2.2.5 Model scenarios
The verified model was used to study the nitrogen cycle in the riparian zone under the coexistence of water level fluctuation and other factors at the site. The amplitude and duration of the water level fluctuation are A  =0.6m, T  =3d respectively. The initial groundwater level (7.74m) was assigned of the average base flow water-level at the site from 2014 to 2015. This paper aims to explore the methods and principles of improving the denitriding capacity in the riparian zone from many aspects. For example, biological method such as adding denitrifying bacteria into the aquifer; chemical methods include increasing DOC concentration of surface water and groundwater; hydrogeological methods include enhancing hydrological connectivity and initial surface water-groundwater hydraulic gradient; topography methods include changing the slope and concave and convex shape of the bank. All the numerical test cases are shown in Table 2.