‘Bo’s, not Bows, in the rivers

I sometimes worry that my voc…., my vocb.., my word-bank-in-head-thing is failing as I spend too much time in Korea.  At other times, such as this, possibly appropriate words that are very technical and arcane are used very nonchalantly in newspaper articles.


The Dong-A Ilbo has such an article with the offending term right in the title.  To my surprise, it’s term  that I want to know.

The article is about ‘Bo’s, or what I always thought were ‘low-head dams’. A google search for weir shows me images similar to low-head dams.  Bos, for which I can find no appropriate images, seem to consist of a weir plus a liftable-gate to control water levels.

I also finally investigated what a ‘barrage‘ was. Turns out it is not only an artillery term. The barrage in Busan looks like a series of mighty jaws that can close to reduce salt influx during high tide, but open to let the river water flow.

About Civil (engineering) offers a comparison:

The only difference between a weir and a barrage is of gates, that is the flow in barrage is regulated by gates and that in weirs, by its crest height.

Barrages are costlier than weirs.

Weirs and barrages are constructed mostly in plain areas. The heading up of water is affected by gates put across the river. The crest level in the barrage (top of solid obstruction) is kept at low level.

During flood, gates are raised to clear of the high flood level. As a result there is less silting and provide better regulation and control than the weir.

Alright, back to the original Dong-A article:

It is chiefly a defense of various bos that will be placed in the four rivers as part of President Lee’s Four Rivers Project.

I am torn about the project for idealogical and ecological reasons.

Ideologically, the Four Rivers Project feels too much like a revamping of the Great Korean Canal Project that would allow ships to travel upstream from Incheon and Seoul via the Han River to Taebaek and down the Nakdong River to Daegu and Busan.  I can see no benefit to such a project and am glad it has been scrapped.

Ecologically, I would prefer that rivers and natural areas be left alone, but humans rendered that option untenable when we reached a number of six billion.  As we are now at seven billion, and our presence is felt everywhere, no place is ‘natural’ so careful management is often the wisest course.

The bos – or low-head dams or weirs – do seem among the most environmentally-friendly of options. As with anything else that is new or strange, we won’t know how well they work until they are built and the Dong-A article ends somewhat ominously:

The bos in the four rivers are reportedly designed in a much more eco-friendly manner than traditional bos because they have the features of weirs. The people must now see the bos of the four major rivers and judge them.