IASH General Assembly, Sapporo (Japan), 3-11 July 2003


                      TRANSACTIONS


GLOBAL CHANGE--RISK ASSESSMENT AND REAL TIME HYDROLOGICAL FORECASTING OF 
FOREST CONFLAGRATIONS FOR WATER MANAGEMENT

S. LOBANOV 
 Far Eastern Regional Hydrometeorological Research Institute (FERHRI) 
690600, 24, Fontannaya St., Vladivostok, Russia 

V. Kulik , CYPUM PTY LTD, P.O. Box 863, Canberra City, ACT, AUSTRALIA 2601 


                             ABSTRACT 

The global change makes irrelevant many methods of risk assessment and
forecasting. In particular, changing climate means a greater probability
of forest conflagrations. This results in disabling of water supply
watersheds and reservoir contamination. Old methods of meteorological
forecasting of conflagrations will become less reliable, being based on
correlations, obtained for a period of stable climate. EXISTING
hydrological networks can be used for wild conflagration prediction. Runoff
data allows the prediction of high fire danger earlier, with less overcaution, 
highlights the most dangerous watersheds and makes forecast more foolproof. 
In some cases hydroforecast improves the likelihood of prevention of a major
disaster. This technique has certain DIFFERENCES from the standard
meteorological methods: (1)It predicts bushfires not for an administrative
or geographical region, but for a watershed-- so, a bushfire can be
forecast for certain water supply reservoirs; (2) It allows forecast of
the bushfire danger earlier and estimates of the amount of time available
for active measures; (3) It is less overcautious, thus excluding most false
alarm situations;(4) It is more accurate, simply because it uses hydrographical
data, which is more representative than meteorological data;(5)It is more
foolproof and less dependent on the errors of observations; (6) It
depends less on the stochastical nature of summer rains and other
meteorological elements.(7) It is simpler than any other method.There are
two groups of PREDICTORS. (A) Early Predictors:(A1) Low flow; (A2) Change
of the curvature of the recession curve from concave to convex (semi log
paper);(A3) Accelerated recession. These early predictors can be used to
estimate how many days there are before the critical fire danger starts
(by an extrapolation of the recession curve). (B) Later Predictors: (B1)
Stabilization of the runoff to a "zero flow" value; (B2) Steep rate of the
recession after intermediate minor rains;(B3) Convex recession after
intermediate rains.(B4) Abrupt stabilization of the runoff to "zero flow"
several days after a minor rain. The manifestation of these late
predictors means that the probability of a bushfire has increased
dramatically. This method allows a forecast of the CRITICAL fire danger, when a bushfire is almost inevitable. Experimental risk assessment and real time forecast were successful for for water supply watersheds of Russia and Australia. Quite different tools may be used in any particular case, due to local customs, hardware and software. For example, in some cases a deviation from normal rainfall-runoff relationships (runoff-rainfall or water balance models) could be a good indicator. A conflagration is a very rare phenomenon and
to collect sufficient amount of information for any development of the
forecasting technique it is necessary simply to analyze more cases.We ask
everybody who has in their disposal data on watersheds, affected by an
intense bushfire, to try this simple technique, to develop it and to
communicate their results.