Weirs were traditionally introduced to rivers to increase the water covered area mainly for aesthetic reasons and but also thought to have ecological relevance. Today, we know that weirs can disrupt the fish from moving between river sections and decrease the amount of native fish species popular among fishermen. Thus, weir removal or weir adjustment is being considered in many regulated rivers as a way to re-establish the river to its original form. In environmental design projects, manipulating weirs can be part of mitigation measures of ecological (i.e. fish and invertebrates) and morphological (the physical environment) relevance.
The master student will do the following:
- Literature study on weir removal and weir adjustment
- Find and summarize examples of weir manipulation projects
- Set up potential ways of manipulating a weir
- Field work sessions for setting up a full terrain model for the riverbed in relevant river sections
- Measure terrain using GPS, echo sounding, drones or other available equipment
- GIS analysis for manipulation of riverbed terrain
- Set up original terrain files (from point cloud to raster) in GIS
- Manipulate terrain files using available methods and establish different terrain scenario files as input to hydraulic modelling
- 2D hydraulic modelling of scenarios for weir removal and weir adjustment
- Set up and calibrate a 2D hydraulic model for the river reach
- Introduce the different terrain scenario files and simulate each of them
- Summarize the findings in a report
The results will be relevant for investigating the potential hydraulic properties of river sections before and after weir manipulation. The analysis will be part of the HydroCEN environmental design case study project in River Nea in Mid-Norway.