Hacia una nomenclatura y clasificación de formas de fondo transversales generadas por flujos de agua Towards a nomenclature and classification of transversal bedforms generated by water flows

Existe un gran diversidad de nombres y clasificaciones de formas de fondo en todos los idiomas, lo que redunda en complicaciones a la hora de describirlas. Nuestro idioma no es una excepción y por lo tanto es tiempo de establecer un esquema que reúna una nomenclatura y clasificación de formas de fondo. El objetivo del presente trabajo es dar una primera aproximación hacia ese logro para formas de fondo, principalmente transversales al flujo. Estos flujos se consideran tanto unidireccionales (en sentido amplio) y oscilatorios. Se presenta también una breve rese a de las relaciones dinámicas entre el flujo y el sedimento necesario para comprender el porque de estas formas. Pero no se incluyen las estructuras primarias generadas por las mismas. Entre otros aspectos, se propone el empleo del término "dunas" únicamente para las formas transversales generadas por flujos de agua, y del término "médano" cuando el agente es el viento. As it is common in many languages, Spanish-speaking researchers dealing with bedforms have developed a large variety of terms and classifications which, sometimes, are even contradictory. The main aim of the present article is to provide a nomenclature and classification scheme for transversal bedforms generated by water flows that can serve as the basis for a more elaborated product achieved after several iterations, with the consensus of these researchers. In particular, it is proposed the use of the word "dunas" for the transversal bedforms generated by water flows and "médanos" when the agent is wind. Bedforms are instabilities in the sediment-water interface. Particles displaced from one point in the bed are deposited in another producing a modification in the flow structure and inducing further deposition in and around these particles. The flow instability then propagates downcurrent inducing the formation of new bedforms. Even though there is general agreement about the main formation mechanisms for bedforms, there are many details about their genetic processes, and which variables affect them the most are still unknown. Different authors have suggested that water depth, grain size, presence/absence of fine (silt or clay) particles, flow velocity and asymmetry are some of the most important predicting variables. However, the correlations observed are far from satisfactory or are site or experiment-specific and seldom can be extrapolated to other environments. Some correlations such as H vs d and L vs d are given in figures 4 and 5. A nomenclature of transverse bedforms elements are given in figure 3. The proposed bedform cla