Baseflow concentrations of nitrogen and phosphorus in forested headwaters in Japan.

A comprehensive investigation on all dissolved nitrogen and phosphorus components at both local and regional scales in the headwaters from forested watersheds is valuable to improve our understanding of the factors controlling water quality. Here, we investigated the baseflow concentrations of dissolved nitrogen and phosphorus components, N:P ratio, and their associations with region and vegetation type in forested headwaters in fives regions of Japan. We found that inorganic nitrogen and phosphorus were the dominant components in the 26 temperate forested streams, rather than organic forms.

Characterisation of diffuse pollutions from forested watersheds in Japan during storm events - its association with rainfall and watershed features.

Forest areas have been identified as important sources of nonpoint pollution in Japan. The managers must estimate stormwater quality and quantities from forested watersheds to develop effective management strategies. Therefore, stormwater runoff loads and concentrations of 10 constituents (total suspended solids, dissolved organic carbon, PO(4)-P, dissolved total phosphorus, total phosphorus, NH(4)-N, NO(2)-N, NO(3)-N, dissolved total nitrogen, and total nitrogen) for 72 events across five regions (Aichi, Kochi, Mie, Nagano, and Tokyo) were characterised.