17
V. CONCLUSIONS AND SUGGESTION
5. 1 Conclusions The calibration procedures consist of
two steps parameters optimization. Firstly, optimize the parameters c and WHC
according to the criterion RE. Secondly, optimize the parameter WHC again
according to the criterion R
2
, with the value of c obtained in the first step.
The results of monthly spatial runoff presented in the article had proved to be
quite efficient of describing the monthly runoff with R
2
value of 66.15 and relative error RE of 1.4 . The method can easily
be incorporated in water resources planning program to estimate monthly runoff in the
Cicatih watershed because of their simplicity and efficiency of performance. The
implication of the study is to describe the comparison between monthly spatial runoff
of the 1999 land uses pattern and the recent year land uses pattern.
The result of spatially distributed runoff clearly indicated the influence of rainfall,
land cover types, and water holding capacity WHC. However, the monthly distibuted
runoff was only affected by the rainfall. The runoff distributions of subwaterheds showed
that runoff varied from 263 mm in Ciheulang subwatershed to 26 mm in
Cikembar subwatershed. The monthly runoff distribution of Cicatih watershed showed
that the lowest runoff was 35 mm occurred in September and the highest runoff was 260
mm occurred in January. The spatial runoff distribution in Cicatih watershed reflected
that during the high rainfall period in Cicatih, maximum runoff could be found in
the forest areas 286 mm and followed by cropland areas 269 mm. And minimum
runoff was 251 mm occurred in settlement areas. In the low rainfall period, maximum
runoff 109 mm was found in forest areas. Minimum runoff was 0 mm occured in the
settlement areas, followed by cropland areas 5 mm around the mountain Salak and
mountain Pangrango. It was found that runoff increased with significant incresing
rainfall, following a positive linear function.
5. 2 Suggestion
For future applications, it is suggested to consider the rainfall-runoff pattern in
water resources planning program Cicatih Watershed, Sukabumi, West Java.
VI. REFERENCES
