Riparian land-use ımpacts on stream bank and gully erosion in agricultural watersheds: what we have learned

Abstract

Stream bank and gully erosion are major sources of nonpoint source pollutants, especially in landscapes dominated by agriculture. Implementation of upland conservation practices in landscapes dominated by agriculture reduces upland sediment transport more than water runoff, leading to excessive stream bank and gully erosion. This review focus on ten different studies conducted in streams in Iowa that investigated riparian land-use impacts on stream banks, gullies, and other riparian sediment sources (cattle loafing areas and cattle stream access points). The riparian land-uses investigated were riparian forest buffers; grass filters; continuous, rotational, and intensive rotational pastures; pastures with cattle fenced out of the stream; and row-cropped fields. Results of these studies indicate that maintaining perennial deep-rooted vegetation in riparian areas and excluding cattle from the stream channel stabilizes stream banks and gullies. Cattle loafing areas and cattle stream access points appear to also be important sediment sources. Re-establishing perennial riparian vegetation is a sustainable and cost-effective conservation practice because it reduces sediment in streams while maintaining the majority of the watershed in agricultural production. The limited available funds for the implementation of holistic watershed conservation practices suggest using targeted approaches, at the watershed scale, to improve conservation practice effectiveness.