Rapid Assessment for Resilient Recovery and ... - GFDRR

increased cost of transport across the road network post-flood compared with pre-flood.
The calculation of the losses so defined is based on pre-flood traffic, freight and
passenger, in each province, adjusted for the post-flood condition by reducing travel
speeds (a proxy for increased pavement roughness), increasing journey distances and
times (a proxy for the effect of flood-caused closure of some network links), and making
other adjustments as appropriate. The result across the 26 assessment provinces, for
a range of assumptions for each variable used in the analysis, indicates that overall the
losses have been equivalent to 27–35 percent of the estimated cost of the damage.
Further work is being done, based on a whole-of-country network model operated by
MOT’s Office of Transport and Traffic Policy and Planning (OTP), but for the present
purpose the assumed proportion of 30 percent is considered appropriate.
It is to be noted that this approach is relatively crude. The network model covers only the
higher level road links (routes with 1 to 4 digit numbers); it does not include the local road
network. Some of these lower level roads would have provided alternative routes used by
traffic prevented by flooding from using the primary network. Also, inundation and closure
periods varied from route to route; assuming a constant closure period across the network
is a simplification of the actual situation. Finally, traffic volumes and composition would
almost certainly have changed considerably, particularly during the inundation periods.
However, since there have been no traffic flow or classification surveys done since the
flood commenced, flows have been tested as above, with no change in composition.
Railways
Since the railway continued to operate during the flood period, albeit with diversions for
trains travelling to the north, and the use of buses for the initial section of the link to the
south, losses resulted from longer journeys and slower speeds, lower passenger and
freight volumes, and other factors.
Civil Aviation
As noted above, the impact on the civil aviation sector has been limited to the inundation
of Don Muang airport. Since the domestic flights that used the airport prior to the flood
have transferred to Bangkok’s main airport, there have been no flight-related losses. The
losses assumed relate to services that the airport would normally provide when in service,
such as food concessions, car parking, etc.
Inland Water
The government suspended operation of the inland waterway network for about 33 days
at the peak of the flood, principally because the clearance under bridges crossing flooded
waterways was not sufficient to allow barge traffic to move safely. During this period,
based on annual freight loading on the network, about 3 million tons of principally
agricultural and construction materials would have been transported. Information received
indicates that about half of this traffic transferred to other modes, essentially road, and the
remainder was held in storage until waterway services resumed. Overall, the loss incurred
by the inland water system as a consequence of the floods has been assumed to be
negligible.
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