132
Coastal Engineering: Theory and Practice
Fig. 4.20 A few locations of protection measures along the Kérala coast.
S. no Nameofthe Site
Latitude
Longitude
1.
Ç.heryath.ur,
12’12'59.52"N
75’9’45.40"E
2.
Etttkulam
12’0'51.55"N
75’12'20.22"E
3.
port)
ll’56’7.90"N
75’19'53.49"E
4.
Korapuzha
11’23’52.44"N 75’44'34.64"E
5.
yadakara
Kozhikode
11’36'22.85"N 75’35'30.34"E
5.
Ronpjjji
10’46’3.79"N
75’55’33.24"E
7.
.ÇhdttMya
10’32'13.32“N
76’2'54.95"E
8.
Naravambalam
10’3'39.73"N
76’12'26.29"E
9.
Cochin
9’55'42.94“N
76’16'4.75"E
10.
KanatrnalJj
9’52'27.75"N
76’15'49.44"E
11.
cheiianam
9’50'11.11"N
76’16'25.38"E
12.
çbsUoujj i
9’48'24.97"N
76’16'38.76”E
13.
Allapey
9’29'44.34"N
76’20'19.68"E
14.
9’17'48.03"N
76’23'38.77"E
15.
Azh.ee.kai
9’ 7'54.54"N
76’27'49.92"E
16.
Jayanthi colony
8’53'31.75"N
76’36'51.82"E
17.
Thangasseri
8’53'6.68"N
76’34’8.68"E
18.
BOKJSIC
8’48'45.10"N
76’40'2.31''E
19.
P.Qo.nthura
(Thiruvananthap
uram)
8’26'25.15"N
76’56'54.92”E
overtopping créâtes scour holes at the interface between the land and the
seawall thus leading to its total collapse. In order to reduce the overtopping, gabion boxes of size 1 mxl mxl m was proposed as crown wall and
executed. This was found to be very effective in the last three years without
any damage (Fig. 4.24).
4.6.3.3 Failure of seawalls
As highlighted above, the seawalls hâve been continuously posing maintenance problems due to its failure. The detailed analysis of failure modes
leads to the following salient observations. Due to the low crest élévation,
the overtopping of water is inévitable even during high tide. Since there
is no provision for drainage facilities on the leeside, the water stagnation
poses threat. An inadéquate filter layer makes the érosion on the landward
side of the crown of the seawall that leads to subséquent subsidence of
Coastal Engineering: Theory and Practice
Fig. 4.20 A few locations of protection measures along the Kérala coast.
S. no Nameofthe Site
Latitude
Longitude
1.
Ç.heryath.ur,
12’12'59.52"N
75’9’45.40"E
2.
Etttkulam
12’0'51.55"N
75’12'20.22"E
3.
port)
ll’56’7.90"N
75’19'53.49"E
4.
Korapuzha
11’23’52.44"N 75’44'34.64"E
5.
yadakara
Kozhikode
11’36'22.85"N 75’35'30.34"E
5.
Ronpjjji
10’46’3.79"N
75’55’33.24"E
7.
.ÇhdttMya
10’32'13.32“N
76’2'54.95"E
8.
Naravambalam
10’3'39.73"N
76’12'26.29"E
9.
Cochin
9’55'42.94“N
76’16'4.75"E
10.
KanatrnalJj
9’52'27.75"N
76’15'49.44"E
11.
cheiianam
9’50'11.11"N
76’16'25.38"E
12.
çbsUoujj i
9’48'24.97"N
76’16'38.76”E
13.
Allapey
9’29'44.34"N
76’20'19.68"E
14.
9’17'48.03"N
76’23'38.77"E
15.
Azh.ee.kai
9’ 7'54.54"N
76’27'49.92"E
16.
Jayanthi colony
8’53'31.75"N
76’36'51.82"E
17.
Thangasseri
8’53'6.68"N
76’34’8.68"E
18.
BOKJSIC
8’48'45.10"N
76’40'2.31''E
19.
P.Qo.nthura
(Thiruvananthap
uram)
8’26'25.15"N
76’56'54.92”E
overtopping créâtes scour holes at the interface between the land and the
seawall thus leading to its total collapse. In order to reduce the overtopping, gabion boxes of size 1 mxl mxl m was proposed as crown wall and
executed. This was found to be very effective in the last three years without
any damage (Fig. 4.24).
4.6.3.3 Failure of seawalls
As highlighted above, the seawalls hâve been continuously posing maintenance problems due to its failure. The detailed analysis of failure modes
leads to the following salient observations. Due to the low crest élévation,
the overtopping of water is inévitable even during high tide. Since there
is no provision for drainage facilities on the leeside, the water stagnation
poses threat. An inadéquate filter layer makes the érosion on the landward
side of the crown of the seawall that leads to subséquent subsidence of