Gcians on cliff walk-Varkala, Aug.27, 12

Cliff Walk:  Gcians on foot to Papanasam North Cliff, Geologycafecliffwalk, Aug, 27

(Reliving of my nostalgia)

The cliff walk invented, initiated and promoted by the GC, had participation by geoscientists of minimum three generations. The gen III, was represented by at least nearly half a dozen student gcers, gen-II by some five guys and gen-I exclusively by me.

Thus the program of GC naturally crossed the gen boundaries; aptly mirrored the vibrancy of the GC fraternity and confidence about the future too. The cliff walk started off at Panasam. Professionals (like Manu, Sajith Girinathan and Anil Das, Santosh), academics (viz., Jai kiran,  Pradeep kumar and me) and a fellow geologist and GIS expert professional Riju Stephen added to scientific glitter social wellness to the trip.

The trippers who assembled at the Papnasam beach, were sincerely welcomed by Jaikiran (spirit and lead mover of GC), followed by a brief self introduction session by participants and finally toward the at the end Jaikiran sort of handed the “mike” over to me.

After brief introductory remarks, I narrated the generalities of the Warkalli series and then moved northerly along the beach to stop at the first exposure of the carbonaceous clay at the foot of the cliff.

The significance, specialties, implications of carbonaceous clay (argillaceous facies) were retold to the group. The alternation of organic matter rich and silt rich layers with occasional marcasite tubes of 4 to 6 mm are the hallmark of the carbonaceous clay (argillaceous) bed. Efflorescence of light yellowish Natrojarosite (first report appeared in the Bull GSI, by a visiting Brit. Geologist who was a member of the 1964 IGC, New Delhi) laces the surface of carbonaceous clay bed.  The base of this bed is covered with a thick talus cover mostly of lateritic nature.

In addition the carb.clay samples in a dark room under a UV lamp fluoresced in orangish-yellow glow, indicating presence of uranium in the oxide state. By the way, uranium is a very mobile element and is deposited quickly in a euxenic environment and here in this case the carbonaceous cla forming environment just did that.

This bed is over lain by a bed of sandstone (arenaceous facies) coloured reddish brown at the bottom half of the exposure and yellowish brown on the upper half of the sandstone. Ripple cross lamination and dune cross bedding are characteristic of this arenaceous layer.

This arenaceous layer is overlain by an argillaceous sandstone and as one goes up section (team did not walk all the way up to look at this), what is noticed is its sort of gradual or imperceptible transition to laterite which is a very thick layer and more ferruginous at the top and less ferruginous at the bottom, i.e., toward the bottom transition layer of argillaceous bed.

This laterite capping stands at near vertical or even overhangs with a free face of roughly 10 to 13 m. Occasionally horizontal gashes, of far less lateral extent are noticed, which are interpreted as indications of original bedding or break in sedimentation in the sediment that transformed it self to laterite.

The free face, physically distinct from its base, has a cover of talus of blocks and boulders of laterite as well as the reddish sandstone. The free face is also called the waning slope, while the talus covered section is aptly denoted as waxing slope.

Further north springs are active, which emerges immediately above the carb.clay horizon. Legend has it that these springs are medicinal in nature. A piece of research exists in a MSc (chemistry) thesis submitted to Travancore University, where the attribution is to the presence of radon (?) in the spring waters.

Further these springs are ephemeral, in that they disappear at the peak of summer, while springs in the road to Sivagiri and flowing easterly are perennial in nature. Interestingly the easterly and westerly subsurface discharge in the springs indicate some sort of a subsurface divide doing this forcing.

My talk show thus ended with a thank you not to the GCians.

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thrivikramji@gmail.com

 geology cafe cliff walk thrivikramji

Origin of Diagenetic Pyrite in the Quilon Limestone, Kerala, India K. K. MENON

Letters to Nature

Nature 213, 1219-1220 (25 March 1967) | doi:10.1038/2131219a0; Received 28 November 1966

Origin of Diagenetic Pyrite in the Quilon Limestone, Kerala, India

K. K. MENON

1.     Department of Geology, University of Kerala, Trivandrum, India.

Topof page

Abstract

ALTHOUGH microscopic pyrite from marine and non-marine argillaceous sediments of most geological ages has been extensively studied, its mode of origin has not been clearly understood. Berner¹ and Kalliokoski² attributed the origin to the reaction of hydrogen sulphide formed by sulphite reduction, with iron-bearing minerals in sediments; but these minerals were not discovered. I have recorded framboidal and other types of diagenetic pyrite in the thin bed of marine, fossiliferous, Quilon limestone³ of Burdigalian age⁴. Recent examination of the heavy minerals from limestone samples at Padappakara the type area has brought forward some new evidence, which clearly establishes that the fine-grained pyrite was produced by an alteration of detrital, iron-bearing mica, optically identified as biotite.

MINE SEA SAND - Why not?

MINE SEA SAND - Why not?

Prof. (Dr.) Thrivikramji. K.P. (Retd.)

University of Kerala, Dept. of Geology

Kariavattom Campus 695 581

Sea sand – a part of the mixture of clay and sand that gathered in the sea bed during the last several 10’s of million years - finally graduated as a promising substitute for vanishing river sand or the fine aggregate, along with cement in the construction industry. The proposal for dredging of seabed is wrought with several objections, viz., a). Loss of the fishing ground (hence livelihood of thousands of fish workers and their families); b). “Death” of the mud bank and consequent “demise” of Chakara; c). Deepening of the seabed to the disadvantage of opportunities for fisheries; d). Aggravation of beach erosion by waves, and e). Aggravation of water scarcity in the already water scarce coastal belt due to water washing of salty sea sand to remove salt for sale.

Firstly, some unknown facts about sand. For the layman sand is the granular, nearly clean accumulation of relatively hard natural material covering the riverbed, the sandy beaches, small and large deserts and a chief component enhancing soil quality and hence profitability of the farmer. If sand is not available from any of these sources, then one will go blast the rock –the ultimate source - crush and grind it to manufacture sand.

For the specialist sand is mineral quartz, SiO2, and has no doubt about the existence of an extensive sheet of sandy-clayey sediment and associated heavy minerals, hidden below the vast expanse of seawater of the Laccadive Sea, adjacent to the mainland in the continental shelf with in a depth of 100 m. As far as Kerala goes, the area of the continental shelf is almost as large as 4 to 5 sixth of the 38, 855 Km2 land area.

Most people do not worry about the ultimate source of sand and for them, source is where it is found. It is untrue. Sand is an original constituent (~1/3 of the bulk) of the common crystalline rocks, The latter is now also marketed as sawed and polished slabs, as raw stone for foundation. Lions share of the 2/3 of bulk is feldspar – an aluminum silicate of potassium or sodium and calcium. The accessories (the ferromagnesian  silicates) and heavy minerals (ilmenite, sillimanite, zircon, garnet and monazite) together contribute to 1 or 5 % of the total.

A process known as chemical weathering, Wc, unique to the monsoon climate of clear wet dry spells, is responsible for transforming the hard crystalline rock in to a state (soil formation) enabling running water to erode and transport the constituent rock minerals (soil erosion) to new sites of deposition. Wc also chemically converts feldspars and ferromagnesian minerals to a group of minerals called clays. Quartz and heavy accessories are an exception. This Wc, an extremely slow process, and a 1.0 m. thick slab of crystalline rock takes at least a million years to weather to soil or laterite. The water erosion did remove all the minerals including the clay. While the quartz and heavy (black sand) traveled down the river by rolling and jumping on the riverbed during flood, the micron sized clay physically floated down river in times of flood at the very same velocity of floodwater to reach the final resting place in the sea bed.

Land, Sea and Sand

In fact, a portion (6500 Km2. of the coastal land) of today’s land area (38855.0 Km2) of Kerala, is only a later addition, in the last 12,000 years ago, i.e., by end of the last glaciation. Coastal land added by deposition of SW monsoon wave driven seabed sand.

During the Pleistocene (1.8 ma ago), due to at least 4 different phases of continental ice sheet and glacier ice advances, the sea level did stand well below 100.0 m. exposing vast expanses of the continental shelf around the continents. Kerala was no exception. As a result, a shelf area nearly equivalent of present extent of Kerala stood above sea level, enjoying a sub-aerial environment and forcing the Kerala Rivers to have a longer run up, say 30 to 40 Km. more to the then shoreline. Thus, today a large alluvial deposit of sandy-clayey nature sits in the sea bed.

But then, on set of monsoon climate in Kerala ~50-55 M.a. ago, initiated Wc, Consequently during the same time span at least 50-55 m of crystalline rocks would have been transformed to laterite/soil, and that too along the length and breadth of the 30000 Km2 (pre-Pleistocene area) of the state. And handsome portion of the detritus (heavy mineral laden sandy-clayey sediment) must be now sitting in the Laccadive sea bed. A portion of the latter is has already been deposited (since the Pleistocene) as the low coastal land. This process of deposition continues even today, driven by the monsoon waves to renew the blacksand deposit in the Chavara – Neendakara – Thirkunnapuzha sector.

Myths of Sea Sand Mining Uncovered

The response of fisheries potential to sea sand mining is beyond my specialty and hence not addressed in the following. Let us examine the concerns one by one. The chakara, a relatively thick suspension of bottom mud (like a submerged break water) triggered by the onslaught of the SW monsoon waves on the seabed sediment appears between Thirkunnapuzha and Kozhikode. The nutrients stirred up from bottom, attracts large schools of fish and fish-workers like a magnet. The fundamental requirements for chakara are the wave climate and substrate of mud. The dredging process automatically enhances the mud content in the sea bed and hence only adds to strength and vigor of chakara.

The dredging removes large volumes of sand and hence will lower sea bed. Look at the ship channels in the Kochi harbor that require dredging of huge volumes of sediment to maintain a draft of 13.8 m. This dredging is due to reasonably fast redistribution of bottom sediment by the currents. In the sea, currents are much vigorous and probably of longer duration, tending to repair the depth changes at the heel of dredging. Further, the dredging related disturbance at no point in time exceeds a tract of 15-20 times the diameter of the length of the dredger. More over the monsoon wave climate should be a quickest sediment redistributor and a healer of the submarine scars.

The Chief Hydrographers maps do not show any depth changes either. The sea bed has a very rich in sediment reservoir. The plume of murky water of about 20 to 30 times the diameter of the barge is in fact very short lived, especially in a region with the monsoon wave climate. Secondly, the dredger will have to remain in-operational during the same period for safety reasons.

Secondly, the clayey sandy sediment with ilmenite and other placer minerals is stirred up by the monsoon waves and is transported shoreward toward the mining lease tracts of the IRE and KMML. But the finer clay particles do not settle in the beach and is kept in suspension and is transported seaward, southward or northward toward Thirkunnapuzha and beyond to nurture the source sediment of Chakara. The proof of northerly transport is absence of chakara in any place to the south of Thirkunnapuzha.

The acceleration of beach erosion is a natural concern of the public. In Kerala, no single beach is known to have consistently undergone erosion. It is always a mixed bag. When there is erosion it is featured in the press and media, but not when there is accretion and gain. In fact about 6000 Km2 area in the coastal land was created by wave deposition only and that too in the last 12,000 yr. Therefore, erosion and deposition are two sides of the same coin and dredging as such does not influence both as long as seabed has an optimal reserve of sediment.

Finally about the waste of water in washing the sand coming off the dredger before it is sold. Take a look at the bridge constructed by the L&T Ltd., connecting Kochi with Island or the wharfs in the Kochi harbour. These are structures on concrete columns bathed in brackish water for 24 hours of the day. There are salt water tolerant cements and hence concrete (e.g., Bahrain Bridge). That is the sand does not require to be washed to the purity of a downstream use in a pharmacy industry.

Therefore, we can always look at the sea not only for food but also for the mineral wealth including sea sand waiting to be mined or exploited. The choice of words is yours.

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thrivikramji@gmail.com

DESILTING MALAMPUZHA RESERVOIR,

DESILTING MALAMPUZHA RESERVOIR, PALAKKAD DIST., KERALA, INDIA:

ECOGEOLOGICAL OBJECTIONS

. thrivikramji@gmail.com

(An English language version of a talk presented in a seminar organized by Malampuzha Dam Samrakshana Samithi, in Palakkad, July 11, 09)

It is 55 yr., since commissioning of the Malampuzha dam and the Malampuzha lake in Palakkad dist. of Kerala. The KERI (Kerala Engineering Research Institute) came up with a suggestion that the reservoir already lost 12% of the reservoir capacity due to the siltation. Walayar, another tributary of Kalpathipuzha, has a smaller dam and reservoir (Walayar reservoir) upstream of confluence of Malampuza and Kalpathipuzha. Both dams have been built on the right bank tributaries rising from the western ghats on the northern escarpment of Palakkad Gap.

            Table: 1. Vital facts, Malampuzha Reservoir, Palkkad..

River basin	Bharathapuzha
Dammed Tributary	Malampuzha
Catchment area	147.63 km2
Reservoir Capacity	226 mm3
Water spread at FRL	23.13 km2
Level of siltation (KERI) Level of “garbage” (NRSA)	12% or 27.12 mm3 17.0 mm3 or 7.5%
So sediment volume	Between 17 and 27 mm3

In the Budget speech for FY09, the minister concerned made an announcement in the state assembly, following a recommendation of the water resources ministry, a program of desilting of the Malampuzha lake will be implemented at cost of Rs.800 crores and at net revenue of Rs.400 crores out of the sale of sand and mud in the sediment in the lake. Undoubtedly and seemingly, a definitely worthwhile and pragmatic proposal.

Yet, the issues of desilting are not about making additional revenue or raising the storage of the reservoir as the desilting is loaded with umpteen eco-geological problems about which no transparent answers are offered by the concerned authorities of the government.

First and foremost of all, my questions are: 

1. Is there such a reserve of silt or sediment in the reservoir?. As an advance answer, I will say there is no such quantum of accumulated silt in the lake basin.
2. What management practices and technological solutions have been readied to overcome the sediment plume rising in the reservoir water and contaminating the sole drinking water source of 20 million humans in and around the Palakkad town?
3. Will the sediment laden water be fit for irrigating the cultivavable fileds in the ayacut as the soil characteristics may slide to a different consistence and nature perhaps even deleterious to the crops at least in the short or medium terms?
4. What is the fate of the mud (silt and clay) once the sand fraction (15%) is removed for sale? (A proposal is to sell the mud to the Burned brick industry?)
5. Will the highly organic carbon laden mud be acceptable to the brick industry? If they reject how and where the mud will be disposed?
6.  In addition to sediment, the catchment also supplies dissolved chemical ions in to the reservoir waters, from the farm residues of fertilizers as well as biocides. The loading of such in the sediment will be at least a 100 times larger than its level in the water. Have the quanta and species of these ions have been ascertained before hand and made public to allay the fears of the civil society of Palakkad?
7. When the sediment comes out of the reservoir into the washing plant, it is logical that two fractions of sediment, viz., sand and mud  will be stored separately in the storage areas and will be subject the wind (currents) which will hasten the drying the top layer of stored materials. The finer mud grains will be picked up the wind and resulting in “duststorm”  like contexts, harming the lungs of the very young and older citizens and  the other immuno-compromised members of the society. In fact we have been enjoying the Palakkadan Kattu season from time immemorial. To further worsen the situation; in the aerosolic mineral particles (chiefly clay), several lethal and non-lethal chemical radicals will enjoy a piggy ride.
8. Now it is the question of the sediment volume. Take for example some specific aspects of the Malampuzha lake. No detailed topographic survey at a scale 1:1000 or 1:2000 exists, other than the SOI toposheets of 1:63360 scale. It is precisely so in respect of all the reservoirs of the state of Kerala and of India in general. This study/mapping is considered as “unnecessary” expenditure while proposing the estimate of the investment.
9. What is available now is the bathy chart of sediment water interface of the Lake. As Pre-lake map of the basin of a very gross scale, despite the accuracy of the map of the sediment prism and its size in the reservoir shall be far from precise. As far as I know, no “sparker” survey has been under taken yet to establish the bottom or base of the sediment prism enabling a better precision in the quantum of sediment.
10. But NRSA went one step ahead using DGPS (?) and other satellite image based technologies and came up with a an estimate of “garbage” in the lake bed at 17.0 mm3, roughly half of what KERI came up with. I shall assume that the truth is somewhere else and would take the NRSA number as a ceiling figure. So the lost storage of the reservoir is at variance with the proposal of KERI and used by the water resources ministry to launch a scheme of desilting of the reservoir. And this accumulation took a span of 55 yr.
11. For argument sake, at the rate of 27.0 mm3 rounded to 30.0 mm3 per every 55 yr., it might take 400 yr. for the lake to become a marsh. Or the lake will loose 50% storage only by 150 yr. from today. From the eco-geological point of view I do not see any compulsion for desilting Malampuzha Lake to day or ten years from now. The only counter point is that the sand in the sediment is a commodity in short supply in the state and this program will go a long way in saving the rivers of Kerala.

Now let us take a closer look at problems of handling the mud after removal of sand. We have been given to understand that the desilting is a two year long process. Fine. But what about the strategies for preventing mixing of mud in the lake water which is used for piped water supply in the region. And removal also will undoubtedly result in the destruction of the ecosystem and the food pyramid of the lake. The depth to the photic zone (depth of reach of sunlight) will contract to adversely affect the life in the lake.

Further, even if a modern suction dredging technology is used, the region or a pond that collects the slurry of mud after removal sand fraction will be quite large attracting scavenging birds and animals-  a local irritant and nuisance however short lived it is.

Obviously one pond is insufficient, as the plans are to separate water from the slurry to collect the mud for sale to the red-brick industry.  In fact a battery of ponds will be needed to handle and clarify the large volumes of the mud slurry to ready the mud for sale. A problem which is part of the operation is wind blowing over the mud spreading the mud particles and smell in the downstream regions of wind to the dislike of the public and even can harm the very young and very old.

Then, what are the plans for handling the water used in the sand washing plant? Where ever this water is headed, say the river or the canals or the farmlands, everywhere it will lead to one or other harmful consequences, either to the water, or to the soil or both to air, water and soil. Are there any new technologies easily available to counter such harms? Let us not ignore the fact that, the entire process is to take place in the backyard of a population center. When many of the villagers in Plakkad depend on tanker lorries for drinking water during part of the year, the government is toying with the idea of sand washing and separation. What a paradox? 

My own rough estimate tells me that if the mud is stacked in a tower of vertical walls, in a patch of land of 1.0 km2 area it shall reach a height of an eight storey building.. In other words, if you like, the stack would rise to the height one storey in an area of 8.0 km2. As a gross estimate of sand in the sediment is only 15%, imagine the huge bulk of mud after washing and removal of sand fraction. Moreover, the water seeping from stacks of mud would have high loads of dissolved chemicals whose environmental safety is still an open question. We are unsure of the surprises this water might pose. Wise decision will be to prevent this water from escaping into the surface or subsurface water sources of the region.

Therefore my earnest view is that before implementation of the desilting program, a research study needs to be undertaken addressing the short-, medium- and long-term impacts to the civil society, soil, water and air of the region around Palakkd.    I propose a careful scientific scrutiny of impact on the a) lake and life in the lake, b) sand separation and mud handling and storage before shipment, c) the region and people around a 10.0 km radius of the center of operations and a cost benefit analysis on the basis of proven reserve of sediment in the lake and all these with a fair degree of transparency.

Finally, my gut feeling is, as this lake takes at least another 150 yr to loose 50% of the storage, that we leave the Malampuzha lake undisturbed, with which the Yakshi of Malampuzha garden will concur with.

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 .

SIR CV RAMAN –

THE DEC. 1952 MEETING OF INDIAN ACADEMY OF SCIENCE, TRIVANDRUM & VISIT TO THE MUSEUM OF MS&RD, TRAVANCORE UNIVERSITY.

In 1952, the Indian Academy of Sciences, on the invitation of the Vice-Chancellor of Travancore University (TU), decided to hold the annual meeting in Trivandrum. Dr.C.S.Venkateswaran, was the local organizer. The Pro-Vice Chancellor, Sri Parameswara Panicker was the Chairman of the reception committee.

The Annual Meeting was held from 26th to 29th Dec., 1952, and the scientific sessions met at the V.J. Town Hall and the Physics Lecture Hall of the University College, Trivandrum.  His Highness the Rajapramukh of Travancore-Cochin state inaugurated the meeting.

There was a Symposium on the 27th entitled "Methods and results of Infra-red Spectroscopy".

Besides the Presidential Address by C.V. Raman on "Iridescent Crystals", there were Public Lectures by CV Raman on the "Nature of X-Rays" and another by Homi J Bhabha on "Elementary Particles and Cosmic Rays".

During this meeting, Dr C S Venkateswaran, (a former student of Sir CV Raman, Principal, University College, Trivandrum, and Director in Charge, of Central Research Institute of TU), invited Sir CVR to go on a tour of the museum of the Mineral Survey &Research Division (MS&RD), Central Research Institute (CRI) of TU, where slabs of zircon mega crystal bearing pegmatite facies of the zircon syenite rock of Puttetti were on display. Dr C S Venkateswaran knew quite well that Sir CVR will be very much amazed especially by the unique mega-crystals of zircon and the zircon syenite rock.

Zircon syenite slabs and mega crystals of zircon in the museum were the topic of research of Sri KVK Nair, who is a now leading a peaceful life with the family on retirement from the Dept. of Geology, Kariavattom Campus. According to Sri K.V.K. Nair, Sir CVR was awed at the sight of mega crystals of zircon and zircon Syenite of Puttetti, now in the Kanyakumari Dist of TN State.

Sir CVR went around the museum of MS&RD where minerals, rocks and other geologic materials were on display. Sir CVR on viewing the slabs of zircon mega crystals commented that if some slabs of the rock were on display in his IISc laboratory, the international scientific community will have the rare opportunity to closely see and examine these unique zircon crystals and zircon syenite.

Then, Dr CSV readily agreed to forward a parcel of the rock samples. But on the contrary, Sir CVR wanted the rock slabs with crystals be packed right away under his own eyes, so that they will safely travel along with him to Bangalore. In fact, Sri KVK Nair still vividly recalls Sir CVR choosing the samples from the museum of the MS&RD for packing

A word or two about the MS&RD of the TU. In 1947, it was created as a division of the CRI of TU.  And Dr.K.L. Moudgil was the founder Director of the CRI. The other divisions of the CRI are the Applied Chemistry, Pharmacognosy, Statistics etc. The MS&RD was mandated to make an inventory of the industrial/commercial mineral deposits of the state and to impart professional training to the young scientific staff. The TU offered Mr. T.R.M. Lawrie, British educated geologist, the position of Chief Geologist in the MS&RD, who readily agreed by accepting the offer.     

However after independence, the National Mineral Policy of the Indian Republic identified

the Geological Survey of  India as the sole agency to be in charge of exploration and inventory of the non-living natural resources  (minerals, ores etc). This shift in mineral policy divested the MS&RD of its responsibility in Mineral exploration.

Consequently, in 1953, the TU (by making use of the infrastructure of MS&RD) with the professional and laboratory facilities began to offer a B.Sc., degree course in Geology in the University College, Trivandrum. Using the major chunk of the infrastructure of MS&RD of TU,  in 1963 June, the Department of Geology, University of Kerala (now in the Kariavattom Campus) was inaugurated in the University of Kerala.

Hence, it is more than a pleasant coincidence that a bust of Sir CVR, a great scientist son of India, was unveiled a little earlier in the campus, wherein the museum of the Dept. of Geology (which might still reminisce Sir CVR’s tour), also stands tall with slabs of zircon syenite and samples of mega-crystals of zircon - all from Puttetti. .

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Note by Dr.Thrivikramji,K.P. in consultation with Shri KVK. Nair; part of the information is due to G. Madhavan through Dr. Kusala Rajendran and CP. Rajendran, IISc, Bangalore.

6 DECADES OF SEAWALLS; YET MISERY CONTINUES UNABATED.

6 DECADES OF SEAWALLS; YET MISERY GOES ON UNABATED.
thrivikramji@gmail.com

Advance summary
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 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.

COASTAL EROSION
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. 

CRUISE IN THE COASTAL LACCADIVE SEA: THRIVIKRAMJI

THRIVIKRAMJI: WORK STORY – 8

CRUISE IN THE COASTAL LACCADIVE SEA.

My boss during 1980-82, Prof. C. Karunakaran (founderDirector, CESS, Trivandrum), quite often made it a point, if and when I was readying my team in MSD (Marine Sciences Div.) to go for sea-work. My boss, Prof. CK had a knack of making this poser to me in the Head of Divisions meeting held once a month in his office.

Well, luck played a very surprising role in this respect, when the Harbour Engineering Department of the GoK came to CESS to explore for the type of scientific help with regard to the severe siltation in the boat basin of the Vizhinjam harbor near Trivandrum, I had the first opportunity to go for seawork.. The siltation in the harbor was triggered right after the completion of the main breakwater – one covered with tetrapods on the sea facing side. In order to contain the siltation and erosion of the backshore coastal hills to the south, and after some model studies, a second EW oriented breakwater was designed and put in place.

In fact, the Harbours Chief Engineer retained the CESS (i.e., the MSD) as a consultant on a fee to study the siltation issue, based on a research proposal developed by us in the MSD. In fact, this study was very significant locally as this happened to be the first of its type as far as the organization was concerned.

With me as the leader, I had put together a team consisting of M/s Suchindan, Terry Machado, Vasudevan et al to be in direct charge of the project. We had two surveyors on loan from the Harbours department. The workhorse was S/V. Rocket owned by the ISRO, Trivandrum. This small 18 ft. single engine boat had no navigation system and usually relied on dead reckoning.  Our own boat driver was asked to join the cruise as he would be of help chiefly in the deck work, like casting and retrieving the samples and sampling process. We had a van Veen grab for collecting bottom sediment. We also retrofitted the boat with a fish finder category of echo sounder. In fact we were all set to go off land on the cruise.

Then, we based on an approved project, went into the coastal sea to collect bottom profile data as well as seabed samples at certain fixed intervals. It was in fact early January, and the sea was calm – ideally suited for working out of a small boat. It was so clam that water surface appeared like a sheet of glass to me, with the exception of the evenings when the sea became kind of choppy – anyway only on our way back to the harbor.

The cruise had covered water depths of 60 to 70 m and six profiles of 12-16 km each in length and spaced between Poovar in the south and Varkala in the north. The entire trip was very enjoyable; no one got seasick; boat worked very well not defying our expectations. The sea exposure primed the team for more work in the study relating to the siltation of the Vizinjam harbor as well as in backwaters of Kerala.

One of the important outcomes of the study was reported in the Indian Journal of Marine Sciences, on the find of “Glauconite ”in the relict sediment at the seabed off Trivandrum. The identification was purely based on the morphology of the particles of grass grains in the medium sand fraction of the sediment. Some of the organismic casts were re-designated as pterapods by Singh. Further P. Rao, basing the results of his mineralogical investigations re-identified the glauconite grains as a different authigenic mineral.