The effect of typhoon induced rainfall on settling fluxes of particles and organic carbon in Yuanyang Lake, subtropical Taiwan

A sediment-trap monitoring program measured the fluxes of settling particles and organic carbon in Yuanyang Lake, northern Taiwan, from July 2004 to July 2006 and assessed their relations to the amounts of normal monthly and typhoon-event precipitation. The flux of settling particles varied from 0.7 mg cm−2 month−1 to 14.7 mg cm−2 month−1, and the monthly precipitation ranged from 56 mm to 1218 mm during the survey period. The contributions from typhoon-event precipitation to monthly rainfall amounts were generally larger than 70%. Higher inputs of both particulate and organic carbon into the lake were found during typhoon seasons. Of the annual settling particle loading of 14.9 tons year−1 to the lake floor, 69% occurred during the typhoon months, and 62% of the annual organic carbon loading of 2.3 tons year−1 happened during the typhoon months. These results show the importance of typhoon events on the fluxes of settling particles and organic carbon and their delivery to lakes.

Research highlights► High settling particle (SP) fluxes concur with heavy rainfalls in Yuanyang Lake. ► Heavy rainfall was triggered by episodic typhoon (tropical cyclone) events. ► Typhoon events contributed more than 70% of the monthly rainfall amounts. ► Sixty-nine percent of the annual SP loading to the lake floor occurred during the typhoon months. ► Sixty-two percent of the annual organic carbon flux to the lake floor emerged in typhoon months.