名词解释：堰塞湖是由火山熔岩流，冰碛物或由地震活动使山体岩石崩塌下来等原因引起山崩滑坡体等堵截山谷，河谷或河床后贮水而形成的湖泊。由火山熔岩流堵截而形成的湖泊又称为熔岩堰塞湖。你知道怎么用英语表达吗?

Floodwaters in a barrier lake formed after Sunday's earthquake in Yunnan province will be discharged within two days after an explosion is set off in the debris barrier.

The plan for removing the barrier lake has been approved, and a flood relief channel, measuring 5 meters wide and 8 meters deep, will be excavated on the top of the barrier.

If the water overflows the debris barrier, it might affect more than 2,000 people and 5,500 houses. Roads and two power stations that are downstream also could be damaged. More than 4,200 people living downstream have been relocated to avoid the flooding.

云南省上周日地震后形成的堰塞湖洪水将会通过堰塞体爆破来清除，泄洪将在两天内完成。

清除堰塞湖的工作已经得到审批，将在堰塞体顶部开凿一个宽5米、深8米的泄流槽。

如果洪水溢出堰塞体，将会影响到2000多位居民和5500户房屋。下游的道路和两座发电站也将遭到毁坏。目前，为了避免洪水灾害，居住在下游的4200多位居民已经转移安置。

【讲解】

文中的barrier lake就是“堰塞湖”的意思，堰塞湖是由火山熔岩流、冰碛物或地震活动使山体岩石崩塌堵截山谷、河谷或河床后贮水而形成的湖泊。此处的barrier用作名词，解释为“障碍”，形象地说明了堰塞湖的形成。世界上著名的湖泊有：Black Sea(黑海)、the Great Lakes(北美五大湖)、Lake Victoria(维多利亚湖)、the West Lake(西湖)等。

此外，文中还有一些值得学习的短语：set off(点燃)、power stations(发电站)、a flood relief channel(泄流槽)。