The wooden arch bridges, found mostly in Fujian and Zhejiang provinces, were built using structures fitted together without using a single metal nail or rivet.
The Chinese building practice was put on Unesco's List of Intangible Cultural Heritage in Need of Urgent Safeguarding in 2009.
The four bridges -- Longjin, Sanxi, Guanshan and Xianwuting -- are all cultural sites under protection, with the oldest dating back to 1631.
Qiu Changrong, deputy director of the cultural bureau in Minhou county, said that after the typhoon passed, most structural wooden planks of the Guanshan and Xianwuting bridges were retrieved due to the narrow waterway underneath.
"After the typhoon, we called on villagers to join the government's efforts in looking for the missing parts downstream. Anyone who finds them can get a reward from hundreds to thousands of yuan depending on how much they find," Qiu said.
A week since the typhoon passed, around one-third of the missing pieces of the bridges have been recovered, as people trekked downstream to a reservoir in a neighbouring county with the help of local farmers.
Typhoon Meranti, the strongest typhoon to hit China this year, left 28 people dead and 15 others missing in Fujian and Zhejiang, after making landfall on September 15.
