NEED FOR BARRAGE AT THE ENTRANCE OF THE

TAMBRABARANIESTUARY

LAYOUT OF THENGAPATTANAM FISHING

HARBOUR

EnayamChinnathurai PuthenthuraiRamanthuraiMullurthuraiEraiyumanthuraiPoothuraiThoothur EzhuthesamChinnathurai Eravi PuthenthuraiVallavilaiMarthandamthurai Neerodi.

Satellite Map showing

Tambrabarani River Mouth on 3rd

may 2007

Fishing Crafts:Total population = 52,105Fishermen population = 28500Fishermen likely to be benefittedDirect Beneficiaries = 17401Indirect beneficiaries =5400

Fishing Crafts and Fishermen to be benefitted

FISHING CRAFTS BENEFITTED:

Motorised Fishing Vessels =676 NosFibre Vallams = 1432NosFibre Catamarans = 70 Nos

Designed accommodation 750 MFVs 300 nos of 12-13m and450 nos of 15-16m

• Fishing Harbour under construction at Thengapattanam is located at the estuary of river Tambraparani

• At river mouth, sand deposit is formed to about (+) 1.00m and above, which forms natural backwater.

• Water is always stagnating for about 4m depth in the tail reach of the river.

• Width of river mouth at Thengapattanam is 750 m.

• Some reaches in lower and upper lower plains, river width is only around 100m , which causes submergence of patta lands during flood season.

EXISTING CONDITION OF RIVER

• Ground level on estuary =RL +2.00 m to +2.4 m

• Bed levels in the estuary =2.0m to -3.5m • The average rise of the spring tide

=+.18m to +.79m w.r.t chartered datum(MSL=+.49m CD)

• The average rise of neat tides = +.43 to +.55m .

Estuary Details

SALT WATER INTRUSION PROBLEM

• If there is no barrage at the place where tambraparani joins estuary, the problem of influx of saline water during the high tide will affect the underground water quality of the nearby villages and severely affect the livelihood of people.

• The sea water entering estuary is diluted by the fresh water flowing from river.

• If there is no barrage across tambraparani river where it meets estuary there will be severe siltation which will reduce depth of water at estuary.

• Because of this siltation problem the entry of trawlers and other fishing vessels into the fishing harbour will be affected.

SILTATION PROBLEM

Tambrabarani River Estuary and

the river mouth on

Erayumanthurai side

 

• Maximum flood 4000 cumecs (141000 cusecs)

observed in NH 47 Bridge @ L.S 14.76 Km

upstream river mouth on 13-11-1992.This is

mainly due to overflow from four dams which

are• Petchiparai dam • Perunchani dam • Chittar I dam • Chittar II dam

Observed Maximum Flood(in 25 years

duration)

SI. No R.F. Station Year 1992

Nov.14

Year 2010

Dec 8

1 Petchiparai 220 mm 168 mm

2 Chittar I Not Available 194

3 Chittar II 97 136

4 Kuzhithurai 124 240

5 Thiruvattar 145 110

6 Adayamadai 177 235

7 Perunchani 200 204

Maximum Daily Rain Fall (in mm)

Causing Maximum Flood Damages in

Tambraparani Basin Area

• 1.Petchiparai dam – 27000 cusecs

• 2.Perunchani dam - 15000 cusecs

• 3.Chittar I dam - 2000 cusecs

• 4.Chittar II dam - --

• Total over Flow from Dams - 44000 cusecs

• 5.Kuzhithurai Sub-Path(River Mid Reach) – 78000

cusecs(8.12.2010)

• 6.River Mouth at Thengapattanam (Harbour Site) –

100000 cusecs approximately(8.12.2010)

Maximum Flood Discharge in

Tambraparani Basin (on 7.12.2010

Night)

Tambrabarani River Estuary where AVM canal

joins and Erayumanthurai Boat jetty.

Location L.S from River

Mouth

Flood Level Area

Submerged

Vaikalloor 1.71 KM

upstream

+3.80M 2KM stretch

in plain

terrain(Right

Flank)

Parthibapura

m Bridge

5.8 KM

upstream

+6.00M 1KM stretch

in plain

terrain(Left

Flank)

Kuzhithurai

Sub-path

14.76 KM

upstream

+7.50M 200M on

either side of

river

Submergence details(As on 8-12-

2010)

• If there is no barrage across tambraparani river where it meets estuary there will be severe siltation which will reduce depth of water at estuary.

• Because of this siltation problem the entry of trawlers and other fishing vessels into the fishing harbour will be affected.

• Also if there is no barrage at the place where tambraparani joins estuary, the problem of influx of saline water during the high tide will affect the underground water quality of the nearby villages and severely affect the livelihood of people.

Necessity for providing Barrage

• To avoid salt water intrusion in to the Tambrabarani river beyond estuary , a 140 m long barrage at the location where river meets the estuary , with its top level at +1.00m w.r.t Chart Datum must be constructed before connecting sea with river by removing the temporary approach to Main breakwater at the river mouth.

• The Location of the 140m long proposed barrage with top level of +1.00m w.r.t CD is as below,

• At the western end – on Erayumanthurai side -UTM 737978.38m E and 912819.50mN. 

• At the eastern side – UTM 738093.84m E and 912768.75m N.

Solution to Avoid Salt Intrusion

Location of Proposed Barrage

Photo showing the entrance of Tambrabarani

River Estuary where a Barrage is proposed. -

24Apr14