I-MAG STS Corporation
Part of the esteemed geologist Brian Atwater's research revolves around
what happens when an eastbound tsunami - either from the Cascadia
subduction zone or further west - crashes into westward flowing rivers.
When we had rerun Atwater's famous 1700 Cascadia tsunami today two
things that caught our attention were that there are a lot more people
300 years later AND that dams are not symmetric. Dams are built to
withstand water pressure from only one direction. A tsunami tearing at
the "wrong" sides of dams could be very nasty indeed.
However, we were not of the opinion that was Pakistan's immediate
problem. What we had considered there was that floods are slow
riverine tsunamis. Of interest was whether a flood could induce a series
of dam failures: could normal river flow PLUS excessive glacier runoff
PLUS a rush of water from a collapsing small dam upriver overwhelm a
larger downriver dam? So far, the Pakistani geologist is correct - no
dams have broken yet. Warshak dam collapsing would be very grim for
the elegant facades of the Walled City in Peshawar (Pekhawar). And the
flooding, while worse than some of our scenarios, is not as bad as our
worst case scenarios. Yet. We have been battered by a small tsunami of
emails about the Soviet-inspired earth-fill dams, what monsoons might
do, and whether floods might trigger eathquakes. We'll see what the
final butcher's bill is - we are hoping that Pakistan avoids follow-on
famines and epidemics.
As we had pointed out in the 2004 documents, besides losing drinking
and irrigation water, it has long been known that prolonged floods
are very destructive of perennials such as fruit trees as well as livestock.
Restoring dams, reservoirs and canals and rebuilding becomes more
difficult because electricity will be in short supply. In urban areas
flooding damages cables for television, internet, telephone and
electricity as well as water and sewage pipes and, in some cases,