DAMS & RESERVOIRS

http://osp.mans.edu.eg/tahany/dams1.htm#D A M S

PULICHINTALA PROJECT

PULICHINTALA PROJECT

 Pulichintala project on the river Krishna, estimated to cost Rs. 180 crore in 1988 impounds about 46 thousand million cubic feet (tm cft) of and directly benfits about 12 lakh acres of land in guntur & Krishna districts resulting in an additional yield of 3 qunitals of paddy per acre per year. The additional benfit was estimated ar Rs. 120 crore per year in 1988. The project generates 150 megawatts (MW) of electricity which will benfit  Nalgonda and guntur districts, the dam was 1290 metres long and 42 metres high is proposed to be built across the river krishna at Pulichintala village in Guntur district and nemalipuri village on other side of the river is Nalgonda district. The project is 120 km down stream project and above the prakasham barrage which goes waste into bay of bengal in August, September & October months in every year. The Pulichintala project which is a balancing reserviour with a capacity of 47 tm cft, doesnot have its own ayacut but strengthens the ayacutunder the prakasham barrage. The project does not have distributary canals, if pulichintala project becomes a reality, the ayacut under prakasham barrage need to depend on release of water from Nagarjuna sagar during nursery and transplantation of paddy periods the lower levels of water in nagarjuna sagar in august & september this year coupled with inadequate water in the prakasham barrage reserviour, transplantation of paddy in guntur and krishna district was delayed and the area under the paddy shrank. The pulichintala project will augment water in the prakasham barrage reserviour the surplus water impounded in the pulichintala reserviour will be released to the prakasham barrage reserviour  with rapid development  of 22 lakhs acre command area under the nagarjuna sagar project and constructions of dams in the upper reaches of krishna river in karnataka and maharastra , inflows into the prakasham barrage have been dwinding, dislocating the agricultural operations in the krishna delta . Incidentally the proposed project wil lreduce the road lenght  between chennai & Hyderabad by about 40 km and improves water table in parts of guntur and nalgonda districts adjoining the reserviour.

A balancing reservoir is proposed across river Krishna near Pulichinta Village in Guntur District ( 85.0 Km upstream of Prakasam barrage and 115.0 Km down stream of Nagarjuna Sagar Dam), for storing 45.77 TMC of water for stabilization of existing ayacut of 13.08 Lakh acres of Krishna delta and for early transplantation of paddy crop during June and July.

Administrative approval for Rs. 681.604 Crores was accorded by the Government vide G.O.Ms. No. 208 dt. 18-11-2005. Revised administrative approval for Rs. 1281.0 Crores was accorded by the Government vide G.O.Ms.No. 90 dt. 04-08-2009.  The construction of head works of the Project were entrusted to M/s Srinivasa Constructions Limited CR 18G JV, Hyderabad for their quoted amount of Rs. 268.87 Crores with a tender premium of less 18.4% and agreement concluded vide S.E’s agt. No. 1SE/2004-2005 Dt. 30/9/04.

CLEARANCES: - 

All the mandatory clearances to proceed with the execution of the Project were received.

1.River Basin                                KRISHNA

2.Location                   Village     : Pulichinta

                            Mandal    : Bellamkonda ,Guntur Dist.

                            Longitude: 80⁰ 03' 33'' E

                            Latitude   : 16⁰ 46' 14'' N

3.Reservoir             Guntur & Nalgonda Districts

4.Head Works in     Guntur & Nalgonda Districts

5.Area under Irrigation Stabilisation of Krishna delta (13.08 Lakh Acres in       

   Guntur, Krishna, West Godavari and Prakasam districts)

6.Head Works                                                                           

   a) Total Length of concrete dam        = 934.00 M

      i)N.O.F. on Left side                     = 232.75 M,                                                                         

     ii) N.O.F. on Right side                  = 141.00 M &      

    iii) Length of spillway                     = 560.25 M         

   b) Earth dam                                  = 355.00M                                    

7. Crest Level                                    =+36.34 M     

8. Size & No. of Gates            =18.50 M x 17.00 M  &24 Nos.                   

9.T.B.L.                                            =+ 58.24 M

10.MWL/FRL                                      =+ 53.34 M

11.M.D.D.L.                                       =+ 42.67 M

12.Deepest bed level of Krishna River   =+ 21.58 M

13. Maximum Designed Flood discharge =57,700 Cumecs (20,37,656 c/s)

14) Catchment Area between N.S. Dam to

      Pulichintala dam site                     =20,028 Sq. Kms.             

15.Gross Storage Capacity                    =1296 M.Cum. (45.77 TMC)

16. Live Storage Capacity                     =1026 M.Cum. (36.23 TMC)

17. Storage at Crest(+36.34m)             =102.24 M.Cum(3.61 TMC)

BENEFITS OF THE PROJECT:

1)Additional yield of Paddy can be achieved due to early transplantation of paddy crop, resulting an additional benefit to the ayactudars of Krishna delta every year.

2)Additional yield of pulses in Krishna delta resulting additional benefit every year.

3)Coconut trees can be grown on the bunds of nursery tanks which gives annual benefit.

4)Pisci culture can be developed in the reservoir to give an additional income

5)Hydro Electric power can be generated upto 120 MW.

•     Administrative Approval             = Rs. 681.604 Cr.

•     Revised Administrative approval = Rs. 1281.00 Cr.

  (G.O.Ms. No.90 Dt.4-8-2009)

   Details of Rs. 1281.00 Cr

   a) Head works                        = Rs.390.00 Cr.

   b) Land Acquisition                 = Rs.264.13 Cr.

   c) R&R                                   = Rs.364.72 Cr.

   d) Environment&Ecology(Forest) = Rs.109.73 Cr.

   e) Others( incl. establishment)  = Rs.152.42 Cr.

                                              -------------------

                                              = Rs.1281.00 Cr.

                                              -------------------

•           Value of Work                  = Rs.314.96 Cr.

 (Agt. amount 268.87+ Supplemental items (Agt to be concluded)+Rs.46.09Cr)

 Supplemental items =SLB to DLB=22.45Cr.Raised trunnion=12.91Cr. & Extra   stilling Basin=10.73Cr.

•   Storage Capacity (Gross)            = 45.77 TMC

•   Live Capacity                            = 36.23 TMC 

        

.............EDITOR

VELIGONDA PROJECT

                              VELIGONDA PROJECT

Our long-awaited tour to pula subbayya veligonda project began on the morning of 8^th july  2011. It was an exciting start.

 Prakasam district may have to wait for three more years for completion of its dream project, Veligonda that would bring 43.58 tmcft of Krishna water from the foreshore of Srisailam project to irrigate 3.36 lakh acres in its most backward upland areas.

  Veligonda project envisages drawing flood waters of Krishna river for 45 days in a year through two tunnels running over 18.8 km in the Nallamala reserve forest and empty them into Nallamala Sagar formed by closing three gaps in the hill ranges by constructing cement concrete dams at Gottipadia, Sunkesula and Kakarla villages near Markapur. Three canals would take off from the huge reservoir to supply water in all to 4.47 lakh acres in Prakasam, Nellore and Kadapa districts. The Rs. 5,150 crore project, which should have been completed by 2008, is bogged down due to delays in drilling the tunnels, construction of dams, acquisition of land for canals and rehabilitation of 11 villages that would face submersion.  
While L & T has completed the Gottipadia dam, the other two smaller dams are expected to be completed in one year.    Meanwhile, tunnel drilling was delayed due to technical problems hampering the project. As a tiger reserve is located in Nallamala forest, manual blasting was not permitted on the plea that it would affect the big cats.

Machinery imported:
Tunnel boring machines (TBMs) were imported from Germany and US at a cost of Rs. 200 crore each. The twin tunnels would cost Rs. 1,350 crore.   Work on the first tunnel was started in May 2005 and scheduled for completion in Dec 2013. After drilling the tunnel for over 3.4 km, the machine encountered gushing water and slushy soil. It increased its speed only to get stuck in mud and stopped work for the last 11 months. All efforts to restart the machine proved futile. Experts, who came from Italy, closed the seepages spraying costly chemical. They are working strenuously to restart the machine.
The experience was rewarding for the second TBM that also drilled the tunnel up to 3.4 km and encountered same problem. But it went cautiously arresting leakages successfully. Though started one year late, it has taken over the first tunnel now and forging ahead.

Chief Minister Late Dr. Y. S. Rajasekhara Reddy said that the Rs. 4,500-crore Veligonda project would be completed in the next three years to permanently end drought in Prakasam district.

The Rs. 120-crore machine was imported from Germany to make the tunnel without disturbing wildlife in the Rajiv Gandhi Tiger Reserve. No other State had taken up construction of such a huge tunnel for irrigation purposes. Beneath India’s largest tiger sanctuary, the Nagarjuna Sagar National Park, tunnel boring machines are orchestrating one of the largest water transfer schemes in India. A Robbins Double Shield TBM is boring tunnel No. 2 of the Pula Subbaiah Veligonda project for Coastal Projects Ltd. (CPL), of the CPL/ Hindustan Construction Company (HCC) JV.

On the Krishna River, on the right bank of the Srisailam Canal, lies the future inlet site for the Pula Subbaiah Veligonda Project. Once complete in 2014, the system will draw 1.2 billion cubic meters (317.0 billion gallons) of flood water annually from the foreshore of the Srisailam reservoir.   Two parallel, 19.2 km (11.9 mi) long tunnels will transfer water via a network of five canals to over 1,600 square kilometers (395,368 acres) of farmland in the three districts of Prakasam, Nellore, and Kadapa.  Up to 243 cubic meters per second (64,193 gallons per second) of water will travel through the bored tunnels to a feeder canal.

In October 2007, a USD $180 Million contract was awarded to Coastal Projects Pvt. Ltd (CPPL). In November, CPPL signed a contract for a 10.0 m (32.8 ft) diameter Robbins Double Shield TBM and continuous conveyor system. In addition to the machine and conveyor, spares and key operating personnel were sent to the jobsite to excavate tunnel no. 2 starting from the outlet end.

The Veligonda tunnel no. 2 is located in sedimentary rock on the western margin of the Cuddapah Basin, where a number of faults and folds make for complex geology.  Rock includes quartzite with interbedded shale (60%) and shale with limestone and phyllite (40%) ranging from 90 to 225 MPa (13,000 to 33,000 psi) UCS. Two major faults are expected along with some ground water.

The Double Shield machine utilizes sixty-seven 20-inch diameter back-loading cutters to combat the tough ground conditions. Specially designed drive motors allow the machine to run at a higher than the normal RPM, compensating for low penetration rates in the hard rock.  In squeezing ground, the cutter head is also capable of vertical movement  allowing for over boring. The machine also has a probe drill which allows for verification of geology 30 m (98 ft) ahead of the TBM.  The drill is capable of 360º rotation and can alternatively serve as a grout consolidation drill.  Large 40 kW (54 hp) dewatering pumps located on the back-up system have been specially designed to pump any water away from the tunnel face. As the TBM bores, it erects 300 mm (12 inch) thick concrete segments in a 6+1 arrangement, making the final tunnel diameter 9.2 m (30 ft).

Muck haulage requires one of the most extensive conveyor systems ever used in India.  The continuous steel cable belt, the longest single flight ever provided by Robbins, will extend 19.2 km (11.9 mi) and requires four main drives and three booster drives.


Finally, having kept the cherished memories of our   tour we returned to vijayawada on 9^th july 2011 at 2AM. It was not only a pleasure trip but also an educational tour that gave us a clear idea of our theoretical subjects. We thank Almighty God for bringing us safe and sound!

................EDITOR.