2 Hydraulic Engineering for Nature - 2.1 River Water Bodies Flashcards
Learning objectives:
You understand morphological processes in rivers, and their ecological importance.
You know relevant hydraulic structures, in particular for supporting fish migration.
Basics in hydraulic computation are subject of other lectures in civil and environmental engineering, e.g. hydromechanics
Basics in river ecology are treated in this module within the Fresh Water Ecology course (Dr. Bäthe). We connect engineering and biology!
River Water Bodies
Typical situation of rivers with intensively used flood plains in Central Europe. Even after restoration, there are levees on both sides of the river for flood protection of the surrounding area – but now, the river course is more heterogenous with higher variability of hydraulic conditions.
Morphological Zones (Longitudinal)
see image slide 4
Spring region:
– temperature depends on groundwater, low amplitude
– low oxygen, low primary production
– often without fish
Upper part (rhithral):
– temperature amplitude low
– high oxygen, high velocity/turbulence
– stones and sand
Lower part (potamal):
– high amplitude of water temperature
– low oxygen, low velocity/turbulence
– sand and mud
River Course within the Flood Plain
See image slide 5
natural course of river
man-made layout of river
near-natural layout of river
natural course of river partially preserved as bayou
valuable biotopes
bay
Some Terms from Ecology:
Ecology
scientific discipline about the interrelationships between creatures with each other and with the environment
Some Terms from Ecology:
Biocenosis
community of different kinds of plants and animals within a biotope, which is based on interdependency and interference.
Some Terms from Ecology:
Biotope
living space of a biocenosis, which contains several habitats.
Some Terms from Ecology:
Habitat
living space of one species (animal or plant).
Some Terms from Ecology:
Ecosystem
functional unit from biocenosis and biotope, characterised through interdependency of matter, energy and information fluxes between organisms with each other and with their environment.
Environmental Factors:
- Abiotic (inanimate) factors
– climatic (temperature, precipitation, light),
– physical (flow velocity, depth of water, waves),
– chemical (pH, oxygen, conductivity, nutrients),
– orographic (elevation, land surface, exposition),
– anthropogenic (structures and infrastructure).
Environmental Factors:
- Biotic (animate) factors
– Influence of microorganisms, plants, animals and humans against and with each other
– Food chain: animals eat plants, animals eat other animals
Simplified scheme of matter cycles and energy
flow in a closed system
see image slide 7
Abundance and Diversity of Creatures:
Abundance
Number of organisms per area or spatial unit.
– Absolute abundance of individuals: number of individuals of one species within a habitat (population density)
– Absolute abundance of species: number of species within a habitat
– Relative abundance: number of individual words of one species related with the total number of individuals
Abundance and Diversity of Creatures:
Dominance
single species dominate according to the number
Abundance and Diversity of Creatures:
Diversity
diversity of species in a biocenosis under consideration of the number of species and relative abundance