Prof.T.Shivaji Rao,
Director, Centre for Environmental Studies, GITAM UNIVERSITY, Visakhapatnam
Bio-data-http://www.gitam.edu/old/www.gitam.edu/science/envstud/envr_achievements%5Cshivajirao.html.
Browse all the 7 (0 to 6) websites on Polavaram dam
POLAVARAM DAM SAFETY PROCEDURES VIOLATED BY AUTHoRiTIES.WHY?see web
http://www.cwc.gov.in/main/downloads/Report%20on%20DS%20Procedures.pdf
https://www.youtube.com/watch?v=jzxUgRqabsA [Morvi DAm Burst]
POLAVARAM DAM SAFETY PROCEDURES VIOLATED BY AUTHoRiTIES.WHY?see web
http://www.cwc.gov.in/main/downloads/Report%20on%20DS%20Procedures.pdf
https://www.youtube.com/watch?v=jzxUgRqabsA [Morvi DAm Burst]
(See other chapters from 1 to 8 of the above website)
http://www.sscac.gov.in/p_maindam.html [Drainage:88,000Sq.km.Design flood:1 in 1000 years:87,000 cumecs]
http://profshivajirao.googlepages.com/modifyingsardarsarovardam [sardar sarovar dam]
http://www.sfenvironment.com/articles_pr/2003/article/120503.htm [safety principles]
http://www.fmd-online.de/indien/news/Samata%20Report.pdf#search=%22pushkaram%20lift%20irrigation%20project%2CA.P.Government%20scheme%22[ Too costly project]
www.cehq.gouv.qc.ca/loisreglements/barrages/reglement/index-en.htm [ Safety Check Flood,Canada]
http://origin-www.courts.state.pa.us/OpPosting/Supreme/out/J-60-2002mo.pdf [PIL,pp.9&10]
The above 2 sites are good- Design Flood Criteria is for Dams for Asian and other countries .
Having accepted the use of a Design flood of 1 in 1000 years,of 87,000 cumecs for the catchment of 88,000 Sq.km.for Sardar sarovar project, how can CWCaccept blindly the Design flood of 1,02,000 cumecs for polavaram Dam for its 3.5 times higher adjoining catchment of 3,06,643 sq.km,unless CWC considers Polavaram Dam as a prescription for Disaster that kills 45 lakhs of people in the Godavari Delta.?[see EIA ]
some experts treat 500-year return flood as equivalent to 0.4 PMF in some specific cases
For the above graph see page 33 of http://www.partnerre.com/pdf/Flood-2002.pdf#search=%22%22Figure.8%3ARelationship%20between%20short%20term%20rainfall%22%22
Causes of dam breaks and their percentages due to Chinese statistics
No< namespace="" prefix="o" xml="true">
|
Causes
|
Percentage
|
1
| Overtopping, including 1) insuffiency of spill facilities 2) extreme flood exceeding design criteria |
51.5
42.0 9.5 |
2
| Piping and other seepage problems, including 1) Piping in dam body 2) Piping at foundations 3) Piping around spillway 4) Piping around tunnel |
29.1
22.7 1.3 0.6 4.5 |
3
| Other structural problems 1) Slope, slide of dam body 2) Quality trouble in spillway 3) Quality trouble in tunnel |
9.4
2.6 6.0 0.8 |
4
| Poor management, including 1) Decrease of reservoir standard for flood control due to over storage prior to flood season 2) Poor maintenance and operation 3) Temporary bag dam on spillway crest failed to remove in time 4) Nobody in charge of management |
4.2
1.1 1.3 0.5 1.3 |
5
| Others including 1) Spillway blocked due to blank slide in reservoir 2) Digging breach on dam face for discharging 3) Poor planning of general layout of project |
4.6
1.7 2.3 0.6 |
6
| Unknown |
1.2
|
The Chinese statistics show well that in a tightly populated country also small dams may cause potential hazards and threat to human lives. < namespace="" prefix="st1" ns="urn:schemas-microsoft-com:office:smarttags" xml="true">China has a significant dam & reservoir building program of 200 to 250 dams every year: Due to the establishment of rules and regulations and the development of modern techniques in design, construction, operation and management, only a few dam break events have happened in China after 1980. The potential risk for dam fallures and related hazards is nevertheless well understood in China, and the research on dam break dynamics has been evaluated one of the most important tasks for future development. http://www.hydrocoop.org/rsmgeneralstatus.htm
Dam Failures:USA[ASCE]
http://www.training.fema.gov/EMIWeb/downloads/ses3hthandouttech.doc
There are over 80,000 dams in the U.S. (FEMA 1993, 12). More than 20,000 have been rated as “significantly” hazardous, with about 10,000 of these rated as “high” hazard (FEMA 1993, 12). High hazard signifies that significant loss of life and property is likely.
35% of the high hazard dams have not been inspected since 1990. (ASCE 1998)
More than 2,000 communities are at risk from dams that have been identified as unsafe. (FEMA 1995, p. SM Sim 1-3)
A 6 March 1998 American Society of Civil Engineers report notes that in the past ten years more than 200 dam failures occurred (ASCE 1998). The report goes on to state that:
…an alarming number of dams across the country are showing signs of age and lack proper maintenance. Downstream development is increasing. Most older dams were build without adequate spillways to release water in heavy rains, which causes water to run over the top. Inadequate spillway capacities are the most common deficiency and a major cause of dam failures. Dam safety officials estimate that thousands of dams are at risk of failing or are disasters waiting to happen. (Quoted in National Hazards Observer 1998)
It has been estimated that the average cost of repairing one unsafe dam is approximately $500,000, meaning that it would cost approximately $1 billion to rehabilitate all unsafe U.S. dams (ASCE 1998).
“At the present time, about one-third of all dam failures are caused by over-topping due to inadequate spillway design, about one-third are caused by seepage through the dam and the remaining third are due to foundation problems and other effects, such as the liquefaction of earth dams as a result of earthquakes or landslide-generated waves within the reservoir” (Smith 1996, 318).
In May of 1889, over 2,200 people died when a 36-40 foot wall of water hit Johnstown, Pennsylvania, when an earthen dam failed (FEMA and NOAA 1996, p. III-28).
On March 12, 1928, the St Francis dam in Ventura County, CA failed catastrophically, releasing “[a] wall of water 60 meters high…into the [San Francisquito] canyon and dispersed into the Santa Clara Valley, through the towns of Piru and Fillmore on its way to the Pacific Ocean (Reisner 1993). The flood killed 450 people, destroyed 1,250 homes, and inundated 7,900 acres of prime agricultural land, thus constituting one of the worst human-made disasters in US history (Outland 1977).” (Bolin/Stanford 1998, 108)
1972: “a poorly maintained dam burst…in the coal mining valley of Buffalo Creek, West Virginia…[with] no warning and 125 people were killed and 4,000-5,000 were made homeless” (Smith 1996, 260).
1985, October 7: 29 people died in Puerto Rico when water overflows the in-need-of-repair Coamo River Dam and collapse a pan of the Las Americas Expressway (NRC 1994, 120).
1992, June 9: 238 people died in Rapid City South Dakota when the Pactola Dam failed after 15 inches of rain fell overnight causing the water to rise 12 feet behind the dam. Approximately $160 million in property damage was recorded. (Abbot 1996, 303-304)
Eminent Irrigation Expert , Dr.K.L.Rao WARNS AGAINST SAFETY OF POLAVARAM DAM
Extract from Indian Express (Vijayawada 1-5-1983)
In an exclusive interview to Express News Service Dr.Rao who is taking rest at Nellore said yesterday that there was not enough water in the Krishna to take up any new projects upstream without affecting the existing ones downstream.
Referring to claims of the people of Telangana region and the districts of Cuddapah and
Chittoor for Krishna waters through Srisailam right and left canals and extending the benefits of Telugu Ganga to more areas Dr.Rao said “They are fighting for water that is not there”
Dr.Rao ruled out the possibility of diverting surplus Godavari waters to the Krishna owing to defective designing of the Polavaram project and high cost involved in the Sriramapada Sagar project.
Only 1800ft spillway was provided in the Polavaram project to clear 40 lakh cusecs of flood waters in the Godavari as against 13,000 ft long Dhowlaiswaram anicut designed by Sir Arthur Cotton. Even Prakasam barrage was designed to 6,280 ft. long though the flood water would not be more than 12 lakh cusecs, Dr.Rao said.
It was simple arithmetic to understand that the Polavaram design would not work, he said.
EXTRACTS FROM GOVERNMENT OF ANDHRA PRADESH, IRRIGATION & C.A.D DEPARTMENT ON “POLAVARAM PROJECT” (TELUGU GODAVARI SUJALA SAGARAM) PREPARED BY POLAVARAM BARRGE INVESTIGATION CIRCLE, RAJAHMUNDRY, Oct-Dec 1986.
1. But it is after the confluence with Sabari that some of the most picturesque scenes of the world are seen. The Godavari begins to wind amongst the spurs of the Eastern Ghats, which gradually close on it, till it is forced to go through a picturesque gorge at papikonda which for 3km is as narrow as 200 or 300 meters. ( 200 to 300 feet as per Inchampalli project report of June 1970) The depths of the river in the gorge is between 30 to 80m at flood time. The hills rise with steep sides to heights upto 700 to 1000m and are clothed from the water’s edge to the summit with luxurious vegetations. When Dr.Kari Terzaghi, the great soil scientist visited this place, he was a complete ecastacy and remarked that such sights are almost unique and unparalled.
2. INTERSTATE ASPECTS : SHARING OF WATERS AMONG BASIN STATES:
The waters of the river Krishna and Godavari were allotted among the basin states as per the 1951 agreement. After the reorganization of the states in 1956 there were major changes in the boundaries of the basin states and all attempts for an amicable settlement between the party states proved futile. The Government of India, therefore, on 10-4-69 constituted the Godavari water disputes tribunal.
The tribunal could not take-up the hearing on sharing of Godavari water till April 1974 in view of its pre-occupation with similar issue on Krishna River. In view of this no new project could be taken up by any state. To resolve this crisis the Ministry of Agriculture, Government of India on 19-7-1975 has convened a meeting of the Chief Ministers of party states which paved the way for concluding bilateral agreements. These agreements were subsequently ratified on 19-12-75 under a common agreement. Further agreements have also been concluded which were incorporated in the final adjudication of Godavari water disputes tribunal dated 7-7-80.
As per clause VI of the final order of the Tribunal.
i) the Polavaram project shall be cleared by the Central Water Commission as expeditiously as possible for FRL / MWL +150ft.
ii) the matter of design of the dam and its operation schedule is left to the Central Water Commission which itself decide keeping in view of all the agreements between the parties including the agreement dated 2-4-80 as far as practicable.
iii) If there is to be any change in the operation schedule as indicated in the agreement dated 2-4-80, it shall be made only after consultation with the states of Andhra Pradesh, Madhya Pradesh and Orissa. The design aspects shall however be left to the Central Water Commission.
EXTRACT FROM REPORT ON INCHAMPALLI PROJECT (JUNE 1970), PWD, GOVERNMENT OF A.P.
Protection to establish and contemplated irrigation in Godavari delta: The last project proposed in the Lower Godavari basin is a barrage a Polavaram which is about 8 miles below Inchampalli dam. The canals of Polavaram barrage scheme follow on the same alignment as envisaged in the Rampadasagar project originally proposed in 1951 to serve the upland areas in Krishna, West Godavari, East Godavari and Vizag districts. The requirements for the canals taking off from the Polavaram barrge as well as the supplies for the existing Godavari delta system will be met from the regulated releases from the power house at Inchampalli with an MDDL of 360.00, the FRL required for Inchampalli reservoir is +390.00. The evaporation losses in the reservoir are about 80 TMC
Silt storage and dead storage:
The drainage area at Inchampalli is 1,00,300 sq.miles. This area will be intercepted by three main storages at Pochampad on Godavari (35,425sq.miles) at Watra Badruka Talai on Pranahita (36,900 sq.miles) and at Bhopalapatnam on Indravthi (14,013 sq.miles) and at Potgal on Lower Manair (2,567 sq.miles) near Karimnagar. Therefore the free catchment area at Inchampalli is 1,00,300-88,905=11395 sq.miles. The rate of silting from the free catchment is reckoned at 75 acre per 100 sq.miles of catchment per year. Further in the case of intercepted catchment, the rte of silting is assumed as 20 per cent of what is due from free catchment area. Therefore to provide at least 200 years life before silting encroaches on live storage, a dead storage capacity of 190.00 TMC will be required as detailed below.
1. 11,395 x 75/100x 4840 x 9 x 200 = 75 TMC
2. 88,905 x 75/100x 5 x 4840 x9 x 200 = 115 TMC
------------
Total = 190 TMC
------------
The corresponding dead storage level for 190 TMC is 359.50 or say 3 60.0 . As it is a key structure on the main river, catering not only to direct ayacut but also has to ensure supplies to the ayacuts under the Polavaram and Dowlaiswaram barrage a life period of 200 years is considered essential.
Extract of.Shivaji Rao's Talk at a SEMINAR on Water Management on 24-9-2006 ,Maruteru,W.Godavari .
Mr.Walch in his book on Engineering works on Godavari Delta says"Godavari drains 115,000 sq.miles area and produces maximum flood of one and a half million cusecs[15 lakhs cusecs].As Godavari begins to wind amongst the spurs of the eastern ghats,it forces its way through a gorge which for 2 miles is so narrow that a stone may be thrown from either bank into the middle of the river.During floods,the rocky river bed is scoured to great depths of 100 to 200 feet and the high floods rise to 50 ft.,there is a torrent from 150 to 250 deep.On 16-9-1849,high flood occured,with 33.5 feet mark at Rajahmundry and 25.4 feet mark at Dowleshwaram.
When I asked an experienced person on the Godavari Bank at Achanta about the depths of river banks above the river bed level,I was told that it varies from about 30 feet at polavaram to 40 feet at Rajahmundry , Dowleshwaram and Alamur and falls to 30 feet at Gannavaram and Achanta and will be 15 to 20 feet at Antarvedi
POLAVARAM BACKWATER AFFLUX - AP STATE GOVERNMENT
Name of the site
|
Discharge in cusecs
| |
30,00,000
|
36,00,000
| |
(i) Without Dam:
Polavaram Dam
Kunavaram
Konta
|
92.07
157.37
158.07
|
94.88 (28.92)
165.57 (50.46)
166.10 (50.63)
|
(ii) With Dam (and with different pond levels during
floods
(a) Polavaram dam
Kunavaram
Konta
|
140.00
163.80
164.23
|
140.00 (42.67)
170.09 (51.84)
170.75 (52.04)
|
(b) Polavaram dam
Kunavaram
Konta
|
145.00
165.85
166.23
|
145.00 (44.20)
172.03 (52.44)
172.33 (52.53)
|
(c) Polavaram dam
Kunavaram
Konta
|
150.00
168.23
168.54
|
150.00 (45.72)
173.97 (53.03)
174.22 (53.10)
|
POLAVARAM PROJECT – BACKWATER PROFILE CALCULATIONS< namespace="" prefix="o" ns="urn:schemas-microsoft-com:office:office" xml="true">
Name of the site
|
Discharge in Cumecs
| |||
85,000
(30 lakh cusecs)
|
1,02,000
(36 lakh cusecs)
|
1,36,200
(48 lakh cusecs)
|
1,54,300
(54lakh cusecs)
| |
i) Without dam
| ||||
Polavaram
|
28.06m (92.07ft)
|
28.92m (94.88ft)
|
30.6m (100.48ft)
|
31.5m(103.20ft)
|
Kunavaram
|
47.9 m (157.2 ft)
|
50.5m (165.8ft)
|
54.57m(179.0ft)
|
55.68m(182.7ft)
|
Konta
|
48.18m(158.1ft)
|
50.63m(166.1ft)
| ||
Bhadrachalam
|
54.23m(177.9ft)
|
57.09m(187.3ft)
|
61.76m (202.6 ft)
|
63.57m(208.6ft)
|
ii) With the dam (with different pond levels due to floods)
| ||||
a) Polavaram
|
42.67m(140ft)
|
42.67m(140ft)
|
42.67m(140ft)
|
42.67m(140ft)
|
Kunavaram
|
50.39m(165.3ft)
|
52.58m(172.5ft)
|
56.86m(186.5ft)
|
58.95m(193.4ft)
|
Bhadrachalam
|
55.38m(181.7ft)
|
58.04m(190.4ft)
|
62.89m(206.3ft)
|
65.16m(213.8ft)
|
b) Polavaram
|
45.72m(150ft)
|
45.72m(150ft)
|
45.72m(150ft)
|
45.72m(150ft)
|
Kunavaram
|
52.18m (171.2 ft)
|
54.18 m(177.8)
|
58.22m(191.0ft)
|
60.21m(197.5ft)
|
Bhadrachalam
|
56.40m(185.0ft)
|
58.93m (193.3)
|
63.64m(208.8ft)
|
65.88m(216.1ft)
|
Note: The above values are based upon the information from the Bachawat Tribunal Report and the calculations made by the author on the basis of the Advanced Numerical Methods using the Standard-step Method described by K.Subrahmanya in his standard book on flow in open channels.
GOVERNMENT GUIDELINES FOR ESTIMATING DESIGN FLOODS
Design Flood:
For the design of hydraulic structures like aqueducts, pick up weirs, anicuts, barrages, minor dams, medium and major dam spillways. The volume of the flood selected from economic considerations do not provide for handling the maximum possible flood from the catchment and hence they are designed for less severe flood because the damages likely to be caused by higher extreme floods than the selected design flood may not be very serious. Hence such selected flood used for the design is called the design flood.
Spillway Design Flood (SDF): SDF spillway design flood may be considered as the design flood used for spillway design and its maximum discharge can be passed through the spillway without causing any damage to the structure.
Stand Project Flood (SPF): SPF is defined as a flood resulting from a severe combination of Meteorological and hydrological factors reasonably applicable to the region. However extremely rare combinations of meteorological and hydrological factors are excluded. It is used where failure of the structure could not cause severe damages and its value is 40% to 60% of the Probable Maximum Flood (PMF) for the same drainage area.
Probable Maximum Flood (PMF): PMF is that extreme flood which is physically possible in a region due to extreme combinations including rare events of Meteorological and hydrological factors. PMF is used when failure of the dam would cause considerable loss of life and catastrophic damage and hence complete security from potential floods is essential.
Since design criteria for selecting the design flood for different structures like anicuts, barrages, small, medium and large dams vary from one country to another the guidelines formulated by the Central Water Commission [CWC] are presented in the following table.
GUIDELINES FOR SELECTING DESIGN FLOODS, (CWC, INDIA)
S.No.
|
Structure
|
Recommended design flood
|
1.
|
Spillways for major and medium projects with storages more than 60Mm3
|
a) PMF determined by unit hydrograph and probable maximum precipitation (PMP)
b) If (a) is not applicable or possible flood-frequency method with T = 1000years
|
2.
|
Permanent barrage and minor dams with capacity less than 60Mm3
|
a) SPF determined by unit hydrograph and standard project storm (SPS) which is usually the largest recorded storm in the region.
b) Flood with a return period of 100 years (a) or (b) whichever gives higher value
|
3.
|
Pickup weirs
|
Flood with a return period of 100 or 50 years depending on the importance of the project.
|
4.
|
Aqueducts (a) Waterway
(b) Foundations and free board
|
Flood with T = 50 years
Flood with T = 100 years
|
5.
|
Project with scanty or inadequate data
|
Empirical formulae
|
Ref: CWC India “Estimation of Design Flood Peak”, Report No.1/73, New Delhi, 1973.
| ||
Similar guidelines for design floods used for fixing the spillway capacity of dams issued by the Indian Bureau of Standards in 1985 are presented in the following table
SIZE CLASSIFICATION OF DAMS
Class
|
Gross storage (Mm3)
|
Hydraulic head (m)
|
Small
|
0.5 to 10.0
|
7.5 to 12.0
|
Intermediate
|
10.0 to 60.0
|
12.0 to 30.0
|
Large
|
>60.0
|
>30.0
|
INFLOW DESIGN FLOOD FOR DAMS
Size/Class (based on Table 7.9 (a)
|
Inflow design flood for safety
|
Small
|
100-year flood
|
Intermediate
|
Standard project flood (SPF)
|
Large
|
Probable Maximum flood (PMF)
|
Hydraulic Head : Hydraulic head is defined as the difference between the maximum water level on the upstream and the normal average flood level on the downstream side of the dam.
Ref: Indian Bureau of Standards “Guidelines for fixing spillway capacity” IS:11223-1985
EXTRACT from THE HINDU , 21-11-2006: CPI{M]DEMAND FOR REDESIGN OF POLAVARAM DAM
< namespace="" prefix="st1" ns="urn:schemas-microsoft-com:office:smarttags" xml="true">HYDERABAD: The CPI(M) State Committee has asked the Government to explore alternatives for the construction of Indirasagar (Polavaram) project as the present design will adversely impact the livelihood of lakhs of people, tribals in particular. The two-day meeting of the State Committee that commenced here on Monday observed that the design was not in tune with the probable maximum flood report of the Central Water Commission, national rehabilitation policy and draft national tribal policy. < namespace="" prefix="o" ns="urn:schemas-microsoft-com:office:office" xml="true">Maximum flood The probable maximum flood in the design was pegged at 47.67 lakh cusecs which was over 30 per cent higher than the 36 lakh cusecs maximum flood recorded in the Godavari's history. Given the huge damage incurred during the recent flood that recorded 28 lakh cusecs of flow, the damage that would be caused by 47.67 lakhs would be enormous.
Harmful impacts of Flood Banks While the Government was claiming that strengthening of flood banks would be a solution, it ought to recall the letter written by former Principal of Administrative Staff College of India E.A.S. Sarma that mentioned about the harmful impact of the flood banks.
Rehabilitation policy The party urged the Government to consider the recent national rehabilitation policy that made it mandatory to conduct a social impact study of projects. The draft national policy on tribals was against permitting any major project that would affect more than 50,000 tribals whereas over one lakh tribals would be displaced by the Indirasagar project. In view of this, the party asked the Government to explore alternatives that would ensure minimum submergence.
