Soil is said to be waterlogged if any part of the plant root zone is saturated with water. In severe cases soil is saturated to the surface and waterlogging is obvious. Waterlogging is distinguished from flooding in which surface runoff brings down water from higher up in a catchment. However, flooding may result in waterlogged sites.
McFarlane, D J.
"Assessment of waterlogged sites,"
Journal of the Department of Agriculture, Western Australia, Series 4: Vol. 26
, Article 6.
Available at: http://researchlibrary.agric.wa.gov.au/journal_agriculture4/vol26/iss4/6