Dampak Perubahan Penutupan Lahan Terhadap Evapotranspirasi Aktual

Abstract

This paper presents an attempt to investigate the changes on land cover that have occurred due to human activities and its impact on actual evapotranspiration, a E , in Monsoon Asia. Comparison between current and potential vegetation classifications has been done to identify the impact of human activities on land cover distribution. The current vegetation was obtained from satellite data, while the potential vegetation was defined from climatic data. As a result of comparison of the both vegetation maps, we realized that India, and China were as the center of land cover changes. This also appears in tropics region, such as Indonesia and Malaysia. In general, the type of changes is from forest to non-forest such as, paddy field, cropland and grassland. These anthropogenic changes caused the decreased up to 180mm or 12% per year. The 0 value indicates such area where the has no changed, while the positive value indicates the of current condition has been decreased from potential one. The lower value (less than 5%) was happened when evergreen broadleaf forest (seasonal) changed to rice paddy such as in Shandong (China). It also occurred in Punjab and Uttar Pradesh (India) when the subtropical rain forest has been changed to cropland. In addition, when the sub tropical rain forest changed to rice paddy, such as in Assam (India) and Guangxi, and Guangdong (China), thewas decreased by 9%. The highest decreased value (12%) was occurred when the tropical rain forest was changed to rice paddy such as in Kalimantan Selatan (Indonesia) and Pahang (Malaysia).Key words : land cover changes, actual evapotranspiration, Monsoon Asia. ABSTRAKTulisan ini memaparkan perubahan penutupan lahan akibat kegiatan manusia serta dampaknya terhadap perubahan evapotranspirasi actual,, di Monsun Asia. Perbandingan antara vegetasi aktual dan potensial menjadi indikator dampak perubahan lahan akibat kegiatan manusia. Kondisi vegetasi akual diidentifikasi dengan menggunakan citra satelit, sedangkan vegetasi potensial ditentukan dengan menggunakan data iklim. Dengan membandingkan distribusi vegetasi potensial dan aktual, perubahan banyak terjadi di India, China, Indonesia dan Malaysia dengan perubahan dominan dari hutan ke non hutan. Perubahan ini ternyata mengakibatkan penurunan sampai 180mm atau 12% per tahun. Penurunan sebesar kurang dari 5% teridentifikasi di daerah yang mengalami perubahan dari evergreen broadleaf forest ke padi sawah ataupun dari hutan subtropikal menjadi lahan pertanian, seperti yang terjadi di Shandong (China), Uttar Pradesh (India). Penurunan mencapai 9% teridentifikasi pada saat hutan sub tropis berubah menjadi padi sawah, seperti yang terjadi di Assam (India), serta Guangdong dan Guangxi (China). Penurunan tertinggi sebesar 12% terjadi pada saat hutan tropis berubah menjadi padi sawah seperti yang terjadi di Kalimantan Selatan (Indonesia) and Pahang (Malaysia).Kata kunci : perubahan penutupan lahan, evapotranspirasi aktual, Monsun Asia. Runtunuwu E JIPI 13

Catchment Discharge Modelling for Maintaining the Water Resources in the Lesti Sub-Catchment of Upstream Brantas

“…In addition, the sand that comes from the mountains every rainy season will increase the sediment which will accelerate the critical level of the catchment. Therefore, it is necessary to make the conservation effort based on the catchment condition (Runtunuwu, 2007, Rajiman, 1998. Although there is the soil cover vegetation on the upstream Lesti sub-catchment, the rainfall which drops to the surface soil does not intercept in the soil.…”