Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Modelling hydrologically relevant structures and processes of the initial development phase of a man-made catchment
The present dissertation deals with the model-based investigation of hydrologically relevant structures and processes of the initial development phase of the 6 ha large man-made catchment ‘Chicken Creek’ located near Cottbus (Germany). A highly threshold-like relationship between measured rainfall and total runoff was revealed in the catchment. In the first part of the thesis, a new model based on Percolation Theory was developed to simulate the subsurface flow paths and the threshold-like runoff response to rainfall. The sudden establishment of a high hydrologic connectivity between soil elements was shown to be the key factor to explain the nonlinear behaviour of the rainfall-runoff response. The initial phase of catchment development was characterised by the evolution of erosion rills driven by surface runoff. In the second part of the thesis, two models were developed to describe the emergence of the erosion rills. First, we used a self-organised critical network (SOCN) approach with soil erosion and deposition governed by a local critical shear stress. Second, a model based on the Manning equation was developed to compare the results of the SOCN approach with results from a simple, but more physically-based approach. Both models were able to simulate the rill characteristics (rill network length, rill depth) in the right order of magnitude, as well as the position and temporal evolution of the erosion rills. In the third part of the thesis, a new hydrological model was conceptualised to tackle a few drawbacks of present models. By describing water transport in discrete volume units, the new model was able to represent nonlinear runoff processes, water transit times and the emergence of macro-scale patterns in the same model framework. First encouraging model simulations were able to reproduce transit times and the temporal evolution of runoff patterns, and to estimate the effect of the rills on runoff quantities.
Modelling hydrologically relevant structures and processes of the initial development phase of a man-made catchment
The present dissertation deals with the model-based investigation of hydrologically relevant structures and processes of the initial development phase of the 6 ha large man-made catchment ‘Chicken Creek’ located near Cottbus (Germany). A highly threshold-like relationship between measured rainfall and total runoff was revealed in the catchment. In the first part of the thesis, a new model based on Percolation Theory was developed to simulate the subsurface flow paths and the threshold-like runoff response to rainfall. The sudden establishment of a high hydrologic connectivity between soil elements was shown to be the key factor to explain the nonlinear behaviour of the rainfall-runoff response. The initial phase of catchment development was characterised by the evolution of erosion rills driven by surface runoff. In the second part of the thesis, two models were developed to describe the emergence of the erosion rills. First, we used a self-organised critical network (SOCN) approach with soil erosion and deposition governed by a local critical shear stress. Second, a model based on the Manning equation was developed to compare the results of the SOCN approach with results from a simple, but more physically-based approach. Both models were able to simulate the rill characteristics (rill network length, rill depth) in the right order of magnitude, as well as the position and temporal evolution of the erosion rills. In the third part of the thesis, a new hydrological model was conceptualised to tackle a few drawbacks of present models. By describing water transport in discrete volume units, the new model was able to represent nonlinear runoff processes, water transit times and the emergence of macro-scale patterns in the same model framework. First encouraging model simulations were able to reproduce transit times and the temporal evolution of runoff patterns, and to estimate the effect of the rills on runoff quantities.
Modelling hydrologically relevant structures and processes of the initial development phase of a man-made catchment
Modellierung hydrologisch relevanter Strukturen und Prozesse in der initialen Entwicklungsphase eines künstlich geschaffenen Einzugsgebiets
Hofer, Markus (Autor:in) / Universitätsbibliothek Braunschweig (Gastgebende Institution) / Krafczyk, Manfred (Akademische:r Betreuer:in)
2011
Sonstige
Elektronische Ressource
Englisch
| UB Braunschweig | 2012