The Morphological Evolution of River and Water Body in Urban Area of Guangzhou City in 1990-2010

The shapes of urban rivers and water body were deeply affected by the rapid industrialization and urbanization in recent decades in Guangzhou.The article used topographic maps,remote sensing images and related socio-economic data as a basis data to research the space-time evolution of urban rivers and water body and its causes in Guangzhou in the past two decades.The results indicated that: 1) The changes of area of river and water bogy showed a slight increase trend in the first decade and a sharply reduce trend in the last decade,the area increased 9.11 km2 from 1990 to 2000,and reduced 32.37 km2 from 2000 to 2010.The water front length of river and water body showed a continuous reduce trend in the past two decades,the length reduced 26.49 km from 1990 to 2000 and 1 008.19 km from 2000 to 2010.The landscape shape index were 83.49(1990),80.19(2000) and 71.83(2010),which showed an accelerated decline trend,and indicated that the shape complexity of rivers and water body was decreasing and human intervention was strengthening in study area.2) There were great differences between the changes of rivers and water body in different regions and periods.The increased parts from 1990 to 2000 mainly located in Baiyun and Luogang District in the outskirts of Guangzhou,because a lot of ponds had been excavated and porcelain clay lodes had been exploited in those areas.In 2000-2010,decrease happened in every district in study area as a common trend.The rate and speed of change in Tianhe District is the biggest in the past two decades,and that coincided with the "East" development direction of Guangzhou.3) The changes of rivers and water body in study area were mainly affected by human activities.The reduced parts contain the occupation of the built-up areas,and increased parts contain new ponds,porcelain cay pits,new landscape water body and other water body for special uses.