Introduction

  1. Nagarjunasagar Scheme is a multipurpose project, comprising a dam across the river Krishna and two main canals, one on either flank of the river with distributory system to provide irrigation water supplies to about 0.90 Mha of parched lands in 6 districts of Andhra Pradesh state. Besides irrigation water supplies, the project generates 960 MW of hydropower and supplies, industrial and urban and rural drinking water apart from providing regulated irrigation water to Krishna Delta system located on the downstream side of the project.
  2. Nagarjunasagar dam constructed across the river Krishna about 185 km upstream of Prakasam Barrage and about 140 km from Hyderabad is the largest stone masonry dam in the world. The dam comprises 1450 m long gravity masonry dam flanked by 2650 m long earth dam on the left side and 853 m long earth dam on the right side. The spillway is 471 m long and consists of 26 gates of size 13.72m x 13.41m each. The crest level of the spillway is +166.42m. The F.R.L and M.W.L are +179.95 and +181.10m respectively.
  3. The Nagarjunasagar Right Canal, called “Jawahar Canal” runs for about 203 km to irrigate 0.475 Mha in Guntur and Prakasam districts. There are nine branch canals with total length of 269 km and a vast network of distributory system running for a total length of 5342 km and 14,400 km of filed channels.

The Nagarjunasagar Left Canal, called “Lal Bahadur Canal” runs for a length of 180 km as main canal and a further length of 127 km as 21st Main Branch Canal to irrigate 0.420 Mha in Nalgonda, Khammam, Krishna and West Godavari districts. It has seven branch canals with a total length of 198 km and vast network of distributory system running for a total length of 7,722 km and 9,654 km of field channels.

  1. The Rehabilitation and Modernization of Nagarjunasagar irrigation system and Dam Safety works for Nagarjunasagar Dam have been taken up under one of the components of Andhra Pradesh State Water Sector Improvement Project (APWSIP). This involves various types of construction, construction materials, construction procedures and a variety of construction techniques as well as deployment of a wide range of construction equipment. Major part of the works under Rehabilitation and Modernization of Irrigation system comprise repairs to the existing structures, restoration/ replacement of damaged structures, rehabilitation of mechanical and electrical equipment, resectioning of canal sections along with improvement, whenever required as per Bureau of Indian Standards, as well as construction of new structures, replacement of some of the mechanical and electrical components (gates and associated hoisting arrangements, pumps, motors etc.). The Dam Safety works mainly relate to the repairs to the spillway glacis, repairs/ replacement of gates for diversion tunnel, improvement to lighting arrangement on dam and inside galleries, strengthening of foundation grout curtain, unchoking of porous drainage shafts in the dam body etc.

The works relating to the N.S. Canals system are being taken up under the following packages.

  1. Main and branch canals24 packages
  2. Major distributories (under Distributory Committees)80 packages
  3. Minor distributories (under WUAs)672 packages
  1. M/s SMEC International Pty Ltd., Australiain association with SMEC (India) Pvt. Ltd., Gurgon have been engaged by the Government of Andhra Pradesh as Consultants for the Engineering Design for APWSIP under contract agreement No. 2/ 2009-10 dated January 6, 2010. As per the terms of the contract agreement the Consultants have to conduct training programme for the Engineers of Nagarjunasagar Project. As a part of this, the First Training Programme was conducted from 25th to 31st march, 2011.

The training was conducted for three batches of Engineers at three locations in the Nagarjunasagar Project area, as indicated below

S.No / Venue / Dates / No. of trainnes
1 / N.S. Dam / 25th & 26th March, 2011 / 42
2 / Narasaraopet / 28th & 29th March, 2011 / 40
3 / Khammam / 30th & 31th March, 2011 / 29
  1. The following subjects were covered in the First Training Programme

(i)Design of canals

(ii)Aqueducts and Level crossings

(iii)Drops

(iv)Bridges and Culverts

(v)Under tunnels and Super passages

(vi)Regulators and escapes

(vii)Meters

  1. The Second Training Programme – 2012 is proposed to be conducted during March, 2012 as per the following programme.

S.No / Venue / Dates
1 / Khammam / 16th & 17th March, 2011
2 / N.S. Dam / 21st & 22nd March, 2011
3 / Narasaraopet / 26th & 27th March, 2011

It is proposed in this programme to deal with the design of structures, most commonly provided in the distributory system like drops, O.T. sluices, pipe culverts etc. and also the construction procedure relating to most common items of work like earth work, concrete work, C.C. canal lining etc., which will be useful to the field engineers of N.S. Project for understanding the design principles for the structures and execution of the works.

  1. Experts in the fields of the designs and construction of the irrigation projects will be engaged for delivering the lectures on various topics relating to designs and construction procedures. The details of venues and dates of training are given in Annexure 1(A) and the time table for the two day training programme is given in Annexure 1 (B).
  2. The examples of design of structures and the write ups on the construction procedures to be dealt with in the training programme will be supplied to the Engineers. It is expected that this will be helpful to the Engineers in execution of the works of Nagarjunasagar Project.

APWSIP

Consultants’ Services for Engineering Design1