3. Sédiment Transport
69
Indian National Centre for Océan Information Services (INCOIS) has
categorized the entire Indian coast into 4 zones
• Very high risk zones, VHRZ (Surge height >5m)
• High risk zone, HRZ (Surge height between 3-5 m)
• Moderate risk zone, MRZ (Surge height between 1.5 m to 3 m)
• Minimal risk zone (Surge height <1.5m).
The Indian Meteorological Department, classifies the tropical cyclones
based on their wind speed intensity as follows
• Super cyclone storm >222km/hr
• Very severe cyclone storm 118-221 km/hr
• Severe cyclone storm 88-117 km/hr
• Cyclone storm 62-87 km/hr
• Deep dépréssion 52-61 km/hr
• Dépréssion <51 km/hr
3.10.2 Case study
The Thane cyclone (29-30 December 2011) which hit the east coast of
Indian Peninsula was one of the most devastating cyclone that resulted
in significant damages along the Tamil Nadu coastline (13°26'40//N and
80°19/34//E to 8°17'41"N and 77°05/37"E). Waves as high as 8-12m in a
water depth of 20 m hâve been measured. Such huge waves, combined with
a storm surge of 0.5 m, lead to severe damages to Coastal structures during
the passage of the cyclone.
A measurement campaign to measure the characteristics of waves and
tides to understand the flow characteristics and sédiment dynamics in
between an existing groin field serving as Coastal protection on the north of
Chennai harbor (at 13°N) has captured the dynamics of a cyclone, Thane,
that had encountered during 25-30 December 2011. The flow field, that
is, orbital velocities normal (w) and parallel (v) to shoreline, and vertical
(w) hâve been measured using a directional tide gauge in a shallower water
depth of 5.0 m (St-4) and in a water depth of 8 m (St-2). A wave rider buoy,
commissioned in a water depth of 20 m (St-1), had recorded the directional
wave climate at an offshore distance of 6.5 km. The tide gauge is of pressure
sensor type, from which the surface élévation has been derived. It was of
bottom mounted type and hence, not suitable for deepwater deployment to
measure the wave climate. Any such measurement in deeper water might
69
Indian National Centre for Océan Information Services (INCOIS) has
categorized the entire Indian coast into 4 zones
• Very high risk zones, VHRZ (Surge height >5m)
• High risk zone, HRZ (Surge height between 3-5 m)
• Moderate risk zone, MRZ (Surge height between 1.5 m to 3 m)
• Minimal risk zone (Surge height <1.5m).
The Indian Meteorological Department, classifies the tropical cyclones
based on their wind speed intensity as follows
• Super cyclone storm >222km/hr
• Very severe cyclone storm 118-221 km/hr
• Severe cyclone storm 88-117 km/hr
• Cyclone storm 62-87 km/hr
• Deep dépréssion 52-61 km/hr
• Dépréssion <51 km/hr
3.10.2 Case study
The Thane cyclone (29-30 December 2011) which hit the east coast of
Indian Peninsula was one of the most devastating cyclone that resulted
in significant damages along the Tamil Nadu coastline (13°26'40//N and
80°19/34//E to 8°17'41"N and 77°05/37"E). Waves as high as 8-12m in a
water depth of 20 m hâve been measured. Such huge waves, combined with
a storm surge of 0.5 m, lead to severe damages to Coastal structures during
the passage of the cyclone.
A measurement campaign to measure the characteristics of waves and
tides to understand the flow characteristics and sédiment dynamics in
between an existing groin field serving as Coastal protection on the north of
Chennai harbor (at 13°N) has captured the dynamics of a cyclone, Thane,
that had encountered during 25-30 December 2011. The flow field, that
is, orbital velocities normal (w) and parallel (v) to shoreline, and vertical
(w) hâve been measured using a directional tide gauge in a shallower water
depth of 5.0 m (St-4) and in a water depth of 8 m (St-2). A wave rider buoy,
commissioned in a water depth of 20 m (St-1), had recorded the directional
wave climate at an offshore distance of 6.5 km. The tide gauge is of pressure
sensor type, from which the surface élévation has been derived. It was of
bottom mounted type and hence, not suitable for deepwater deployment to
measure the wave climate. Any such measurement in deeper water might