08 Feb 6 DECADES OF SEAWALLS; YET MISERY GOES ON UNABATED.
6 DECADES OF SEAWALLS; YET MISERY GOES ON UNABATED.
The erosion of beaches during the SW monsoon was long known to the administration, public and the beach-erosion-refugees. Even during the days of British Raj, engineering solutions were implemented (like building of groins and seawalls) in locations like the sea cliffs south of Papansam and at Anjego fort. In the post-rai India, despite huge investments and 290 km of sea wall of all ages, problem of beach erosion continues unabatedly. Settlers on the backshore of beaches in Kerala, continue to cry for protection of their property by building more seawalls. From time to time, Government and politicians afford a very patient ear to such demands as the seawall projects are obviously, are acts of pork barreling.
Instead, I take a point of view that the anti-erosion-project-funds also should be used for construction of clusters of tenements for the immediately affected.
Kerala, one of the littoral states of the union, with a shoreline of about 560 km. has a coastal land (elevation.=
Yet, this patch of land stuck at SW edge of the peninsular India, has problems and opportunities, primarily due to relatively higher density of population, better average literacy in comparison with the rest of the country (of course with the exception of New Delhi) and relatively a commendable better quality-of-life-index.
Kerala is handicapped by very few occurrences of economic mineral resources (with the exception of Black mineral sand and china clay and some gold that becomes viable in the new gold price hike), and practically low level of industrialization.
Yet the only glimmer of hope is the plantation sector (viz., coffee, tea and cardamom in the higher elevations), where fortunes are typically in roller-coaster and especially rubber plantations in the lower elevations including large swaths of midland (elevation=7.5-75.0 m. above m.s.l.). But for Palakkad dist., paddy farming as a pursuit is facing nearly insurmountable difficulties.
Historically speaking, the British tried to afford protection from wave erosion to the Anjengo Fort and the eroding cliffs south of Papanasam beach at Varkala, (both in Trivandrum Dist.,) by placing a battery groynes (circa 1935 AD), which are shore perpendicular stone “walls” of relatively low-length-to-width ratio .
Soon after independence, to prevent the monsoon-season-erosion of the beaches, construction of seawalls and beach nourishment with sand of design gradation was the chief engineering interventions.
These were tried and experimented in the sector of a beach in Thottapally (now in Alappuzha dist.). Two American engineers (Mr. Watts and ) in fact demonstrated the efficacy of seawall – a pack of rubble with a cladding of large blocks of designed size –with a relatively deep foundation with its toe facing the sea and heel turned landward.
During monsoon beach erosion, the promise of sea wall became an integral part of relief package with shelters for the displaced population in schools along with free soup kitchens, primary health care and some amount of financial compensation to those who lost homes fully or partly.
Truly, the foundation of seawall is very much comparable to human feet. This structure is given a cladding of huge dimension stones and size of each block is a determined by the hydrodynamics, wave characteristics, nature of beach material and so on. Beach nourishment, however, was never pursued later.
Seawalls: a great porkbarrel
Funds for seawalls are part of central grants. According to one estimate, about 300 km of the 560 km shoreline has been protected by seawalls belonging to several generations and through all the five-year-plans. However, “this sweet-pot” has started drying up. A rough estimate says that at so far, least (300km x Rs.2.00 crores/km) or Rs.600 crores of rupees have gone into the seawall, and the mind set of the immediately affected population is such that they are crying for seawalls. Until now, no civic leader or political out fit in Kerala, had searched for or thought of any alternative. That is the intention of this note.
A different model
Are seawalls the only remedy? Way back in the late 70’s, in a brain-storming session organized by the CESS, a famous Marine Geologist at that time with the Geological Survey of India, but later joined as Director of the NIO, Panaji, (late) Dr. Siddique,H.N., proposed and I restate, ” possibly nothing tangible could be done to prevent wave erosion of beaches and coasts of Kerala, which is only a manifestation of SW monsoon waves dissipating their energy. Further, SW monsoon is triggered by an atmospheric condition prevailing in the central Indian ocean, say at least 500 km, away from the west coast of India.
Or else, by way of a permanent solution, there is not much one can do about erosion of the beaches during SW monsoon. The erosional phase of monsoon wave climate, is closely followed by, just like the two sides of a coin, a beach reconstruction phase by re-deposition of sand from the seabed.
Interestingly, it is during this phase of reconstruction of eroded beaches in the Chavara-Kayamkulam segment, that large volumes of ilmenite rich black sand (running into a few million tons) along with subsidiary monazite, garnet etc are welded to the shoreline. This raw sand has long been the chief source of mineral separation plants operating this region, which produce rutile for the titanium dioxide pigment industry (and recent program for the possible manufacture of sponge Titanium metal-a joint sector initiative between KMML-and ISRO with Russian technology).
Yet another offshoot of ferocity of SW monsoon waves, is what is known as mudbanks (named so by Mr. Bristow, the founder of Cochin Port), a unique phenomenon a suspension of fine sandy-mud in sea water in the inshore region, which also acts as a very effective off-shore breakwater, affording protection to the beaches on the shore-side.
An attendant-bonus of monsoon wave setup is the mud-bank-fisheries, which has been around right from the days of organized commercial fishing. For instance, the story of the movie “Chemeen”, based on a Malayalam novel of the same name by late Thakazhy Sivasankara Pillai, is set in the background of fisheries or fish-harvesting during the eruption of a mud-bank at Purakkad, a coastal hamlet in Alappuzha dist.
I might also add that this phenomenon, in the coastal waters of Kerala (between Thirkunnapuzha and Kozhikod), has been enjoyed by the fisheries sector, ever since the monsoon had set in the proto-Laccadive sea.
New Potential Strategies
With this background of Kerala monsoon’s bounty on the one hand and the and influx of “monsoon refugees” on the other, the points I state below might be an interesting side bar for you. The State Planning Board (SPB) also could examine these.
Long-term measures for to protect coastal population
Instead constructing the seawall at the current price of Rs.50 million/km, ( I could be little bit anachronistic about coasts, but that is beside the point any way), at your behest, SPB can recommend construction (using the same fund) of 3 or 4 storey (or say 9.0 or 12.0 meter tall) residential blocks to permanently rehabilitate the affected families, that had to move to the relief shelter annually and consecutively during the last 5 yr. (A better basis can be worked out by the SPB).
Such residential blocks would have free ground floor (as if the building stands on stilts) open of the block (Carpet area can be again some thing board can identify. Further, such blocks are to be constructed with a set back of at least 500 m, landward of the high-tide-line as stipulated in the CRZ act. The required land needs to be acquired by the government.
On the contrary, whenever land scarcity and acquisition process bogs down the construction project residential blocks standing on concrete stilts can also be considered. Such blocks can effectively handle and survive the backshore flooding and potential loss to the residents.
Piped in safe water to the coastal population is now met locally from the coastal aquifers, which get salty in the lean months of the summer. Another”brilliant” proposal Is to construct large reservoirs in the midland or low highland to store water and then distribute the same to coastal population. Alternatively, RO desalination of brackish (lagoon) or saline (sea) water needs active consideration of the board. For cities in the coastal land, supplementing the drinking water from desalination (based on reverse osmosis) can alone solve their water shortages.