What do hydrologists mean when they use the term flushing?

✍ Scribed by Doug Burns

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 68 KB
• Volume: 19
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/hyp.5860

✦ Synopsis

The term has been used in an engineering sense to describe releases of water from dams or through sewer systems and the resulting effects on sediment transport (Kondolf and Wilcock, 1996; Campisano and Modica, 2003), but here I focus on the use of the term flushing to describe natural processes in catchments. In a recent search of 'hydrological flushing' on google.scholar.com, the term appeared in 2030 references. Of the 100 most cited references containing the term, only two predate 1997 and 73 have appeared since 2000, which indicates increasing recent use of the term in the peerreviewed literature. Given the increasing use of the term in the literature, it seems prudent to explore how the term is currently used and understood, how use of the term has evolved, and how our understanding of hydrological flushing is likely to evolve in the future. Webster's Collegiate Dictionary defines flush as '4. to become cleaned, washed, or emptied out with a sudden flow of water'. In the hydrological literature, the term typically refers to the movement of a solute to a stream during snowmelt or a rain event. Early work identified flushing associated with the behaviour of dissolved organic carbon (DOC) during snowmelt in a stream in the Rocky Mountains (Hornberger et al., 1994; Boyer et al., 1997). However, the term has since been applied to describe the behaviour of many solutes, including: nitrate, silica, base cations, phosphorus, sulphate, and pesticides (