How do changes to the wetted perimeter of the River Lyn compare with the Bradshaw model?
Consolidate your thinking – fieldwork to calculate changes in the wetted perimeter of the River Lyn
According to the Bradshaw model the wetted perimeter(the length of a river’s bed and banks in contact with the water) will always increase with distance from source to mouth as more water enters the river system through tributaries and run off as it progresses downstream. To test this assumption against the real world example of the River Lyn measurements can be taken at sample points along the course of the river. The film and narration in
The video below shows clearly how to measure the wetted perimeter of a river.
If at least 8 measurements of the wetted perimeter are made along the upper course of the River Lyn and a minimum of 8 in its middle course and a further 8 in the lower course then the Mann Whitney U test can be used to assess whether the difference between the medians of two sets of data e.g. Upper and Middle; Middle and Lower and Middle and Upper and Lower are significantly different assuming a null hypothesis of no significant difference existing between the locations.The following sites along the river are suggested as possible locations to take the sets of wetted perimeter measurements required:
Assessing risk and identifying control measures to manage risk
Please refer back to guidance on this page and use the template with regard to fieldwork above.
Secondary data sets
If access to these locations is not possible for primary data collection then the following tables provide sets of secondary data obtained from 11 sites along the length of the river system for the students to test statistically:
- Book a Visit
- Exmoor Learning Resources
- Pinkery Centre for Outdoor Learning
The River Lyn Enquiry
- Introducing the Lyn Catchment
- Info for Teachers and resources
- 1: The Lynmouth flood disaster of 1952
- 2:The topography of the River Lyn and its catchment
- 3: The benefits of the River Lyn ecosystem
- 4:Writing up your River Lyn enquiry
- Coastal Management In Porlock Bay
- The Moorland Classroom
- Paddlesteamers, Postcards and Holidays Past
- Exmoor - a Journey Through Time
- Exmoor Facts and Figures
- Did You Know?
- North Hill in World War 2