FLOOD00113

• County: Statewide
• Title: Changes in the Hydrological Response of a Small Mediterranean Basin a Year After a Wildfire
• Date: 6/8/1992
• Prepared For: Journal of Hydrology
• Prepared By: Elsevier Science Publishers
• Floodplain - Doc Type: Educational/Technical/Reference Information

286

J. LAVABRE ET At.

. Rainfal
. Observed Runo"

II Gr3 Simulaled Runoff

(mm)

240

192

144

96

48

o

Aug. Sept. Oct. Nov. Dee. Jan. Feb. Mar. Apr. May June July

Fig. 6. Comparison between the monthly runoff observed and simulated by GRJ in 1990.

To corroborate this hypothesis, we repeated the simulation but took into
account this reduction and tested whether a reduction of the evapotranspira-
tion values used by the model can produce better results. It should be
remembered that OR3 only utilises the potential evapotranspiration. There-
fore, instead of using the interannual mean of the potential evapotrans-
piration of the Real Collobrier as previously (Lavabre, 1989; Lavabre, 1990,
see Table 5), we have used different reductions of these initial evapotranspira-
tions.
Finally a 50% reduction was used to obtain a new simulation which
provides better monthly estimates (compare its performance shown in Table
6 with those of Table 4). Moreover the annual estimate is improved: it is this
time slightly overestimated, 19 mm instead of 148 mm. This confirms that a

TABLE 5

Monthly potential evapotranspiration used for the Rimbaud basin (from data at the Real
CoJlobrier meteorological station)

Monlh J F M A M J J .A SON D

Monthly potential 180 110 75 40 25 35 30 60 90 140 160 210
evaportranspiration
(mm)

j

HYDROLOGICAL RESPONSE OF A MEDITERRANEAN BASIN

287

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