Fluvial Geomorphology

Course Description

Objectives

The course on Fluvial Geomorphology is an introduction to basic concepts related to drainage networks and drainage basins. It addresses fluvial processes related to flowing water and their results, which are fluvial landforms. The main goal is to understand natural processes such as erosion by the action of surface water, the transportation of erosion products (sediments) through riverbeds, and fluvial sediment deposition in areas of reduced transport capacity. Additionally, the course aims to understand the morphological characteristics and the mechanisms of fluvial landforms formation (riverbeds, bend points, river terraces, floodplains, alluvial fans).

During the teaching of the course, theoretical lessons are combined with laboratory exercises aimed at familiarizing students with the concepts taught in the lectures. The laboratory exercises also have practical significance, such as learning methodologies for geomorphological mapping of fluvial systems, quantitative analysis of drainage networks, and assessing the rates of river incision in tectonically active areas.

Throughout the semester, a field trip is held. The purpose of the field exercise is to familiarize students with the fluvial landscape, to be able to recognize fluvial landforms, and to assimilate what has been taught in the theoretical lessons.

Content

Theory: Fluvial processes: the action of raindrops, types of flow, non-concentrated surface flow, non-concentrated surface flow Horton (Hortonian flow), non-concentrated surface flow due to saturation, sporadically concentrated flow in small rills (rill flow), subsurface flow. River flow in riverbeds (laminar flow, turbulent flow, Reynolds number, plunging flow). Longitudinal profiles of rivers: base level (absolute – local), stages of river landscape evolution (youth, maturity, old age, rejuvenation). Fluvial erosion: energy of river current, downcutting, lateral erosion, headward erosion. River transport: sediment load – sediment transport (dissolved load, suspended load, bedload). Fluvial deposition: bed deposits, overbank deposits, valley margin deposits. River erosion landforms: alluvial beds (straight – meandering – dendritic), valley types (V-shaped, U-shaped, wind gaps, river piracy), knickpoints. Fluvial deposition landforms: floodplains, fluvial terraces (straths – alluvial, terrace correlation, fluvial terraces dating methods), alluvial fans.

Laboratory: The exercises include the ordering of a drainage network, the delineation of its drainage basin, its quantitative analysis according to the three HORTON laws, and the estimation of the parameters of the drainage texture (frequency and density). Additionally, the incision rates during the Upper Quaternary are calculated in rivers of the northern Peloponnese.

Teaching & Assessment

There are 13 weeks of lectures and laboratory exercises. Lectures: 1 hour/week, laboratory exercises: 2 hours/week.

The laboratory sessions focus on a specific drainage network and its corresponding drainage basin. Attendance in the exercises is mandatory, and absences are recorded. The exercises are submitted after their completion, usually before the final exam at the end of the semester.