EVALUASI KINERJA DAS DAN SIMULASI KONSERVASI MENGGUNAKAN SWAT (SOIL AND WATER ASSESSMENT TOOL) (StudiKasus : Sub DAS Tapung, Siak, Provinsi Riau)

Abstract

Alteration of land use which is happening at left Tapung watershed (DAS
TapungKiri) is effect to rate of flow of the watershed. Marked by the decreasing of
forest area from 15.624,36 ha at 2002 to 12.186,32 ha at 2012. Evaluation of
watershed condition and performance is needed. Evaluation using (i) Percentage
of critical land (PLK) (ii) Percentage of vegetation cover (PPV) (iii) Coefficient
regim of flow(KRA) (iv)Coannual of flow (KAT) efficient criteria. Evaluation
result of PLK is 9,82%, PPV 71,6%, KRA 14,28 and KAT 0,45. After receiving
existing evaluation value, conservation simulation using SWAT program is done
by changing a part of open land area and shrub on land use map of 2012 with
forest. From simulation result, SWAT model validity parameter R2 is 0,50 and
NSE 0,50. These result have satisfied the research objectives as the finding
coefficient were > R2 0,4 and >NSE 0,35 From this simulation, watershed
condition is evaluated again. Evaluation result after doing conservation
simulation are PLK 6,52 % PPV 73,08 % KRA 5,78, and KAT 0,44. Values after
conservation simulation gives better result than the condition before conservation
simulation is done.
Keywords: altration of land use, SWAT, watershed performance.