Evaluation of dynamic groundwater quality simulation based on Cloud-GIS: a case study in Harbin urban area, China

This paper consists of two parts. The first part addresses the joint modeling of both spatial and temporal elements to perform dynamic evaluation of groundwater quality. In this part, a grey prediction method was used to predict missing values and then, on the basis of an entropy-weighting method, to build a dynamic weight model which continually changes with time; finally, a fuzzy evaluation method was used to evaluate groundwater quality. MATLAB was used to integrate these mathematical models. The second part describes the construction of a dynamic simulation platform which integrated mathematical models, a property database, and a spatial database, with secondary developments in geographic information system (GIS) and cloud-based simulation technology. All calculation steps and simulation programs were carried out on the simulation platform. The results indicated the grade of groundwater quality between II and IV. Groundwater quality gradually rose in the first and fourth quarters, but continually decreased in the second and third quarters. The lowest groundwater-quality value for the entire year appeared in October. This result also illustrates that turning points in groundwater quality appear when groundwater levels increase or decrease along rivers.