METHOD FOR FORECASTING FLOODS FOR MULTIPLE LEAD TIMES
A method for forecasting flood, the method including: 1) collecting historical flood information, estimating a mean concentration time of a basin, and determining a length of a lead time; 2) establishing hydrological models, inputting hydrological variables including precipitation and evaporation to the hydrological models while neglecting the precipitation within lead times; 3) determining an objective function, which is a sum of squared errors between a forecasted streamflow and an observed streamflow within multiple lead times, and utilizing optimized algorithms to calibrate hydrological model parameters; and 4) selecting criteria to evaluate forecasting performance of the hydrological model including a Nash-Sutcliffe efficiency, a root mean square error, a water balance index, a qualified rate of peak flow, and a qualified rate of a peak time.
1 . A method for forecasting flood, the method comprising:
1) collecting historical flood information, estimating a mean concentration time of a basin, and determining a length of a lead time;
2) establishing hydrological models, inputting hydrological variables comprising precipitation and evaporation to the hydrological models while neglecting the precipitation within lead times;
3) determining an objective function, utilizing optimized algorithms to calibrate hydrological model parameters, which is a sum of squared errors between a forecasted streamflow and an observed streamflow within multiple lead times as follows:
min
F
=
∑
t
=
1
N
(
(
Q
t
obs
-
Q
t
,
t
-
1
pre
)
2
+
(
Q
t
obs
-
Q
t
,
t
-
2
pre
)
2
+
…
+
(
Q
t
obs
-
Q
t
,
t
-
k
pre
)
2
)
where Q t obs is the observed streamflow at time t (t=1, 2, . . . , N), Q t,t−k pre is the forecasted streamflow at time t which is based on inputs of forecast-time k hours earlier than the time t, N is a total number of observations; and
4) selecting criteria to evaluate forecasting performance of the hydrological model comprising a Nash-Sutcliffe efficiency, a root mean square error, a water balance index, a qualified rate of peak flow, and a qualified rate of a peak time.