The sediment distributed and insolated under lake was collected for ex periments. The nutrient layer distribution conditions of sampled sediment and it s physical and chemical characteristics were analyzed to simulate and assess the influence degree to lake water quality. Based on the dynamic water exchanging e xperiments the nutrient release process in sediment and influence mechanism to s ubstance exchanging on water-sediment interface was studied, and the correlation between the changing content of total phosphors and total nitrogen in sediment and covered water were analyzed for setting up a simulation model. At the same t ime the influence degree is explained in detail. The experimental results indica ted that even if clean water without nutrient contents was used for water exchan gement so as to decrease pollution or prevent eutrophication, however owing to t he vertical nutrient distribution in lake sediment, it will lead to the increasi ng release amount greatly especially when the organic nutrient contained in sedi ment turns into inorganic status because of isolation. Besides the release proce ss of total phosphate(TP) and total nitrogen(TN) were modeled and each nutrient’ s exchanging equation at interface caused by covered water nutrient concentratio n changing was set up. According to the simulating prediction, TP and TN content of cover water will also sustain a steady higher level in a long period. The nu trient release amount of sediment is not only affected by the covered water conc entration but also connects with accumulative time. The experiments provide the fundamental theoretical and practical basis for taking ecological restoration pr oject. And research is helpful to prevent or restore lake eutrophication.
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