A spatial–temporal analysis of impacts from human development on the Shih-men Reservoir watershed, Taiwan

Abstract

Human activity such as the development of slope land around watersheds has dramatically affected the ecological environment in Taiwan. This situation has been aggravated by heavy precipitation from typhoons in the summertime. The results include serious soil erosion and mass movement in the Shih-men Reservoir watershed. In order to identify the most fragile areas and seek the triggering factors of landslide changes that can cause turbid currents in the Shih-men Reservoir watershed, this study integrates different types of satellite imagery and geographic information system data to determine changes in land cover and vegetation cover since the early 1970s. Results from spatial regression models indicate road and land uses are the main factors that lead to slope failure along roads and contribute to a large number of landslides in environmental hotspots like the Baishih River sub-watershed. Soil erosion estimates indicate a positive relationship between the increases in landslide and soil loss areas and the road system development. Therefore, human development has a significant negative influence both on sensitive mountainous watersheds and on critical environmental hotspots.

Acknowledgements

The authors thank the National Science Council of Taiwan for financially supporting this research (NSC95- 2116- M- 003- 007, NSC96- 2815- C- 003-013-M) and NTNU academic research funding (NTNU ORD93-1). The authors also thank the National Space Office and NTNU IADC for providing satellite imagery, Professor Che-Ming Chen of the NTNU Department of Geography for his insightful comments, and Professor Chy-Rong Chiou of the NTU School of Forestry and Resource Conservation for providing time-series land-use data. Finally, we also acknowledge the two anonymous referees for their comments.