BLANKET BANS on coastal development in Sri Lanka could put lives at risk, Sri Lankan engineers warned their government last month.
Offi als from the Lanka Hydraulic Institute (LHI) have met offi ials from the Coast Conservation Department to urge it to overturn the bans, intended to head off tsunami risks.
The bans apply to areas within 100m of the sea on the western coast and within 200m of the eastern seaboard.
LHI ffi cials fear that blanket buffer zones - known as setbacks - will force householders to move from safe sites on coastal headlands to riskier, lower lying sites further inland.
'Setback lines based on erosion and on blanket buffer zones do not have a scientific basis when looking at coastal vulnerability in terms of wave travel into the coastal hinterland, ' said LHI chief executive Malith Mendis.
He said some waves from the Boxing Day tsunami travelled further inland in some areas while stopping closer to the coast in others.
The distance which high waves can travel inland depends on the near-shore bathymetry - seabed contours - and the existence of rock outcrops, coral reefs and beach rock.
Slope of the shore, hinterland, sand dunes and other coastal features are also factors.
Sri Lanka's 1998 Coastal Zone Management Plan bases setbacks on historical data. They vary from 35m to 300m depend ing on the stretch of coast.
'We believe that to scientifically assess the possible inland propagation, detailed data must be obtained near-shore and comprehensive near-shore hydrodynamic modelling carried out, ' said Mendis.
'Vulnerability can then be classifi generally as low, medium or high, ' said Mendis.