam with medium permeability. In Karnal district considerable sedimentation and alkalinization of the soil has occurred due to rise in water table by canal seepage and from excessive use of irrigation water.

The area is predominantly an agricultural tract, with about 76% area under cultivation. The major crops grown in the area are wheat (58% area), rice (20% area), Gram (10% area), Maize (13% area), Jowar (4% area), Barely (3% area), Bajra (7% area), and sugar cane (19% area).

Betwa Canal

The sanction of the estimate of the Betwa canal in 1881 marked the opening of yet another and a very important era in the history of irrigation works in India, namely the era of protective works or the works designed primarily for the protection, of precarious areas against famine, the direct return obtainable from them being the secondary consideration.

The Betwa canal was the first protective work in India which was constructed in the United Provinces. A report was prepared in 1868 which established the practicability of such a canal for irrigation of the triangular area in the Jalaun district formed by three rivers: Yamuna, Pahuj and Betwa. The subsoil water throughout this tract was at immense depth. The project was completed in 1893.

The head works of the canal are situated on the Betwa River near Parichcha, 27 km from Jhansi. The river at this point has a discharge of 23,000 m³/s. Canal regulator has five bays. This weir forms a reservoir in the river channel and impounds 48 MCM of water at crest level. In 1899 automatic shutters were erected which increased the capacity of the reservoir to 61 MCM.

The main canal is 30 km long. At its termination it bifurcates into Hamirpur and Kathound Branches. In 1904-05, the Kathound branch was remodelled to carry discharge of 17.0 m³/s. But the greatest weakness of the canal lay in the general inefficiency of its cold weather supply and in 1905 works was commenced on the construction of a supplementary reservoir at Dhukwan 40 km above the Parichha. The Dhukwan weir is 1,196 km long and has maximum height of 17.4 m. The work was completed in the year 1910.

Dhasan Canal

The Dhasan and Bearma are tributaries of Betwa, flowing from the east. The canal lies in Hamirpur district between a triangular area made by above rivers. The project was sanctioned in 1905. Two dams have been constructed upon Dhasan River, the upper one at Pahari, the lower at Lachaura some 11 km further down. Both dams have same maximum height of 16 m, the Pahari dam is 580 m, the Lachaura dam 542 m long. Gates, 2.5 m high, are erected on the crests and effective storage of 78 MCM at Pahari and 15 MCM at Lachaura are thus obtained. Both dams are of concrete, with masonry facing up and downstream.

The Dhasan canal has a head discharge of 20 cumec and a bed width of 13.7 m. With its 3 branches, it has a total length of 170 km and feeds 300 km of distributaries. There is only one masonry work of importance on the main line the Kohina Nala aqueduct. The canal was opened for irrigation in 1910.

Ken Canal

To irrigate the watershed between the Ken and the Bhagin, the Ken canal has been constructed. It was sanctioned in 1903 and came into operation in 1908. It consists primarily of a weir across the Ken at Bariarpur, some 100 km south of Banda, a main canal 59 km long, and two branches with a connected distributory system.

The Bariarpur weir has a crest length of 512 m and a maximum height of 8.0 m above the solid rock on which it is founded. The weir is capable of impounding 14 MCM of water. The canal takes off direct from this reservoir and is designed to carry a normal supply 22.5 cumec, which can be increased to 28 cumec at time of intense demand. The steep slope of the country necessitated a large number of masonry falls – there are 22 such falls in the first 13 km of the main canal. Two principal works for cross drainage being Majhgawan and Mawapura aqueduct.

To supplement the supply in canals, the Gangao dam has been constructed. This dam is situated on the Ken River some 50 km above the head works of the canal. The work was taken up in 1911 and completed in 1917. The dam is of masonry, of the same design as those in the Dhasan and Bariarpur. It is 740 m long with a maximum height of 16 m and is capable of 76 MCM of water at crest level. Ken is very formidable river, carrying in flood a discharge of 17,000 cumec and consequently both at Bariarpur and Gangao the works are on a scale of considerable magnitude. The canal system has 138 km of main canal and branches and 413 km of distributaries. In addition to large works smaller storage schemes were also provided in the Bundelkhand area.

Ghagar Canal

Construction of the Ghagar canal was commenced near the end of 1912 and completed in 1918. The main feature of the scheme is the masonry dam at Dhandraul, which has been constructed across a gorge where Ghagar River pierces a low line of hills on its way to join the Sone. This dam, which is 305 m long and 20.72 m high forms in conjunction with an earthen embankment, 5.23 km long of a mean height of 7.6 m, a reservoir capable of storing more than 140 MCM of water.

Two low saddles in the hills provide means of escape with their crests at the full supply level of the lake while the third, which forms the main escape is divided into 12 bays each of 6.1 m span. A supplementary dam, 152 m long and 13.7 m high, on the neighbouring Karamnasa River diverts the water of that river also into the reservoir through the so called Karmnasa cut, thereby supplementing the supplies in the Ghagar. From this reservoir, the canal system consisting of 100 km of main canals and branches and 120 km of distributaries is fed. The canal is crossed by 48 drainages. The steep slope of the country necessitated the provision of numerous masonry falls in the beds of various channels.

Sarda Canal

The scheme consists of two parts: the Sarda canal proper and the Sarda Kichcha Feeder which leaves it at about 11 km. The former comprises a comprehensive project for irrigation of the north western district of Oudh, while the latter assures a supply to the extension of the existing Rohilkhand canals. The head works and the first 11 km of the canal are common to both. Thereafter, the Sarda canals runs in a southerly direction, while the feeder flows through the Tarai, the low-lying land at the foot of Himalayas.

The head works of the combined project are situated on the Sarda River a few km below the point where it debauches from the hills. At this place, the river forms the boundary between (British) India and Nepal; the government of Nepal had courteously consented to a small exchange of territory so as to permit the British Government jurisdiction over the land upon which the left abutment of weir and left bank training works are situated. A channel is built on the left flank to irrigate certain area of Nepal. The weir and sluices have been designed to pass a maximum flood of 11,300 cumec. The head regulator and first 11.26 km of combined canal were constructed to carry 233 cumec.

The Sarda canal proper, below bifurcation consists of main canal with a length of 28.15 km, after which it bifurcates into three branches. The project comprises 769.10 km of main canal and branches, 5,422.33 km of distributaries and 160.90 km of escapes or 6,352.33 km of channel in all.

The Upper Sarda Barrage is located in Banbassa of Nainital district for purpose of directing water in Sarda main canal for irrigation and power generation. Design flood discharge was 16,900 m³/s. Length of barrage is 598 m and it has 4 under sluice bays. The barrage was completed in 1928.

The 1920 Sarda river agreement between the British Indian Government and Nepal guaranteed 11.3 m³/s for the summer (Kharif) irrigation and 9.25 m³/s for the winter (Rabi) irrigation. Trishuli and Devighat hydroelectric projects on the river Trishuli, Chatra canal and renovation and extension of the Chatra canal were completed by the Government of India, which bore the complete costs of these projects. At least on the Indian side it is felt that all these projects, fully funded by India, have provided large benefits to the two countries.

The Ganga River system has substantial hydropower potential, besides being a vast source for irrigation in the Gangetic Plains. The hydropower potential of the Ganga and its tributaries has been assessed as 10,715 MW. So far, very small amount of this potential has been exploited. There are no storages on the main river and its two arms Bhagirathi and Alaknanda. To harness the hydropower potential of the river, a major storage dam is being constructed on Bhagirathi at a point 1.5 km downstream of Tehri town in the State of Uttaranchal. To meet the peaking power needs, another dam is planned downstream of Tehri at Koteshwar. It will cater for pumped storage operation also. The entire Tehri Hydro Power Complex, as envisaged, would have an installed capacity of 2,400 MW and would provide substantial benefits by way of irrigation and domestic water supply.

The Tehri dam project was first conceived in 1949 and was sanctioned by the Planning Commission of India in 1972 when approval of the proposal for a 260.5 m rock-filled dam at Tehri was given in. Tehri dam is located on the outer Himalaya in the Tehri-Garhwal district of Uttaranchal in the Ganga Basin. The dam will be the fifth highest dam in the world with a height of 260.5 meters and spread over an area of 45 sq. km in the Bhagirathi and Bhilangana valleys near Tehri town. The dam, when finished, will completely submerge the Tehri town and nearly 100 villages will be totally or partially submerged. Nearly one lakh persons have been displaced and resettled because of the dam and a whole new city, known as New Tehri has been developed. The Government of India sanctioned the project in 1972. It is a multipurpose project, the main purposes of the dam being hydropower, irrigation, flood control, fisheries & tourism. The designed annual irrigation from the reservoir is 2,700 million sq. meter. The Tehri dam on the Bhagirathi (under construction) will provide a live storage capacity of 2,613 million cubic m (gross storage capacity of 3,540 million cubic m) to be used for power generation and irrigation. The project is being executed by The Tehri Hydro Development Corporation with its headquarters at Rishikesh.

The average river flows in the Ganga near Haridwar in monsoon season (July to Sept.) range between 2,000 to 3,000 cumec and the lean flows are about 100 cumec. The average river slope up to Haridwar is 20 m/km. The salient features of the project are given in Table 8.10. The main features of the project are:

Reservoir
M.W.L.	835 m
F.R.L.	830 m
Dead Storage Level	740 m
Gross Storage	3,540 MCM
Live Storage	2,615 MCM
Main Dam
Type	Earth & Rockfill
Top Level	839.50 m
Height	260.50 m above deepest foundation level
Width at river bed	1,141 m
Length and width at top	575 m, 20 m, Flared 25 m on abutments
Diversion Tunnel
Type	Horse Shoe
On Left Bank	2 number, 11.30 m dia, 1,774 & 1,778 m long
On Right Bank	2 number, 11.30 m dia, 1,298 & 1,429 m long
Diversion Flood	8,120 Cumec
Spillway
(A) Chute Spillway
Crest Elevation	815.00 m
Design Discharge	15,480 Cumec
No. & Size of Bays	3, 10.50 m each
(B) Right Bank Shaft Spillway
Crest Elevation	830.20 m
Design Discharge	3,879 Cumec
Intake Type	2 Number, Ungated Funnel Shaped
(C) Left Bank Shaft Spillway
Crest Elevation	815.00 m
Design Discharge	3,750 Cumec
Intake Type	2 Nos. Gate Weir type Intake
Power House (Underground 2 Number)
Installed Capacity	2,000 MW
Conventional Units	4 X 250 MW
Reversible Units	4 X 250 MW
Design Head	231.5 m
Gross Head	188 m
Head Race Tunnel	4 Number, 8.50 m dia

The project would generate about 4,300 million units of energy on the 90% dependable water availability and about 5,000 trillion units on the average water availability. The peak load power generation is 2,400 MW. Besides, the project will provide irrigation facilities to 2.7 lakh ha of area in the command of existing canal systems off taking from the Ganga downstream of Haridwar. The project will also provide about 10 cumec of water to Delhi to meet its future domestic requirements. The total cost of project including the cost of transmission system but excluding the cost of modernizing and extending the canal distribution system is about Rs. 5,060 crore.

The Tehri dam project area is seismically active and falls in Zone-IV of the seismic zoning map of India, which corresponds to intensity VIII on MM Scale. Most of the past earthquakes have magnitudes of 5-7 on the Richter scale. The dam is designed for a probable earthquake of magnitude 8.0. A site specific assessment of seismicity has been made for detailed designs.

Catchment Area Characteristics

The catchment area at the dam site is 7,511 sq. km. Out of this 2,323 sq. km is snow bound. This catchment varies in elevation from 9,600 m to 600 m in a length of 187 km. The valley is narrow and moderately forested. The catchment area below the perpetual snow line (4,880 m) is divided into following the three types:

Agriculture land (1,240 sq. km).
Forest land (2,400 sq. km).
Soyam land lying between the above two types being mainly used by villagers for cattle grazing, etc. (1,500 sq. km).

The spread of Tehri dam reservoir will be about 42 sq. km at the full reservoir level of 830 m. The length of reservoir along the Bhagirathi River is 44 km and along the Bhilangana River, it is 25 km. The Tehri dam will affect 22 villages fully and 74 villages partially besides submerging the Tehri Town. Out of the total submerged area, about 1,600 ha is the cultivated land, about 1,600 ha is the forest land and the remaining is uncultivated. In addition, some area will be acquired for the Tehri Town, project colony, workshop, stores and roads, etc. which affect 13 additional villages. The project will displace about 13,840 families.

Hydrology

The snow-bound catchment has little rainfall but it contributes runoff in non-monsoon period due to snow melt. The rest of the catchment has the annual precipitation varying from 101.6 to 263.0 cm. More than eighty percent of the annual precipitation occurs during the monsoon period causing occasional floods. These floods often cause soil erosion bringing heavy sediment loads in the river. The river discharge at the dam site generally varies from 30 to 2,000 cumec, the minimum being in January and the maximum in August.

The probable maximum flood (PMF) has been worked out at 15,540 cumec which corresponds to a frequency of 1 in 10,000 years and has been adopted as the design flood. The routed discharge for which spillway structures have been designed has been worked out to be about 13,100 cumec.

The Debate over the Tehri Dam

Opposition to the Tehri dam began in 1976 when the Anti-Tehri Dam Committee was formed by local opponents mainly in respect of the question of displacement, compensation and rehabilitation. The opposition on environmental grounds came in prominence in 1978 when a massive landslide dam-burst occurred in the upper catchment of the river producing devastating floods to some distance downstream of the dam site. A social activist, Mr. Sunderlal Bahuguna was the leader of this movement which led to the establishment of a governmental working group for the assessment of the environmental impact of the proposed dam.

The report of the governmental working group further stressed the issue of seismicity in the Himalayan region as a major factor to be considered for dam safety. In 1990 a more detailed investigation was undertaken by the Environmental Appraisal Committee (EAC) of the Ministry of Environment. Three important factors that were examined by the committee were: compensation and resettlement for the involuntarily displaced population, siltation and economic life of the dam, and the seismic risk associated with large dams in the tectonically active Himalayas. These factors are not specific to the Tehri dam alone and will apply equally in the case of any other large dam in the Himalayas. It may be added that the construction of large dams to store water to augment lean-period flow is a solution to many water related problems in the lower parts of Ganga Basin.

Intense public debate on the Tehri dam has centered around seismicity and dam safety in Himalayas. As expected, there was divergence in expert opinions on the seismicity issue which caused considerable confusion. While this debate over the desirability or otherwise of large dams in Himalayas has generated much controversy, it has also generated a wealth of literature. Anti-dam campaigners also tried to the sensationalize campaign by highlighting the scenario of a possible dambreak-generated flood that might wipe many districts of Western UP.

The opposition to the Tehri dam began on the question of displacement and compensation for the affected people and constructing a dam in earthquake prone Himalayan region (Valdiya 1991). But it grew beyond the resettlement and safety aspects and later ecological and environmental issues dominated the debate. A wide range of literature on the broad policy issues has been generated by the Tehri Dam debate (Bandyopadhyay, 1990) and some of this could be a rich information base for future projects. In this way, it can serve as a vital information base and important background for the evolution of overall policy guidelines for decision making on other big dams proposed in the Himalaya. Admittedly, some of the questions that have been raised in the Tehri dam debate are of vital significance in finding appropriate solutions to the question of optimal utilization of the Himalayan water resources on a sustainable basis and good governance.

The possibility of occurrence of an earthquake of magnitude 7.0 or higher on Richter Scale in the Himalayan region has been widely accepted. On the basis of the risk associated with possible damage from earthquakes, the wisdom behind the decision in favour of the construction of large dams in the Himalayas has been questioned by many. Debate has been going on for years about the adequacy of the design of the Tehri dam to sustain the dam against the maximum credible earthquake expected in the area. The occurrence of a major earthquake in 1991 in the upper catchment areas of the dam was a shot in the arms of the opponents. It may be added here that Tehri dam is an earth and rock fill dam and that such dams can withstand earthquakes of quite high magnitude. One may recall that the construction of the Sardar Sarovar dam was also disrupted by activists on many counts.

With the closure of tunnels in Oct. 2005, first filling of the reservoir commenced. Trial run of the turbines of the power house was conducted in March 2006.

Lakhwar Dam

The Lakhwar dam site is proposed on the Yamuna River at latitude 80° 31' 3" N and longitude, 77° 56' 58" E in the Dehradun district of Uttaranchal, about 2 km south-west of the Lakhwar village, which is about 28 km upstream of the Dak Pathar Barrage.

Initially in 1967 it was envisaged to construct a 176 m high concrete gravity dam at Lakhwar and an underground power house on the right bank of the river with an installed capacity of 158 MW. Along with this, another auxiliary project involving construction of 60 m high concrete gravity dam at Vyasi was also envisaged. But in December 1972 the proposal was modified and now the plan is to construct:

A 192 m high concrete cored gravity dam across the Yamuna River near the Lakhwar village by which a head of 169 m would be created. This head will be utilized by a powerhouse at the foot of the dam with an installed capacity of 300 MW. For the main dam, the deepest anticipated foundation level is at an elevation of 608 m, with top level at EL 800.00 m. The length of the dam at the top level of EL 800.00 m will be 450.0 m. The capacity of reservoir, behind Lakhwar dam, at full reservoir level of EL 796.00 m will to be 580×10⁶ cum.
An auxiliary cored concrete gravity dam, 5 km downstream of Lakhwar, at the Vyasi with a height of 58 m from its deepest foundation level. From this dam water will be conducted through twin power tunnels to a surface powerhouse at Hathiari with an installed capacity of 240 MW.
The discharge released from the Hathiari powerhouse will be balanced by a proposed barrage at Katapathar 2.25 km downstream of the Hathiari powerhouse.

The entire Lakhwar Vyasi Scheme is divided into two stages. The first stage involves the Lakhwar dam and the Lakhwar underground powerhouse, while the 2^ndstage involves the Vyasi dam, Hathiari powerhouse, and Katapathar barrage. The National Hydroelectric Power Corporation will be constructing the project. However, preparation of DPR for the project is stalled for want of consent of the Govt. of UP & NCT of Delhi to fund the irrigation & drinking water component of project, respectively.

Tapovan Vishnugarh Project

The Tapovan Vishnugarh Project is one of the Mega projects being constructed on the Dhauliganga River in the Chamoli district of Uttaranchal state. The construction work on this 520 MW project began in February 2005. The approximate cost of the project is 2,158 crore. After completion the project will generate 2,558.37 million units per year on 90% dependability. This project is being constructed by the National Thermal Power Corporation (NTPC).

Vishnuprayag hydroelectric project on Alaknanda River in Chamoli District of Uttranchal is a run-of-the-river consisting of a 63 m barrage and an underground powerhouse. This project is likely to commence power by the year 2007 and will generate about 200 crore units each year.

Ramganga Multipurpose Project

The Ramganga dam on the tributary by the same name has created a reservoir at Kalagarh with a live storage capacity of 2,190 million m³. The Ramganga dam is situated about 3 km upstream of the Kalagarh village, 45 km from Dhampur, Bijnor District, Uttar Pradesh. It is about 110 km to the North East of the Moradabad city. The exact location of the dam site is latitude 29º 31' 13" North and Longitude 78º 45' 35" East. Its construction began in 1961. The Ramganga project comprises a 127.5 m high earth dam, a power house, irrigation outlet system and a vast canal system. It is one of the first few high earth dams in India constructed close to areas prone to seismic activity. The dam has been constructed over weak rocks, having relatively complex geological features, in thickly wooded forests infested by wild animals. The valley where the dam exists is known by the name of Patli Dun. The catchment area at the dam is 3,134 km². The reservoir has a live storage capacity of 2,450 MCM at FRL 365.3 m and the MDDL is at 317 m.

Two earthen dams, one 125.6 m high on the main Ramganga River and the other 72.2 m high Saddle dam on one of its tributaries Chui Sot, comprise the Multipurpose Ramganga River Project. The Saddle dam is about 3 km away from the main dam on the North Eastern rim of the reservoir. The area is seismically active and falls in a seismic belt. A feeder channel takes off from the dam to provide extra supplies of water to the upper and lower Ganga canal and the Agra canal, besides direct irrigation. A total of 666,000 ha cropped area will be irrigated by this project.

The Ramganga Reservoir creates a lake submerging 55 sq. km in the famous Corbett National Park. The reservoir does not only add to the beauty of this famous wild life sanctuary but also helps in developing pisciculture and a bird sanctuary. Apart from these, the development of boating facilities, crocodile pockets and the project area provides an attraction to the tourists. The project is located in industrially undeveloped area of Pauri Garhwal and has provided a great impetus to its economic and social development. The life of the reservoir has been estimated as 100 years and the design sedimentation rate is 4.25 ha-m/100 sq. km/year.

The multipurpose project has brought in additional benefits of flood control and power generation. The existing resources of power in western U.P. are the hydroelectric power stations located on falls on the Upper Ganga and Sarda Canals and a few thermal stations. The major power projects included in the third five-year plan were the 90 M.W. thermal station at Harduaganj and Yamuna Hydro Electric scheme stage I and II. The existing Ganga, Sarda and the Yamuna power stations have to depend on river supplies, there being no storage reservoirs.

The water available for utilization from the Ramganga reservoir is estimated to be 0.215 M ha-m annually. With this water, 5.75 lakh hectares of additional land can be brought under irrigation by means of a network of canals. This added irrigation has improved agriculture in 14 districts of U.P. and three lakh tons of additional food grains are being produced annually. It has provided substantial flood protection to the districts of Moradabad, Rampur, Bareilly, Shahjahanpur, Bijnor and Farrukhabad.

The Ramganga Project has provided irrigation to new areas and has increased the firm power available in the combined Ganga-Sarda-Yamuna Ramganga grid. A powerhouse with an installed capacity of 198 MW comprising 3 units of 66 MW each is located at the toe of the dam. With mean annual inflow of 2,683 MCM, the project has a firm power of 38 MW. Ramganga power house, in conjunction with the existing Ganga-Sarda grid, the Yamuna stage I and II and existing thermal power station, is expected to increase the firm power of the grid by 82.25 MW. The Ramganga powerhouse output is nearly 450 million units of power per year.

Irrigation outlets have also been provided for emergency when the powerhouse is not functioning and irrigation demands have to be met. The water released from the powerhouse flows down the Ramganga for 25.6 km. It is diverted into a feeder channel at Harevelli where a 416.3 m long barrage has been constructed across the Ramganga River. The river and the barrage allow for the balancing of daily fluctuation of load as the Ramganga power House is mainly as a peaking station. The Feeder Channel, with a full supply discharge of 135 cumec, is 74 km long and discharges into the Ganga River opposite Garhmukteshwar. The augmented supplies of the Ganga River are picked up at Narora in the Bulandshahar district and utilized for the Lower Ganga Canal.

The Ramganga River used to cause flood havoc in the past in the districts of Moradabad, Bijnor, Rampur, Bareilly, Shahjahanpur and Farrukhabad, during monsoons. Due to the storage of river water in the Ramganga Reservoir, the flood havoc has been eliminated in most of the years. In addition to direct advantages 5.5 cumec water would also be supplied to Delhi to overcome the shortage of drinking water supply.

PROJECTS IN THE VICINITY OF DEHRADUN

A number of medium and small projects have been constructed in the region around Dehradun.

Dhalipur Hydropower Plant

Dhalipur hydropower plant is located on Yamuna River, 5 km from Herbertpur, in Dehradun District, Uttaranchal. The project utilizes tail water of upstream Dhakrani power house which uses Yamuna waters diverted by Dak Patthar barrage into Dakrani power channel. The rate of inflow is 198.24 m³/s. The power house has 3 units of 17 MW each. It has a firm power of 39 MW. This project was commissioned in 1965-70.

Giri Diversion Project

Giri is a diversion project on Giri River, tributary of Yamuna River, located 25 km from Paonta Sahib in Sirmaur district in Himachal Pradesh. The barrage is 163 m long. Commissioned in 1978, Giri power house has 2 units of 30 MW each.

Chibro Hydropower Project

Chibro hydropower project is located near Ichari diversion dam on Tons River, a tributary of Yamuna, 67 km from Dehradun, in Dehradun District, Uttaranchal. The catchment area at the dam is 4,890 km². The height and length of the dam is 59.25 m and 155 m respectively. It has a small pond of live storage capacity of 5.11 MCM. The power house has 4 units of 60 MW each and produces a firm power of 98 MW.

Khodri Power House

Downstream to Chibro is the Khodri power house, 52 km from Dehradun, in Dehradun District, Uttaranchal. The project uses the tail water of Chibro powerhouse (5.6 km upstream) for power generation. Khodri powerhouse has 4 units of 30 MW each and is able to generate a firm power of 51.5 MW. This project was commissioned in 1984.

Chilla Hydropower Project

Chilla hydropower project is located downstream of Pashulok diversion barrage on Ganga River, 4 km from Haridwar, in Dehradun District. The catchment area at the Pashulok barrage is 21,400 km². The maximum and minimum pond level is 336.5 m and 333.15 m respectively. The barrage is designed for a designed flood of 13,200 m³/s. The power house has 4 units of 36 MW each and a firm power of 143 MW. This project was commissioned in 1980-81.

Khara Hydropower House

Khara hydropower house is located on Ahsan River, tributary of Yamuna River, 50 km from Saharanpur, in Saharanpur District, Uttar Pradesh. The hydropower project utilizes tail water of upstream Kulhal on Asan River. The mean rate of inflow here is 186 m³/s. The power house with 3 units of 24 MW each and has a firm power of 62 MW was commissioned in 1992.

Maneri Bhali-I Hydropower Project

Maneri Bhali I hydropower project comprises of 39 m high and 127 m long Maneri diversion dam on Bhagirathi River, 150 km from Rishikesh, in Uttarkashi District, Uttaranchal. The catchment area at the dam is 4,024 km². The project was completed in 1984. A small reservoir with live storage capacity of 0.60 MCM has been created behind the dam. The power house has 3 units of 30 MW each which produce a firm power of 42 MW.

Tanakpur Barrage

Tanakpur Barrage was constructed in 1992 on Sarda River, a tributary of Ghaghara which in turn is a tributary of Ganga. The powerhouse is 12 km away from Tanakpur in Udhamsingh Nagar District, Uttaranchal. Tanakpur barrage is 475.30 m long and its design flood is 19,824 m³/s. The pond level of the barrage is 246.7 m. Tanakpur power house has 3 units of 40 MW each. It has a firm power of 53 MW.

Kishau Dam

Kishau dam is proposed on the Tons River, a tributary of the Yamuna River, at about 95 km from Dehradun. A concrete gravity dam about 236 meters high will be constructed at this place. The total extra electric power generated will be to the tune of 1,688.19 x 10⁶. On completion of the project, 1.015 maf of irrigation water will be available, out of this only 0.515 maf will be utilized by the Eastern Yamuna Canal to irrigate 97,076 ha of extra land and the rest of 0.500 maf will be made available for drinking water to Delhi State.

The cost has been estimated to be about Rs. 35,662 million (December 1998 price level). A provision of 372 MGD (about 1.7 million cubic m/day) has been earmarked for Delhi's use from the storage of this dam.

Jamrani Multipurpose Dam Project

This dam is situated about 10 km from Kathgodam. The proposed dam is 130.6 m high roller compact concrete structure. In the first phase a barrage on the Gola River and a Feeder Channel and rejuvenation of the existing canal system is proposed. After completion, 89,702 hectares land will be irrigated, 52.93 million m³ drinking water and in future 15 MW hydro-electric power house is proposed.

Rihand Dam

The Rihand Dam was constructed on the Rihand River in the Sonbhadra district of Uttar Pradesh in the year 1962. The objective of the project was to provide water mainly for generation of hydropower necessary for speedy development of agriculture and industry in the backward areas of Eastern and South- Eastern parts of the State of Uttar Pradesh.

The river above the dam site drains an area of 13,333 sq. km and has a length of 257.50 km. The stream slopes down from an elevation of about 915.50 m in the upper valley to 190.5 m at the dam site. The region is hilly and is covered with vegetation. At Chopan in the Sonbhadra district (U.P.), the Rihand River joins the Sone River.

The Rihand dam is located at a latitude of 24˚ 12’ 30” N and a longitude of 83˚ 03’ E. It comprises a 90 m high and 934.2 m long concrete gravity dam near the Pipri village. The dam impounds 10608.32 million cubic meters (Mm³) of water at the full reservoir level (FRL) of 268.22 m. A powerhouse with 6 units of 50 MW each is also constructed at the toe of the dam on the right bank of the river to provide a firm power of 105 MW with a total annual power output of 912 million units.

The reservoir can attain an MWL of 271.52 m during the passage of PMF of 13,339 cumec. The reservoir has a dead storage of 1,628.38 Mm³ below R.L. 236.22 m and a live storage of 8,979.94 Mm³ between R.L. 236.22 m and the FRL. Its water spread area is 469.40 sq. km at FRL which lies in both Uttar Pradesh (347 sq. km) and Madhya Pradesh (122 sq. km).

The average annual rainfall in the Rihand basin is 1,422 mm while the average annual runoff is 475 mm. The Rihand River experiences heavy floods during the monsoon season and has little discharge during the remaining part of the year. The maximum and minimum runoffs have been estimated to be 8,993 Mm³and 3,503 Mm³, respectively, the average annual runoff being 6,328.47 Mm³.

Although the original project envisaged generation of only hydroelectric power, these days the reservoir water is used mainly for the generation of thermal power as the coal is available in adjacent areas. The following thermal power stations have been installed at the periphery of the reservoir:

Anpara Super Thermal Power House of 2,000 MW,
Renu Sagar Power Station of 600 MW,
Shakti Nagar Super Thermal Power Station of 2,000 MW,
Vindhya Nagar Super Thermal Power Station of 2,000 MW, and
Rihand Nagar Super Thermal Power Station of 1,000 MW.

The reservoir is encroached upon by construction of several ash dykes and other structures near its periphery. Consequently, the capacity of the reservoir has reduced by 44.7 Mm³. Thus, the net original capacity of 10,563.62 Mm³ and the net live storage capacity of 8,979.94 Mm³ is available for regulation of water. The reservoir could be filled up to FRL only in the years 1964, 1971 and 1995 and it was well below FRL during the rest of the years. Consequent upon installation of several thermal power stations around the periphery, the reservoir level is now not allowed to fall below 252.98 m. Therefore, the new dead storage level is 252.98 m.

The provision of dead storage in the reservoir is made considering the sedimentation in 140 years of its operation. During this period, the live storage was expected to reduce from 8,979.94 Mm³ to 8,185.49 Mm³. However, the capacity survey of the reservoir carried out before the monsoon of 1995 indicates that the sediment deposition has reduced the live storage to 8,009.94 Mm³ in only 33 years of operation. This gives a sedimentation rate of 2,918 m³/sq. km/year against the assumed value of 904 m³/sq. km/year. The large difference in the assumed and the estimated rates is partly attributed to inaccuracies in the original capacity surveys.

Rakghat Dam Project

Rajghat dam in Bundelkhand region provides irrigation facilities for area in Uttar Pradesh and Madhya Pradesh States. The financial burden will be borne by both states under the central command of the Betwa River Board. This project has been cleared by the Central Government. The canal network is proposed to be borne by individual state governments. The pump canal system of the Betwa, Gurshahai, and Bargaon is being considered.

Halali Dam

The Halali dam, also known as Samrat Ashok Sagar project, was constructed across the Halali River which is a tributary of the Betwa River. The dam site is located both in the Raisen and Vidisha districts of Madhya Pradesh, 40 km away from Bhopal and 16 km away from the Salamatpur railway station. The Halali River rises around Bhopal at an altitude of about 487.68 m above msl and joins the Betwa near Vidisha. After flowing for a length of about 38 km NE, it enters a narrow gorge with high hills on both sides. The dam has been constructed at this gorge at 23° 30' N latitude and 77° 30' E longitude. The rock at the dam site belongs to Upper Vindhyans and consists of massive to current bedded, course grained sand stone, grits, conglomerates together with minor bands of shales and pockets of soft friable sand rock.

Halali is a rolled-filled earthen dam, 945m long with a maximum height of 29.57m above the foundation level. The catchment area of the project is 699 sq. km with a maximum rainfall in the area as 1680 mm and the average rainfall of 1,108 mm. About 25% of the catchment area is hilly and the rest is in plains. The project envisages a gross command area of 374.19 sq km with CCA as 279.24 sq km. The intensity of irrigation in the command is 135%. The design rate of sedimentation is 0.476 mm / year for gross storage. The top bund level of the reservoir is fixed at 466.32 m and MWL is fixed at 464.19 m. The water spread at FRL is 52.59 sq. km. The width of the earthen dam at its top is 4.57 m. Additional spillway with a 41.15m length is provided at RL 459.61 m.

Gamdhisagar Dam

Three important storage reservoirs constructed in the basin include Gandhisagar, Jawaharsagar and Rana Pratapsagar cascade which provide a live storage of 8,500 million cubic m. The barrage at Kota diverts water into canals on either side, irrigating a total of 0.57 million ha agriculture area.

Gandhisagar is the main storage dam constructed across the Chambal River, intercepting a catchment area of about 23,025 sq. km. The dam serves as a backup storage for power generation in the Gandhisagar, Rana Pratapsagar and Jawaharsagar dams and irrigation through canal systems taking off from the Kota Barrage. The dam is 64.63 m high, straight gravity masonry type with an installed capacity of 115 MW and an irrigation potential of 7.57 lakh ha.

The Gandhisagar is the upper most dam in the series of three dams and a barrage of the Chambal Valley Project.

Catchment area intercepted up to various structures

Name of Structures	Catchment area (sq. km)
Gandhisagar Dam	23,025
Between Gandhisagar & Ranapratap Sagar Dam	2,103
Between Ranapratap Sagar Dam & Jawahar Sagar Dam	2,054
Between Jawahar Sagar Dam & Kota Barrage	137
Total	27,319

The live and dead reservoir storages provided for at planning stage were 6,910 Mm³ and 836 Mm³, respectively with a gross storage of 7,746 Mm³. The original reservoir submergence area at FRL was 680 sq. km.

The Gandhisagar dam was constructed in 1960 as a 64.63 m high straight gravity masonry dam 514 m long with a 182.93 m central spillway and five power blocks on its right along with non-overflow blocks at both flanks. The installed hydropower capacity is 115 MW and the irrigation potential created is 7.57 lakh ha. The dam is located at a latitude of 24^o44’ N, longitude of 75^o33’E, 8 km north-east of Bhanpura. The spillway section consists of 10 spans each of 18.3 m length and 9 sluice piers 7.927 m wide, accommodating 9 sluices of 3.05m x 7.62m each with their sill level at 363.872 m and steel crest gates 18.3m x 8.54m with crest at 391.46m. The discharging capacity of the spillway is 13,705 cumec at MWL. At the foot of the power intake is the power house which has five generating units. The gross storage capacity of the reservoir was assessed as 7,746 MCM at the time of first impounding.

The Full Reservoir Level (FRL) and the Maximum Water Level (MWL) of the dam is 400 m, and the Dead Storage Level (DSL) is 381.0 m. Sedimentation surveys were conducted in the reservoir area in 1975 and 1989. Surveys conducted in 1975 indicated a reduction of the gross capacity by 333 MCM over a period of 15 years. Those conducted in 1989 indicated a further reduction of 419 MCM in the gross storage.

A hydrographic survey using modern equipment was conducted during March-October, 2001 up to the maximum water level. The rate of sedimentation adopted at the project planning stage was 3.6308 ham/100 sq. km/year. However, the average rate of sedimentation during the first 41 years, on the basis of 2001 survey, works out to 5,508 ham/100 sq. km/year. The anticipated feasible life of the reservoir works out to be 125 years, as against the planning stage stipulation of 100 years.

The gross storage capacity of Gandhisagar dam was assessed from toposheets at the planning stage as 8450 M cu m, with full reservoir at 400 m. Subsequently, based on aerial photographs and contour surveys, the gross storage was refixed at 7,746 M cu m. In all subsequent publications, this value is considered as original gross capacity. The surveys conducted from time to time have indicated a progressive reduction of the storage capacity.

Storage in the Gandhisagar dam on various dates

	Project Planning Stage	1960-61 Reassessment	1975 Resurvey	1989 survey
Gross Storage at FRL	8,450 MCM	7,746 MCM	7,413 MCM	7,323 MCM
Live Storage	7,620 MCM	6,910 MCM	6,827 MCM	6,798 MCM
Dead Storage	830 MCM	836 MCM	586 MCM	525 MCM

Rana Pratap Sagar Dam

Rana Pratap Sagar is a masonry gravity dam on Chambal River, 54 km from Kota, in Chittaurgarh District, Rajasthan. The catchment area at the dam is 24,576 km². The height and length of the dam is 38.3 m and 1,143 m respectively. The reservoir has a live storage capacity of 2,899.5 MCM at FRL 352.9 m and the MDDL is at 343 m. The power house has 4 units of 43 MW each, producing a firm power of 54 MW with mean annual inflow of 49,538 MCM. RRVPN Ltd. commissioned the project in 1968-69.

Jawahar Sagar Dam

Jawahar Sagar is a straight gravity concrete dam on Chambal downstream of Rana Pratap Sagar, 36 km from Kota, in Kota District, Rajasthan. The catchment area at the dam is 26,880 km². The height and length of the dam is 37 m and 336 m respectively. This reservoir has a live storage capacity of 7.40 MCM. Its FRL is at 298.78 m and MDDL is at 295.78 m. With 3 units of 33 MW each, the power house produces a firm power of 32 MW. This project was completed in 1972-73.

Chanbal Valley Project

The Chambal Valley Project would provide water for both irrigation and industrial purposes in the south eastern part of the State, primarily in the districts of Kota, Baran, Bundi and Sawaimadhopur. Three dams and a barrage on the Chambal River have been created with a canal network in Rajasthan & Madhya Pradesh. The project will irrigate approximately 5 lakh ha.

Salient features of Chambal Canal System

Name of canal	Length (km)	Design/head discharge	CCA (ha)	Design irrigated area (ha)	Tehsil
Right main canal	179	110.40	68,400	47,800	Shopepur & Vijapur
Lower main canal	53	53.80	29,200	20,300	Sabalgarh & Joura
Ambah branch canal	171	35.40	132,100	92,500	Sabalgarh, Joura, Ambah & Bhind
Morena branch canal	38	14.20	48,600	34,100	Morena
Asan outfall canal	3	41.00	-	-	-
Bhind main canal	82	35.70	96,200	60,700	Gohad, Bhind & Mehgaon
Mau branch canal	48	9.90	40,100	28,100	Gohad

Obra Dam

Obra is an earth and rockfill dam constructed across Rihand River, 33 km from Robertsganj, Uttar Pradesh. The catchment area at the dam is 546.5 km². The height and length of the dam is 29 m and 2000 m, respectively. Commissioned in 1970-71, the Obra powerhouse has 3 units of 33 MW each and has a firm power of 21 MW.

Bansagar Tons

Bansagar Tons hydropower project is located on Beehar barrage on Tons River and Beehar River, tributaries of Yamuna, 50 km from Rewa, in Rewa District, Madhya Pradesh. The catchment area at the Bansagar dam is 8,648 km², at Tons bridge is 4,457 km², and at Beehar Bridge is 1,637 km² respectively. The height and length of the Beehar barrage is 9.1 m and 138 m respectively. The maximum and minimum pond levels of the barrage are 180 m and 277 m respectively. The power house has 3 units of 105 MW each. It has a firm power of 35 MW with mean annual inflow of 2,100 MCM and 700 MCM at tons bridge and Beehar Bridge respectively. MPEB commissioned the project in 1991-92.

Bansagar Tons II and III

Bansagar Masonary gravity dam on Sone River in Rewa District, Madhya Pradesh. At the dam site, the catchment area is 18,648 km². The height of the dam is 63 m and the live storage capacity of the reservoir is 5,410 MCM at FRL 341.65. Corresponding to a 90% dependable year, the annual inflow of the dam is 4,840 MCM. Bansagar Tons II and III powerhouses are located at a distance of 8 km and 70 km from Rewa. The Bansagar Tons II power house has 2 units of 15 MW and Bansagar Tons III has 3 units of 20 MW each. Bansagar Tons II and Bansagar Tons III projects have initial phase firm power of 12.9 and 16.4 MW and final phase firm power of 3.3 and 13.3 MW respectively. MPEB commissioned the project in 2001-02.

Parbati Dam

The Parbati dam is situated across Parbati River in the Chambal basin in the Baseri tehsil in the Dhaulpur district of Rajasthan. It is located nearly 50 km away from the district headquarters and almost 15 km from Bari town. Figure 3 shows the location map of Parbati project. The geographic coordinates of dam are 26°37'36" N latitude and 77°26'52" E longitude. The area experiences extreme temperature variation with minimum and maximum temperatures as 1 ° C to 49° C, respectively. The average annual rainfall in the area is nearly 67 cm. Farmers in the area grow wheat, gram, barley, pulses, bajra, etc. The forest in the area falls under the dry deciduous variety. Physiographically, the area is characterized by a dissected plateau and alluvial plain region. The geological sequence of the area forms part of vindhyan supergroup, which is essentially made up of sedimentary rocks including sandstones, shales and limestones.

The catchment and gross command area (GCA) of the Parbati project are approximately 780 sq. km and 325 sq. km, respectively. The project has a live storage capacity of 102.893 MCM as per the hydrographic survey carried out during the impounding year 1963. The length of the main canal is 58 km. The project command is restricted to main course on its southern side. The design rate of sedimentation is 0.157 mm/year.

Matatila Reservoir

Matatila dam was constructed in the year 1956 across Betwa River, a tributary of the Yamuna River. The dam lies at 25° 6’ 15” N latitude and 78° 23’ 00” E longitude. It is located in Lalitpur tehsil of Matatila district, Uttar Pradesh, at about 56 km from Jhansi.

Matatila is an earthern dam 6.6 km long with masonary spillway of ogee shape. The height of the dam is 24.40 m. It has 23 vertical lifting gates and 4 sluices. The dam has a live storage capacity of 1,019.40 MCM and dead storage capacity of 113.30 MCM. The total capacity of the reservoir at FRL 308.46 m is 1,132.70 MCM with a water spread area of 142.43 m². It is a multipurpose dam which provides facilities for irrigation, water supply and fish cultivation.

Ramsagar Dam

The Ramsagar dam is situated across the Bamani River, a tributary of the Ramsagar River (which is a tributary of the Chambal River) in Bari tehsil, the Dhaulpur district of Rajasthan. It is located nearly 40 km away from the district headquarters and almost 8 km from the Bari town. The geographic coordinates of the dam are 26° 35' N latitude and 77° 35' E longitude. The area experiences extreme temperature variations with minimum and maximum temperatures as 1° C to 49° C, respectively. The average annual rainfall in the area is nearly 67 cm. Major crops in the area are wheat, gram, barley, pulses, bajra, etc. The forest in the area falls under the dry deciduous variety. Physiographically, the area is characterized by a dissected plateau and alluvial plain region. The geological sequences of the area are part of Vindhyan supergroup, which is essentially made up of sedimentary rocks, including sandstones, shales and limestones.

The catchment and gross command area (GCA) of the Ramsagar project are approximately 176 sq. km and 62 sq. km, respectively. The project has a gross and live storage capacity of 30.83 and 29.39 MCM, respectively as per the hydrographic survey carried out during year 1905, which is the impounding year. The length of the main canal is 11.27 km. The design rate of sedimentation is 0.81 mm/year.

Massanjore Reservoir

The Massanjore reservoir is located on the Mayurakshi River upstream of the confluence of Sidheswari with Mayurakshi. The total length of the Mayurakshi River up to the dam site is 70 km from its origin, out of which 43% lies in the reservoir waterspread area. The reservoir was created in 1954 by the construction of a stone masonry dam at Massanjore in the Santhal Parganas in the district of Bihar about 24 km from the West Bengal border to irrigate the lands in West Bengal and Bihar and to generate 4,000 kW of hydro power. The lake extends over 30 km upstream in the Bihar State. The 1,859.62 sq. km catchment of the river above the dam is leaf shaped with no appreciable vegetal cover. Rolling and undulating in nature with scattered hillocks the catchment comprises various types of lands.

Forests constitute only 6% of the catchment area. The vegetation is generally limited to hill tops and slopes. About 44% of the catchment area comprises lands under paddy cultivation.

Dhauliganga Power Project

The Dhauliganga project has been constructed in the Pithoragarh district of the Uttaranchal state. Under this project a 56 m high concrete dam on the Dhauliganga River, a 750 m long diversion tunnel, and a 5.3 km long head race tunnel have been constructed. The total installed power capacity of the underground power house is 280 MW (4*70 MW). Constructed by the National Hydropower Corporation (NHPC), this project has started generation of electricity in 2006. This hydropower project will generate 1,134 million units of electricity each year. The beneficiary states of this project are Delhi, Punjab, Himachal Pradesh, Rajasthan, Chandigarh, Uttaranchal, Uttar Pradesh, and Jammu and Kashmir. The estimated cost of the project is Rs. 1,578 crore.

The DVC System

To control the Damodar River, the Damodar Valley Corporation (DVC) was set up in 1948. Construction work on four dams at Tilaiya, Konar, Maithon and Panchet was completed in 1953, 1955, 1957 and 1959, respectively. Along with these, a barrage at Durgapur was completed in 1958. One more dam was constructed at Tenughat at a later date. First four reservoirs, viz., Maithon, Panchet, Konar and Tilaiya, come under the purview of the Damodar Valley Corporation (DVC), whereas the Tenughat reservoir is being operated by the Bihar Government. The operation of the Durgapur barrage is being controlled by the Government of West Bengal. Further, the Central Water Commission has the responsibility to operate the Maithon and Panchet reservoirs. These dams are being operated for flood control, municipal and industrial water supply, irrigation, and power generation.

i. Tilaiya Reservoir

The Tilaiya dam is located in the upper reaches of the Barakar River about 64.4 km downstream of its source. The river at this site passes through a narrow gorge approximately 91.4 m wide with banks steeply rising about 45.7 m on either side. The dam was completed in 1952. Barakar River rising from the hilly forests of the Hazaribagh district at an elevation of 610 m has a catchment area of 984 km², comprising mainly forests, pastures, cultivated lands and wastelands. The annual rainfall in the area is 127 cm. The reservoir has a water spread area of 5,921 ha at FRL with a volume and mean depth of 394 MCM and 6.65 m respectively.

The Talaiya dam is a concrete gravity dam with a maximum height of 30.2 m above the river bed. The spillway has 14 tainter type crest gates of 3.05 m * 9.1 m, with a maximum discharge capacity of 3,852 cumec. Two modified butterfly type undersluice gates 1 m high and 1.7 m wide with a discharge capacity of 14.2 cumec are provided in the body of the dam mainly to supply irrigation water during dry season. The power house is 41.5 m long 19.5 m wide and 22.6 m high and is located on the left bank of the river. It consists of two of generating units of 2 MW capacity each with a provision for a third future unit of the same capacity.

ii. Konar Reservoir

Completed in 1955 on a river with the same name, the Konar reservoir is located on the Konar River, a seasonal tributary of the Damodar River, about 30.6 km from its confluence with Damodar River in the district of Hazaribagh in Bihar. This dam was the second of the four dams which was completed in the first phase of development of DVC. The dam is primarily responsible for flood control and to supply cooling water to Bokaro thermal power station in the downstream.

The Konar earth and concrete dam has a catchment area of 997 km² which comprises thick jungles, wastelands and cultivated areas. The total length of the dam was 4.00 km with earthern embankment flanked on either side of the concrete structure. At FRL, the reservoir has a capacity of 336.16 million m³ and a mean depth of 12.97 m. In the basin of the Konar reservoir, the main soil is sandy loam to clay with 0.3 to 0.9% of organic carbon.

The spillway was provided with 9 tainter crest gated each of 10.4 m * 9.9 m. Two 2.3 m dia. undersluices were embedded in the body of the dam. The spillway has a maximum capacity of 6,792 cumec. Two power stations with a total capacity of 35 MW have been proposed.

iii. Maithon Reservoir

The Maithon dam is a concrete cum earthen dam located on Barakar River at a distance of 26 km from Asansol in Bardhaman District, West Bengal. The dam was constructed for flood conrol, irrigation and power generation. This reservoir came into being in 1957. At the dam site, the catchment area is 6,249 sq. km. The average annual basin precipitation is 114 cm and the average annual run off is 2,616 million cubic m. In the basin, and the maximum observed flood (June 1949) was 7085 cumec. For the project, the spillway design flood is 14,736 cumec. The live storage capacity at the dam is 566 MCM at FRL 152.4 m and the MDDL is at 132.5 m. For generation of hydropower, 3 units of 20 MW each have been installed. It has a firm power of 16 MW with mean annual inflow of 2,615 MCM.

Salient features of the Maithon Reservoir

	Elevation (meters)	Storage (Million cu m)
Minimum draw down level	132.62	165.30
Spillway crest	140.24	397.29
Maximum conservation pool	146.35	738.59
Maximum flood control pool	150.91	1,120.30
Full and maximum pool	152.44	1275.77
Top of dam	156.09

It can be seen that a separate storage is earmarked at the Maithon dam for flood control storage amounting to 539.39 million cu m (between EL 146.34 m to 152.44 m. The land has been acquired up to RL 150.91 m.

iv. Panchet Dam

The Panchet dam, an earthen dam with concrete spillway, was commissioned in 1958 on the Damodar River located at a distance of 20 km from Asansol in Jharkhand. The height and length of the dam are 47.85 m and 2,345 m respectively. The reservoir traps a catchment area of 10,961 sq. km. The average annual basin precipitation is 114 cm and the average annual run off is 4,540 million cubic m. At the dam site, the maximum observed flood (June 1949) was 8,558 cumec. For the project, the spillway design flood that was adopted was 17,853 cumec. Two units of 40 MW have been installed at the powerhouse for generation of hydropower.

Salient features of Panchet Reservoir

	Elevation (m)	Storage (Million cu m)
Minimum draw down level	119.50	170.26
Spillway crest	123.47	312.15
Maximum conservation pool	125.00	392.36
Maximum flood control pool	132.62	1,058.62
Full and maximum pool	135.67	1,475.65
Top of dam	139.33

At the Panchet dam also, flood control storage amounting to 1,083 million cubic m (between EL 125.0 m to 135.67 m) has been earmarked. The land acquisition has been made up to RL 129.57 m. Houses have been acquired up to RL 132.62 m at the Panchet.

Operation guidelines of the Maithon and Panchet Dams

The conservation storage level for the Maithon and the Panchet is 146.34 m and 125 m, respectively. The operation of the reservoirs during monsoon season below the conservation storage (i.e., 146.34 m and 125 m) consists in releases to meet the downstream requirements. The operation curves guide the flows such that on the first of October, the reservoir will be at the monsoon storage level of 146.34 m for the Maithon and 125 m for the Panchet. When the reservoir level rises or shows a tendency to rise above 146.34 m and 125 m for the Maithon and the Panchet reservoirs, flood control operation commences and they shall cease as soon as the level comes down to RL 146.34 m and 125 m.

As regards the operation of the Panchet reservoir, the reservoir may be drawn down to EL 119.51 m to meet the power requirements in June, when the monsoon flows arrive in June the reservoir will be, if at a lower level, allowed to build up to RL 121.95 m as quickly as possible after allowing releases for the essential downstream and power requirements.

On the 1^st of July, the Panchet reservoir is to be kept as near to RL 121.5 m as possible for ensuring generation of hydro-electric power. The reservoir level shall be kept between curves A & B during July, August and closer to curve A during September and as far as possible at the monsoon storage level RL 125 m during October.

Guidelines for releases from the Maithon and Panchet dams taken together for flood control operations during June, July, August and September are:

Limit the combined outflow to the safe limit indicated by the West Bengal, except that the outflow shall not be less than the actual inflow or 1,983.7 cumec (70,000 cusecs) whichever is less, till 20% of the combined flood reserve is used up.
Limit the combined outflow to 3,400 cumec (120,000 cusec) while using the combined flood reserve between 20% to 50%.
Limit the combined outflow to 4,534 cumec (160,000 cusec) while using the combined flood reserve between 50% to 70%.
Limit the combined outflow to 5,668 cumec (200,000 cusec) while using the combined flood reserve between 70% to 100%.
Balance outflow with inflow when all available combined flood reserve is used up, when the Maithon and Panchet reaches 150.91 m and 132.92 m, respectively, and the combined inflow is more than 5,667 cumec (200,000 cusec).

Emergency operation

Flood starts when 50% of the flood reserve is occupied.
Between 50% to 70% occupation, the inflow and outflow is balanced up to a maximum of 4,534 cumec (160,000 cusec).
Between 70% to 100% occupation, half inflow is released subject to a maximum of 7,085 cumec (250,000 cusec) and a minimum of 5,668 cumec (200,000 cusec).
At 100% occupation balance the outflow with inflow.

Dry weather operation: The water available from monsoon storage and dry season flows are utilized for meeting the committed requirements of Kharif, Rabi, Industrial and drinking water and hydro-electric power requirements.

Allocation of surplus, if any, after meeting the committed requirements will be made in November, the surplus water will be allocated for irrigating Bore paddy (Jan 21 to April 30), hydro-electric power and other requirements and a working table is prepared on the basis of allocation of waters for different uses. The reservoir is operated as per the working table.

Farakka Barrage

Farakka is a gauging site very close to the India-Bangladesh border. At Farakka the river has a stable cross-section with a long history of monitoring. In Figure 8.6 information on the annual volume of water flow of the Ganga is shown. The hydrograph does not show any trend in the hydrological characteristics of the Ganga from 1950 to 1985. The annual fluctuation is extremely high, but there is no obvious change over the recorded time period.

Near the Indo-Bangladesh border, a barrage has been constructed at Farakka to divert water to the river Hooghly to increase and maintain adequate depths of flow for navigation and operation of Calcutta port. Farakka barrage was completed in 1975.

OTHER PROJECTS

In addition to the above there are several other reservoirs in the basin. Some other important projects on the tributaries of the Ganga include Sarda sagar on the Sarda, and Mayurakshi on the Mayurakshi River. A brief description of a few follows.

Baigul Reservoir

Baigul (Sukhi) is a small tributary of the Ganga originating from the foothills of Kumaon Himalayas. In the year 1967, the river was harnessed for irrigation purposes to form the Baigul reservoir. The dam is located at 28°56' N and 79°40' E, and provided with four gates and two sluices for outflow. The catchment area of dam is 305 km², comprising of wooded forests and fields. The reservoir has an area of 2,995 ha at FRL of 211 m above MSL. The maximum spillway discharge amounts 566 m³/s.

Baghla Reservoir

Baghla reservoir is a small irrigation impoundment, created on the rivulet Barica in 1952. Situated at a distance of 55 km southwest of Allahabad, the reservoir covers 250 ha at the FRL of 119 m above MSL. The water retention capacity is 9.58 million m³ at FRL and 0.141 million m³ at DSL. Catchment comprises 32 km² of hilly land, receiving a rainfall of 100 cm.

Renuka Dam

This is a proposed project in Himachal Pradesh. The expected total cost of the project is Rs.1,224.64 crore. A provision of 275 MGD (about 1.25 million cubic m/day) has been earmarked for Delhi's use in the proposed Renuka Dam project.

Kosi Project

Kosi is one of the highly silt-laden rivers in the world. The resultant lateral migration of Kosi has caused considerable misery in Bihar and because of this, it came to be known as Bihar's 'river of sorrow'. There was considerable pressure in India to control the Kosi River, especially after a major flood in 1954. As a response, a Kosi river barrage was built below Chatra in Nepal, along with a pair of embankments to confine the Kosi to its existing course. The Kosi embankments were completed in 1959 and the barrage in 1963. The cost of the barrage and the associated works were borne by India. Nepal received about 10 MW of power, some flood protection and a bridge over the barrage which facilitated east-west communications in that part of Nepal.

The Kosi, the Karnali and the Pancheshwar projects are three mega projects which have received a lot of attention and discussion over the past three decades. Of these, the Kosi high dam is the oldest project, which was proposed by the Government of India in 1950s. The project was originally proposed to have a 239 m high dam at Barakshetra in Nepal, and a downstream barrage at Chatra, also in Nepal. The 850,000 ha-m storage has considerable flood attenuation capacity, reducing a peak flow of 24,050 m³/s to 5,660 m3/s, thereby providing substantial flood control benefit. The project would generate 1,800 MW of power and irrigate large tracts of land in Nepal and Bihar.

Karnali Dam

The original Karnali dam proposal suggested a height of 240 m for the dam and a power potential of 4,500 MW. The Himalayan Hydro Development Company (HHDC) in 1988 proposed raising the height of the dam to 262 m so that the power potential might be increased from 4,500 MW to 10,000 MW. Another suggestion by HHDC is to phase the Karnali Project with an upstream run-of-the-river hydroelectic project and storage development on the Bheri and Seti rivers, which are tributaries of the Karnali. These supplements to the Karnali Project would generate an additional 5,400 MW of electricity. The 1988 cost of the Karnali Project was estimated at about US$ 4.4 billion; 95% of the power generated by the Karnali Project is to be exported to India.

Pancheshwar Project

The Pancheshwar project on the Mahakali River is of interest to both India and Nepal. The Mahakali River is a western boundary river between India and Nepal. The project can generate 2,000 MW and provide Irrigation benefits. India has completed the Investigation of the Pancheshwar site on its side of the border and wants the project to move ahead fast. However, Nepal is still investigating the conditions on its side of the border. Between the two, Karnali will be a completely Nepalese project and the Pancheshwar a joint project between India and Nepal.

Gandak Project

The Gandak Project was designed to irrigate 0.96 million ha in nine districts of Bihar, 56,650 ha in Nepal, some area in Uttar Pradesh and supply 15 MW of hydroelectric power to Nepal. This project was commissioned in 1971 and was declared complete in 1985. This project was also fully financed by the Government of India.

The Sarda canal provides protective irrigation to nearly 0.6 million ha area. Some other major projects under construction are Rajghat on the Betwa, Bansagar on the Sone and Lakhwar-Vyasi on the Yamuna. The National Hydroelectric Power Corporation is running a 120 MW Tanakpur Project and also signed an agreement with the Uttaranchal state government for constructing an 850 MW BHEL project on the Alakhnanda River in February 2005.

Madhya Ganga Canal

Agra Canal

YAMUNA CANAL SYSTEMS