Chaos Analysis on Series of Groundwater Depth in Sanjiang Plain, China

Sanjiang Plain is the largest swamp area of freshwater and an important production base of commodity food grain in China. The groundwater resource plays an important role in the development of well-irrigation paddy. The groundwater system is a kind of complicated nonlinear system. Based on the power spectral analysis on groundwater depth series in Sanjiang Plain qualitatively, the several characteristic quantities, which are the Kolmogorove entropy, the correlative dimension and the Lyapunov index of groundwater depth series, have been calculated through reconstruction of state space. Results of the analysis and calculation show that there is an obvious chaos characteristic in groundwater depth series in Sanjiang plain. The results offer theoretical basis for building prediction model of groundwater depth in Sanjiang plain in the future.