The water resources potential in Godavari basin has been assessed by Central Water Commission to be 110.54 km³. The utilizable surface water is about 76.3 km³; the replenishable ground water is about 45 km³. There is a vast potential for irrigation development and hydropower generation in the basin. The present utilization is of the order of only 40 km³ in the case of surface water and 6 km³ in the case of ground water.

Water resources of Upper Godavari catchment are fully utilized up to Sriram Sagar Dam. Downstream of this dam, Godavari is joined by many major tributaries, namely, Pranhita, Indravati and Sabari which carry large volumes of flood waters during monsoon.

Annual average observed runoff at Important CWC sites in Godavari basin

Source: CWC (2002).

Pranhita, Indravati and Sabari contribute a huge amount of flow to Godavari in its lower reaches. Since there is no large storage reservoir in this area, most of this water (except a small quantity diverted at Godavari barrage to meet the requirements of delta irrigation) goes to the sea unutilized during the monsoon period. Of course, the scope of additional new irrigation is limited due to typical topography of the lower Godavari basin. Therefore, it is important to construct storages at Inchampalli and Polavaram to utilize huge quantity of water going waste to the sea every year. Potential storage sites for hydropower generation have also been identified on Indravati at Bhopalpatnam and Bodhghat. These storages will also regulate flows for utilization in the downstream areas. The surplus waters of lower Godavari could be transferred to the water deficit areas after meeting all the requirements of the basin in Andhra Pradesh.

Prior to independence, only a few irrigation projects were constructed in Godavari basin. Important among these are Godavari delta system (with Dowlaiswaram weir as head works). Nizamsagar reservoir, Kadana dam and Pravara dam. After independence, under various five-year plans a large number of multi-purpose and irrigation projects were taken up. The most important among them are the Jayakwadi, Sri Ram Sagar and Godavari Barrage (by remodeling the existing Dowlaiswaram) weir. Prominent among the proposed major projects in the basin are Bhopalapatnam on Indravati, Inchampalli and Polavaram on Godavari.

Inchampalli

The Inchampalli project is proposed on the Godavari River about 12 km downstream of the confluence of Indravati with the Godavari River in Andhra Pradesh. It is a joint project among the States of Maharashtra, Madhya Pradesh and Andhra Pradesh. It is a multi purpose project envisaging irrigation benefits for upland areas, generation of hydropower, navigation facilities in the river, development of pisciculture and providing recreation benefits, besides mitigating flood hazards. Flows in abundance are available at Inchampalli, as it is just downstream of the place where two major tributaries, Pranhita and Indravati join the Godavari River. The catchment area of the dam is 269,000 Mm². The FRL and MDDL of the reservoir will be 112.77 m and 106.98 m respectively. The gross storage capacity and live storage capacity of the reservoir will be 8,959 and 4,098 MCM respectively. The annual irrigation from the dam is 950 Mm² and annual utilization is 620,000 Mm². For hydropower generation install capacity at the dam is 875 MW.

Salient features of Inchampally Project

 Polavaram

The Polavaram project is planned downstream of Inchampalli after the confluence of another major tributary the Sabari with the Godavari River. It is also a multi-purpose project for irrigation, hydropower, and water supply to Vizag city. The catchment area of the dam is 307,000 Mm². The FRL and MDDL of the reservoir are at 45.72 m and 41.15 m, respectively. The gross storage capacity and live storage capacity of the reservoir is 4,945 and 2,043 Mm³ respectively. The project has been planned to utilize the significant quantum of flows that would be received from Sabari and power releases and spills from Inchampalli for its own uses and also for regulating releases for the Godavari delta. The annual irrigation from the dam is 4,720 Mm² and annual utilization is 3,823,000 Mm². For hydropower generation install capacity at the dam is 720 MW.

Salient features of Polavaram Project

Dowleswaram Barrage (Cotton Barrage)

The Dowleswaram Barrage is the terminal project on Godavari, located downstream of Polavaram, catering to the needs of Godavari delta. This 3,500 m long barrage built in the mid 19^th century is supposed to be Asia’s largest barrage. It was named as Cotton Barrage after Sir Arthur Cotton, who built the barrage and who is fondly remembered and revered in regard to his yeoman services to the upliftment of the people in the area. This barrage has completely transformed the famine and poverty wracked areas in the Godavari Delta into a prosperous place. Sir Cotton is credited with preparation of a grand plan for development of water resources of Peninsular India but this could not materialize due to some reasons. The catchment area at the barrage is 312,800 million sq. m. The gross storage capacity of the pond at FRL 13.81 m is 10 Mm³. The annual irrigation from the barrage is for 9,800 Mm² area for which, on an average, annually 777,400 Mm³ of water is utilized.

Karanja Project

The Karanja Reservoir Project is a major project constructed on Manjra River, a tributary of Godavari River. The dam is located near Byalhalli in Bhalki Taluk in Bidar district. The catchment area of the dam is 2,025 km². The length of the dam is 3,480 m with FRL as 584.15 m.   

Salient features of Karanja Project

Sriram Sagar Project (SRSP)

Although the Telangana area of Andhra Pradesh State is endowed with great natural water resources, such as the Godavari and Krishna Rivers, their tributaries and extensive fertile lands, it largely remains undeveloped partly due to lack of assured irrigation facilities. The extent of Irrigation is small and even this is by means of numerous small tanks, which are dependent on uncertain rainfall. The completion of Sriram Sagar Project Stage-I is expected to make up and set right the shortfalls and imbalances in the economy of the region and would greatly contribute to the well being and prosperity of the people of the region. Thus, this project has great importance for the development of this region.

The Sriram Sagar Project is a multipurpose project, located across the Godavari River near Pochampad of Nizamabad District in Andhra Pradesh at a distance of 200 km from Hyderabad. The dam is located at a latitude of 18° 58' N and a Longitude of 78° 20' 0"E. The catchment area at the dam site is 91,760 km². The water spread of the reservoir is 453 km², with a capacity of 3.17 BCM (Subramanyam, 1979). The reservoir utilizes 1,869 BCM of water to irrigate 0.23 M-ha of land in the Districts of Karimnagar and Nizamabad, of which one-third would be under wet cultivation and the rest under dry crops such as maize, jowar, chillies and pulses.

The masonry spillway is designed for a maximum discharging capacity of 45,307 cumec with MWL at 333.146 m. The arrangement for energy dissipation of the spillway consists of slotted roller bucket for the first 20 spans from left end of the spillway and ski jump bucket in the remaining 22 spans. The left and the right earthen dams are of rolled type. Three 2.438 * 3.657 m river sluices have been provided to serve for diversion purposes during dam construction and to serve as permanent low level river outlets. Four sluices of 2.438 * 3.657 m size have been provided for south canal with sill at 307.850 m.

The command area of the SRSP consists of undulating terrain with extensive granite rocks.  The area comprises of prominent ridges and valleys formed by gully erosion; it slopes towards the Godavari River and is drained by many small streams that empty into Godavari and its distributaries. The majority of the soils are sandy loams.  Though soil conditions support easy drainage, there are a number of low-lying areas which require systematic drainage facilities.

The main rock types occurring in command area are pink and gray granites, with fine to coarse-grained texture. Most of the ridge and relief areas are developed into poorly to moderately weathered formations.  Low lying and plain areas are developed into moderately to highly weathered formation.  The thickness of weathering extends up to 11 m.  It is observed that weathering intensity decreases with depth and generally basement is encountered without fracturing.  Hence dug wells are feasible and bore wells are not feasible in general.

The area is drained towards Godavari River. The drainage pattern is dendritic.  Undulating topography is characteristic of the area and hence distributaries are aligned on ridges. The maximum and minimum elevations of the area are 300 to 200 m above mean sea level respectively.  The normal monsoon rainfall in the area is 986 mm.

The predominant soil type of the area is red sandy loams of good permeability.  Black sandy, silty loams are found in low-lying areas stretching along the streams and also in the commands of irrigation tank.  Paddy is the principal crop which is grown extensively in the areas receiving irrigation from canal and tank water.  Sugarcane is grown but quite sparsely. In areas that do not receive canal water, paddy is grown under well irrigation.

Water table depth varies from shallow ground level in canal fed areas to 10 m in tail end areas.  In the areas receiving canal supplies, the wells existing prior to the project are not being put to use now.  These areas are under sugarcane cultivation. Wells are found to be excavated to maximum depths of 2.5-4.0 m to meet the water demand during canal closures.  In the tail-end areas, wells are used in both the seasons.

Salient features of Sriramsagar Project

Nizamsagar Project

The Nizamsagar project is a multipurpose project, constructed in Nizamabad district in Telengana area of Andhra Pradesh. The project was completed on Manjira River in 1931, a tributary of Godavari, which was a single state river. The canals and distribution system was completed in late 1935. It is a masonry dam, 3.2 km long and 48.15 m high above deep foundation. At the time of its completion, this project was one of the largest in the state but also one of the biggest schemes in India.

The live storage capacity of the reservoir is 724.736 Mm³, irrigating an ayacut of 967.233 Mm². The filling period is generally from July to August and depletion period is from September to June. The installed capacity of the power house at the dam is 15 MW. 

Lower Manair Reservoir

Manair River is a tributary of Godavari River and the reservoir is located at latitude 18°24' N and longitude 79° 8' E in Karimnagar district of Andhra Pradesh state. The total catchment area of the river up to confluence with Godavari River is 13,106.25 km². The lower Manair dam was constructed in 1985 across Manair River at tits 110^th km and at its confluence with Mohedamada River. The dam is located at 18° 8’ 24” N and 79° 8’ 6” E.  The total catchment area up to the Lower Manair dam site is 6,464 sq. km; the free catchment area at the Lower Manair Dam is 1,797.46 km² and the rest is intercepted. The original capacity of the reservoir at F.R.L. 280.46 m is 680.648 Mm³. The spillway has 20 gates of 15.24 m × 7.31 m and has been designed for maximum flood of 14,158 cumec.

There are no sediment observation stations on Manair River. Based on Khosla's formula, sediment inflow is assessed at the rate of 4.97 ha.m/year/100 sq. km.

Kaddam Reservoir

The Kaddam reservoir was constructed across Kaddam River at its 80^th kilometer of run in the Adilabad district of Andhra Pradesh. After traversing a distance of 6.5 km from the dam, Kaddam joins the Godavari River. The latitude and longitude of the dam are 19° 07' N and 78° 47' E. The dam was constructed during the year 1958 and was remodified in the year 1965. The total drainage area of the Kaddam River up to the dam site is 2,631 sq. km. The original capacity of the reservoir at full reservoir level 213.300 m is 215.80 Mm³.

Upper Indravati Project

This project, constructed on the Indravati River in Orissa is one of the major multipurpose transbasin diversion projects in India. It involves diversion of the waters of the Indravati River, a tributary of the Godavari River into the Mahanadi basin for power generation and irrigation. The whole scheme envisages construction of 4 dams (Indravati masonry dam; Podagada earth dam; Kapur earth dam; and Muran concrete, masonry and earth dam) and 8 earthen dykes (4 on left and 4 on right). The main dam is on the Indravati River in Nowrangpur and Kalahandi districts of Orissa; the other three being on its three tributaries: the Podagad, the Kapur, and the Muran. All these form a single reservoir, connected together through two link channels, to generate, in all, 1990 million kWhr of electricity per year and simultaneously to annually irrigate 2,185 Mm² from the releases through the power house. The reservoir has gross storage capacity of 2,300 MCM and live storage of 1,486 MCM. At FRL, the reservoir covers and area of 112 sq. km. At the dam site, the catchment area of Upper Indravati basin is 1,153 sq. km.

The distinct feature of this project is the trans-basin diversion of water from, Godavari Basin up to river Hati (Mahanadi basin) for power generation and irrigation. Tailrace release from powerhouse is picked up at Hati Barrage constructed across river Hati at Mangalpur in Kalahandi district with two canals taking off on either bank. Left main canal is 52 km long and commands an ayacut 49,078 ha.. 83 km. long right main canal provides irrigation to 27,191 hectares. Another lift canal is under consideration for irrigating CCA of 33,027 ha.

Water from the reservoir is to be conveyed through a water conductor system for power generation.  Thereafter, the release through 7.8 km long tail race channel discharges into the Hati stress, a tributary of the Tel River in Mahanadi basin and is picked up by a weir across the Hati for utilization in irrigation. While designing this project, the aim was to provide as much irrigation as the available resources can provide.  With the calculated runoff, the project could provide irrigation of about 1,214.10 Mm².

For power generation, the power house is connected to reservoir by a water conductor system consisting of a pressure tunnel, a surge tank and five numbers of penstocks. The tunnel has a length of 4,215 m and is of 7 m diameter.  The tunnel discharges into a differential surge tank of 18 m diameter and 96.75 m deep. There are 5 penstocks of 3.05 m diameter each.  The annual power potential of this project is 1,990 million KWH at 100 percent load factor. The installed capacity of 600 MW consists of 5 units of 120 MW, each operating under an average load of 374 m. It is a surface power house.

The tail race discharge is utilized for irrigating 1,093 Mm² of C.C.A. in Sadon and Dharamgarh subdivisions of Kalahandi District.  The intensity of irrigation is 200 percent. The project is located in Kalahandi and Koraput districts which are among the most undeveloped districts of Orissa and are predominantly inhabited by adivasis and tribals. Although there is immense scope of industrial growth and agricultural development, the progress is slow as the rich mineral resources of the districts are not yet properly tapped.  When the full potential of this project is utilized, it will undoubtedly accelerate growth of economy of these two districts.

Although droughts are frequent in these districts, even when rainfall in good, rainfall distribution is in variance with the crop water requirements and artificial irrigation is the only means to increase crop production. There is no other project in these districts which has such a high irrigation potential. Further, this region suffers from shortage of electricity. Even after the full utilization of the additional power from the Balimela Power Station (360 MW, 1,980 MKWhr), Talchur Thermal Expansion (220 MW, 1012 MKWhr) and Rengali Power Station (100 MW, 523 MKWhr) that are now under construction and the Upper Kolab Project, shortage of power with both in energy and capacity will exist.

Bhopalpatnam Reservoir: This is a proposed reservoir on Indravati River, a tributary of Godavari River. The gross storage, dead storage and live storage capacity of the reservoir will be 8,368.00, 549.00 and 7,819.00 Mm³ respectively. The FRL and MDDL of the reservoir will be 200.254 and 176.48 m respectively. The maximum and minimum dependability has been assessed at 21,969.00 and 3,290.00 Mm³ respectively.

Balimela Dam

The Balimela Project on the Sileru River in the state of Orissa in India consists of a 70 m high earthfill dam and 3 earthen dykes on the saddles in the left abutment hill. The project is located at a distance of 35 km from Malkangiri in Godhra in Malkangiri District, Orissa. The catchment area at the dam is 4,910 km².  At FRL 462.7 m, the reservoir has a live storage capacity of 3,610 MCM. The spillway is located on a saddle to the right. Half of the stored water is diverted to another valley and a head of 275 m is created for power generation. The other half quantity of water is used for power generation at successive power stations on the Sileru River itself.  Balimela power house has 6 units of 60 MW each, with mean annual inflow of 5,190 MCM. It has a firm power of 161 MW. It was commissioned during 1973-77.   

Mula Irrigation Project

Mula is a major irrigation project on the Mula River, a tributary of Pravara, which in turn is a tributary of Godavari. The Mula project is located at longitude 74°34’30’’ E and latitudes 19°1’30” N. This multipurpose project caters for irrigation and municipal (Ahemdnagar city) water supply. It provides industrial water supply to defense units, sugar factories, and other industries. The project infrastructure consists of an earthen dam with gated spillway at Baregaon-Nandur in Rahuri Taluka of Ahmednagar district. The FRL, MDDL and MWL of the reservoir are 552.30 m, 534.21 m and 553.21 m respectively. The Gross storage, live storage, and dead storage of the reservoir are 736.32 Mm³, 608.88 Mm³ and 127.44 Mm³ respectively. The water spread area of the reservoir at FRL is 56.397 km². Project’s right bank and left bank canals with an extensive distribution system provides irrigation to an area of 80,810 ha. Major portion of command has black cotton soil. The rainfall is very scanty in this area; average rainfall is 50 cm in lower catchment and evaporation is moderate.

Pench Projects

The Pench River is a tributary of Kanhan River which lies in the Godavari River Basin. There are two major projects on the Pench River. Pench hydropower project comprises of Totaladoh masonry cum concrete dam on Pench River, 3 km from Totaladoh, in Nagpur District, Maharashtra. The catchment area at the dam is 4,275 km². The height and length of the dam is 75 m and 680 m respectively. The reservoir has a live storage capacity of 1,249 MCM at FRL 490 m and the MDDL is at 464 m. The power house has 2 units of 80 MW each. It has a firm power of 34 MW with annual inflow of 1,857 MCM in a 75% dependable year. MSEB commissioned the project in 1986-87.

Pench Irrigation Project comprises a storage-cum-diversion dam, 23 km downstream of Totladoh Dam on Pench River to impound releases through the tail race discharge after power generation at Totladoh reservoir. It has lined canals on both the banks, envisaging irrigation of 104,476 ha area in Nagpur and Bhandara districts. Besides irrigation, this project also provides 145 MCM of water for Nagpur water supply and 87 MCM for Koradi Thermal Power Station through its right bank canal. The temperature in the area rises above 36°C in summer and goes below 20°C in winter. The average annual rainfall is 1,051 mm. Free catchment area between Totladoh and Kamthi Khedi is 388.0 sq. km with an inflow from free catchment of 112.6 MCM. The Kamthi­ Khedi diversion dam near Parsheoni Village has a gross storage capacity of 230.00 MCM resulting in live storage of 180.00 MCM. It is 2,248 m long, with height 44.50 m, above cut-off trench in case of earth dam and 45.5 m in case of masonry dam above the lowest foundation level. The dam comprises of a central spillway with earth dam on right flank and earth dam in left saddle. The spillway has 16 gates of size 12 m x 8 m.

Upper Kolab

Upper Kolab is a straight masonry gravity dam completed in 1990 on Kolab River, 5 km from Jeyapore in Korapt District, Orissa. The catchment area at the dam is 1,630 km². The height and length of the dam is 55 m and 631 m respectively. The reservoir has a gross storage capacity of 1,215 MCM and live storage capacity of 935 MCM at FRL 858 m, and mean annual inflow of 1,803 MCM; its MDDL is at 844 m. At FRL, the reservoir water spread covers 114 sq. km. Peak of design flood hydrograph is 10,020 cumec. The spillway has 11 radial gates of 12.2 m × 12.2 m with crest level at 845.8 m. Two canals take off from the reservoir: right bank canal is known as the Jeyapore main canal which is 58.83 km long with discharge at head 98.1 cumec, and the left bank canal is known as the Padampur canal which is 12.47 km long with 2.79 cumec discharge at the head. Upper Kolab power house has 4 units of 80 MW each. With a design head of 261 m, it has a firm power of 111 MW. OHPC Ltd commissioned the project in 1988-93.

Projects in Sileru (Machkund) Basin

Three important projects of this basin are described here. Machkund project comprises of Kalaput dam, constructed on Machkund River (Sileru River is known by this name in upper reaches). The project is located at a distance of 65 km from Jeypore, in Onukudelli District, Orissa. The catchment area at the power house is 1,932.85 km². This 60.7 m high dam has created a reservoir with live storage capacity of 893 MCM at FRL 839 m and the MDDL is at 819 m. At the dam site, mean annual inflow has been estimated at 1,023.7 MCM.  For power generation, it has 3 units of 17 MW each and 3 units of 23 MW each respectively. This project, commissioned in 1955-59, has a firm power of 81 MW.

Upper Sileru hydropower project is located on Guntawada masonry gravity dam on Sileru River, 230 km from Visakhapatnam in Andhra Pradesh. The height and length of the dam are 31 m and 625 m respectively. The reservoir has a live storage capacity of 109.5 MCM at FRL 414.5 m and the MDDL is at 406.3 m. The power house has 4 units of 60 MW each. It has a firm power of 58 MW with mean annual inflow of 2,000 MCM.

Lower Sileru hydropower project is located on Donkarayi masonry gravity dam on Sileru River also known as Machkund in upper reaches, 94 km from Bhadrachalam, in Khammam District, Andhra Pradesh. The catchment area at the dam is 2,254 km². The height and length of the dam are 71.5 m and 1,399 m respectively. The reservoir has a live storage capacity of 380 MCM at FRL 316 m; its MDDL is at 291.2 m. The power house has 4 units of 115 MW each. It has a firm power of 154 MW with mean annual inflow of 90.6 MCM. This project was commissioned in 1976-78.

Upper Wainganga

This project, later renamed as Sanjay Sarovar Project, is a major irrigation scheme in Seoni and Balaghat Districts of Madhya Pradesh. It envisages the construction of a composite earth and masonry dam with maximum height of 42.67 m across Wainganga River near Bhimgarh village at latitude 22º 22’ 51” N and 70º 30’ 20” E. The construction of the dam was completed in 1995.  The dam intercepts a catchment area of 2,008 sq. km. At FRL of 519.38 m, the reservoir has gross and live storage capacities of 507 MCM and 410 MCM. In the catchment of the dam, the maximum and minimum annual rainfalls are 1,748 mm and 647 mm, the average being 1,225 mm. The 75% dependable yield at the dam site is 703.1 Mm³. Ten radial type gates of size 15.24 m × 10.67 m have been provided at the spillway whose crest lies at 508.71 m.