Feature image:- Damaged Annamayya dam on Cheyyeru river in Kadapa (Source:NaveenReddy@navin_ankampali)
After Pulichintala dam gate disaster[i] of August 05, 2021, the state of Andhra Pradesh has witnessed another dam induced flood disaster in 2021. This started with, part of Annamayya dam in Pennar (also called Penna) river basin[ii] getting washed away resulting in widespread destruction in downstream areas on November 19.
Around same time, there were more incidents of damages to dams and dam induced flooding in Kadapa, Chittoor, Anantapur districts of Rayalaseema and adjoining Nellore district. Firstly, the collapse of Pincha project ring bund contributed to Annamayya flood disaster. Then, one of metal bund of Mylavaram project was washed away.
Fourthly, the sudden releases from Veligallu and Buggavanka dams in Kadapa and Kalyani dam in Tirupati resulted in flash flood destruction in downstream areas. Apart from this, the leakages in Rayalacheruvu tank bund in Chittoor district could have turned into a big disaster.
Interactive google map showing locations of impacted dams and dams that aggravated flood disaster in Andhra Pradesh in November 2021.
About affected dams
The Pincha is medium irrigation project built in 1954 on Pincha River, a tributary to Pennar near the Mudumpadu Village, under T. Sundupalli mandal in Kadapa district costing Rs. 60 lakhs. Its gross storage capacity is 0.3276 thousand million cubic feet (TMC). The project is located about 50 km upstream on Annamayya dam project.
Salient features of Pincha project from CWC’s National Register of Large Dams, 2017.
|Project Identification Code||AP01MH0016|
|Longitude, Latitude||NOT GIVEN|
|Earthen Dam height above lowest Foundation||21 m|
|Length of Dam||486 m|
|Gross Storage Capacity||9.284 MCM|
|Effective Storage Capacity||9.1 MCM|
|Reservoir Area||207.3 ha|
|Spillway Capacity||1644 cumecs|
Annamayya Project is a medium irrigation project[iii] constructed across Cheyyeru river a tributary to Pennar. It is located near Badanagadda village under Rajampet mandal in Kadapa district. The project started in 1981 and completed in 2001 at a cost of Rs. 60.44 crores.
Salient features of Annamayya project from CWC’s National Register of Large Dams
|Name||Cheyyeru Project (Annamayya)|
|Project Identification Code||AP01MH0129|
|Longitude, Latitude||79° 01′ 15″ E; 14° 12′ 06″ N|
|Height above lowest Foundation||25 m|
|Length of Dam||409 m|
|Gross Storage Capacity||63.5 MCM|
|Effective Storage Capacity||44.89 MCM|
|Reservoir Area||760 Ha|
|Spillway Capacity||8069 cumecs|
Mylavaram is a major irrigation project[iv] constructed across Pennar river with a gross storage capacity of 9.960 TMC near Mylavaram village in Kadapa. The construction of dam, canals and distributary system were completed in 1986. In 2015-16, the modernization of main canals and distributary system was taken up with an estimated cost of Rs.151 crores.
Salient features of Mylavaram Project from CWC’s National Register of Large Dams
|Project Identification Code||AP01MH0058|
|Longitude, Latitude||78° 20′ 00″ E; 14° 51′ 00″ N|
|Height above lowest Foundation||24 m|
|Length of Dam||2850 m|
|Gross Storage Capacity||283 MCM|
|Effective Storage Capacity||265 MCM|
|Reservoir Area||4100 Ha|
|Spillway Capacity||8190 cumecs|
About dams that induced flood disaster
Veligallu dam[v] is constructed across Papagni river near Veligallu village in Galiveedu mandal of Kadapa district. The full storage capacity of the project is 4.64 TMC. It was planned in 1995 and got completed in 2008 costing about Rs. 288.16 crores.
Salient features of Veligallu project from CWC’s National Register of Large Dams
|Project Identification Code||AP01HH0081|
|Longitude, Latitude||78° 28′ 40″ E; 14° 01′ 50″ N|
|Height above lowest Foundation||44 m|
|Length of Dam||789 m|
|Gross Storage Capacity||131.47 MCM|
|Effective Storage Capacity||104.12 MCM|
|Reservoir Area||NOT GIVEN|
|Spillway Capacity||4361 cumecs|
Buggavanka dam[vi] is a medium irrigation project constructed across Buggavanka river near Ippapenta village under CK Dinne mandal of Kadapa district. It was completed by 2000 costing Rs. 39 crores and has a storage capacity of 0.50 TMC. In December 2005, the project area developed a sink hole and government had sanctioned Rs. 210.60 lakhs to fix it.
Gandikota reservoir[vii] is an irrigation project located across Pennar river between Gandikota village and Kondapur villages of Kadapa district. It receives water from Galeru Nagari Sujala Sravanthi project canal. It was inaugurated in Sep 2013 and has a gross storage capacity of 26.84 TMC.
It acts as a balancing reservoir to supply Krishna river water into Pennar river basin in Kadapa, Nellore and Chittoor districts. The state government has a plan to build another[viii] 20 TMC storage capacity dam downstream Gandikota reservoir to draw the Krishna floodwaters through Pothi Reddy Padu reservoir from Srisailam dam.
There are 4 major, 5 medium completed irrigation projects[ix] in the Kadapa district apart from 1836 minor irrigation tanks. 5 major, 1 medium irrigation projects and 218 tanks under minor irrigation scheme are under construction. The irrigation profile of Kadapa district can be seen here[x].
Somasila[xi] is an earth filled and gravity reservoir constructed across Pennar river near Somasila village of Ananthasagaram mandal in Nellore district. The project has 78.00 TMC storage capacity and 12 MW hydel scheme with plans to add 11 MW more.
The project can get water by gravity from the Srisailam reservoir located in Krishna basin. It is the biggest storage reservoir[xii] in Pennar river basin and can store all the inflows from its catchment area in a normal year. This reservoir can also feed by gravity nearby 72 TMC gross storage capacity Kandaleru reservoir. There is plan to connect the reservoir with the Nagarjunasagar reservoir to augment its water inflows.
With 2 TMC storage capacity, Rayala Cheruvu is a historical and largest tank located in Ramachandrapuram mandal under Rayalaseema region 15 km from Tirupati city in Chittoor district.
The Kalyani[xiii] is a gravity dam constructed across Swarnamukhi river in Seshachalam hill ranges of Tirupati city in Chittoor. It was constructed in 1977 with 25 TMC storage capacity. According to CWC National Register of Large Dams, Kalyani Dam Gross storage capacity is 25.79 MCM (0.91 TMC) and Effective Storage Capacity is 24.83 MCM (0.88 TMC). Height of the dam from lowest foundation is 36 m, length is 500 m and Reservoir area is 2255 ha. Spillway Capacity is 1615 Cumecs.
Pincha and Annamayya Dam Failures
The Pennar river catchment was facing very heavy rainfall since November 17. All the rivers in the basin were in spate flooding most of the irrigational projects by the evening of November 18. Through Mandavya and Bahuda rivers feeding Pennar the Annamayya project had received around 1.80 lakh cusec inflows by November 18 night.
Amid heavy downpour, the ring bund of upstream Pincha dam project got damaged in the wee hours of November 18 flushing additional inflows of around 1.40 lakh cusec in Annamayya dam. Cumulatively, the project received about 3.20 lakh cusec inflows against the total discharge capacity of 2.85 lakh cusec in early morning hours of November 19.
As a result, part of left portion of dam’s earthen bund collapsed around 06:00 am on November 19, causing flood disaster in dozens of downstream villages. It is also reported that one of 5 spillways of the dam got jammed during peak flood causing massive damages to the project.
Apart from this, the Mylavaram dam structure faced threats as its metal bund was washed away[xiv] 300 metres from crest gates due to heavy inflows. Executive engineer Sudhakar said restoration of damaged parts of the project were taken up and there was no fear of the dam collapse.
Other Dam Induced Flood Incidents
The sudden flood discharge from Veligallu dam led to the collapse of a busy bridge[xv] on river Papagni cutting off the road link between Kadapa and Anantapur districts besides inundating and damaging crops on large areas. Officials said a temporary bridge would be built after recede in flood level and construction of new bridge would take more than a year.
The Kadapa district headquarters was affected by floods following heavy flows from Buggavanka dam. The encroachment of canals & streams further aggravated the flood situation.
The Gandikota dam received highest-ever flood in its history and the officials started releasing about 1 lakh cusecs of water to the downstream Pennar since November 18 night which eased pressure on the project but wreaked havoc[xvi] in the downstream areas. The project has been facing controversies[xvii] for incomplete compensation and rehabilitation of affected villagers.
NH-16 was damaged at several places after massive releases from Somasila dam. It also caused inundation and damages to railway tracks in Nellore district.
Similarly, huge water was released from Kalyani dam triggered flash floods[xviii] across Chandragiri, Tirupati and Srikalahasti assembly constituencies. The link bridge between Tiruchanoor and Pudi was washed away in the Swarnamukhi floods in the early hours on November 20 cutting off road connectivity to several villages in the Tirupati rural mandal.
Leakages in Rayala Cheruvu tank bund
Rayala Cheruvu tank developed some cracks in the bunds[xix] and started leaking which created panic of a sudden deluge in surrounding villages on November 21. While the tank capacity is 0.2 TMC, it was filled with 0.9 TMC. After the leakages, villagers were warned to carry essential items, documents, and move to higher locations.
According to CWC’s National Register of Large Dams, Rayalacheruvu Dam (Project Identification Code: AP01LH0115) with longitude latitude 77° 15′ 00″ E; 15° 05′ 20″ N, Height 10 m, length 920 m has gross storage capacity of 2.39 MCM and Effective Storage Capacity of 1.84 MCM, Reservoir Area 232.3 Ha and spillway capacity of 21 cumecs.
With help of local villagers, Irrigation Department tried to stop leakages[xx] using cements and sand bags. There was also an attempt to open gateways[xxi] to release water and lessen pressure on the water body. However, due to heavy inflows from the upper catchment areas the bund overflowed.
Finally the leakages were plugged[xxii] on November 27 by irrigation department officials with the help of experts from the IIT-Chennai and Tirupati. The officials were asked to closely monitor the inflows and the outflows to the project and to ensure water does not go beyond its full storage capacity levels.
The heavy rains measuring 12-14 cm on November 18 had already inundated several parts of Tirupati town. The releases from Kalyani dam on November 19 further aggravated the flood situation there. It happened when the water bodies were full, Swarnamukhi river was in spate and soil was hyper saturated.
The gushing waterfall at the Kapila Teertham temple swelled further as several check-dams along the ghat road overflowed. Some portion of the temple was washed away in the floods. Officials say for 10 days before November 18 downpour, it had been raining continually. The encroachments[xxiv] and blockage of drainage system only worsened the flood situation.
The failure of Pincha and Annamayya projects have caused significant damages[xxv] in dozens of downstream villages including Togurupeta, Mandapalle, Pulapathur and Gundlur. The disaster has also damaged several homes and destroyed agricultural crops on hundreds of acres of land.
So far 44 people have reportedly been killed and about 15 remained missing. Most of the casualties have taken place in Kadapa district particularly due to breach in Annamayya project. The toll consisted mostly of people who went to Shiva temples for shelter or worship during the Karthika Pournami.
Mandapalli and Togurupeta villagers have blamed administration[xxvi] for no timely warning and evacuation. Even the rescue and relief work was done by volunteers and police personnel in initial hours.
The Indian Express reported, “A sudden gush of about 2 lakh cusecs of floodwater, with the level reaching upto 10 feet height, caught the villagers unaware and scampering for their lives. Tens of houses in these villages downstream the project were reduced to rubble. Tens of cattle heads were washed away. Nothing of the household items was left as the deluge gulped them. The villagers literally lost everything, except the clothes on their person.”
As per The News Minute report, in Mandapalle alone 12 villagers were washed away[xxvii]. They said flood had never entered the village before this. “It all happened in a flash. There was no warning whatsoever about the impending disaster and we were left to face the fury. Now, our lives are in total ruin,” villagers of Togurupeta and Mandapalli said.
In Pulapathur village 13 and in Gundlur 5 people were swept away in flooded Cheyyeru. An APSRTC bus fell into floodwater from Nandaluru bridge on Cheyyeru river killing 10 people. The Rajampet area witnessed heart rending scenes with dead bodies of people being washed away in the floods due to lack of advance alerts.
The Chennai-Kolkata NH-16 was breached[xxix] at many locations including at Kovuru and at Padugupadu suspending vehicular movements. As a result hundreds of vehicles stranded for kms on either side of NH. The State Disaster Management Authority said more than 2 lakh cusecs of floodwater flowed out of the Somasila dam in Nellore district, leading to the deluge.
According to the South Central Railway, more than 100 express trains were cancelled and 29 were diverted following inundation of railway tracks near Nellore. The Chennai-Mumbai rail route that runs through Kadapa district was shut as about 1.5 km long tracks got washed away near Nandaluru.
Rail and road connectivity to the temple city of Tirupati was cut off with closure of several highways[xxx] including leading to Kadapa, Nellore, Bengaluru, Tiruttani. The district headquarters was under threat of floods following heavy flows from Buggavanka reservoir.
The deluge has badly damaged[xxxi] several roads and buildings in 4 districts of Kadapa, Chittoor, Anantapur and Nellore. Officials said it would require around Rs 2,000 crore for their permanent restoration. The estimates may go up to Rs 4,000 crore as many bridges have also been washed away. “We will require at least Rs 150-200 crore to take up immediate restoration of roads in the affected areas,” said a senior official.
The flood cut off road connectivity to nearly 500 villages in the 4 districts. The R&B department has estimated that about 1,632 kms of road network including 539 kms in Kadapa, 217 kms Chittoor and 715 kms in Nellore has been damaged. Breaches were reported at nearly 125 places in these districts including at 48 places in Chittoor and 46 places in Kadapa district.
Principal Secretary (Disaster Management) Usha Rani informed centre’s inter-ministerial team[xxxii] deputed to AP that about 44 persons have been killed in the floods and 15 are still missing. The official also said that 2.31 lakh people living in 211 villages and 23 towns have suffered due to inundation. 98,514 houses got inundated with 5,740 houses of them getting damaged, the highest 911 in Chittoor causing a loss of Rs 5.18 crore.
Kadapa district bore the brunt of the flash floods with about 866 villages marooned due to the breach in Annamayya project and overflowing of Cheyyeru river. She also informed the central team that crops have been damaged in 2.86 lakh hectares and 75 per cent of the damaged crop is paddy. The loss on account of cattle and livestock was Rs 2.47 crore in these districts. A chain of tanks built during Krishnadevaraya regime in Chittoor district had breached or got severely damaged because of heavy rains.
Reasons behind flood disaster?
The official report submitted to Chief Minister (CM) Y S Jagan Mohan Reddy on November 24 by officials led by District Collector V Vijayarama Raju – as reported in media – attributed unprecedented rains a reason behind flood destruction[xxxiii]. It further mentioned that timely interventions were made and about 1250 families in flood prone areas were alerted apart from safe evacuation of 400 families before the breach in Annamayya dam.
As per the Collector the dam breach was the major factor that caused such a major calamity. It is said that Annamayya project has not received this volume of water in past 50 years. “The river course changed but the dam breach was what caused the real destruction. We still moved some 600 people to safety,” he said. “Yes, it was a major calamity, the scale of which could not be imagined,” Raju added.”
Same day, CM directed irrigation authorities to redesign the existing project[xxxiv] and also increase storage capacity of the Annamayya dam to avoid complications in future. The project has only a right canal of 23.63 km, though there had been proposals for a left canal too.
Though there is no official data, the Central Water Commission (CWC) says the recent floods in AP could be the worst in the past 10 to 20 years[xxxv]. Somasila reservoir in Nellore district discharged all-time high of 5.5 lakh cusecs of water. Irrigation officials lifted 10 crest gates of the reservoir following heavy rain in catchment areas.
B Rajsekhar, special officer appointed for Nellore, said the CWC had informed them that Nellore barrage had got a record 140-year high inflow from the Pennar river, “which has never been flooded like this”.
V Vasantha Kumar, executive engineer, hydrology division, CWC, said the heavy rains (8 cm to 10 cm rainfall in three hours) along the Cheyyur river and the continuous rains for a few days from November 18 were the major reasons for the floods.
Rayalaseema region witnessed good rainfall during the southwest monsoon and most of the irrigation projects in the region received good inflows. But the sudden heavy rains led to massive floods in the region. Dismissing social media reports claiming that ‘the recent floods in AP are the worst in 140 years,’ Vasantha Kumar said they might be worst in the past two decades.
Though India Meteorological Department (IMD) warned heavy rainfall over Rayalaseema region and Nellore district, the officials didn’t release the water from the reservoirs initially to mitigate the flood situation. The heavy inflow of rainwater led to breaches to some waters bodies and that led to floods in some parts of the Rayalaseema region, said a senior officer with IMD.
Controversy over Breach of Annamayya Dam[xxxvi] While speaking on the dam safety bill in Rajya Sabha on Dec 3, 2021, Union Jal Shakti Minister Gajendra Shekhawat said the dam got breached due to the failure of the Andhra Pradesh government in ensuring the dam safety. He pointed out that one of the gates of the reservoir failed to open during the floods, as a result of which the earthen bund got breached and floods gushed into the adjacent villages. “As many as 33 people were washed away and there was a destruction of massive properties. Who is responsible for this deluge? Is it not the failure of the state government?” he asked. He said the Annamayya project incident brought a bad name to the country. “If engineers of other countries want to study why Annamayya dam breached, it shows our failure,” Shekhawat said. However, Andhra Pradesh irrigation minister P Anil Kumar denied these charges: “All the gates were functional, but because of the heavy floods, there was a pressure on the bund and it breached”.
Summing Up The Andhra Pradesh state has indeed seen one of worst flood disasters in recent years causing large scale destruction in Kadapa, Chittoor, Anantpur and Nellore districts of Pennar river basin.
The concerned officials from Sate have largely blamed weeklong rainfall spell from November 13-19 which is reportedly highest ever precipitation in recorded history since 1850 as main reason behind the devastation. The warming up of Arabian Sea causing considerable increase in numbers of cyclones and extreme rainfall events as part of climate change is also being attributed for the unprecedented deluge.
However, the episode has once again raised questions over scientific and efficient operations of irrigation and dam projects specifically before and during the peak floods. There are several reports mentioning how sudden releases from Somasila, Veligallu, Kalyani, Buggavanka and Gandikota dams aggravated flood situation in downstream areas thus causing massive destruction to government infrastructure and public properties.
Further the failure of Pincha, Annamayya and Mylavaram projects highlights the basic problem in designing and execution of these projects. Moreover these projects have caused flood disasters in recent past also. The bund of Pincha project was breached and shutter of Annamayya project was damaged even in 2020.
Though, Andhra Pradesh Water Resources Information & Management System (APWRIMS[xxxvii]) is very informative portal but it does not share inflows and outflows data of minor and medium irrigation projects. This information is given only for 5 major reservoirs and excludes the Somasila project.
Paradoxically, Rayalaseema is a drought prone region facing this scale of flood destruction. Moreover, paddy is the crop which has been largely damaged by the deluge. One wonders why this water intensive crop is being grown in drought affected area for which government has been building more and more irrigation projects with improper design and no monitoring, accountability mechanism during floods.
Ironically, groundwater continues to be main source of irrigation in Rayalaseema and the Rayala Cheruvu incident shows prevalent government apathy towards proper maintenance of historical tanks in the region which can to large extent help absorb excess run-offs, recharge groundwater and meet the irrigational needs.
In fact, given advance weather forecast, the dam operators clearly once again kept waiting for TINA [There is no alternative, (but to release)] situation and then conveniently blamed heavy downpours for the flood destruction.
There is no denying that there is increase in extreme weather events, however the destruction on ground is largely due to anthropogenic reasons and unscientific operations, mismanagement of dams and irrigation projects have its large share of blame apart from encroachments of drainage system and water bodies.
Similarly, there is gradual increase in dams, embankments breach incidents and dam induced flood disasters in the state. The latest being the faulty operation of Pulichintala dam gate[xxxviii] causing flood in downstream areas on August 05, 2021.
Sadly, this indicates there is no learning from these events and unless there is radical change in approach pushing building of more and more dam projects, they would continue to create such avoidable flood disasters.
No doubt, rainfall pattern is changing, but scientific, efficient and accountable operations of dams, irrigation projects can to great extent help floods don’t turn into a disaster. There is complete lack of preparedness to face the new rainfall pattern induced by climate change.
Bhim Singh Rawat (firstname.lastname@example.org)