Preface

This book is on soil erosion caused by rainfall and runoff at the basin scale. Why is the study of soil erosion significant? Soil erosion products are transported by runoff into the streams of a basin and through the streams to the basin outlet, which may also be a coastal zone or the inlet of a natural or artificial lake. The transport of large amounts of eroded soil by runoff, and consequently the transport of large amounts of suspended sediment in the streams, is mainly dependent on the frequency and intensity of rainfall events. Removal of fertile soil and acceleration of reservoir sedimentation are some additional unfavorable effects of soil erosion. Soil erosion modeling contributes to the quantification of eroded soil and informs actions against soil erosion.

This book contains three sections. In the first section, soil erosion is defined, the stages of soil erosion are described, factors influencing soil erodibility are discussed, and severe soil erosion consequences are reported. Additionally, the historical evolution of soil erosion models is briefly presented. In the first part of the second section, the coefficient of rainfall erosivity in the Universal Soil Loss Equation (USLE) is estimated on the basis of pluviograph records on the one hand, and cumulative rainfall depths by means of empirical equations and machine learning methods on the other hand. Rainfall data from 84 meteorological stations in Greece are used. In the second part of the second section, a physically-based, hydrodynamic, finite element model is analytically described for the computation of surface runoff, that causes soil erosion and contributes to channel flows. The model is applied to a low-relief agricultural basin in the Mississippi River alluvial plain. In the first part of the third section, soil erosion risk is assessed under different geographical, topographical, climatological, and land occupation/management scenarios, in the French Claise and Lebanese Nahr Ibrahim basins. In the second part of the third section, the erosion risk management in the OuedBeht basin (Morocco) is evaluated, and the delimitation of the areas requiring priority planning is achieved.

#### **Vlassios Hrissanthou**

Emeritus Professor, Section of Hydraulic Engineering, Department of Civil Engineering, Democritus University of Thrace, Greece

**Konstantinos Kaffas** Free University of Bozen-Bolzano, Italy

**1**

Section 1

Introduction to Soil

Erosion Problem

Section 1
