Pengaruh Perubahan Tutupan Lahan Terhadap Koefisien Limpasan (Run Off) di Kampus Universitas Negeri Manado

Abstract

Manado State University was originally the Manado State Teachers' Training College which moved to Tonsaru-Tondano in 1992. Since 2000, the Manado State Teachers' Training College changed its status to Manado State University according to RI Presidential Decree No. 127 in 2000. Since becoming a university, the land cover on the campus and its surroundings has changed very rapidly. These changes occurred not only because of the increase in the construction of physical facilities, but also the development of new settlements, shops or stalls around the campus. These changes result in changes in surface flow. This study aims to determine the pattern and distribution of land cover changes and their effect on changes in the total value of the runoff coefficient on the Unima campus. Changes in land cover were observed based on land cover maps for 2002 – 2022 which were derived from high-resolution Google Earth satellite imagery with ArcView GIS version 3.3. The total value of the coefficient is calculated using the rational method based on the type of land cover and the area of each type of land cover. The results of the study showed that there was a change in land cover on the Unima campus within 20 years, from densely vegetated land cover to sparsely vegetated land cover to not vegetated. Densely vegetated land in 2002 covered 94.90% of the area, then shrank to 87.06% in 2022. On the other hand, non-vegetated or sparsely vegetated land cover increased from 5.10% in 2002 to 12.94% in 2022. Changes in land cover affect the change in the value of the runoff coefficient, from 0.099 in 2002 to 0.125 in 2022. Changes in the runoff coefficient are caused by an increase in the area of built-up land cover and open land reaching above 100%. Changes in coefficient values affect an increase in runoff which has the potential to increase flood discharge in the Unima campus area.