expertsmisleadonbackwaterimpactsofalamattidam

EXPERTS MISLEAD ON BACKWATER IMPACTS OF ALAMATTI DAM

Prof.T.Shivaji Rao, Director, Center for Environmental Studies, GITAM University, Visakhapatnam

 

WHY CWC IS NOT GIVING  DATA ON ALAMATTI BACK WATER CURVE AND DAMBRERAK ANALYSIS?see website: http://www.asianage.com/india/cwc-cic-draw-swords-over-info-979

http://tshivajirao.blogspot.com/2011/02/alamatti-back-water-curve-at_4653.html

It is shocking for people of Kolhapur, Sangli and Karad of Maharashtra and  Belgaum of Karnataka to know that hundreds of their  villages including major cities like Sangli and Kolhapur will be forcibly drowned frequently during rainy seasons and cyclonic periods due to heavy downpours that are bound to cause extreme floods such extreme floods have to be calculated on scientific lines and by using internationally accepted envelop cures as published by the top most experts like Lempererie of France and L.Berga of Spain who worked as Chairman, Technical Committees on Floods and Dams  of the International Commission on large Dams (ICOLD).  Unfortunately the Engineering experts of the CWC and the State Governments of Maharashtra, Karnataka and Andhra Pradesh chose to ignore the state-of-art technology on estimating the extreme floods expected in the catchment areas of Krishna river and its tributaries and they did not even consider the Probable Maximum Precipitation estimates made by International Hydrology expert like PR Rakhecha and others.  Consequently these Indian experts are deliberately underestimating the extreme floods expected in Krishna river basin and Godavari river basin inspite of the fact that the October 2009 floods in Krishna river proved that the spillway design floods estimated upto the previous decade do not hold good anymore after 2010 when the state-of-art technology must be followed to estimate the Probable Maximum Floods for calculation of backwater cures and to avoid dam collapses and to plan for safety of lakhs of people, their properties and agricultural wealth.  In the present case of Alamatti dam a comparative statement of the backwater calculations made by the CWC and the independent experts is presented in the following pages to create awareness among the people and particularly the farmers, the non-Governmental organizations, the intellectuals and the patriots like Anna Hazare who have to fight against the social evils being perpetrated by some of the unethical and immoral scientific and engineering experts who occupy possession of power and use the garb of development to destroy the life and culture of the farmers and farm workers who form the backbone of the social democratic welfare state.  Unless the people exert pressure over the elected representatives in panchayats, state legislatures and the parliament.  The present and future generations of Indian will stand to lose their right to life and the right to livelihood and right to natural resources as envisaged by the constitution of India.

 Backwater levels calculated from MWL/Maximum Flood Level as per Narmada Tribunal  Award

Sub-Clause II - Lands Which are to be Compulsorily Acquired.  

II(1) : Madhya Pradesh and Maharashtra shall acquire for Sardar Sarovar Project under the provisions of  the Land Acquisition Act, 1894, all lands of private ownership situated below the FRL + 138.68 m (455') of  Sardar Sarovar and all interests therein not belonging to the respective States. If on the basis aforesaid, 75 per cent or more land of a contiguous holding of any person is required to be compulsorily acquired, such person shall have the option to compel compulsory acquisition of the entire contiguous holding.  

II(2) : Madhya Pradesh and Maharashtra shall also acquire for Sardar Sarovar Project under the provisions of the Land Acquisition Act, 1894, all buildings with their appurtenant land situated between  FRL + 138.68 m (455') and MWL + 141.21 m (460') as also those affected by the backwater effect resulting from MWL + 141.21 m (460').  

II(3) : The backwater level at the highest flood level in Sardar Sarovar shall be worked out by the Central  Water Commission in consultation with Madhya Pradesh and Gujarat.

http://nca.gov.in/forms_pdf/nwdt_finalorder.pdf

Govt. of India,  Central Water Commission,  F.E. & S.A Directorate

Backwater study for Alamatti and Hippargi Reservoirs in Karnataka

1.      INTRODUCTION:  Director, Project Appraisal (S), CWC vide U.O. No.21/10/99-PA(S)/585 dated 29th May 2003 requested for an independent study by FE&SA Dte.. CWC regarding the backwater effects and submergence in Maharashtra territory due to  construction of Alamatti and Hippargi Reservoirs in Karnataka, in pursuance of the decision taken in the meeting held on 23-2-99 under the chairmanship of Chairman, CWC.  The original study regarding backwater effects and submergence in Maharashtra territory due to construction of Alamatti and Hippargi Reservoirs in Karnataka was carried out by Indian Institute of Science, Bangalore which was submitted by the Karnataka Government.  The then Direcotr (FE &SA) vide lr.No.CWC/DBAG/FE&SA/2001/602 dt.11th June 2003 observed that the methodology adopted for the back water study and the value of the rugosity co-efficient taken for the study were found to be in order.  However, in cae an independent confirmation of the result is required then necessary data/information may be supplied to FE&SA directorate. Subsequently, necessary data comprising of cross sections of Krishna river upstream of Almatti dam and Hippargi Barrage and rating curve of Almatti spillway submitted by Government of Maharashtra  and Karnataka were forwarded to this Directorate vide U.O.No.21/10/2004-PA(S)/1246 dated 22nd December, 2004.

Accordingly, a study was carried out in FE&SA Directorate using one-dimensional mathematical model MIKE 11.

2.      SCENARIO STUDIED: Following scenario were considered for study of backwater effects and submergence in Maharashtra territority due to construction of Almatti and Hippargi Reservervoirs in Karnataka;

1.      PMF discharge of 31000 cumec at Almatti and 24609 cumecs (proportionate discharge proportional to square root of catchment area as per suggestion of the February, 1999 meeting at CWC as mentioned in back water study report of IISC, Bangalore) at Hippargi taking Almatti FRL at 524.25m, considering both Almatti and Hippargi reservoirs.

2.      PMF discharge of 31000 cumec at Almatti and 24609 cumec at Hippargi taking Almatti FRL at 524.25m, considering Almatti reservoir only, as Hippargi is yet to be constructed.

3.      PMF discharge of 31000 cumec at Almatti and PMF discharge of 25485 cumec at Hippargi taking Almatti FRL at 519.60m, considering both Almatti and Hioppargi reservoirs.

4.      PMF discharge of 31000 cumec at Almatti and PMF discharge 25485 cumec at Hippargi taking Almatti FRL at 519.60m, considering Almatti reservoir only, as Hippargi is yet to be constructed.

5.      This yars discharge of 10100 cumec at Almatti and 9000 cumec u/s of Hippargi taking Almatti FRL  at 519.60m, considering Almatti reservoir only.

3.      STUDY RESULTS: The results of hydrohynaci modeling of Krishna river upstream of Almatti dam under various scenario, enumerated above, are tabulated in Tables 1 to 5 respectively.  The corresponding plots of water surface profiles are given in plate 1 to 5 .  From the above tables and plates it can be seen.

i)        The backwater profile of Almatti dam for FRL at 524.25m PMF discharge of 31000 cumec at Almatti and 24609 cumec at Hippargi, considering both Almatti and Hippargi reservoirs merges with water profile in the natural condition of Krishna river, just downstream of the Hippargi barrage (Table 1 and Plate 1).  Hence the backwater effect of Almatti reservoir is upto the downstream of Hippargi barrage is upto about 221 km upstream of Almatti dam.

ii)      The backwater profile of Almatti dam for FRL at 524.25m, PMF discharge of 31000 cumec at Almatti and 24609 cumec at Hippargi, considering Almatti reservoir only merges with water profile in the natural condition of Krishna river at about 145 km upstream of Almatti dam (Table 2 and Plate 2)

iii)    The backwater profile of Almatti dam for FRL at 519.60 PMF discharge of 31000 cumec at Almatti and PMF discharge of 25485 cumec at Hippargi considering both Almatti and Hippargi reservoir, merges with water profile in natural condition of Krishna river  just downstream of the Hippargi barrage (Table 3 and Plate3).  Hence the backwater effect of Almatti reservoir is upto the downstream of Hipprgi barrge only.  The backwater effect of Hippargi barrage is upto about 221km upstream of Almatti dam.

iv)    The backwater profile of Almatti dam for FRL at 519.60 , PMF discharge of 31000 cumec at Almatti and PMF discharge of 25485 cumec at Hippargi, considering Almatti reservoir only merges with water profile in the natural condition of Krishna river at about 126km upstream of Almati dam (Table 4 and Plate 4)

v)      The backwater profile of Almatti dam for FRL at 519.60m for this years flood of 10100 cumec considering Almatti reservoir only merges with water profile in the natural condition of Krishna river at about 175km upstream of Almatti dam (Table 5 and Plate 5).

4.      COMPARISION WITH IISC STUDY: The study carried out for case 1 and above has been compared with IISC, Bangalore study.  The trend of profile has been found to be matching.  However, there is a difference of 1-2m in water level at different cross sections of Krishna river u/s of Almatti dam.  This is due to difference in method of backwater calculation.  The IISC Bangalore has used the standard step method, which is an approximate method to calculate the profile.  In the above method, first the trial value of water level at the upstream location is assumed based on the known water level at the downstream location.  The velocity is then calculated dividing the discharge with the cross section area corresponding to assumed water surface.  This gives a lower velocity in comparison to the velocity calculated by MIKE 11 model using finite difference solution of St.Venants’s equations of conservation of mass and momentum.  Hydrodynamic modeling used in MIKE11 models the complete river stretch together to provide physically balanced water surface profile, which is more accurate than the approximate standard step method.

 Table-1: Back water calculations for Almatti FRL at 524.25m with  Almatti and Hippargi

(Discharge considered 31000 cumec at Almatti, 24609 cumec at Hippargi)

Cross-Sec No. As per data Supplied

Ch.U/S of Almatti dam (km) as per input data

Cn (km) as per MIKE  11 Set up

Manning’s “n” considered

Discharge considered (cumecs)

Bed  level (m)

Water level (m) without Almatti dam and Hippargi

Water level (m) with Almatti dam and Hippargi

14-14

250.64

0

0.0264

18785

524.33

543.97

543.97

13-13

246.64

4

0.0252

18808

523.92

543.31

543.31

12-12

229.84

20.8

0.0252

--

--

540.56

540.56

11-11

221.04

27.6

0.0268

21065

519.35

539.29

539.30

10-10

216.64

34.0

0.0242

21097

518.31

538.27

538.28

9-9

192.40

48.24

0.0242

22594

517.46

537.23

537.26

8-8

180.50

58.24

0.0242

22782

514.76

536.60

536.64

7-7

174.80

75.84

0.0242

23006

516.42

535.01

535.13

6-6

170.80

80.64

0.0259

23100

512.85

534.57

534.74

5-5

159.20

91.44

0.0257

23166

512.45

532.96

533.35

4-4

154.24

96.40

0.0245

23174

512.33

532.49

533.00

3-3

145.60

105.04

0.0245

24282

511.54

531.62

532.50

2-2

139.20

111.44

0.0245

24443

513.19

530.89

532.20

*A

 

126.00

 

 

 

529.24

531.75

*B

124.00

126.64

0.0245

24609

511.66

529.21

529.33

10B-10B

115.50

135.14

0.0245

24676

508.99

528.28

528.51

10A-10A

108.00

142.64

0.0245

24745

510.13

527.29

527.75

9A-9A

97.25

153.39

0.0245

25106

508.10

526.62

527.30

8A-8A

91.00

159.02

0.0245

25310

509.02

526.30

527.11

7B-7B

77.50

173.14

0.0245

25361

506.04

524.57

526.22

7A-7A

67.75

182.89

0.0245

25583

506.97

523.09

525.64

6A-6A

58.00

192.64

0.0241

25741

498.76

521.37

525.15

5A-5A

45.25

205.39

0.0244

25866

505.28

519.13

524.65

4A-4A

34.30

222.14

0.0239

25962

501.01

514.02

524.42

3A-3A

21.25

229.39

0.0257

26183

502.85

510.28

524.31

2A-2A

10.00

240.64

0.0283

30794

496.04

507.04

524.28

1-1

6.00

244.64

0.0267

30822

495.34

505.60

524.28

Almatti

0

250.64

0.0267

31000

489.12

502.95

524.25

*A -  C/S inserted for specifying Hipp.Barr

*B -  1-1 /11A-11A (Hippargi Barrage)

 Table-2: Back water calculations for Almatti FRL at 524.25m with  Almatti

(Discharge considered 31000 cumec at Almatti, 24609 cumec at Hippargi)

 

Cross-Sec No. As per data Supplied

Ch.U/S of Almatti dam (km) as per input data

Cn (km) as per MIKE  11 Set up

Manning’s “n” considered

Discharge considered (cumecs)

Bed  level (m)

Water level (m) without Almatti dam and Hippargi

Water level (m) with Almatti dam and Hippargi

14-14

250.64

0

0.0264

18785

524.33

543.97

543.97

13-13

246.64

4

0.0252

18808

523.92

543.31

543.31

12-12

229.84

20.8

0.0252

--

--

540.56

540.56

11-11

221.04

27.6

0.0268

21065

519.35

539.29

539.29

10-10

216.64

34.0

0.0242

21097

518.31

538.27

538.27

9-9

192.40

48.24

0.0242

22594

517.46

537.23

537.23

8-8

180.50

58.24

0.0242

22782

514.76

536.60

536.60

7-7

174.80

75.84

0.0242

23006

516.42

535.01

535.01

6-6

170.80

80.64

0.0259

23100

512.85

534.57

534.57

5-5

159.20

91.44

0.0257

23166

512.45

532.96

533.96

4-4

154.24

96.40

0.0245

23174

512.33

532.49

532.49

3-3

145.60

105.04

0.0245

24282

511.54

531.62

531.63

2-2

139.20

111.44

0.0245

24443

513.19

530.89

530.92

C/S inserted

 

126.00

 

 

 

529.24

529.36

1-1/11A-11A

124.00

126.64

0.0245

24609

511.66

529.21

529.33

10B-10B

115.50

135.14

0.0245

24676

508.99

528.28

528.51

10A-10A

108.00

142.64

0.0245

24745

510.13

527.29

527.76

9A-9A

97.25

153.39

0.0245

25106

508.10

526.62

527.31

8A-8A

91.00

159.02

0.0245

25310

509.02

526.30

527.13

7B-7B

77.50

173.14

0.0245

25361

506.04

524.57

526.25

7A-7A

67.75

182.89

0.0245

25583

506.97

523.09

525.67

6A-6A

58.00

192.64

0.0241

25741

498.76

521.37

525.19

5A-5A

45.25

205.39

0.0244

25866

505.28

519.13

524.69

4A-4A

34.30

222.14

0.0239

25962

501.01

514.02

524.46

3A-3A

21.25

229.39

0.0257

26183

502.85

510.28

524.36

2A-2A

10.00

240.64

0.0283

30794

496.04

507.04

524.33

1-1

6.00

244.64

0.0267

30822

495.34

505.60

524.33

Almatti

0

250.64

0.0267

31000

489.12

502.95

524.25

 Table-3: Back water calculations for Almatti FRL at 519.6 with  Almatti

(Discharge considered 31000 cumec at Almatti, 25485 cumec at Hippargi)

 

Cross-Sec No. As per data Supplied

Ch.U/S of Almatti dam (km) as per input data

Cn (km) as per MIKE  11 Set up

Manning’s “n” considered

Discharge considered (cumecs)

Bed  level (m)

Water level (m) without Almatti dam and Hippargi

Water level (m) with Almatti dam and Hippargi

14-14

250.64

0

0.0264

18785

524.33

543.98

543.98

13-13

246.64

4

0.0252

18906

523.92

543.32

543.32

12-12

229.84

20.8

0.0252

--

--

540.59

540.59

11-11

221.04

27.6

0.0268

21261

519.35

539.34

539.35

10-10

216.64

34.0

0.0242

21391

518.31

538.34

538.35

9-9

192.40

48.24

0.0242

22986

517.46

537.30

537.33

8-8

180.50

58.24

0.0242

23272

514.76

536.67

536.71

7-7

174.80

75.84

0.0242

23594

516.42

535.11

535.25

6-6

170.80

80.64

0.0259

23786

512.85

534.68

534.87

5-5

159.20

91.44

0.0257

23950

512.45

533.06

533.52

4-4

154.24

96.40

0.0245

24056

512.33

532.58

533.17

3-3

145.60

105.04

0.0245

25262

511.54

531.72

532.69

2-2

139.20

111.44

0.0245

 

513.19

531.00

532.40

*A

 

126.00

 

25485

 

529.35

531.97

*B

124.00

126.64

0.0245

25581

511.66

529.32

529.33

10B-10B

115.50

135.14

0.0245

25648

508.99

528.40

528.43

10A-10A

108.00

142.64

0.0245

25717

510.13

527.42

527.49

9A-9A

97.25

153.39

0.0245

26008

508.10

526.77

526.87

8A-8A

91.00

159.02

0.0245

26212

509.02

526.46

526.58

7B-7B

77.50

173.14

0.0245

26263

506.04

524.74

525.05

7A-7A

67.75

182.89

0.0245

26485

506.97

523.27

523.88

6A-6A

58.00

192.64

0.0241

26573

498.76

521.56

522.62

5A-5A

45.25

205.39

0.0244

26698

505.28

519.29

521.13

4A-4A

34.30

222.14

0.0239

26794

501.01

514.99

520.16

3A-3A

21.25

229.39

0.0257

26945

502.85

511.26

519.79

2A-2A

10.00

240.64

0.0283

30864

496.04

507.84

519.71

1-1

6.00

244.64

0.0267

30892

495.34

506.24

519.68

Almatti

0

250.64

0.0267

31000

489.12

502.95

519.60

*A -  C/S inserted for specifying Hipp.Barr

*B -  1-1 /11A-11A (Hippargi Barrage)

 Table-4: Back water calculations for Almatti FRL at 519.6 with  Almatti

(Discharge considered 31000 cumec at Almatti, 25485 cumec at Hippargi)

 

Cross-Sec No. As per data Supplied

Ch.U/S of Almatti dam (km) as per input data

Cn (km) as per MIKE  11 Set up

Manning’s “n” considered

Discharge considered (cumecs)

Bed  level (m)

Water level (m) without Almatti dam and Hippargi

Water level (m) with Almatti dam and Hippargi

14-14

250.64

0

0.0264

18785

524.33

543.98

543.98

13-13

246.64

4

0.0252

18906

523.92

543.32

543.32

12-12

229.84

20.8

0.0252

--

--

540.59

540.59

11-11

221.04

27.6

0.0268

21261

519.35

539.34

539.34

10-10

216.64

34.0

0.0242

21391

518.31

538.34

538.34

9-9

192.40

48.24

0.0242

22986

517.46

537.30

537.30

8-8

180.50

58.24

0.0242

23272

514.76

536.67

536.67

7-7

174.80

75.84

0.0242

23594

516.42

535.11

535.11

6-6

170.80

80.64

0.0259

23786

512.85

534.68

534.68

5-5

159.20

91.44

0.0257

23950

512.45

533.06

533.06

4-4

154.24

96.40

0.0245

24056

512.33

532.58

532.58

3-3

145.60

105.04

0.0245

25262

511.54

531.72

531.72

2-2

139.20

111.44

0.0245

 

513.19

531.00

531.00

*A

 

126.00

 

25485

 

529.35

529.36

*B

124.00

126.64

0.0245

25581

511.66

529.32

529.33

10B-10B

115.50

135.14

0.0245

25648

508.99

528.40

528.43

10A-10A

108.00

142.64

0.0245

25717

510.13

527.42

527.49

9A-9A

97.25

153.39

0.0245

26008

508.10

526.77

526.87

8A-8A

91.00

159.02

0.0245

26212

509.02

526.46

526.58

7B-7B

77.50

173.14

0.0245

26263

506.04

524.74

525.05

7A-7A

67.75

182.89

0.0245

26485

506.97

523.27

523.88

6A-6A

58.00

192.64

0.0241

26573

498.76

521.56

522.62

5A-5A

45.25

205.39

0.0244

26698

505.28

519.29

521.13

4A-4A

34.30

222.14

0.0239

26794

501.01

514.99

520.16

3A-3A

21.25

229.39

0.0257

26945

502.85

511.26

519.79

2A-2A

10.00

240.64

0.0283

30864

496.04

507.84

519.71

1-1

6.00

244.64

0.0267

30892

495.34

506.24

519.68

Almatti

0

250.64

0.0267

31000

489.12

502.95

519.60

*A -  C/S inserted for specifying Hipp.Barr

*B -  1-1 /11A-11A (Hippargi Barrage)

 Table-5: Back water calculations for Almatti FRL at 519.6 with  Almatti

(Discharge considered 10100 cumec at Almatti, 9000 cumec at Hippargi upstream)

 

Cross-Sec No. As per data Supplied

Ch.U/S of Almatti dam (km) as per input data

Cn (km) as per MIKE  11 Set up

Manning’s “n” considered

Discharge considered (cumecs)

Bed  level (m)

Water level (m) without Almatti dam and Hippargi

Water level (m) with Almatti dam and Hippargi

14-14

250.64

0

0.0264

9000

524.33

541.52

541.52

13-13

246.64

4

0.0252

 

523.92

540.83

540.83

12-12

229.84

20.8

0.0252

 

 

536.95

536.95

11-11

221.04

27.6

0.0268

 

519.35

535.18

535.18

10-10

216.64

34.0

0.0242

 

518.31

534.26

534.27

9-9

192.40

48.24

0.0242

 

517.46

533.48

533.48

8-8

180.50

58.24

0.0242

 

514.76

532.89

532.89

7-7

174.80

75.84

0.0242

 

516.42

531.00

531.00

6-6

170.80

80.64

0.0259

 

512.85

530.39

530.39

5-5

159.20

91.44

0.0257

 

512.45

529.50

529.53

4-4

154.24

96.40

0.0245

 

512.33

529.10

529.11

3-3

145.60

105.04

0.0245

 

511.54

528.24

528.29

2-2

139.20

111.44

0.0245

 

513.19

527.61

527.69

C/S inserted

 

126.00

 

 

 

525.96

526.10

1-1/11A-11A

124.00

126.64

0.0245

10100

511.66

525.91

526.05

10B-10B

115.50

135.14

0.0245

 

508.99

524.91

525.12

10A-10A

108.00

142.64

0.0245

 

510.13

523.88

524.20

9A-9A

97.25

153.39

0.0245

 

508.10

522.62

523.29

8A-8A

91.00

159.02

0.0245

 

509.02

521.92

522.78

7B-7B

77.50

173.14

0.0245

 

506.04

519.71

521.41

7A-7A

67.75

182.89

0.0245

 

506.97

518.24

520.71

6A-6A

58.00

192.64

0.0241

 

498.76

516.77

520.20

5A-5A

45.25

205.39

0.0244

 

505.28

515.29

519.86

4A-4A

34.30

222.14

0.0239

 

501.01

512.04

519.68

3A-3A

21.25

229.39

0.0257

 

502.85

508.37

519.62

2A-2A

10.00

240.64

0.0283

 

496.04

503.27

519.61

1-1

6.00

244.64

0.0267

 

495.34

501.64

519.61

Almatti

0

250.64

0.0267

 

489.12

497.45

519.60

 

According to the international Irrigation expert Dr.Lempererie, Chairman of ICOLD committee for France, the extreme flood is calculated by the formula S>3000Km2, Q=10,000(S/300)0.4 as published in his paper under the website:

http://bhujangam.blogspot.com/2010/12/dams-and-floods.html

http://www.hydrocoop.org/Shall_we_forget_the_traditional_design_flood.doc

The extreme Probable Maximum Flood for Alamatti dam with a catchment area of 35,200 sq.km works out to 67,300 cumecs.  However we opted to use 50,000 cumecs as PMF  value for calculating the backwater curve for Alamatti Dam by using Mannings coefficient of 0.05

 According to table-6 in the website the PMF in cumecs could be 2 to 3 times the catchment area measured in sq.km as in the case of Gandhi Sagar catchment area on Chambal river in Madhya Pradesh.  Hence the peak flood assumed by the CWC for Alamati dam is an underestimate and the backwater calculations are also under estimated and hence the engineers of the Karnataka and Maharashtra state are completely mislead on the issue of submersion of Sangli and Kolhapur areas due to backwater impacts of Alamatti dam.

http://onlinelibrary.wiley.com/doi/10.1017/S1350482700001389/pdf

Roughness Coefficients (Manning’s “n”) for Overland Flow

http://www.shippensburgtownship.com/2010-01/media/development/Table%20B-4.pdf

Surface Description

n

Dense Growth

0.4 - 0.5

Pasture

0.3 - 0.4

Lawns

0.2 - 0.3

Bluegrass Sod

0.2 - 0.5

Short Grass Prairie

0.1 - 0.2

Sparse Vegetation

0.05 - 0.1

Bare Clay-Loam Soil (eroded)

0.01 - 0.0

Concrete/Asphalt - very shallow depths

(less than ¼ inch)

- small depths  (1/4 inch to several inches)

 

0.10 - 0.1

0.05 - 0.1

Roughness Coefficients (Manning’s “n”) for Channel and Pipe Flow                 

Reach  Description

n

Natural stream, clean, straight, no rifts or pools

0.03

Natural stream, clean, winding, some pools or shoals

0.04

Natural stream, winding, pools, shoals, stoney with some weeds

0.05

Natural stream, sluggish deep pools and weeds

0.07

Natural stream or swale, very weedy or with timber underbrush

0.10

Concrete pipe, culvert or channel

0.013

Corrugated metal pipe

0.012 – 0.024*

Spiral rib metal pipe

0.012

Corrugated polyethylene pipe

0.020

Smooth-lined corrugated polyethylene pipe

0.012

* Based on pipe diameter and manufacturer’s design specifications

 

BACKWATER CALCULATION MADE INDEPENDENT EXPERTS.  SEE http://tshivajirao.blogspot.com/2011/02/alamatti-back-water-curve-at_4653.html

ALMATTI Back water profile Calculations 15-01-2011 (for n=0.05, 50,000 cumecs, 524.25 m  stage near Alamatti dam widths 1500 m)

 

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

Station

No. Trail

Elv. BL

depth,m

Elv.stage

Width

Area

Discharge

Velocity

Vel.Head

Total H

R

Sf term1

Sf term2

Sf

ALMATTI

0

489

35.25

524.25

1500

52875

50000

0.945626

0.045576

524.2956

33.66762

6250000

3.00395E+11

2.08059E-05

NH218

3

491

34.08388

525.0839

1500

51125.82

50000

0.977979

0.048748

525.1326

32.60226

6250000

2.69092E+11

2.32263E-05

N to Res Approach

1

494

31.13

525.13

1500

46695

50000

1.070778

0.058439

525.1884

29.88939

6250000

1.99976E+11

3.12537E-05

N to Res Approach

2

494

32.2211

526.2211

1500

48331.66

50000

1.034519

0.054548

526.2757

30.89386

6250000

2.23869E+11

2.79182E-05

A Res approach

3

494

32.2292

526.2292

1500

48343.8

50000

1.034259

0.05452

526.2837

30.9013

6250000

2.24053E+11

2.78952E-05

Res App to Algur

1

498

28.28

526.28

1500

42420

50000

1.178689

0.070811

526.3508

27.2524

6250000

1.45959E+11

4.28204E-05

Algur

4

498

30.39464

528.3946

1500

45591.96

50000

1.096685

0.061301

528.4559

29.21084

6250000

1.84906E+11

3.3801E-05

Al to Hippargi

1

508

20.45

528.45

1500

30675

50000

1.629992

0.135417

528.5854

19.9072

6250000

50263485051

0.000124345

Hippargi

4

508

24.35977

532.3598

1500

36539.66

50000

1.368376

0.095436

532.4552

23.59347

6250000

89400931672

6.99098E-05

Hi to Halyal

1

513

19.45

532.45

1500

29175

50000

1.713796

0.149699

532.5997

18.95835

6250000

42608510058

0.000146684

Halyal

4

513

23.90094

536.9009

1500

35851.42

50000

1.394645

0.099135

537.0001

23.16279

6250000

83981691905

7.4421E-05

Ha to Kudichi

1

514

23

537

1500

34500

50000

1.449275

0.107054

537.1071

22.31565

6250000

74009754815

8.44483E-05

Kudichi

4

514

25.91604

539.916

1500

38874.06

50000

1.286205

0.084318

540.0004

25.05043

6250000

1.09583E+11

5.70343E-05

Ku to Diggerwadi

1

515

25

540

1500

37500

50000

1.333333

0.09061

540.0906

24.19355

6250000

97360537527

6.41944E-05

Ku to Diggerwadi

2

515

23.96622

538.9662

1500

35949.34

50000

1.390846

0.098596

539.0648

23.2241

6250000

84738443941

7.37564E-05

Old Diggerwadi

3

515

26.56713

541.5671

1500

39850.69

50000

1.254683

0.080236

541.6474

25.65824

6250000

1.18889E+11

5.25698E-05

Odigg to Shaharpur

1

518

23.64

541.64

1500

35460

50000

1.410039

0.101336

541.7413

22.91764

6250000

81003413824

7.71572E-05

Shaharpur

7

518

28.1521

546.1521

1500

42228.15

50000

1.184044

0.071456

546.2236

27.13361

6250000

1.43803E+11

4.34621E-05

Shr to Narsobawadi

1

520

26.22

546.22

1500

39330

50000

1.271294

0.082375

546.3024

25.33431

6250000

1.13863E+11

5.48907E-05

Narsobawadi

3

520

27.28208

547.2821

1500

40923.12

50000

1.221803

0.076086

547.3582

26.3245

6250000

1.29723E+11

4.81797E-05

Nar to Ankali

1

525

22.35

547.35

1500

33525

50000

1.491424

0.113371

547.4634

21.70324

6250000

67346548672

9.28036E-05

Nar to Ankali

2

525

23.8858

548.8858

1500

35828.7

50000

1.395529

0.099261

548.9851

23.14857

6250000

83806770070

7.45763E-05

Ankali

3

525

25.8827

550.8827

1500

38824.04

50000

1.287862

0.084536

550.9672

25.01927

6250000

1.09121E+11

5.72761E-05

Ank to Sangli

1

528

22.96

550.96

1500

34440

50000

1.4518

0.107427

551.0674

22.278

6250000

73587073961

8.49334E-05

Ank to Sangli

2

528

21.14007

549.1401

1500

31710.11

50000

1.576784

0.12672

549.2668

20.56054

6250000

56070098083

0.000111468

Sangli

3

528

24.25576

552.2558

1500

36383.65

50000

1.374244

0.096256

552.352

23.49588

6250000

88151855212

7.09004E-05

















Comments :The information in this table clearly shows that Sangli city will experience floods due to backwater curve upto an elevation 552.35m while the backwater levels presented by the CWC experts show an elevation of flood only upto 544.0m . This difference is due to differences in the input data used by the different authors. The calculations made by the independent authors show that Sangli and Kolhapur will be submerged under the depth of more than 8m of floods due to backwater curve. Consequently hundreds of villages all along the course of the river between Kolhapur, Sangli and Karad districts and Alamatti dam will be submerged resulting in great losses.

 



 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


 

 

 

 

 

 

 

 

 


 

ĉ
Shivaji Rao Tipirneni,
Apr 29, 2011, 5:44 AM
Comments