Connecting AnnAGNPS and CE-QUAL-W2 models for reservoir water quality prediction

Jinpen Reservoir is a multi-purpose reservoir with the main objective of supply water for Xi'an city as well as irrigation, electricity generation and flood control . In recent years, nonpoint pollutions have threatened the water quality protection of water source area in the reservoir. To prevent the environmental pollution, protect the water quality of the ground water body, and to exert enough the productive potentialities of resources, it is important to control nonpoint pollutions in the protection zone of headwater area of a reservoir at present. We have connected two powerful watershed and water quality models (AnnAGNPS and CE-QUAL- W2). AnnAGNPS model outputs with the nonpoint source pollution loading as the CE-QUAL-W2 model input. The CE-QUAL-W2 model was applied to simulate water quality in the Jinpen Reservoir, studying of nonpoint source pollution on water quality of reservoir. The results show that when predicting the water quality of reservoir, nonpoint source pollutions should be treated differently in the flood and non-flood period. Nonpoint source pollution had great impact for water quality of Jinpen Reservoir in the flood period, but nonpoint source pollution had less impact for reservoir water quality in the non-flood period. The impact made a great difference between longitudinal and vertical water quality. Forest played a significant role for nonpoint source pollution reduction in the watershed.