(41CV) Ephemeral Gully Erosion

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An extract from Calculator Program and Nomograph for On-Site Prediction of Ephemeral Gully Erosion, Civil Engineering Department (CSU) & Sedimentation Laboratory (Oxford MS), FEB 1985 (29 pgs)

1. INTRODUCTION AND PURPOSE
Rill and interrill erosion in arable fields can be estimated quickly and simply using the Universal Soil Loss Equation (USLE). No similar approach to estimating soil loss due to ephemeral gullying is available. This is unfortunate, because ephemeral gully erosion may be comparable to the rill and interrill erosion. Under these circumstances, application of the USLE alone may result in soil loss estimates which are about half the true loss.
This report presents a preliminary attempt to develop a simple, easy-to-apply technique to estimate ephemeral gully erosion on the basis of a single field visit, consultation with the farmer, and practical experience. Either a hand held calculator (HP-41CV), or a Nomograph is used to aid calculations. The method is intended to predict ephemeral gully erosion for the first year of gully development--that is from gully initiation following seed bed preparation, to its eradication about one year later by annual tillage. The method cannot be used, with modification, to estimate ephemeral gully erosion in subsequent years, when the gully has not been eradicated at the end of the first year.
This method is intended for use by field personnel. It is hoped that whereever possible, the results will be tested against field data to test their realism …
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This report is intended as a user's guide and only the data collection procedure and calculation methods are presented. First, the field data needed are outlined; second, the three methods of undertaking the necessary calculations are presented; and third, a worked example is given. Finally, the main points are summarized.
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4.2 Using the Calculator Program and HP-41CV or CX …
… PROGRAM LISTING …
4.2.3 Running the Program …

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