water Article Phosphorus Dynamics along River Continuum during Typhoon Storm Events Ming Fai Chow 1,3 ID , Jr-Chuan Huang 2 and Fuh-Kwo Shiah 3,* 1 Center for Sustainable Technology and Environment (CSTEN), Universiti Tenaga Nasional (UNITEN), 43000 Kajang, Selangor, Malaysia;
[email protected] 2 Department of Geography, National Taiwan University, Taipei 10617, Taiwan;
[email protected] 3 Research Center for Environmental Changes, Academia Sinica, Taipei 115, Taiwan * Correspondence:
[email protected]; Tel.: +886-02-2783-9910; Fax: +886-02-2789-3234 Received: 11 February 2017; Accepted: 14 July 2017; Published: 18 July 2017 Abstract: Information on riverine phosphorus (P) dynamics during typhoon storm events remains scarce in subtropical regions. Thus, this study investigates the spatial and temporal dynamics of riverine phosphorus in a headwater catchment during three typhoon events. Continuous sampling (3 h intervals) of stormwater samples and discharge data were conducted at five locations, which represent the upstream, transitional zone, and downstream areas of the main inflow river. The results revealed that the average event mean concentrations (EMCs) for total dissolved phosphorus (TDP) and particulate phosphorus (PP) in the upstream catchment of Fei-Tsui reservoir were 15.66 µg/L and 11.94 µg/L, respectively. There was at least a 1.3-fold increase in flow-weighted concentrations of TDP and PP from the upper to lower reaches of the main stream. PP and TDP were transported either in clockwise or anticlockwise directions, depending on storm intensity and source. The transport of TDP was primarily regulated by the subsurface flow during the storm event.