Though there has enough water resource,the runoff collecting area also can not sustain the lush growth of vegetation,because of its siltation,evaporation and salinization.

• 而范围较广的集水地形即因淤积、蒸发作用而导致盐渍化,虽水量充裕亦难助植物繁生,有限降水的水源,反成加剧荒漠化过程的动因。