NEED OF SHORE PROTECTION WORKS TO SAFEGUARD THE LAND SIDE FACILITIES TO BE CONSTRUCTED ON THE WESTERN SIDE
Jul 18, 2015
NEED OF SHORE PROTECTION
WORKS TO SAFEGUARD THE
LAND SIDE FACILITIES TO BE
CONSTRUCTED ON THE
WESTERN SIDE
NEED FOR SHORE PROTECTION
AT LAND SIDE
About 600 m to 700 m stretch of coast on the western side
breakwater is unprotected .
Due to the predominant northerly (westerly) drift, the coast
on the western side of the breakwater tends to be eroded.
By protecting the coast, in addition, the occasional break
out of the estuary water into the sea through the
unprotected coast line can be minimized.
Hence, it is necessary to provide a series of groins, at least
three groins to protect the coast line of nearly 630 m. This
would act as a shore stability structures for the safe
creation of land side facilities.
Satellite Map showing the Erayumanthurai side before
construction of Fishing Harbour
Feasibility Study By IITM Fisheries department, Govt of Tamil Nadu engaged the
services of Ocean Engineering Department in IIT Madras vide
Director's Letter no RC No :T1/7038/2012 dated
5.9.2013 .
The professors from Ocean Engineering Department of IIT,
Madras Prof. S.A.Sannasiraj and Prof.V.Sundar visited these
coastal area three times on 27.9.2013, 4.10.2013, and
20.11.2013.
The Chief Engineer, Fishing Harbour Project Circle, Chennai
and The Director, Central Institute of Coastal Engineering
for Fishery (CICEF), Bangalore visited these sites on
26.11.2013.
CICEF insisted for the Construction of RMS wall for Shore
protection of the western side of Main Breakwater in
Irayumanthurai, based on the report from IIT Madras and
expressed the immediate need of this works to safeguard
the Fish Landing Facilities for the Erayumanthurai side
villages.
Waves over flowing Land on western side of Main Breakwater
where the Land side Facilities proposed
TIDAL VALUES
Mean high water Spring tides level = + 0.79m
w.r.t Chart Datum
Mean high water Neap tides = + 0.59m
Mean Sea level = +0.49m
Mean low water Neap tides = +0.43m
Mean low water Spring tides = +0.18m
Waves over flowing Land - view from Main Breakwater
towards west
PROPOSED SITE DETAIL
Due to High wind waves on 15th April 2014 , the sea water
flowed over the Land area on western side of the main
breakwater where the land side facilities proposed.
In view of predominant long shore drift accompanied by the
cross shore sediment movement which is quite visible from
the field observation, coastal protection measures have to
be suitably proposed.
As the land side facilities are proposed to be over a strip of
land in between the Sea and the river Thamaraparani,
utmost care should be taken in protecting it from coastal or
river hazards.
From the coastal side, it is proposed to construct a seawall
of length about 650m, on the western side of the existing
western breakwater of Thengapattanam harbor.
Western side of main breakwater where 650m RMS wall is
proposed
LOCATION DETAILS
The Location of the 650m long RMS wall with +5m height is
proposed as below,
At the western end – from existing RMS wall on
Erayumanthurai side -UTM 738145.76mE and 912010.41mN.
At the eastern side – LS 50m of Main Breakwater - UTM
738668.32m E and 911628.61m N.
Western side of main breakwater where 240m Diaphram wall
is proposed
Proposed coastal protection by seawall
-1.0
0.0
+1.0
+2.0
+3.0
+4.0
+5.0
+6.0
NGL+0.7
-0.3
+1.7
+5.5
+1.16LTLHTL
3
1
2.51
2.51
CORE MATERIAL (50 kg - 300 kg)
QUARRY STONES OF 1.5T - 2.5T WITH 75% OF
GREATER THAN 2T (1.85m THICK)
TOE MOUND (500 kg - 1000 kg)
1.5
1
GEOTEXTILE LAYER
All Dimensions are in "m"
Proposed cross section of the seawall