Stream network expansion: a riparian water quality factor

• Published in: Hydrological processes Vol. 19; no. 8; pp. 1715 - 1721
• Main Authors: Wigington Jr, P. J., Moser, T. J., Lindeman, D. R.
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-05-2005; Wiley
• Subjects: aerial photography; agriculture; catchment; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Freshwater; Hydrology; Hydrology. Hydrogeology; Pollution, environment geology; riparian areas; stream network expansion; water quality; Water resources; Oregon; United States; USA, Oregon; impact statements; catchment; aerial photography; fertilizers; nitrogen; agricultural waste; streams; concentration; drainage patterns; nitrates; pollution; nonpoint sources; North America; pollutants; agriculture; drainage basins; stream network expansion; land use; hydrochemistry; water quality; water resource management; drainage; riparian environment; riparian areas
• ISSN: 0885-6087; 1099-1085
• DOI: 10.1002/hyp.5866

Little is known about how active stream network expansion during rainstorms influences the ability of riparian buffers to improve water quality. We used aerial photographs to quantify stream network expansion during the wet winter season in five agricultural catchments in western Oregon, USA. Winter stream drainage densities were nearly two orders of magnitude greater than summer stream densities, and agricultural land use was much more abundant along transient portions (e.g. swales, road ditches) of stream networks. Water moving from agricultural fields into expanded stream networks during large hydrologic events has the opportunity to bypass downstream riparian buffers along perennial streams and contribute nonpoint‐source pollutants directly into perennial stream channels. Copyright © 2005 John Wiley & Sons, Ltd.