Yongding River sand land is the largest area of wind-sand land sand and is one of the most severe wind sand damage region in Beijing,Which has important influence to eco-entironment in Beijng.

• 永定河沙地是北京市面积最大的风沙化土地和风沙危害最严重的地区之一，对北京市的生态环境有重要影响。