taken into account
8, 2000, Gazette)
Dr. Leonard Lye
in Mozambique, China, United States and Canada. There is no place
in the world protected from the risk of flooding.
research in flood risk analysis and estimating magnitude in rivers
is there to alleviate these catastrophes. Dr. Leonard Lye, Engineering,
is in the process of developing a new method of flood prediction.
His project is titled Generalized Linear Models, Physical Factors,
and Long Range Dependence in Flood Risk Analysis.
common method of flood risk estimation uses a regional approach.
Even if there is not enough data from the river it is still possible
to estimate flood risk using the concept of homogeneous regions
where flooding occurs in similar way.
is like trying to predict human behaviour, said Dr. Lye.
You are not going to take a bunch of Chinese people to
predict the behaviour of a bunch of Europeans. Sometimes you
have a river that is near the boundary. You can use the equation
for the region A, but you might get a total as if you would use
it for the region B.
someone near the border and you dont know whether he behaves
like a Scandinavian or Russian.
avoid the problems of defining homogeneous regions, Dr. Lye uses
a technique called generalized linear models. With this method,
a model is formulated so that the effect of the gauges and the
effect of the year are taken into account. The generalized linear
model automatically shows the regional differences.
a dry spell you expect rivers to behave in a similar fashion,
Dr. Lye explained. You dont usually expect two rivers
side by side one to be dry and the other one to be very
there is no data for a river it is also possible to predict floods
with the help of local physical factors such as the size of the
river basin, vegetation, and the amount of rainfall.
use all kinds of data from the map. People measure everything.
However, you cannot just measure things from the map and say
thats it. There are things you dont see just by measuring
things on the map.
from other provinces and other countries like to use Newfoundland
data in their work. But they just take it as numbers and they
may have no knowledge of what is going on. Sometimes there may
be a river affected by tidal effects or by prevailing storm direction.
For them if the number fits, even for the wrong reason, they
will leave it in.
aspect of Dr. Lyes research is dealing with the issue of
long range dependence. A short term dependence analysis does
not show long range dependence. There are small changes occurring
from year to year that short term dependence cannot indicate.
The most prominent case would be the major flood of the Red River
Valley in Winnipeg in 1997. Dr. Lye has used this data in his
of his findings was the relation between the flooding and the
soil moisture stored in the heavy soils of the Red River basin.
Heavy soil holds water for years and can cause potential flood
the Red River flood does not prove that our method is more correct,
Dr. Lye said. It only shows that high flooding tends to
come together in bunches. It is very clear in the Red River flood
series that there is a bunch of low floods in 1930s and 1940s.
Then a bunch of very high values 1950s and 1970s. There
is no cyclical effect. It is that they just tend to bunch together.
Long range dependence does not necessarily mean that a flood
100 years ago will have an influence on flooding today.
many researchers do not believe in long range dependence. However,
this whole area of long range dependence is actually blossoming
now despite some controversy. Lately long range dependence has
become somewhat important in financial data analysis. Research
on long range dependence is published in many financial type
journals, monetary economics papers, and statistical papers.
Earlier this type of research could be found only in hydrology
type papers, or papers on water resources.
general my kind of research is statistical. Statistics is something
people are really afraid of. It is complicated. I am not a statistician
myself, although all my work is in statistics. You have to collaborate
with people who know the statistics.
the end you want a simple model that captures what you want.
The problem is how to translate this highly complicated stuff
and make it usable for a simple engineer. They do the designing
of flood control schemes. People have a tendency not to use anything
that is complicated I cannot understand it, so it cant
be right. You have to simplify this and explain it. It is a very
good engineering practice to take whatever evidence you see and
use it in your design and not ignore it.
Lye communicates with researchers from all around the world
Malaysia, United States, Germany, to exchange data and information.
dont have enough records. If I have data from all around
the world Ill use it. There is only a limited amount of
easily accessible data, he added.
cant predict floods, only estimate its risk. Nobody knows.
Only God knows.
Lyes project is funded by NSERC.
SPARK, Students Promoting Awareness about Research Knowledge,
is a NSERC funded program designed to encourage writing about