Application of SWAT in selecting soil and water conservation techniques for preparing management recommendation of Cilemer watershed, Banten, Indonesia

The quality of watershed ought to be maintained because of its function as a life buffer of living things, especially in water and other material needs provision. From the indication result, Cilemer watershed was degraded, therefore, it demanded planning efforts to restore watershed quality. This study aimed to determine watershed management directives and selecting some alternatives of soil and water conservation techniques by using Soil Water Analysis Technique (SWAT) method. Six scenarios were applied, there were: strip cropping (Scenario 1), agroforestry (Scenario 2), reservoir or small reservoir (Scenario 3), strip cropping and agroforestry combination (Scenario 4), strip cropping and reservoir combination (Scenario 5), and strip cropping, agroforestry, and reservoir combination (Scenario 6). The result showed Scenario 6 was the most effective to maintain watershed quality. Compared to the existing conditions, Scenario 6 could decrease Qmax-Qmin ratio by 34.57%, decreased the surface flow by 33.64%, so, the runoff coefficient decreased from 0.25 to 0.16. Moreover, Scenario 6 also increased the base flow by 52.16% (from 357.55 mm to 544.07 mm), water yield by 4.16% (from 904.55 mm to 943.68 mm). However, Scenario 2 was the most optimal scenario since its input was lighter and involving a smaller restored area.