Submitted to: Encyclopedia of Soils in the Environment
Publication Type: Book / Chapter
Publication Acceptance Date: March 2, 2004
Publication Date: October 25, 2004
Citation: Bonta, J.V. 2004. Precipitation, watershed analysis. In: Hillel, D., Rosenzweigh, C., Powlson, D., Scow, K., Singer, M. and Sparks, D., editors. Encyclopedia of Soils in the Environment. Oxford, UK: Elsevier Limited. p. 314-322.
This chapter summarizes the current state of knowledge regarding precipitation characterization to address problems in watersheds such as general hydrology, sediment, water quality, design, and abatement alternatives. Both temporal and spatial charaterizations of precipitation are discussed. The importance of and lack of representative precipitation measurements are highlighted. Precipitation measurements are often not representative of precipitation actually reaching the ground because of wind effects around the orifice of rain gages. Suggestions are made for obtaining representative precipitation measurements. Precipitation characterization, considering and not considering watershed characteristics, is discussed as storage characteristics on watersheds affect the characterization of storms for some purposes. Watershed processes of preferential flow, infiltration, and interflow are described and their importance on runoff generation and spatial and temporal variation of precipitation characterization are presented. The GEM and CLIGEN weather models, the StormGen storm generator model, and watershed models are briefly reviewed.