This article presents a scientific overview of the basic implementation of the principles of ecological engineering in riparian zone management and restoration. Buffer zones transform a pollutant signal as a sink within the catchment area from source emission to surface water bodies. Riparian zones and buffer strips are linear landscape components, receiving diffuse flow. The first sections of the article discuss the main elements in riparian zones, especially riparian buffer zones and buffers strips. The subsequent sections concentrate on the various functions of riparian buffer zones and design criteria in agricultural watersheds. The dimensioning, efficiency assessment, management, and restoration principles of riparian buffer zones, as well as investigation results from selected case studies, will be analyzed in the last sections.