The law of water balance states that the inflows to any water system or area is equal to its outflows plus change in storage during a time interval.[2][3] In hydrology, a water balance equation can be used to describe the flow of water in and out of a system. A system can be one of several hydrological or water domains, such as a column of soil, a drainage basin, an irrigation area or a city.
The water balance is also referred to as a water budget. Developing water budgets is a fundamental activity in the science of hydrology. According to the US Geological Survey:[4]
An understanding of water budgets and underlying hydrologic processes provides a foundation for effective water-resource and environmental planning and management. Observed changes in water budgets of an area over time can be used to assess the effects of climate variability and human activities on water resources. Comparison of water budgets from different areas allows the effects of factors such as geology, soils, vegetation, and land use on the hydrologic cycle to be quantified.
- ^ Brun, P., Zimmermann, N.E., Hari, C., Pellissier, L., Karger, D.N. (preprint): Global climate-related predictors at kilometre resolution for the past and future. Earth Syst. Sci. Data Discuss. https://doi.org/10.5194/essd-2022-212
- ^ Sutcliffe, J.V. (2004). Hydrology: A Question of Balance. Intl Assn of Hydrological Sciences (IAHS).
- ^ Viessman, W.; Lewis, G.L. (1996). Introduction to Hydrology (Fourth ed.). HarperCollins College Publishers.
- ^ Healy, R.W.; Winter, T.C.; LaBaugh, J.W.; Franke, O.L (2007). Water Budgets: Foundations for Effective Water-Resources and Environmental Management. U.S. Geological Survey. p. 90.