The Method of Remote Sensing Monitoring and Analysis about the Changes of Liao River Watershed

Abstract

In order to monitor Liao River watershed, Modified Normalized Difference Water Index model (MNDWI and NDWI-B) was used to imitate the changement of Liaohe River watershed based on Landsat TM and HJ-1B CCD remote sensing data from 1992 to 2009. The influencing factors also be analyzed via hydrological and meteorological data. The results showed that the area reduced 35.58% in these 18 years, with the runoff decreasing 11.15% and average water level descending 0.454m. Furthermore, the volume of runoff decreases 51% and the average water level descends 1.031m in 2009 than that in 1999, but the watershed is almost the same in these two years. The water depth becomes shallower and makes river floodplain because of sediment deposition and riverbed elevation, and part of reason is the dam block the river at the same time. The results of its experiment indicated that the change of watershed is not only affected by natural factors, but also relative with social development.