Sand is of to two types, viz., the fine aggregate used in cement mortar and cement concrete and mineral sand primarily containing one or more valuable ore or industrial minerals and gravel, the coarse aggregate. Both are either natural (coming off modern alluviam) or machine made (by crushing stones and rubble of suitable quality).
Most of the sand (size = 2000 - 62.5 microns), is composed of the common rock forming mineral quartz, which dominates nearly all known accumulations of sand in the world, whether in beaches of seas and lakes or in modern or ancient river alluviam or in deserts. Fluvio-glacial deposits of the outwash plains in regions at higher latitudes and shallow-seabed have also been other important sources of sand.
Fine aggregate, a chief ingredient of cement-mortar and cement- concrete, in the construction industry parlance, has been river-sand as several of its properties very well satisfied the stipulations in the specification guide. With the advent of modern construction In India, river-sand emerged as the chief component of cement mortar and concrete, and Kerala is no exception either.
However, in the erstwhile states of Travancore or Travancore-Cochin or later in Kerala, given the size of then economies, use of borrowed river-sand was at a very low level, especially due to the native or ethnic building technologies of the region emphasized use of locally and easily available natural materials like stone, rubble, mud, Laterite, timber and thatch or tile and relatively little or very little cement based materials..
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.
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.
To day’s (Jan 4, 12) DC carried a report on the weed clogged water ways and water bodies of the state. Well, all said and done, there is a hidden upside of the weed menace. The fact of the matter is the role of the weeds in sequestering carbon in their biomass. Recent investigations have brought to light the large and significant role of these aquatic plants, rooted plants in the marshes and finally the microscopic algae in the water in carbon sequestration.
Even though geoscientists are familiar with climate transitions of the geologic past, to day’s concern on global climate change (GCC) due to tropospheric heating, - a forcing by steadily rising accumulation of green house gases (like CO2, NOx, CH4, H2O as water vapour)- portends a blunt global threat to every facet of human life as well as other ecosystems.
The Intergovernmental Panel on Climate Change (IPCC), a panel of scientists drawn from the various UN member countries, in a four volume report (one solely meant for chiefs of member nations of the UN) draws up a grim picture of the manner in which various systems and subsystems will be affected by GCC and prescribes a set of ‘urgent’ measures for mitigation and adaptation to minimize the impacts.In respect of Ground water (GW) resources, the IPCC report laments about lack of access to available and reliable data bases and non-uniform standards across the world and proposes to concerned nations to undertake research to monitor and create quality data sets on GW resources in order to come up with reliable forecasts.
By about noon today –this year’s Vishu day, April 15, 11- the sad disappearanceof a well digger into a well due to wall collapse happened in the MoonnamPuthen Theruvu, Fort, Thrivandrum. The TV channels brought this incident to our living rooms along with the rescue efforts to save a...
The highland, midland and low land of Kerala enjoying a tropical monsoon climate in the current climate situation is boud to shift in the coming decades for worse. Unless the mind set of the several generations of dwellers are changed the state and its population will go through the severities of climate change phenomenon.
The red teris of southern Tamil Nadu has demonstrable signatures of a wetter climate than the current semi arid climate. These are stabilized coastal dunes of preholocene age.
