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By analyzing the multi-year runoff and rainfall data at 15 hydrological stations from 1980 to 2007, as well as monthly runoff data from 1964 to 1984 at the Zipingpu hydrologic station, the relationship between precipitation and runoff has been established and the trend was explored. Based on the catastrophic floods of August 13 and August 18, 2010, characteristics and control factors on the post-seismic floods are summarized. Firstly, the Wenchuan earthquake and rupture zone provides the background for post-seismic floods to develop in the upper Minjiang River, which follows a post-seismic disaster-chain pattern: earthquake collapse to landslide debris flows to floods. Secondly, heavy rainfall controlled by the orographically-enhanced precipitation after the Wenchuan earthquake is the trigger factor for the development of devastating post-seismic floods. Thirdly, the post-seismic floods contain high sediment discharge, cause abrupt and severe damages, and have a large of volume and higher frequency.

An eco-environmental geochemical investigation was carried out in and around the Dexing mining area to determine the concentrations of heavy metals in the surface water, sediments, soils and plants. The main objective of this study is to assess the environmental situation and evaluate the transferring of heavy metals from mining activities into the food chain. Some samples of water, sediment, topsoil and plant were collected along the Lean River in the Dexing mining area. The total concentrations of Cu, Pb, Zn, Cd, and As were determined by AAS, and Hg was analyzed by cold-vapor AAS. Some indices such as ‘contamination degree’, ‘geoaccumulation index’, and ‘biological absorption coefficient’ were used to assess eco-environmental quality. The investigation indicated a highly localized distribution pattern closely associated with the two pollution sources along the Le' an, River bank: one is strong acidity and a large amount of Cu in the drainage from the Dexing Cu mining area; and the other is the high concentrations of Pb and Zn in the effluents released from many smelters and mining, processing and extracting activities in the riparian zone. Results from the investigated localities indicated, at least in part, that some problems associated with environmental quality deterioration should be solved in the future.

Mining and smelting activities are the main causes for the increasing pollution of heavy metals in soil, water body and stream sediment. An environmental geochemical investigation was carried out in and around the Panzhihua mining and smelting area to determine the extent of chemical contamination in soil and sediment. The main objective of this study was to investigate the environmental geochemistry of Ti, V, Cr, Mn, Cu, Pb, Zn and As in soil and sediment and to assess the degree of pollution in the study area. The data of heavy metal concentrations reveal that soils and sediments in the area have been slightly contaminated. Geochemical maps of Igeo of each heavy metal show that the contaminated sites are located in V-Timagnetite sloping and smelting, gangues dam. The pollution sources of the selected elements come mainly from dusts resultant from mining activities and other three-waste-effluents. The area needs to be monitored regularly for trace metal, especially heavy metal enrichment.