Abstract: To improve the water quality and make sure the drinking safety of cellar water in Loess Plateau, the selection of the water sources for harvesting rainwater is imperative. By the method of principal component analysis (PCA), this paper determined the high-quality rainwater sources and the related control indices. Among the different types of test water sources, cement ground and tile roof were the better fields for harvesting rainwater, with their integrated principal component scores being -3.350 and -1.945, respectively. The indices COD, NH₄⁺-N, TP, SS, and fecal coliform had high load values in the main components. The harvested rainwater was mainly pollutted by organic matter, surface dust, and animal and/or human excreta, which obviously related to human activities. Some improvement measures and recommendations for the source rainwater were also proposed from the aspects of policies and regulations, water quality protection technology systems, and water quality testing and protection.

Key words: Dolichomitriopsis diversiformis, Air temperature, Water content, Photosynthetic rate, Irradiation, Model