Subject: karst hydrology
March 26, 1998
THE NATION:

YADANA THREATENS WATER SUPPLIES

JAMES FAHN
The Nation

CONSTRUCTION of the Yadana pipeline and other development project in
Kanchanaburi could affect the water supply for local villagers, a
geologist has warned.

The area through which the Pipeline to being built _ along with many other
areas In Southeast Asia _ is composed of limestone karst formations, which
one means it is riven with underground channels and streams, according to
Dean Smart, a consultant with the Royal Forestry Department.

"Karst hydrology is very fragile," Smart said. "It's virtually impossible to
know which streams produce which springs, so construction work _ on the
Yadana pipeline, for instance _ could divert some channels, causing some
springs to completely dry up and new springs to form elsewhere." Smart noted
that the environmental Impact assessment (EIA) for the Yadana project "does
not even mention karat hydrology.

A review committee, chaired by former prime minister Anand Panyarachun, set
up to evaluate the Yadana pipeline has already voiced strong criticism of
the EIA for failing to provide adequate information on the project's impacts.

Smart also warned that sediment washed down from the construction of the
pipeline track could wash into the karst formation and flow into streams,
again affecting water supply.

"Sedimentation could also cause the diversion of water channels," he added.

The labyrinthine nature of most limestone formations also means that other
kinds of development projects, such as dams and roads, can be quite
destructive. "Dams in karst areas cost about 50 per cent more than in other
areas because there is lots of leakage [through the subterranean channels],"
Smart said.

"For the Khao Laem Dam in Kanchanaburi, they had to build a concrete curtain
inside the mountain to block the leaks."
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