Water quantity and quality changes from forested riparian buffer in Beijing.

As a transitional zone between aquatic and terrestrial ecosystems, the riparian buffer is an important control measure for non-point source pollution. The research presented here mainly discussed the interception efficiencies of different vegetation types for nitrogen and phosphorus pollution. The results showed that canopy, shrub, and grass interceptions basically accounted for about 80.0% of total interception, and therefore riparian buffer configurations should clearly distinguish three levels of vegetation types. (1) Canopy, shrub, grass, and litter interceptions of Pinus tabuliformis (YS) were the highest, up to about 71.1%. (2) Platycladus orientalis (CB) had the highest transportation and enrichment for the elements nitrogen (N) and phosphorus (P) throughout the process, which the value of TP decreased from 0.2 to 0.12 mg/L and the value of TN decreased from 5.0 to 2.5 mg/L. (3) The transportation of total phosphorus (TP) of the three tree species was higher than the transportation of total nitrogen (TN), showing that the enrichment of P was stronger than that of N. Thus, Pinus tabuliformis is the best configuration for rainfall interception, while Platycladus orientalis is the best configuration for N and P removals. Different forest configurations should also be considered to build a riparian buffer to remove nutrient in the future.