[Multiple time-scale analysis of nitrogen retention characteristics and influencing factors in Shanmei Reservoir, Fujian, China.].

The retention effect of reservoir on nitrogen is an important influence factor on the eutrophication prevention and control. In order to reveal the differences of nitrogen retention characteristics and the influence factors at multiple timescales, an ecological dynamic model was developed in Shanmei Reservoir watershed. Based on the retention flux and retention rate calculation, the nitrogen retention effect was analyzed at three time scales of yearly, monthly and daily, respectively.

[Multiple time scales analysis of spatial differentiation characteristics of non-point source nitrogen loss within watershed].

Identification of the critical source areas of non-point source pollution is an important means to control the non-point source pollution within the watershed. In order to further reveal the impact of multiple time scales on the spatial differentiation characteristics of non-point source nitrogen loss, a SWAT model of Shanmei Reservoir watershed was developed. Based on the simulation of total nitrogen (TN) loss intensity of all 38 subbasins, spatial distribution characteristics of nitrogen loss and critical source areas were analyzed at three time scales of yearly average, monthly average and rainstorms flood process, respectively.

[Coupling SWAT and CE-QUAL-W2 models to simulate water quantity and quality in Shanmei Reservoir watershed].

A coupled watershed-reservoir modeling approach consisting of a watershed distributed model (SWAT) and a two-dimensional laterally averaged model (CE-QUAL-W2) was adopted for simulating the impact of non-point source pollution from upland watershed on water quality of Shanmei Reservoir. Using the daily serial output from Shanmei Reservoir watershed by SWAT as the input to Shanmei Reservoir by CE-QUAL-W2, the coupled modeling was calibrated for runoff and outputs of sediment and pollutant at watershed scale and for elevation, temperature, nitrate, ammonium and total nitrogen in Shanmei Reservoir. The results indicated that the simulated values agreed fairly well with the observed data, although the calculation precision of downstream model would be affected by the accumulative errors generated from the simulation of upland model.