Finding an alternative to
river sand
| Even as the boom in construction has been pushing up steadily the
demand for sand, its extraction from riverbeds is being regulated. |
REGULATED: Damage to riverine ecosystems has led to the regulation of
sand-mining.
In the construction sector, sand has always been a tricky thing. Most
essential but in short supply, sand is fraught with controversy, as the
indiscriminate extraction of it has taken a toll on major rivers in the State.
The demand for sand was estimated at more than 3 million
tonnes last year. With the present rate of construction in the State, the demand
is on an uphill climb.
As sand is the main coarse aggregate in concrete, helping to
bind large pieces of crushed metal with cement, its quality is of paramount
importance in construction. Sand should be clean and without salt content.
The main reason for the high demand for river sand for
construction in the State is its cleanliness and absence of salinity.
However, continuous and intense exploitation of sand from the
beds of major rivers in the State has contributed in a big way to the
degradation of riverine ecosystems. There is an urgent need to protect the
rivers and rein in their mindless exploitation.
A danger
However, the construction sector vows that in case an
abundant supply of quality sand cannot be ensured, building activity in the
State can grind to a halt, which may, in turn, affect many ancillary sectors.
The authorities have already imposed severe restrictions on
extraction of riverbed sand as a direct response to the concern being raised
about the degradation of environment caused by sand-mining.
Legal extraction of sand is now allowed through passes issued
by local self-governing bodies such as panchayats and municipal corporations
where kadavus (ghats) for sand-mining are located along major rivers such as the
Periyar, Bharathapuzha and Chalakudy.
Mining is banned for a couple of months every monsoon, to
allow enough time for replenishing the depleting resources of sand on the
riverbeds naturally. Later, the passes are issued through a bidding process for
each kadavu, controlled by the local self-governing bodies. This is done after
hydro-geologists of the Department of Groundwater examine the kadavus. The
panchayats and municipalities get good revenue from the fees charged for mining.
Each panchayat or municipality issues 20 to 30 passes a day.
The contractor has to pay around Rs. 1,800 for a load on an ordinary lorry and
Rs. 2,200 on tipper lorry to the panchayat or municipality. This includes the
charges of loading workers.
For two to three months after May, from the onset of monsoon,
the permits are withdrawn and mining has to be stopped — on paper, at least.
Reality is a far cry from all these statistics. Though panchayats allot only 20
to 30 passes a day, at least 50 loads of sand are transported from each kadavu.
The price of the sand when it reaches the customer is
generally decided by a wide range of factors such as the distance of the work
site from the river. It also varies from person to person.
Search for
alternatives
The shortage and environmental problems have been pointing to
the need for a search for viable alternatives to sand.
The Mining and Geology Department of the State Government has
been exploring alternative sources.
Even a proposal to explore the possibility of bringing sand
from Rajasthan was mooted and studied last year by the department.
The use of manufactured or rock sand is another option being
increasingly resorted to by many in the construction sector.
The Kochi-based architect Sebastian Jose points out that
manufactured sand is in no way inferior to river sand. His house at Thevara was
entirely constructed using manufactured sand. "Strength-wise, manufactured
sand is better," he says.
"The use of riverbed sand is very less worldwide,
compared to that of manufactured sand."
Jose Antony Kokkad, a former executive director of the
Bhagiratha group, is a votary of sea-sand mining.
Mr. Antony vows that sea sand mining, if done judiciously
with proper planning, will not harm the environment and will be able to offer
quality sand at a cheaper rate. But such a venture will need large-scale capital
investment, he says.
The State has, in fact, been debating extraction of sea sand
for a couple of years, to tackle the severe shortage of sand faced by the
construction sector.
Around 2003, the Kerala State Industrial Development
Corporation (KSIDC) came up with a Rs. 180-crore sea-sand mining project, which
had raised more than a few eyebrows.
At least a few people see sea and rock sand as alternatives
to river sand, claiming that these will be less damaging to the environment than
extraction of river sand. However, even the scientific community appears to be
divided over the environmental sustainability of the other processes.
While the process of manufacturing rock sand has been known
to evoke protests among local communities, sea-sand mining is also a tricky
affair, which needs cautious and judicious execution.
RENU RAMANANTH
Courtesy: Property Plus, The Hindu
http://www.hindu.com/pp/2006/12/30/stories/2006123000330200.htm
Replacing river sand in
building
| Research institutions are developing alternatives to river sand for
use in construction. |
An acute shortage of river sand has been affecting the
construction sector. The scarcity has led to the skyrocketing price of sand and
escalating construction costs. The situation has dashed the dreams of many in
the lower- and middle-income groups to own a house.
Indiscriminate mining of sand has depleted the natural
resource and ravaged the rivers of the State. The Bharathapuzha, flowing through
Palakkad district, is a classical example of the malady.
Indanur Gopi, secretary, Bharathapuzha Samrakashana Samithi
(protection committee), says indiscriminate mining has caused an environmental
disaster, destroying rivers and streams throughout the State. Now,
inferior-quality sand, with silt and impurities such as mica and coal, is being
sold. Unscrupulous persons exploit the scarcity and high price by selling river
sand adulterated with cheap sea sand, which causes structural failures in
buildings.
The report of a study on "Kerala model of sand mining
system," taken up as part of a University Grants Commission project by N.M.
Namboodiri, says the possibility of a scientific method of sand-mining should be
looked into to save the rivers and also to provide the much-needed construction
material.
"It is difficult to find out availability of sand on the
river-bed because it is a replenishing product by the geological work of the
running water. Therefore, it is necessary to find out the quantity of products
settling on the riverbed and the quantity transported from the riverbed in a
year."
It is calculated that a minimum of 3,35,710 loads of sand
might have been taken from the Bharathapuzha every year by the earlier
auctioning system from 50 centres. Almost all sources of the river have been
blocked by 11 big dams in different locations on the riverhead. Hence, the flow
of products of erosion from the upper reaches has been blocked.
Manufactured sand
Following the shortage of river sand, some research
institutions are developing alternatives that can be used for construction.
The Faculty of Civil Engineering of the Government College of
Engineering, Thiruvananthaparam, has developed a technology, to produce sand
from hard granite.
Called manufactured sand (M-sand), it is made by Poabs Group
in its plants at Ernakulam, using what the company calls a state-of-the-art
manufacturing process. It is meant for use in concreting and plastering. The
cubical-shaped M-sand has a surface that gives better binding strength and saves
cement, labour and water. One of the pioneers of M-sand in Palakkad, Sainudeen
Pathiripala, says it is cheaper that river sand. But the Government is not
promoting it, though it is of great importance to the State. M-sand can save the
rivers of the State, preventing an environmental disaster. In the State budget,
a 4 per cent tax was imposed on it.
Mani Shankar, founder general-secretary of Licensed Engineers
and Supervisors' Federation, says that M-sand manufacturing units should be
started in every district in the cooperative sector.
G. PRABHAKARAN
Courtesy: Property Plus, The Hindu
http://www.hindu.com/pp/2007/04/21/stories/2007042100470300.htm
