Properties of water equal to that of the hydrogen ion (), which gives a pH of 7 at 25 °C. Action of water on rock over long periods of time typically leads to weathering and water erosion, physical processes that convert solid rocks and minerals into soil and sediment, but under some conditions chemical reactions with water occur as well, resulting in metasomatism or mineral hydration, a type of chemical alteration of a rock which produces clay minerals. It also occurs when Portland cement hardens. Water ice can form clathrate compounds, known as clathrate hydrates, with a variety of small molecules that can
Water management in the Metropolitan Region of São Paulo the state water and sanitation utility Sabesp and 35 municipal governments. A basin committee for the Alto Tietê basin, which supplies the other half of the water for the MRSP, brings together all stakeholders. The legal framework at the state level is based on two key federal laws, Law 9,433 of 1997 concerning water resources management and Law 11,445 of 2007 concerning water supply and sanitation. A key state law is Law 7,663 of 1991 which created what is called the State System for Water Resource Management. The system pioneered shared decision-making in water resources management even before the same