The Polavaram Project is an under-construction multi-purpose irrigation project on the Godavari River in the Eluru District and Polavaram District in Andhra Pradesh, India. The project has been accorded National Project status by the Central Government of India. Its reservoir back water spreads up to the Dummugudem Anicut, i.e. approx back from Polavaram dam on main river side and approx on the Sabari River side. Thus, back water spreads into parts of Chhattisgarh and Odisha States. Polavaram Hydroelectric Project (HEP) and National Waterway 4 are under construction on left side of the river. It is located upstream of Sir Arthur Cotton Barrage in Rajamahendravaram City and from Rajahmundry Airport.
History In July 1941, the first conceptual proposal for the project was mooted by the Madras Presidency. Diwan Bahadur L. Venkatakrishna Iyer, then Chief Engineer in the Presidency's irrigation department, made the first survey of the project site and made a definitive proposal for a reservoir at Polavaram. Sri Iyer not only envisaged cultivation of over two crop seasons through this project, but also planned for a 40 MW hydroelectric plant within the project. The project, when it was conceived in 1946–47, was estimated to cost Rs 129 crore.
In 1980, Chief Minister of Andhra Pradesh Tanguturi Anjaiah laid the foundation stone for the Polavaram irrigation project. The Polavaram Project Authority was constituted by the Union Cabinet in May 2014 and the construction of project head works were taken up. The Naidu government acquired the necessary lands for the right canal by solving court petition issues of farmers who lost their agricultural lands from both districts of West Godavari and Krishna; the Pattiseema Lift Irrigation Project has been launched in order to pump the Godavari river water and sent it to the Krishna river. In June, the state was bifurcated under the Andhra Pradesh Reorganisation Act. In December 2017, it was reported that the project contractor, Transstroy, was seeking a deadline extension and a budget escalation. Transstroy was reported to have its ₹4,300 crore loan turn NPA in July 2015. In January 2018, the state government signed a new contract for the project spillway, spill channel, and stilling basin concrete work with Navayuga Engineering. By June 2018, of the required had been acquired. On 11 June 2018, the Polavaram diaphragm wall was completed, marking a significant milestone in the project construction. On 7 January 2019, the Polavaram project entered the Guinness Book of World Records by pouring 32,100 cubic meters of concrete in 24 hours by Navayuga Engineering. The project beat the existing record of 21,580 cubic meters, which was achieved by Abdul Wahid Bin Shabib, RALS Contracting LLC and Alfa Eng. Consultant (all UAE), in Dubai between 18 and 20 May in 2017. The Chief minister of Andhra Pradesh N. Chandrababu Naidu unveiled the first crest gate on 24 December 2018.
Design and technical details The Polavaram Project incorporates several major hydraulic and geotechnical structures, including an earth-cum-rock fill (ECRF) dam and a gated concrete spillway—the world’s largest spillway by discharge capacity. According to the Polavaram Project Authority, the spillway is long and is fitted with 48 radial gates of size 16 m × 20 m, designed to pass a probable maximum flood of 1,41,435 cumecs, equivalent to about 50 lakh cusecs.
The spillway is located on the right bank of the Godavari River rather than on the river section because the central riverbed comprises deep sand layers unsuitable for stable foundations. To achieve stable foundations and route flood flows through the specially located spillway, the entire river course was diverted for approximately toward the right bank. This large-scale river diversion is considered a rare and major river diversion operation in Indian dam engineering.
The main dam is an earth cum rock fill (ECRF) structure spanning approximately across the river course. The ECRF dam is constructed in three distinct reaches commonly referred to as Gap 1, Gap 2, and Gap 3. Gap 1 — Earth-cum-rock fill section Gap 2 — Earth-cum-rock fill section, located at the deepest and most geotechnically sensitive portion of the riverbed. Gap 2 is the most critical segment because it provides structural continuity between the rock abutments and the main dam body, directly influencing reservoir storage integrity and flood safety. Gap 3 — Concrete section (gravity/concrete structure), not ECRF, forming part of the overall dam alignment and connecting the ECRF portions to the right abutment.
A key geotechnical feature of the project is the diaphragm wall (D-wall), running beneath the dam foundation. The diaphragm wall is long and extends to depths of up to 95 metres (approximately 312 feet) into the riverbed, forming a deep impermeable barrier to control seepage through the alluvial foundation and support the stability of the ECRF dam. The dam construction involves the building of a 1.5-m-thick concrete diaphragm wall up to depths from 40 to 120 m below the river bed under the earth dam, which is the first of its kind in India.
The project reservoir has a live storage of 75.2 tmcft above the canal's full supply level of MSL and a gross storage of 194 tmcft, thereby enabling irrigation of (including stabilisation of existing irrigated lands) in Krishna, West Godavari, Eluru, Polavaram, East Godavari, Visakhapatnam, Vizianagaram, and Srikakulam districts of Andhra Pradesh. The silt-free dead storage water of nearly 100 tmcft above the spillway crest level, MSL, can also be used in downstream lift irrigation projects (Pattiseema lift, Tadipudi lift, Chintalapudi lift, Thorrigedda lift, Pushkara lift, Purushothapatnam lift, Venkatanagaram lift, Chagalnadu lift, etc.) and Dowleswaram Barrage during the summer months.
The project includes a fish ladder. First inbuilt fish ladder in India and the first such structure in South India. Other fish ladders exist elsewhere in the country (for example, at Farakka Barrage), but the Polavaram design integrates the fish ladder into the dam/spillway complex. The fish ladder aims to maintain fish migration pathways and reduce ecological impact on aquatic fauna.
The project also incorporates three natural hillocks that serve as natural abutments, integrating into the overall dam geometry and providing stable anchorage for adjoining dam sections. The project would constitute an earth-and-rock-fill dam long, a spillway long with 48 vents to enable discharge of of water. The spillway is located on the right bank of the river, for which an approach and spill channels nearly long and wide is envisaged involving nearly 70 million cubic meters of excavation which, is nearly 2/3 of the project's total earthwork. The maximum flood level at Polavaram is MSL and lowest water level is MSL. Two cofferdams are planned, one up to MSL, to facilitate a faster pace of work on the dam to complete the first phase of the project by June 2018. With the cofferdams' inclusion and the bed level of the approach and discharge canals of the spillway increased to MSL, the spillway-related rock excavation is reduced by 70%, leading to substantial cost reduction in the project's headworks cost. Ultimately, the material of cofferdams would be excavated and reused for the peripheral portions of the main earth-and-rock-fill dam.
On the left side of the river, 12 water turbines, each having an 80 Megawatt capacity, were to be installed. Without removing the upper and lower coffer dams after the construction of the ECRF dam, the 960 MW hydropower plant cannot be commissioned, as they are blocking the water passages of the powerhouse. The right canal connecting to Krishna River upstream of Prakasam Barrage ( long) discharges at the headworks, and the left canal ( long) discharges of water.
The Central Water Commission (CWC) acts as the apex technical body for the Polavaram Irrigation Project, holding responsibility for approving designs, vetting construction methods, and mediating inter-state submergence disputes across Andhra Pradesh, Odisha, and Chhattisgarh. The Polavaram Project Authority (PPA) is an autonomous statutory body constituted by the Government of India under the Andhra Pradesh Reorganisation Act, 2014. Megha Engineering & Infrastructures Limited (MEIL) was awarded the contract for the construction of the project in November 2019.
Indira Dummugudem lift irrigation scheme starting at is under construction to supply irrigation water for 200,000 acres in Khammam, Krishna, Eluru, and West Godavari districts, drawing Godavari River water from the backwaters of Polavaram reservoir. This is a joint project between Andhra Pradesh and Telangana states. This project was shelved and merged with another project by the Telangana state.
Alternate site The dam could not be taken up for construction during the last century on techno-economical grounds. The proposed dam site at Polavaram is located where the river emerges from the last range of the Eastern Ghats into plains covered with deep alluvial sandy strata. At Polavaram, the river width is about . Due to the depth (more than 30 m) of the bedrock at this dam site, the dam project was not found economical to take up. However, a lucrative alternate site is located upstream of the Polavaram site where the river passes through deep gorges of Papi hill range. The width of river is about in the rocky gorge stretch. This alternative was originally found to be technologically challenging due to the need to connect the reservoir with the irrigation canals via tunnels across the ghat area. Also, it would need a costly underground hydroelectric station, compared to the riverbed-based hydroelectric station. When the project was actually taken up in the year 2004, the old finalised designs at Polavaram site were adopted without re-examining the latest cost of the upstream alternate site in view of state-of-the-art construction technology of tunnels and underground hydroelectric stations.
The spillway and non-overflow dam are founded on Khondalite bedrock in the Polavaram Project. Khondalites, which are feldspar-rich, often contain soft graphite, hard garnet, etc. in addition to other minerals. Khondalites are highly weathered and hence unsuitable at dam sites.
Construction progress +MilestoneStart dateCompletion DateSpill way concreting work30 December 2016mostly completed as of May 2021 Diaphragm wall of earth and rock fill (ECRF) dam 1 February 201711 June 2018Jet grouting8 January 201829 October 2018Upper coffer dam grouting8 June 20178 Jan 2018Lower coffer dam grouting8 June 2017Under constructionSpill channel concreting work 23 Apr 2018Under constructionRight bank canal head worksUnder constructionLeft bank canal head works Under constructionNavigation tunnelUnder constructionRight bank canal works 2016 (90% completed)Left bank canal works Under constructionHydroelectric power plant Under constructionBlocking the natural course of the Godavari by raising the upper coffer dam level above the crest level (17.3 m MSL) of river sluice vertical gates (10 nos) provided in the spillway to divert the Godavari water through these gates. 27 May 2021 Godavari water flows diverted fully through the river sluice gates of the spillway via the approach channel 11 June 2021Upper coffer dam works completed. 31 January 2022All the 48 barrage gates are fully erected and water can be stored in the reservoir to the extent permitted by the upper coffer dam design. 30 June 2022Lower coffer dam works completed 17 February 2023Completion of inspection and field investigation of damaged diaphragm wall during the 2020 Godavari floods and the decision was given to rectify the damage that took place. 5 March 2023New Diaphragm WallCompleted 02 April 2026ECRF dam Work Commenced
Financing
The revised cost of the total project including the 960 MW power station is 47,726 crores at 2017-18 prices.