Natural replenishment of this vast supply of undergroundwater occurs very slowly.
靠自然补充大量地下水是十分缓慢的。
2
In some countries the supply of water from underground can be the only source of water available.
在一些国家由地下水供给的水是仅有的可用水源。
3
So, water enterprises need a set of effective and convenient methods to manage the watersupply network which is valuable underground resource in cities.