Physical Weathering : Breaking down of rock into bits and pieces by exposure to temperature and changes and the physical action of moving ice and water, growing roots, and human activities such as farming and construction
The Flood Control District of Maricopa County, Glossary of Flooding Terms, AZ, USA 2009. http://www.fcd.maricopa.gov/Education/glossary.asp x, (ND/ Flood - Amer) {477}