The Sanjiang Ecological Test Station of Wetland serves as the research base. Firstly typical sampling sites were selected

then general characteristics of wetland hydrochemistry and movement of chemical elements due to drainage were researched by analyzing contents of main ions(HCO_3~-

Cl~-

NO_3~- and SO_4~(2-))

heavy metals(Cu

Zn

Fe and Mn)

nutritive elements(N

P

K)and their availability. Results showed that types of wetland hydrochemistry are HCO_3~--Ca.Mg and HCO_3~--Ca.Na. The serials of heavy metal is Fe>Mn>Cu>Zn>Pb

Cr. Lots of chemical elements have been lost because of draining

which is one cause of wetland degradation.