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Discussion Starter · #1 ·
Polavaram is a multi-purpose irrigation project which is under construction and located on river Godavari near Ramayyapet village of Polavaram Mandal of West Godavari district in Andhra Pradesh. The project has been on cards for almost 75 years. This project is a dream for the 5 crore people of Andhra Pradesh. The project will be a one-stop solution for all the water needs of the state.

The project reservoir has live storage 75.2 TMCs at canal’s full supply level of 41.15 metres (135 ft) MSL and gross storage of 194 TMCs thereby enabling irrigation of 23,20,000 acres (including stabilisation of existing irrigated lands).

Polavaram will benefit all the 13 districts of A.P, directly and indirectly.

Polavaram project dam being built on River Godavari can help divert and utilise Godavari water to Krishna and other rivers. If executed well, this project can make the state drought-free forever.

AP Government is very keen to finish this mammoth project by 2019 at any cost. The progress of the project is being monitored at the highest levels of Government on weekly basis.

Polavaram project: Overview



Major components of the Polavaram Project:

1. Spillway
2. Coffer Dams
3. ECRF Dam (Earth Cum Rockfill Dam) & Diaphragm wall

1. Spillway

Constructing the Spillway is the first step in the process. After constructing the Spillway, 48 huge radial Spillway gates will be fitted to it.

After the gates are fitted, then the Approach and Spill channels will be constructed to channelise river water through Spillway.

Each gate is fitted with 2 hydraulic cylinders to enable faster movement of the heavy gates, to secure dam from heavily flooded Godavari river. The 96 hydraulic cylinders for 48 gates are being manufactured in Germany.

The excess flood water is released through the remote controlled spillway gates.

Spillway Dimensions: Height 45 ft; Width 1000 mts; Concrete required 17 lakh cubic metres

Spillway Radial Gate dimensions: Each Spillway Radial gate: Height 21m; Width 16m; Weight 350 tonnes

2. Coffer Dams (U/S & D/S)

Two Coffer Dams, upstream-U/S and down stream-D/S (pink lines) will be built across the river. The main purpose of the Coffer Dams is to protect the Earth Cum Rock field Dam (ECRF Dam) from floods during construction.

CofferDam Dimensions :
Coffer Dam U/S: Height 41m; Length 2.3 km; Width 145m; 600m from the ECRF Dam.

Coffer Dam D/S: Length 1.45 km

The Coffer dams are being built by renowned German company Keller.

CofferDam U/S can hold up to 120 TMCs of water. The state government is planning to supply water to Polavaram Right and Left Main Canals by gravity from June 2018. This is a temporary solution and will partially benefit farmers until the main dam is built.

3. ECRF Dam (Earth Cum Rockfill Dam) & Diaphragm wall

The ECRF dam will be built between the two Coffer dams.

ECRF dam is the most crucial component of the entire project, constructed across the river Godavari and plays a major role in holding river water.

The ECRF dam will be built between the two Cofferdams. It can withstand up to 50 lakh Cusecs water flow, whereas peak flow of Godavari river recorded till now is 30 Lakh Cusecs. ECRF is being built by Mega Engineering Company.

ECRF dam dimensions:
Length 1750 mts ; Height 41 ; Width 300 mts at the bottom and 30 mts in the top

Diaphragm Wall:
Diaphragm wall is the foundation of ECRF dam. It is constructed below the ECRF dam and prevents leakage of water across the dam from the bottom of ECRF through sand pores. Without Diaphragm wall the ECRF will not sustain and will succumb to water leakage from the bottom of it.

Diaphragm wall dimensions:
Depth (below the ECRF dam) 40–100 mts; length 1450 mts; Width 1.5 metres.

Diaphragm wall is being executed as a joint venture by L&T Geo and renowned German Company Bauer.

Benefits of Polavaram Project:
Polavaram will be the biggest dam dedicated to nation after Sadar Sarovar dam on Narmada river in Gujarat. The Storage capacity of Polavaram compared to the others:

1 Polavaram Reservoir = 1/2 of Nagarjuna Sagar.

1 Polavaram Reservoir = 3/4 of Bhakra Dam.

1 Polavaram Reservoir = 1.5 Times of Tehri Dam

1. Immense advantage to Krishna Delta region:

80 TMCs of Godavari water can be diverted every year to the Krishna River. The Godavari water travels for 174 KM in the Polavarm Right canal with the help of gravity and then meets River Krishna at ‘Pavithra Sangamam’ near Vijayawada, located in the upstream of Prakasam barrage. The diverted Godavari water will be utilised for irrigation and drinking purposes in Krishna Delta region. The river linking benefits a whopping 14 lakh acres in Krishna delta region. Four districts Krishna, West Godavari, Guntur and Prakasam under Krishna delta region will benefit from the Godavari water.

2. Boon to Rayalaseema region:
The Krishna river water meant for the state of Andhra Pradesh is currently being shared by Rayalaseema and Krishna Delta regions. But with 80 TMCs of Godavari water being diverted for Krishna Delta region, the entire Krishna river water meant for AP will be utilised for Rayalaseema region. Earlier the Krishna water meant for AP was shared between both the regions.

This move will help Rayalaseema region a great deal to get additional water. The region has very minimal rainfall, and revival of the entire Rayalaseema region depends on supplying water through irrigation projects.

Before Polavaram-Krishna river current flow:

Srisailam dam (Krishna delta share of AP Krishna water) -> Nagarjuna Sagar dam -> Prakasam Barrage

Srisailam Dam (Rayalaseema region share of AP Krishna water) -> Rayalaseema region

After Polavaram: Krishna river current flow:

Srisailam dam (Entire Krishna river water share of AP) -> Pothireddipadu Head Regulator -> Rayalaseema districts

Four Rayalaseema districts Kurnool, Kadapa, Cuddapah and Anantapur will benefit from the additional Krishna river water, which was earlier meant for Krishna delta region.

3. Beneficial to Northern Andhra districts:

The Polavaram Left Main Canal, running about 175 km, is designed to divert 24 TMC of Godavari water. Four districts East Godavari, Vizag, Srikakulam & Vizianagaram will benefit from Left Main Canal.

The diverted water will be utilised for:

1. Industrial, drinking water needs of Visakhapatnam city.
2. Irrigation & drinking water needs of East Godavari and Vizag districts. Water from Left Main canal is diverted to Yeleru reservoir which has a capacity of 24 TMCs. The water stored in Yeleru reservoir can be utilised for East Godavari and Vizag districts. 2.15 lakh acres across both the districts are benefited from Godavari water.
3. Government is exploring options to build reservoirs and to divert some of the water to Srikakulam and Vizianagaram districts.

4. Power Generation:
The hydroelectric power project will enable 960 Mega Watt power generation, which would be very crucial for the new state.

Miscellaneous facts:

1. Revised estimated Budget: 50,000 crores. Out of which 32,000 crores will be spent for land acquisition, relief and rehabilitation. A sum of 7000 crores has been spent so far for the project.

2. 32 lakh cubic metres of concrete will be required for the entire project.

3. About 2.7 lakh cubic metres of concrete work has been completed so far.

4. A huge mountain had to be cleared off as a part of spillway channel works.

5. Heavy machinery has been imported from many countries to speed up the construction process.

https://medium.com/@prasanth.garapati1992/polavaram-project-all-you-need-to-know-about-the-life-line-project-of-andhra-pradesh-ap-e295ef308895
 

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Discussion Starter · #5 ·
Polavaram powerhouse works in full swing



Earthworks’ component is scheduled to be completed by August, says Chief Engineer
Keeping the monsoon in view, the Polavaram authorities are busy undertaking earthworks of the powerhouse round the clock. The officials as well as the contractor have set a target of 1115.59 lakh cubic metres of earthwork of spill channel, approach channel, pilot channel, left flank, and spillway, and the daily target has been set at 1.57 lakh cubic metres. The contract for the 960 MW hydel project, to be undertaken at a cost of ₹3,220.28 crore, was awarded to Navayuga Engineering Company Ltd in December last. As per the agreement, the company has to complete civil and electro-mechanical works and AP Genco will take up the rest.
http://www.thehindu.com/news/national/andhra-pradesh/polavaram-powerhouse-works-in-full-swing/article23777773.ece
 

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53 per cent progress in Polavaram project

The officials explained that 72.6 per cent of the excavation for the spillway and spill channel was completed, i.e., 817.32 lakh cubic metres of 1,115.59 lakh cubic metres. This week, 5.59 lakh cubic metres of earthwork was excavated for the spill channel, pilot channel, spillway, left bank and approach channel.Concrete laying for the spillway, stilling basin, filling of crevices and spill channel, has witnessed a progress of 21.83 per cent, that is, 29,000 cubic metres have been laid this week, and the cumulative progress achieved is 8.03 lakh cubic metres of 36.79 lakh cubic metres.

They said that the Adavipalli Reservoir was expected to be completed by May 31. Works on the Kuppam Branch Canal will start next week as the contractor has been decided. Officials informed him that the canal would be ready for use by the end of June.

The Chief Minister also asked the officials to complete forest clearances and land acquisition for the Somasila Swarnamukhi and its linked projects, Althurupadu, Mallemadugu and Venugopala Sagar.

He also asked them to extend the Jala Samrakshana Udyamam till the end of June, making it a 139-day programme. About 85 per cent of tank feeder channels and 73 per cent of check dams and restoration of MI tanks have been completed. The CM said that the purpose of the extension was to ensure that all targets could be achieved keeping in view a 13 per cent deficit in rainfall so far.

http://www.newindianexpress.com/cities/vijayawada/2018/may/16/53-per-cent-progress-in-polavaram-project-officials-inform-andhra-pradesh-cm-chandrababu-naidu-1814791.html
 
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