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3.3 Method of Data Analysis
Data were analyzed with a SWAT model for discharge, USLE method to determine the level of
erosion. Farmers income were analyzed using descriptive statistics and correlation erosion and
farmers income by Spearman Rank. .
IV. RESULT AND DISSCUSION
4.1 Hydrology of Watershed
Hydrological watershed is affected by rainfall especially rain transformation process into the
discharge. The rain that falls in a watershed will change to flow in the river, so there is a relationship between
rainfall and flow rate, which depends on the characteristics of the watershed.
4.1.1
River discharge SWAT model analysis results of water discharge
in the river watershed between the rainy season and the dry season is different, namely the average maximum
discharge of 9.37 m
3
s
-1
and the average minimum flow of 2.92 m
3
det
-1
with the river regime coefficient of 3.20 This is caused by the ability of the watershed
ecosystem, especially in the upper watershed in the governance Ayung water began to decline due to
changes in land use and do not apply the rules of soil and water conservation.
Discharge as the output of hydrological processes can be used as an indicator to assess the quality of land
use in a watershed. The results of the above analysis suggests that the rainfall that caused the discharge of
high fluctuation, due to a change in land use from upstream to downstream watersheds, so that a watershed
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ecosystem malfunction as well. The rain that falls all become runoff due to land cover changes, the plant
canopy or canopy covering the less surface of the soil tightly so that there is open ground level.
The kinetic energy of rainfall that fell nothing dampen due to the lack of ground cover, rainfall on the
ground all becomes runoff, then get into water bodies causing great river discharge during the rainy season
and small in the dry season. That is not capable of watershed functions as the manager of the water system
is well proven there are fluctuations in the water flow of the river is quite large. In addition to the influence of
rainfall occurrence of a change in the discharge fluctuating because it is influenced also by soil type,
slope and land use.
4.1.2 Calibration of Model
Calibration is performed to obtain a
discharge
simulation approach measurement value.
discharge
simulation and measurement results are presented in Figure 4.1.
Figure 4.1 Graph of Simulation and observation discharge
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4.2 Erosion in Ayung Watershed
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