Riparian Land-Use Impacts on Stream Bank and Gully Erosion in Agricultural Watersheds: What We Have Learned

Zaimes Zaimes,Schultz Schultz,Tufekcioglu Tufekcioglu

doi:10.3390/w11071343

Zaimes Zaimes, Schultz Schultz + Show 1 more

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https://doi.org/10.3390/w11071343

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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.

Highlights

Enhancing stream and gully channel stability has been a priority for decades with large amounts of money spent on watershed and stream restoration projects [1,2,3]
This review provides insights on best management practices to mitigate stream bank and gully erosion that are applicable in landscapes dominated by agriculture
Stream bank erosion rates of the conservation practices were significantly less in most cases compared to the agricultural practices

Summary

Introduction

Enhancing stream and gully channel stability has been a priority for decades with large amounts of money spent on watershed and stream restoration projects [1,2,3]. In studies conducted in the Midwestern U.S, stream banks contributed 23%–79% of the in-stream sediment load in Minnesota streams [16,17,18,19], 0%–81% in Wisconsin streams [20], and 23%–64% in Iowa streams [21,22,23,24,25] These high sediment contributions from stream and gully banks are the result of the implementation of conservation practices to reduce nonpoint source pollutants originating from upland erosion and runoff [26,27]. In watersheds with significant hydrologic alteration, the major source of sediment in streams has shifted from uplands to gullies and stream channels [29,30,31]

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