Underwater cultural assets that may be found in this project include mines, shells, and sunken vessels from the Sino-French War and underwater telegraph cables. The results of a survey of underwater cultural assets has revealed that the area in which target objects may be found has a sandy bottom with piles of mud; and frag-ments of oyster shells and other shells could be seen in the area. This survey found 35 places where possible target objects may be located. A first and second underwater verification indicated that the possible target ob-jects constituted natural sand mounds, stones and lumps of mud, pieces of wood, and such modern artifacts as discarded rope. No artifacts or relics with tangible archeological or historical value were seen. Based on the results of this survey work, it has been inferred that there is little likelihood that the mouth of the Tamsui River still preserves sunken ships or mines, etc. from the Sino-French War. This survey work again found that there is little chance of finding the foregoing artifacts, and flooding caused by typhoons, currents, and natural burial over the course of time are likely to have caused any sunken vessels to be in a poor state of preservation. Accordingly, it is concluded that the Danjiang Bridge construction project will not affect the forego-ing underwater cultural assets.
Map of underwater topography in the survey area
Target object distribution map
During the first stage, an underwater video recording system was used to perform preliminary verification.